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Sample records for cerebral uma nova

  1. Cyclic Period Oscillation of the Eclipsing Dwarf Nova DV UMa

    NASA Astrophysics Data System (ADS)

    Han, Z.-T.; Qian, S.-B.; Irina, Voloshina; Zhu, L.-Y.

    2017-05-01

    DV UMa is an eclipsing dwarf nova with an orbital period of ˜2.06 hr, which lies just at the bottom edge of the period gap. To detect its orbital period changes, we present 12 new mid-eclipse times by using our CCD photometric data and archival data. The latest version of the O-C diagram, combined with the published mid-eclipse times in quiescence, and spanning ˜30 years, was obtained and analyzed. The best fit to those available eclipse timings shows that the orbital period of DV UMa is undergoing a cyclic oscillation with a period of 17.58(+/- 0.52) years and an amplitude of 71.1(+/- 6.7) s. The periodic variation most likely arises from the light-travel-time effect via the presence of a circumbinary object, because the required energy to drive the Applegate mechanism is too high in this system. The mass of the unseen companion was derived as {M}3\\sin i\\prime =0.025(+/- 0.004) {M}⊙ . If the third body is in the orbital plane (i.e., i\\prime =i=82\\buildrel{\\circ}\\over{.} 9) of the eclipsing pair, this would indicate it is a brown dwarf. This hypothetical brown dwarf is orbiting its host star at a separation of ˜8.6 au in an eccentric orbit (e = 0.44).

  2. Doppler Tomography of the Dwarf Nova IY UMa During Quiescence

    NASA Astrophysics Data System (ADS)

    Rolfe, D. J.; Abbott, T. M. C.; Haswell, C. A.

    Quiescent Doppler tomography of the newly discovered deeply-eclipsing SU UMa system IY UMa reveals properties of the region where the accretion stream from the donor impacts the edge of the disc. A very strong bright spot is produced and the Keplerian disc emission in the impact region is disrupted or obscured. The differing properties of Hα, Hβ and He I emission will allow physical parameters of the converging flow region to be studied.

  3. FUSE Observations of the Bright, Eclipsing Nova-like Cataclysmic Variable, UX UMa (FUSE 2000)

    NASA Technical Reports Server (NTRS)

    Long, Knox; Froning, Cynthia

    2004-01-01

    This was a project to study the disk and wind of the eclipsing nova-like variable UX UMa, in order to better define the wind geometry of the system, including the nature of the transition region between the disk photosphere and the supersonic wind. We proposed to use phase resolved spectroscopy of the system, taking advantage of the fact that UX UMa is an eclipsing system, to isolate different regions of the wind and to use a Monte Carlo radiative transfer code to simulate the spectra through the eclipse.

  4. SU UMa dwarf novae in the period gap showing the negative superhumps

    NASA Astrophysics Data System (ADS)

    Pavlenko, Elena

    2016-07-01

    There are only two known up to date SU UMa dwarf novae in the period gap showing the negative superhumps, namely, MN Dra and 1RXS J003828.7+250920. We present the results of X-ray and spectral investigation for 1RXS J003828.7+250920, multicolor optical investigation for 1RXS J003828.7+250920 and MN Dra at different stages of their activity in 2011-2016 years. We discuss a finding of the accretion disc radius for both dwarf novae, its variation during separated intervals between outbursts for MN Dra as well as high and low temperature regions in quiescent accretion disk for 1RXS J003828.7+250920.

  5. Curious Variables Experiment (CURVE). Superhump Period Change Pattern in KS UMa and Other Dwarf Novae

    NASA Astrophysics Data System (ADS)

    Olech, A.; Schwarzenberg-Czerny, A.; Kedzierski, P.; Zloczewski, K.; Mularczyk, K.; Wisniewski, M.

    2003-06-01

    We report extensive photometry of the dwarf nova KS UMa throughout its 2003 superoutburst till quiescence. During the superoutburst the star displayed clear superhumps with a mean period of P_sh=0.070092(23) days. In the middle stage of superoutburst the period was increasing with a rate of dot P/P=(21+/-12)*10^-5 and later was decreasing with a rate of dot P/P=-(21+/-8)*10^-5. At the end of superoutburst and during first dozen days of quiescence the star was showing late superhumps with a mean period of P_late=0.06926(2) days. This phenomenon was observed even 30 days after beginning of the superoutburst. In quiescence the star shows quasi-periodic modulations with amplitude reaching 0.5 mag. The most common structure observed during this stage was sinusoidal wave characterized by a period of about 0.1 days. Comparing KS UMa to other SU UMa stars we conclude that this group of dwarf novae shows decreasing superhump periods at the beginning and the end of superoutburst but increasing period in the middle phase.

  6. Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. IV. The Fourth Year (2011-2012)

    NASA Astrophysics Data System (ADS)

    Kato, Taichi; Hambsch, Franz-Josef; Maehara, Hiroyuki; Masi, Gianluca; Miller, Ian; Noguchi, Ryo; Akasaka, Chihiro; Aoki, Tomoya; Kobayashi, Hiroshi; Matsumoto, Katsura; Nakagawa, Shinichi; Nakazato, Takuma; Nomoto, Takashi; Ogura, Kazuyuki; Ono, Rikako; Taniuchi, Keisuke; Stein, William; Henden, Arne; de Miguel, Enrique Kiyota, Seiichiro; Dubovsky, Pavol A.; Kudzej, Igor; Imamura, Kazuyoshi; Akazawa, Hidehiko; Takagi, Ryosuke; Wakabayashi, Yuya; Ogi, Minako; Tanabe, Kenji; Ulowetz, Joseph; Morelle, Etienne; Pickard, Roger D.; Ohshima, Tomohito; Kasai, Kiyoshi; Pavlenko, Elena P.; Antonyuk, Oksana I.; Baklanov, Aleksei V.; Antonyuk, Kirill; Samsonov, Denis; Pit, Nikolaj; Sosnovskij, Aleksei; Littlefield, Colin; Sabo, Richard; Ruiz, Javier; Krajci, Thomas; Dvorak, Shawn; Oksanen, Arto; Hirosawa, Kenji; Goff, William N.; Monard, Berto; Shears, Jeremy; Boyd, David; Voloshina, Irina B.; Shugarov, Sergey Yu.; Chochol, Drahomir; Miyashita, Atsushi; Pietz, Jochen; Katysheva, Natalia; Itoh, Hiroshi; Bolt, Greg; Andreev, Maksim V.; Parakhin, Nikolai; Malanushenko, Viktor; Martinelli, Fabio; Denisenko, Denis; Stockdale, Chris; Starr, Peter; Simonsen, Mike; Tristram, Paul J.; Fukui, Akihiko; Tordai, Tamas; Fidrich, Robert; Paxson, Kevin B.; Itagaki, Koh-ichi; Nakashima, Youichirou; Yoshida, Seiichi; Nishimura, Hideo; Kryachko, Timur V.; Samokhvalov, Andrey V.; Korotkiy, Stanislav A.; Satovski, Boris L.; Stubbings, Rod; Poyner, Gary; Muyllaert, Eddy; Gerke, Vladimir; MacDonald, Walter, II; Linnolt, Michael; Maeda, Yutaka; Hautecler, Hubert

    2013-02-01

    Continuing the project described by Kato et al. (2009, PASJ, 61, S395), we collected times of superhump maxima for 86 SU UMa-type dwarf novae, mainly observed during the 2011-2012 season. We confirmed general trends recorded in our previous studies, such as the relation between period derivatives and orbital periods. There are some systems showing positive period derivatives despite the long orbital period. We observed the 2011 outburst of the WZ Sge-type dwarf nova BW Scl, and recorded an O - C diagram similar to those of previously known WZ Sge-type dwarf novae. The WZ Sge-type dwarf nova OT J184228.1+483742 showed an unusual pattern of double outbursts composed of an outburst with early superhumps and one with ordinary superhumps. We propose an interpretation that a very small growth rate of the 3:1 resonance due to an extremely low mass-ratio led to quenching the superoutburst before the ordinary superhump appeared. We systematically studied ER UMa-type dwarf novae, and found that V1159 Ori showed positive superhumps similar to ER UMa in the 1990s. The recently recognized ER UMa-type object BK Lyn dominantly showed negative superhumps, and its behavior was very similar to the present-day state of ER UMa. The pattern of period variations in AM CVn-type objects was very similar to that of short-period hydrogen-rich SU UMa-type dwarf novae, making them a helium analogue of hydrogen-rich SU UMa-type dwarf novae. SBS 1108+574, a peculiar hydrogen-rich dwarf nova below the period minimum, showed a very similar pattern of period variations to those of short-period SU UMa-type dwarf novae. The mass-ratio derived from the detected orbital period suggests that this secondary is a somewhat evolved star whose hydrogen envelope was mostly stripped during the mass-exchange. CC Scl, MASTER OT J072948.66+593824.4, and OT J173516.9+154708 showed only low-amplitude superhumps with complex profiles. These superhumps are likely to be a combination of two closely separated periods.

  7. Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae

    NASA Astrophysics Data System (ADS)

    Kato, Taichi; Imada, Akira; Uemura, Makoto; Nogami, Daisaku; Maehara, Hiroyuki; Ishioka, Ryoko; Baba, Hajime; Matsumoto, Katsura; Iwamatsu, Hidetoshi; Kubota, Kaori; Sugiyasu, Kei; Soejima, Yuichi; Moritani, Yuuki; Ohshima, Tomohito; Ohashi, Hiroyuki; Tanaka, Junpei; Sasada, Mahito; Arai, Akira; Nakajima, Kazuhiro; Kiyota, Seiichiro; Tanabe, Kenji; Imamura, Kazuyoshi; Kunitomi, Nanae; Kunihiro, Kenji; Taguchi, Hiroki; Koizumi, Mitsuo; Yamada, Norimi; Nishi, Yuichi; Kida, Mayumi; Tanaka, Sawa; Ueoka, Rie; Yasui, Hideki; Maruoka, Koichi; Henden, Arne; Oksanen, Arto; Moilanen, Marko; Tikkanen, Petri; Aho, Mika; Monard, Berto; Itoh, Hiroshi; Dubovsky, Pavol A.; Kudzej, Igor; Dancikova, Radka; Vanmunster, Tonny; Pietz, Jochen; Bolt, Greg; Boyd, David; Nelson, Peter; Krajci, Thomas; Cook, Lewis M.; Torii, Ken'ichi; Starkey, Donn R.; Shears, Jeremy; Jensen, Lasse-Teist; Masi, Gianluca; Hynek, Tomáš; Nová; K, Rudolf; Kociá; N, Radek; Krá; L, Lukáš; Kučá; Ková, Hana; Kolasa, Marek; Štastný, Petr; Staels, Bart; Miller, Ian; Sano, Yasuo; de Ponthière, Pierre; Miyashita, Atsushi; Crawford, Tim; Brady, Steve; Santallo, Roland; Richards, Tom; Martin, Brian; Buczynski, Denis; Richmond, Michael; Kern, Jim; Davis, Stacey; Crabtree, Dustin; Beaulieu, Kevin; Davis, Tracy; Aggleton, Matt; Morelle, Etienne; Pavlenko, Elena P.; Andreev, Maksim; Baklanov, Alexander; Koppelman, Michael D.; Billings, Gary; Urbancok, L'ubomír; Ögmen, Yenal; Heathcote, Bernard; Gomez, Tomas L.; Voloshina, Irina; Retter, Alon; Mularczyk, Krzysztof; Zoczewski, Kamil; Olech, Arkadiasz; Kedzierski, Piotr; Pickard, Roger D.; Stockdale, Chris; Virtanen, Jani; Morikawa, Koichi; Hambsch, Franz-Josef; Garradd, Gordon; Gualdoni, Carlo; Geary, Keith; Omodaka, Toshihiro; Sakai, Nobuyuki; Michel, Raul; Cárdenas, A. A.; Gazeas, Kosmas D.; Niarchos, Panos G.; Yushchenko, Alexander V.; Mallia, Franco; Fiaschi, Marco; Good, Gerry A.; Walker, Stan; James, Nick; Douzu, Ken-Ichi; Julian, Wm Mack, II; Butterworth, Neil D.; Shugarov, Sergey Yu.; Volkov, Igor; Chochol, Drahomir; Katysheva, Natalia; Rosenbush, Alexander E.; Khramtsova, Maria; Kehusmaa, Petri; Reszelski, Maciej; Bedient, James; Liller, William; Pojmanski, Grzegorz; Simonsen, Mike; Stubbings, Rod; Schmeer, Patrick; Muyllaert, Eddy; Kinnunen, Timo; Poyner, Gary; Ripero, Jose; Kriebel, Wolfgang

    2009-12-01

    We systematically surveyed period variations of superhumps in SU UMa-type dwarf novae based on newly obtained data and past publications. In many systems, the evolution of the superhump period is found to be composed of three distinct stages: an early evolutionary stage with a longer superhump period, a middle stage with systematically varying periods, and a final stage with a shorter, stable superhump period. During the middle stage, many systems with superhump periods of less than 0.08 d show positive period derivatives. We present observational characteristics of these stages and give greatly improved statistics. Contrary to an earlier claim, we found no clear evidence for a variation of period derivatives among different superoutbursts of the same object. We present an interpretation that the lengthening of the superhump period is a result of the outward propagation of an eccentricity wave, which is limited by the radius near the tidal truncation. We interpret that late-stage superhumps are rejuvenated excitation of a 3:1 resonance when superhumps in the outer disk are effectively quenched. The general behavior of the period variation, particularly in systems with short orbital periods, appears to follow a scenario proposed in Kato, Maehara, and Monard (2008, PASJ, 60, L23). We also present an observational summary of WZ Sge-type dwarf novae. Many of them have shown long-enduring superhumps during a post-superoutburst stage having longer periods than those during the main superoutburst. The period derivatives in WZ Sge-type dwarf novae are found to be strongly correlated with the fractional superhump excess, or consequently with the mass ratio. WZ Sge-type dwarf novae with a long-lasting rebrightening or with multiple rebrightenings tend to have smaller period derivatives, and are excellent candidates for those systems around or after the period minimum of evolution of cataclysmic variables.

  8. JH and K-band spectra of three SU UMa-type Dwarf Novae

    NASA Astrophysics Data System (ADS)

    Ishioka, R.; Sekiguchi, K.; Maehara, H.

    2007-08-01

    We present the results of JH and K-band spectroscopy on three SU UMa-type dwarf novae with orbital periods of 1.33 ~1.37 hr. We performed the SED fitting for the obtained spectra by assuming a power law distribution for the accretion disk and using template spectra of late-type dwarfs for secondary star. ASAS 002511+1217.2 and EQ J183926+260409 are WZ Sge-type or WX Cet-type dwarf novae. We found strong water absorption features in their spectra, which are characteristic in late M- or L-type dwarfs. The SED fitting suggests that their secondary contributions to the overall SED are less than one third. We identified the secondary stars as M9 and L1 type dwarfs, which are rather less massive but still normal stars. The spectrum of SDSS J013701-091235 is dominated by the secondary component. Spectral features of this object are similar to those of an early M-type dwarf in spite of its short orbital period. The spectrum of SDSS0137 strongly suggests that the evolutionary path of this object is different from that of ordinary CVs, and this object is a candidate of EI Psc-like systems.

  9. NY Serpentis: SU UMa-type nova in the period gap with diversity of normal outbursts

    NASA Astrophysics Data System (ADS)

    Pavlenko, Elena P.; Kato, Taichi; Antonyuk, Oksana I.; Ohshima, Tomohito; Hambsch, Franz-Josef; Antonyuk, Kirill A.; Sosnovskij, Aleksei A.; Baklanov, Alex V.; Shugarov, Sergey Yu.; Pit, Nikolaj V.; Nakata, Chikako; Masi, Gianluca; Nakajima, Kazuhiro; Maehara, Hiroyuki; Dubovsky, Pavol A.; Kudzej, Igor; Andreev, Maksim V.; Kuznyetsova, Yuliana G.; Vasiliskov, Kirill A.

    2014-12-01

    We present a photometric study of NY Ser, an in-the-gap SU UMa-type nova, in 2002 and 2013. We determined the duration of its superoutburst and the mean period of its superhump are 18 d and 0.10458 d, respectively. We detected in 2013 that NY Ser showed two distinct states separated by a superoutburst. A state of rather infrequent normal outbursts lasted at least 44 d before the superoutburst, and a state of frequent outbursts started immediately after the superoutburst and lasted at least 34 d. Unlike a typical SU UMa star with a bimodal distribution of outburst duration, NY Ser displayed a diversity of normal outbursts. In the state of infrequent outbursts, we detected a wide ˜ 12 d outburst accompanied by 0.098 d orbital modulation but without superhumps ever established in NY Ser. We classified this as a "wide normal outburst." The orbital period was dominant both in quiescence and during normal outbursts in this state. In the state of the most frequent normal outbursts, the 0.10465 d positive superhump period was dominant and coexisted with the orbital modulation. In 2002 we detected the normal outburst of "intermediate" 5-6 d duration that was also accompanied by orbital modulations.

  10. Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. II The Second Year (2009-2010)

    NASA Astrophysics Data System (ADS)

    Kato, Taichi; Maehara, Hiroyuki; Uemura, Makoto; Henden, Arne; Miguel, Enrique De; Miller, Ian; Dubovsky, Pavol A.; Kudzej, Igor; Kiyota, Seiichiro; Hambsch, Franz-Josef; Tanabe, Kenji; Imamura, Kazuyoshi; Kunitomi, Nanae; Takagi, Ryosuke; Nose, Mikiha; Akazawa, Hidehiko; Masi, Gianluca; Nakagawa, Shinichi; Iino, Eriko; Noguchi, Ryo; Matsumoto, Katsura; Fujii, Daichi; Kobayashi, Hiroshi; Ogura, Kazuyuki; Ohtomo, Sachi; Yamashita, Kousei; Yanagisawa, Hirofumi; Itoh, Hiroshi; Bolt, Greg; Monard, Berto; Ohshima, Tomohito; Shears, Jeremy; Ruiz, Javier; Imada, Akira; Oksanen, Arto; Nelson, Peter; Gomez, Tomas L.; Staels, Bart; Boyd, David; Voloshina, Irina B.; Krajci, Thomas; Crawford, Tim; Stockdale, Chris; Richmond, Michael; Morelle, Etienne; Novák, Rudolf; Nogami, Daisaku; Ishioka, Ryoko; Brady, Steve; Simonsen, Mike; Pavlenko, Elena P.; Ringwald, Frederick A.; Kuramoto, Tetsuya; Miyashita, Atsushi; Pickard, Roger D.; Hynek, Tomáš; Dvorak, Shawn; Stubbings, Rod; Muyllaert, Eddy

    2010-12-01

    Continued from Kato et al. (2009, PASJ, 61, S395), we collected the times of superhump maxima for 68 SU UMa-type dwarf novae, mainly observed during the 2009-2010 season. The newly obtained data confirmed the basic findings reported in Kato et al. (ibid.): the presence of stages A-C and the predominance of positive period derivatives during stage B in systems with superhump periods shorter than 0.07 d. There was a systematic difference in the period derivatives for the systems with superhump periods longer than 0.075 d between this study and Kato et al. (ibid.). We suggest that this difference was possibly caused by a relative lack of frequently outbursting SU UMa-type dwarf novae in this period regime in the present study. We recorded a strong beat phenomenon during the 2009 superoutburst of IY UMa. A close correlation between the beat period and the superhump period suggests that the changing angular velocity of the apsidal motion of the elliptical disk is responsible for the variation of the superhump periods. We also described three new WZ Sge-type objects with established early superhumps and one with likely early superhumps. We suggest that two systems, VX For and EL UMa, are WZ Sge-type dwarf novae with multiple rebrightenings. The O - C variation in OT J213806.6+261957 suggests that the frequent absence of rebrightenings in very short-Porb objects can be the result of a sustained superoutburst plateau at the epoch when usual SU UMa-type dwarf novae return to quiescence, preceding a rebrightening. We also present a formulation for a variety of Bayesian extensions to traditional period analyses.

  11. The first confirmed superoutburst of the SU UMa-type dwarf nova SDSS J083931.35+282824.0

    NASA Astrophysics Data System (ADS)

    Shears, J.; de Miguel, E.; Roberts, G.; Collins, D. F..; Myers, G.; Campbell, T.

    2011-12-01

    We report unfiltered CCD photometry of the first confirmed superoutburst in 2010 April of the recently discovered dwarf nova SDSS J083931.35+282824.0. From a quiescence magnitude of ~19.8 it rose to 14.0, an outburst amplitude of at least 5.8 magnitudes. Only the plateau phase of the outburst was observed, during which superhumps with peak-to-peak amplitude of up to 0.28 magnitudes were present, confirming this to be an SU UMa-type dwarf nova. The mean superhump period was Psh= 0.07836(2) during the first 3 days and this subsequently decreased to 0.07800(3)d. Analysis of the data revealed tentative evidence for an orbital period Porb= 0.07531(25)d. The fractional superhump period excess was e= 0.039(6), which is consistent with other dwarf novae of similar orbital period.

  12. OT J002656.6+284933 (CSS101212:002657+284933): an SU UMa-type dwarf nova with the longest superhump period

    NASA Astrophysics Data System (ADS)

    Kato, Taichi; Tordai, Tamás; Littlefield, Colin; Kasai, Kiyoshi; Shugarov, Sergey Yu.; Katysheva, Natalia; Zaostrojnykh, Anna M.; Pickard, Roger D.; de Miguel, Enrique; Antonyuk, Kirill; Antonyuk, Oksana; Pavlenko, Elena P.; Pit, Nikolai; Itoh, Hiroshi; Ruiz, Javier; Isogai, Keisuke; Kimura, Mariko; Wakamatsu, Yasuyuki; Vanmunster, Tonny; Stone, Geoff

    2017-06-01

    We observed the 2016 outburst of OT J002656.6+284933 (CSS101212:002657+284933) and found that it has the longest recorded [0.13225(1) d on average] superhumps among SU UMa-type dwarf novae. The object is the third known SU UMa-type dwarf nova above the period gap. The outburst, however, was unlike ordinary long-period SU UMa-type dwarf novae in that it showed two post-outburst rebrightenings. It showed superhump evolution similar to short-period SU UMa-type dwarf novae. We could constrain the mass ratio to less than 0.15 (most likely between 0.10 and 0.15) by using superhump periods in the early and post-superoutburst stages. These results suggest the possibility that OT J002656.6+284933 has an anomalously undermassive secondary and it should have followed a different evolutionary track from the standard one.

  13. Survey of period variations of superhumps in SU UMa-type dwarf novae. VII. The seventh year (2014-2015)

    NASA Astrophysics Data System (ADS)

    Kato, Taichi; Hambsch, Franz-Josef; Dubovsky, Pavol A.; Kudzej, Igor; Monard, Berto; Miller, Ian; Itoh, Hiroshi; Kiyota, Seiichiro; Masumoto, Kazunari; Fukushima, Daiki; Kinoshita, Hiroki; Maeda, Kazuki; Mikami, Jyunya; Matsuda, Risa; Kojiguchi, Naoto; Kawabata, Miho; Takenaka, Megumi; Matsumoto, Katsura; de Miguel, Enrique; Maeda, Yutaka; Ohshima, Tomohito; Isogai, Keisuke; Pickard, Roger D.; Henden, Arne; Kafka, Stella; Akazawa, Hidehiko; Otani, Noritoshi; Ishibashi, Sakiko; Ogi, Minako; Tanabe, Kenji; Imamura, Kazuyoshi; Stein, William; Kasai, Kiyoshi; Vanmunster, Tonny; Starr, Peter; Oksanen, Arto; Pavlenko, Elena P.; Antonyuk, Oksana I.; Antonyuk, Kirill A.; Sosnovskij, Aleksei A.; Pit, Nikolaj V.; Babina, Julia V.; Sklyanov, Aleksandr; Novák, Rudolf; Dvorak, Shawn; Michel, Raúl; Masi, Gianluca; Littlefield, Colin; Ulowetz, Joseph; Shugarov, Sergey Yu.; Golysheva, Polina Yu.; Chochol, Drahomir; Krushevska, Viktoriia; Ruiz, Javier; Tordai, Tamás; Morelle, Etienne; Sabo, Richard; Maehara, Hiroyuki; Richmond, Michael; Katysheva, Natalia; Hirosawa, Kenji; Goff, William N.; Dubois, Franky; Logie, Ludwig; Rau, Steve; Voloshina, Irina B.; Andreev, Maksim V.; Shiokawa, Kazuhiko; Neustroev, Vitaly V.; Sjoberg, George; Zharikov, Sergey; James, Nick; Bolt, Greg; Crawford, Tim; Buczynski, Denis; Cook, Lewis M.; Kochanek, Christopher S.; Shappee, Benjamin; Stanek, Krzysztof Z.; Prieto, José L.; Denisenko, Denis; Nishimura, Hideo; Mukai, Masaru; Kaneko, Shizuo; Ueda, Seiji; Stubbings, Rod; Moriyama, Masayuki; Schmeer, Patrick; Muyllaert, Eddy; Shears, Jeremy; Modic, Robert J.; Paxson, Kevin B.

    2015-12-01

    Continuing the project described by Kato et al. (2009, PASJ, 61, S395), we collected times of superhump maxima for 102 SU UMa-type dwarf novae, observed mainly during the 2014-2015 season, and characterized these objects. Our project has greatly improved the statistics of the distribution of orbital periods, which is a good approximation of the distribution of cataclysmic variables at the terminal evolutionary stage, and has confirmed the presence of a period minimum at a period of 0.053 d and a period spike just above this period. The number density monotonically decreased toward the longer period and there was no strong indication of a period gap. We detected possible negative superhumps in Z Cha. It is possible that normal outbursts are also suppressed by the presence of a disk tilt in this system. There was no indication of enhanced orbital humps just preceding the superoutburst, and this result favors the thermal-tidal disk instability as the origin of superoutbursts. We detected superhumps in three AM CVn-type dwarf novae. Our observations and recent other detections suggest that 8% of objects showing dwarf nova-type outbursts are AM CVn-type objects. AM CVn-type objects and EI Psc-type objects may be more abundant than previously recognized. OT J213806, a WZ Sge-type object, exhibited remarkably different features between the 2010 and 2014 superoutbursts. Although the 2014 superoutburst was much fainter, the plateau phase was shorter than the 2010 one, and the course of the rebrightening phase was similar. This object indicates that the O - C diagrams of superhumps can indeed be variable, at least in WZ Sge-type objects. Four deeply eclipsing SU UMa-type dwarf novae (ASASSN-13cx, ASASSN-14ag, ASASSN-15bu, and NSV 4618) were identified. We studied long-term trends in supercycles in MM Hya and CY UMa and found systematic variations of supercycles of ˜20%.

  14. CSS090530:144011+494734: a new SU UMa-type dwarf nova in Boötes

    NASA Astrophysics Data System (ADS)

    Boyd, D.; Dunckel, N.; Foote, J.; Miller, I.

    2010-08-01

    We report photometry and analysis of a previously unknown SU UMa-type dwarf nova in Boötes detected in outburst by the Catalina Real-time Transient Survey on 2009 May 30, with the discovery identifier CSS090530:144011+494734. This apparently stellar object had previously been catalogued by the Sloan Digital Sky Survey as SDSS J144011.01+494733.4. We measured its mean superhump period over the first 3 days following detection as 0.06500(4)d, at which point this changed to 0.06438(3)d. We detected a possible orbital period of 0.06322(8)d implying a mean superhump period excess of 0.020(2). After detection, the dwarf nova maintained steady brightness for 5 days before starting to fade. The outburst amplitude was 5.5 magnitudes above its quiescent level.

  15. Survey of period variations of superhumps in SU UMa-type dwarf novae. IX. The ninth year (2016-2017)

    NASA Astrophysics Data System (ADS)

    Kato, Taichi; Isogai, Keisuke; Hambsch, Franz-Josef; Vanmunster, Tonny; Itoh, Hiroshi; Monard, Berto; Tordai, Tamás; Kimura, Mariko; Wakamatsu, Yasuyuki; Kiyota, Seiichiro; Miller, Ian; Starr, Peter; Kasai, Kiyoshi; Shugarov, Sergey Yu.; Chochol, Drahomir; Katysheva, Natalia; Zaostrojnykh, Anna M.; Sekeráš, Matej; Kuznyetsova, Yuliana G.; Kalinicheva, Eugenia S.; Golysheva, Polina; Krushevska, Viktoriia; Maeda, Yutaka; Dubovsky, Pavol A.; Kudzej, Igor; Pavlenko, Elena P.; Antonyuk, Kirill A.; Pit, Nikolaj V.; Sosnovskij, Aleksei A.; Antonyuk, Oksana I.; Baklanov, Aleksei V.; Pickard, Roger D.; Kojiguchi, Naoto; Sugiura, Yuki; Tei, Shihei; Yamamura, Kenta; Matsumoto, Katsura; Ruiz, Javier; Stone, Geoff; Cook, Lewis M.; de Miguel, Enrique; Akazawa, Hidehiko; Goff, William N.; Morelle, Etienne; Kafka, Stella; Littlefield, Colin; Bolt, Greg; Dubois, Franky; Brincat, Stephen M.; Maehara, Hiroyuki; Sakanoi, Takeshi; Kagitani, Masato; Imada, Akira; Voloshina, Irina B.; Andreev, Maksim V.; Sabo, Richard; Richmond, Michael; Rodda, Tony; Nelson, Peter; Nazarov, Sergey; Mishevskiy, Nikolay; Myers, Gordon; Denisenko, Denis; Stanek, Krzysztof Z.; Shields, Joseph V.; Kochanek, Christopher S.; Holoien, Thomas W.-S.; Shappee, Benjamin; Prieto, José L.; Itagaki, Koh-ichi; Nishiyama, Koichi; Kabashima, Fujio; Stubbings, Rod; Schmeer, Patrick; Muyllaert, Eddy; Horie, Tsuneo; Shears, Jeremy; Poyner, Gary; Moriyama, Masayuki

    2017-10-01

    Continuing the project described by Kato et al. (2009, PASJ, 61, S395), we collected times of superhump maxima for 127 SU UMa-type dwarf novae observed mainly during the 2016-2017 season and characterized these objects. We provide updated statistics of the relation between the orbital period and the variation of superhumps, the relation between period variations and the rebrightening type in WZ Sge-type objects. We obtained the period minimum of 0.05290(2) d and confirmed the presence of the period gap above the orbital period ˜0.09 d. We note that four objects (NY Her, 1RXS J161659.5+620014, CRTS J033349.8-282244, and SDSS J153015.04+094946.3) have supercycles shorter than 100 d but show infrequent normal outbursts. We consider that these objects are similar to V503 Cyg, whose normal outbursts are likely suppressed by a disk tilt. These four objects are excellent candidates to search for negative superhumps. DDE 48 appears to be a member of ER UMa-type dwarf novae. We identified a new eclipsing SU UMa-type object, MASTER OT J220559.40-341434.9. We observed 21 WZ Sge-type dwarf novae during this interval and report 18 of them in this paper. Among them, ASASSN-16js is a good candidate for a period bouncer. ASASSN-16ia showed a precursor outburst for the first time in a WZ Sge-type superoutburst. ASASSN-16kg, CRTS J000130.5+050624, and SDSS J113551.09+532246.2 are located in the period gap. We have newly obtained 15 orbital periods, including periods from early superhumps.

  16. Survey of period variations of superhumps in SU UMa-type dwarf novae. V. The fifth year (2012-2013)

    NASA Astrophysics Data System (ADS)

    Kato, Taichi; Hambsch, Franz-Josef; Maehara, Hiroyuki; Masi, Gianluca; Nocentini, Francesca; Dubovsky, Pavol A.; Kudzej, Igor; Imamura, Kazuyoshi; Ogi, Minako; Tanabe, Kenji; Akazawa, Hidehiko; Krajci, Thomas; Miller, Ian; de Miguel, Enrique; Henden, Arne; Noguchi, Ryo; Ishibashi, Takehiro; Ono, Rikako; Kawabata, Miho; Kobayashi, Hiroshi; Sakai, Daisuke; Nishino, Hirochika; Furukawa, Hisami; Masumoto, Kazunari; Matsumoto, Katsura; Littlefield, Colin; Ohshima, Tomohito; Nakata, Chikako; Honda, Satoshi; Kinugasa, Kenzo; Hashimoto, Osamu; Stein, William; Pickard, Roger D.; Kiyota, Seiichiro; Pavlenko, Elena P.; Antonyuk, Oksana I.; Baklanov, Aleksei V.; Antonyuk, Kirill; Samsonov, Denis; Pit, Nikolaj; Sosnovskij, Aleksei; Oksanen, Arto; Harlingten, Caisey; Tyyskä, Jenni; Monard, Berto; Shugarov, Sergey Yu.; Chochol, Drahomir; Kasai, Kiyoshi; Maeda, Yutaka; Hirosawa, Kenji; Itoh, Hiroshi; Sabo, Richard; Ulowetz, Joseph; Morelle, Etienne; Michel, Raúl; Suárez, Genaro; James, Nick; Dvorak, Shawn; Voloshina, Irina B.; Richmond, Michael; Staels, Bart; Boyd, David; Andreev, Maksim V.; Parakhin, Nikolai; Katysheva, Natalia; Miyashita, Atsushi; Nakajima, Kazuhiro; Bolt, Greg; Padovan, Stefano; Nelson, Peter; Starkey, Donn R.; Buczynski, Denis; Starr, Peter; Goff, William N.; Denisenko, Denis; Kochanek, Christopher S.; Shappee, Benjamin; Stanek, Krzysztof Z.; Prieto, José L.; Itagaki, Koh-ichi; Kaneko, Shizuo; Stubbings, Rod; Muyllaert, Eddy; Shears, Jeremy; Schmeer, Patrick; Poyner, Gary; Rodríguez-Marco, Miguel

    2014-04-01

    Continuing the project described in Kato et al. (2009, PASJ, 61, S395), we collected times of superhump maxima for SU UMa-type dwarf novae mainly observed during the 2012-2013 season. We found three objects (V444 Peg, CSS J203937, and MASTER J212624) having strongly positive period derivatives despite the long orbital period (Porb). By using the period of growing stage (stage A) superhumps, we obtained mass ratios for six objects. We characterized nine new WZ Sge-type dwarf novae. We made a pilot survey of the decline rate in the slowly fading parts of SU UMa-type and WZ Sge-type outbursts. The decline time scale was found to generally follow an expected P_orb^{1/4} dependence, and WZ Sge-type outbursts also generally follow this trend. There are some objects which show slower decline rates, and we consider these objects good candidates for period bouncers. We also studied unusual behavior in some objects, including BK Lyn which made a transition from an ER UMa-type state to a novalike (standstill) state in 2013, and unusually frequent occurrences of superoutbursts in NY Ser and CR Boo. We applied the least absolute shrinkage and selection operator (Lasso) power spectral analysis, which has been proven to be very effective in analyzing the Kepler data, to the ground-based photometry of BK Lyn, and detected a dramatic disappearance of the signal of negative superhumps in 2013. We suggested that the mass-transfer rates did not strongly vary between the ER UMa-type state and novalike state in BK Lyn, and this transition was less likely caused by a systematic variation of the mass-transfer rate.

  17. THE GEOMETRY AND IONIZATION STRUCTURE OF THE WIND IN THE ECLIPSING NOVA-LIKE VARIABLES RW TRI AND UX UMa

    SciTech Connect

    Noebauer, Ulrich M.; Long, Knox S.; Sim, Stuart A.; Knigge, Christian

    2010-08-20

    The UV spectra of nova-like variables are dominated by emission from the accretion disk, modified by scattering in a wind emanating from the disk. Here, we model the spectra of RW Tri and UX UMa, the only two eclipsing nova-like variables which have been observed with the Hubble Space Telescope in the far-ultraviolet, in an attempt to constrain the geometry and the ionization structure of their winds. Using our Monte Carlo radiative transfer code, we computed spectra for simply parameterized axisymmetric biconical outflow models and were able to find plausible models for both systems. These reproduce the primary UV resonance lines-N V, Si IV, and C IV-in the observed spectra in and out of eclipse. The distribution of these ions in the wind models is similar in both cases as is the extent of the primary scattering regions in which these lines are formed. The inferred mass-loss rates are 6%-8% of the mass accretion rates for the systems. We discuss the implication of our point models for our understanding of accretion disk winds in cataclysmic variables.

  18. Peculiarities of the SU UMa-Type Dwarf Nova V1504 Cyg Behavior in 1994 - 2012 Years

    NASA Astrophysics Data System (ADS)

    Antonyuk, O. I.; Pavlenko, E. P.

    2013-12-01

    For the SU UMa-type dwarf nova V1504 Cyg on the data base of the CrAO (1998 - 2009), space telescope "Kepler" (2009 - 2011), AAVSO and VSNET (1994 - 2012) we found as follows: 1) the supercycle length varying in average from 100 to 140 d; 2) the normal outbursts show a bimodal cycles lengths distributions with centers 8 - 9 days and 11 days within the range of 5 - 22 days; 3) for the quiescent data JD 2451737-2451745 we have detected the 0.0677-d periodicity that probably connected to the negative superhumps, and for the JD 245497 - 2454974 - these consisting either with simultaneous existing of positive and negative superhumps or with one of these periods.

  19. Survey of period variations of superhumps in SU UMa-type dwarf novae. VIII. The eighth year (2015-2016)

    NASA Astrophysics Data System (ADS)

    Kato, Taichi; Hambsch, Franz-Josef; Monard, Berto; Vanmunster, Tonny; Maeda, Yutaka; Miller, Ian; Itoh, Hiroshi; Kiyota, Seiichiro; Isogai, Keisuke; Kimura, Mariko; Imada, Akira; Tordai, Tamás; Akazawa, Hidehiko; Tanabe, Kenji; Otani, Noritoshi; Ogi, Minako; Ando, Kazuko; Takigawa, Naoki; Dubovsky, Pavol A.; Kudzej, Igor; Shugarov, Sergey Yu.; Katysheva, Natalia; Golysheva, Polina; Gladilina, Natalia; Chochol, Drahomir; Starr, Peter; Kasai, Kiyoshi; Pickard, Roger D.; Miguel, Enrique de; Kojiguchi, Naoto; Sugiura, Yuki; Fukushima, Daiki; Yamada, Eiji; Uto, Yusuke; Kamibetsunawa, Taku; Tatsumi, Taiki; Takeda, Nao; Matsumoto, Katsura; Cook, Lewis M.; Pavlenko, Elena P.; Babina, Julia V.; Pit, Nikolaj V.; Antonyuk, Oksana I.; Antonyuk, Kirill A.; Sosnovskij, Aleksei A.; Baklanov, Aleksei V.; Kafka, Stella; Stein, William; Voloshina, Irina B.; Ruiz, Javier; Sabo, Richard; Dvorak, Shawn; Stone, Geoff; Andreev, Maksim V.; Antipin, Sergey V.; Zubareva, Alexandra M.; Zaostrojnykh, Anna M.; Richmond, Michael; Shears, Jeremy; Dubois, Franky; Logie, Ludwig; Rau, Steve; Vanaverbeke, Siegfried; Simon, Andrei; Oksanen, Arto; Goff, William N.; Bolt, Greg; Dębski, Bartłomiej; Kochanek, Christopher S.; Shappee, Benjamin; Stanek, Krzysztof Z.; Prieto, José L.; Stubbings, Rod; Muyllaert, Eddy; Hiraga, Mitsutaka; Horie, Tsuneo; Schmeer, Patrick; Hirosawa, Kenji

    2016-08-01

    Continuing the project described by Kato et al. (2009, PASJ, 61, S395), we collected times of superhump maxima for 128 SU UMa-type dwarf novae observed mainly during the 2015-2016 season and characterized these objects. The data have improved the distribution of orbital periods, the relation between the orbital period and the variation of superhumps, and the relation between period variations and the rebrightening type in WZ Sge-type objects. Coupled with new measurements of mass ratios using growing stages of superhumps, we now have a clearer and statistically greatly improved evolutionary path near the terminal stage of evolution of cataclysmic variables. Three objects (V452 Cas, KK Tel, and ASASSN-15cl) appear to have slowly growing superhumps, which is proposed to reflect the slow growth of the 3 : 1 resonance near the stability border. ASASSN-15sl, ASASSN-15ux, SDSS J074859.55+312512.6, and CRTS J200331.3-284941 are newly identified eclipsing SU UMa-type (or WZ Sge-type) dwarf novae. ASASSN-15cy has a short (˜0.050 d) superhump period and appears to belong to EI Psc-type objects with compact secondaries having an evolved core. ASASSN-15gn, ASASSN-15hn, ASASSN-15kh, and ASASSN-16bu are candidate period bouncers with superhump periods longer than 0.06 d. We have newly obtained superhump periods for 79 objects and 13 orbital periods, including periods from early superhumps. In order that future observations will be more astrophysically beneficial and rewarding to observers, we propose guidelines on how to organize observations of various superoutbursts.

  20. Increasing Supercycle Lengths of Active SU UMa-type Dwarf Novae

    NASA Astrophysics Data System (ADS)

    Otulakowska-Hypka, M.; Olech, A.

    2014-12-01

    We present observational evidence that supercycle lengths of the most active SU UMa-type stars are increasing during the past decades. We analyzed a large number of photometric measurements from available archives and found that this effect is generic for this class of stars, independently of their evolutionary status. This finding is in agreement with previous predictions and the most recent work of Patterson et al. (2012) on BK Lyn.

  1. Imagens do céu ontem e hoje - um multimídia interativo de astronomia e uma nova exposição no MAST

    NASA Astrophysics Data System (ADS)

    Caretta, C. A.; Lima, F. P.; Requeijo, F.; Vieira, G. G.; Alves, F.; Valente, M. E. A.; de Almeida, R.; de Garcia, G. C.; Quixadá, A. C.

    2003-08-01

    "Imagens do Céu Ontem e Hoje" é o título de uma nova exposição que está sendo inaugurada no Museu de Astronomia e Ciências Afins (MCT), que inclui experimentos interativos, maquetes, réplicas e 8 terminais de computador com um multimídia interativo sobre Astronomia para consulta dos visitantes. O multimídia apresenta um conteúdo bastante extenso, que engloba quase todos os temas em Astronomia, consistindo numa fonte de divulgação e pesquisa para um público que vai das crianças até estudantes universitários. O conteúdo está distribuído em mais de 500 páginas de texto divididas em 4 módulos: "O Universo", "Espectroscopia", "Telescópios" e "Observando o Céu". Cada módulo é subdividido em 5 seções, em média, cada uma iniciada por uma animação que ilustra os temas a serem abordados na seção. Ao final da animação, uma lista de temas é apresentada sob o título "Saiba Mais". Para exemplificar, o módulo "O Universo" contém as seguintes seções: "O Universo visto pelo homem", "Conhecendo o Sistema Solar", "Indo além do Sistema Solar", "Nossa Galáxia, a Via-Láctea" e "Indo mais além, a imensidão do Universo". A seção "Conhecendo o Sistema Solar", por sua vez, tem os seguintes temas: "A origem do Sistema Solar", "O Sol", "Os planetas", "Satélites, asteróides, cometas e outros bichos..." e "O Sistema Solar em números". Cada texto é repleto de imagens, quadros, desenhos, esquemas, etc, além de passatempos ao final de cada seção, incluindo jogos interativos, quadrinhos e curiosidades, que auxiliam o aprendizado de forma divertida. Apresentamos neste trabalho as idéias gerais que permearam a produção da exposição, e uma viagem pelo multimídia para exemplificar sua estrutura e conteúdo. O multimídia será posteriormente disponibilizado para o público externo pela página eletrônica do MAst e/ou por intermédio de uma publicação comercial.

  2. Classical Novae

    NASA Astrophysics Data System (ADS)

    Bode, Michael F.; Evans, Aneurin

    2008-04-01

    Preface; 1. Novae - a historical perspective Hilmar W. Duerbeck; 2. Properties of novae: an overview Brian Warner; 3. The evolution of nova-producing binary stars Icko Iben, Jr and Masayuki Y. Fujimoto; 4. Thermonuclear processes S. Starrfield, C. Iliadis and W. R. Hix; 5. Nova atmospheres and winds P. H. Hauschildt; 6. Observational mysteries and theoretical challenges Jordi Jose and Steven N. Shore; 7. Radio emission from novae E. R. Seaquist and M. F. Bode; 8. Infrared studies of classical novae Robert D. Gehrz; 9. Optical and ultraviolet evolution Steven N. Shore; 10. X-ray emission from classical novae in outburst Joachim Krautter; 11. Gamma-rays from classical novae Margarita Hernanz; 12. Resolved nova remnants T. J. O'Brien and M. F. Bode; 13. Dust and molecules in nova environments A. Evans and J. M. C. Rawlings; 14. Extragalactic novae Allen Shafter; Index.

  3. Classical Novae

    NASA Astrophysics Data System (ADS)

    Bode, Michael F.; Evans, Aneurin

    2012-07-01

    Preface; 1. Novae - a historical perspective Hilmar W. Duerbeck; 2. Properties of novae: an overview Brian Warner; 3. The evolution of nova-producing binary stars Icko Iben, Jr and Masayuki Y. Fujimoto; 4. Thermonuclear processes S. Starrfield, C. Iliadis and W. R. Hix; 5. Nova atmospheres and winds P. H. Hauschildt; 6. Observational mysteries and theoretical challenges Jordi Jose and Steven N. Shore; 7. Radio emission from novae E. R. Seaquist and M. F. Bode; 8. Infrared studies of classical novae Robert D. Gehrz; 9. Optical and ultraviolet evolution Steven N. Shore; 10. X-ray emission from classical novae in outburst Joachim Krautter; 11. Gamma-rays from classical novae Margarita Hernanz; 12. Resolved nova remnants T. J. O'Brien and M. F. Bode; 13. Dust and molecules in nova environments A. Evans and J. M. C. Rawlings; 14. Extragalactic novae Allen Shafter; Index.

  4. Recurrent novae

    NASA Technical Reports Server (NTRS)

    Hack, Margherita; Selvelli, Pierluigi

    1993-01-01

    Recurrent novae seem to be a rather inhomogeneous group: T CrB is a binary with a M III companion; U Sco probably has a late dwarf as companion. Three are fast novae; two are slow novae. Some of them appear to have normal chemical composition; others may present He and CNO excess. Some present a mass-loss that is lower by two orders of magnitude than classical novae. However, our sample is too small for saying whether there are several classes of recurrent novae, which may be related to the various classes of classical novae, or whether the low mass-loss is a general property of the class or just a peculiarity of one member of the larger class of classical novae and recurrent novae.

  5. Dwarf novae

    NASA Technical Reports Server (NTRS)

    Ladous, Constanze

    1993-01-01

    Dwarf novae are defined on grounds of their semi-regular brightness variations of some two to five magnitudes on time scales of typically 10 to 100 days. Historically several different classification schemes have been used. Today, dwarf novae are divided into three sub-classes: the U Geminorum stars, the SU Ursae Majoris stars, and the Z Camelopardalis stars. Outbursts of dwarf novae occur at semi-periodic intervals of time, typically every 10 to 100 days; amplitudes range from typically 2 to 5 mag. Within certain limits values are characteristic for each object. Relations between the outburst amplitude, or the total energy released during outburst, and the recurrence time have been found, as well as relations between the orbital period and the outburst decay time, the absolute magnitude during outburst maximum, and the widths of long and short outbursts, respectively. Some dwarf novae are known to have suspended their normal outburst activity altogether for a while. They later resumed it without having undergone any observable changes. The optical colors of dwarf novae all are quite similar during outburst, considerably bluer than during the quiescent state. During the outburst cycle, characteristic loops in the two color diagram are performed. At a time resolution on the order of minutes, strictly periodic photometric changes due to orbital motion become visible in the light curves of dwarf novae. These are characteristic for each system. Remarkably little is known about orbital variations during the course of an outburst. On time-scales of minutes and seconds, further more or less periodic types of variability are seen in dwarf novae. Appreciable flux is emitted by dwarf novae at all wavelengths from the X-rays to the longest IR wavelengths, and in some cases even in the radio. Most dwarf novae exhibit strong emission line spectra in the optical and UV during quiescence, although some have only very weak emissions in the optical and/or weak absorptions at UV

  6. Magnetic novae

    NASA Astrophysics Data System (ADS)

    Zemko, Polina; Orio, Marina

    2016-07-01

    We present the results of optical and X-ray observations of two quiescent novae, V2491 Cyg and V4743 Sgr. Our observations suggest the intriguing possibility of localization of hydrogen burning in magnetic novae, in which accretion is streamed to the polar caps. V2491 Cyg was observed with Suzaku more than 2 years after the outburst and V4743 Sgr was observed with XMM Newton 2 and 3.5 years after maximum. In the framework of a monitoring program of novae previously observed as super soft X-ray sources we also obtained optical spectra of V4743 Sgr with the SALT telescope 11.5 years after the eruption and of V2491 Cyg with the 6m Big Azimutal Telescope 4 and 7 years post-outburst. In order to confirm the possible white dwarf spin period of V2491 Cyg measured in the Suzaku observations we obtained photometric data using the 90cm WIYN telescope at Kitt Peak and the 1.2 m telescope in Crimea. We found that V4743 Sgr is an intermediate polar (IP) and V2491 Cyg is a strong IP candidate. Both novae show modulation of their X-ray light curves and have X-ray spectra typical of IPs. The Suzaku and XMM Newton exposures revealed that the spectra of both novae have a very soft blackbody-like component with a temperature close to that of the hydrogen burning white dwarfs in their SSS phases, but with flux by at least two orders of magnitude lower, implying a possible shrinking of emitting regions in the thin atmosphere that is heated by nuclear burning underneath it. In quiescent IPs, independently of the burning, an ultrasoft X-ray flux component originates at times in the polar regions irradiated by the accretion column, but the soft component of V4743 Sgr disappeared in 2006, indicating that the origin may be different from accretion. We suggest it may have been due to an atmospheric temperature gradient on the white dwarf surface, or to continuing localized thermonuclear burning at the bottom of the envelope, before complete turn-off. The optical spectra of V2491 Cyg and V

  7. Firework Nova

    NASA Image and Video Library

    2017-09-28

    Nova Stars are essentially giant fusion reactions occurring in the vacuum of space. Because stars have so much mass, they possess powerful gravitational force—but they don’t collapse because of the outward force generated by nuclear fusion, continually converting hydrogen atoms to helium. Sometimes stars begin orbiting each other, forming a binary star system. Typically this involves a white dwarf star and a red giant. Orbiting the red giant like a moon, the dwarf star rips matter from its companion until it essentially gags on the excess, coughing hot gas and radiation into space. This dramatic phenomenon is relatively common, and the white dwarf is not destroyed in the resulting nova. To learn more about x-ray emissions, read about NASA’s Chandra mission: www.nasa.gov/mission_pages/chandra/main/ --- Original caption: In Hollywood blockbusters, explosions are often among the stars of the show. In space, explosions of actual stars are a focus for scientists who hope to better understand their births, lives, and deaths and how they interact with their surroundings. Using NASA’s Chandra X-ray Observatory, astronomers have studied one particular explosion that may provide clues to the dynamics of other, much larger stellar eruptions. A team of researchers pointed the telescope at GK Persei, an object that became a sensation in the astronomical world in 1901 when it suddenly appeared as one of the brightest stars in the sky for a few days, before gradually fading away in brightness. Today, astronomers cite GK Persei as an example of a “classical nova,” an outburst produced by a thermonuclear explosion on the surface of a white dwarf star, the dense remnant of a Sun-like star. Read Full Article: www.nasa.gov/mission_pages/chandra/mini-supernova-explosi... NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a

  8. Firework Nova

    NASA Image and Video Library

    2015-07-02

    In Hollywood blockbusters, explosions are often among the stars of the show. In space, explosions of actual stars are a focus for scientists who hope to better understand their births, lives, and deaths and how they interact with their surroundings. Using NASA’s Chandra X-ray Observatory, astronomers have studied one particular explosion that may provide clues to the dynamics of other, much larger stellar eruptions. A team of researchers pointed the telescope at GK Persei, an object that became a sensation in the astronomical world in 1901 when it suddenly appeared as one of the brightest stars in the sky for a few days, before gradually fading away in brightness. Today, astronomers cite GK Persei as an example of a “classical nova,” an outburst produced by a thermonuclear explosion on the surface of a white dwarf star, the dense remnant of a Sun-like star.

  9. Classical novae and recurrent novae: General properties

    NASA Technical Reports Server (NTRS)

    Hack, Margherita; Selvelli, Pierluigi; Duerbeck, Hilmar W.

    1993-01-01

    We describe the observable characteristics of classical novae and recurrent novae obtained by different techniques (photometry, spectroscopy, and imaging) in all the available spectral ranges. We consider the three stages in the life of a nova: quiescence (pre- and post-outburst), outburst, final decline and nebular phase. We describe the photometric properties during the quiescent phase. We describe the photometric properties during outburst, the classification according the rate of decline (magnitudes per day), which permits us to define very fast, fast, intermediate, slow, and very slow novae and the correlation between luminosity and speed class. We report the scanty data on the spectra of the few known prenovae and those on the spectra of old novae and those of dwarf novae and nova-like, which, however, are almost undistinguishable. We describe the typical spectra appearing from the beginning of the outburst, just before maximum, up to the nebular phase and the correlation between spectral type at maximum, expansional velocity, and speed class of the nova. We report the existing infrared observations, which permit us to explain some of the characteristics of the outburst light curve, and give evidence of the formation of a dust shell in slow and intermediate novae (with the important exception of the very slow nova HR Del 1967) and its absence or quasi-absence in fast novae. The ultraviolet and X-ray observations are described. The X ray observations of novae, mainly from the two satellites EINSTEIN and EXOSAT, are reported. Observations of the final decline and of the envelopes appearing several months after outburst are also reported.

  10. Portuguese and the Computer: "uma bossa nova".

    ERIC Educational Resources Information Center

    Kelly, John R.

    This paper describes the process of preparing a computer study of Brazilian Portuguese literary texts to be used both in teaching and in the preparation of a reference text. Procedural difficulties encountered in the project point out the potential and limitations of computerized research in literary studies. Seven possible areas for computer…

  11. Typical examples of classical novae

    NASA Technical Reports Server (NTRS)

    Hack, Margherita; Selvelli, Pierluigi; Bianchini, Antonio; Duerbeck, Hilmar W.

    1993-01-01

    Because of the very complicated individualistic behavior of each nova, we think it necessary to review the observations of a few well-observed individuals. We have selected a few objects of different speed classes, which have been extensively observed. They are: V1500 Cygni 1975, a very fast nova; V603 Aql 1918, fast nova; CP Pup 1942, fast nova; GK Per 1901, fast nova; V 1668 Cyg 1979, moderately fast nova; FH Ser 1970, slow nova; DQ Her 1934, slow nova; T Aur 1891, slow nova; RR Pic 1925, slow nova; and HR Del 1967, very slow nova.

  12. Fermi Sees a Nova

    NASA Image and Video Library

    Watch V407 Cyg go nova! A nova is a sudden, short-lived brightening of an otherwise inconspicuous star. The outburst occurs when a white dwarf in a binary system erupts in an enormous thermonuclear...

  13. NOVA 201 ultrasonic thickness gage (NOVA Gage)

    NASA Technical Reports Server (NTRS)

    Garecht, Diane

    1990-01-01

    The measurement integrity of the NOVA 201 digital ultrasonic thickness gage (NOVA gage) was demonstrated by comparing the NOVA gage measurements to the thickness gage measurements, and determining the bias and uncertainty of the NOVA gage when measuring redesigned solid rocket motor (RSRM) hardware per engineering test plans (ETP). The NOVA gage was tested by three different operators on steel and aluminum RSRM hardware for wall thickness. The results show that the measurement bias is not consistent. The uncertainty of the bias is caused by the heterogeneous material properties of the RSRM components that influence the time of flight of ultrasonic waves. The measurement uncertainty inherent to the design and operation of the NOVA gage is less in comparison to the uncertainty of the bias. The total measurement uncertainty cannot be substantially reduced by taking more than one measurement. There is no correlation between bias and the surface finish range of this test unless 3-in-One oil is used as a couplant, in which case there appears to be a slight trend. There is no correlation between uncertainty and the surface finish range. The measurement uncertainty of the NOVA gage can be reduced using 3-in-One oil as a couplant.

  14. Novae as distance indicators

    NASA Technical Reports Server (NTRS)

    Ford, Holland C.; Ciardullo, Robin

    1988-01-01

    Nova shells are characteristically prolate with equatorial bands and polar caps. Failure to account for the geometry can lead to large errors in expansion parallaxes for individual novae. When simple prescriptions are used for deriving expansion parallaxes from an ensemble of randomly oriented prolate spheroids, the average distance will be too small by factors of 10 to 15 percent. The absolute magnitudes of the novae will be underestimated and the resulting distance scale will be too small by the same factors. If observations of partially resolved nova shells select for large inclinations, the systematic error in the resulting distance scale could easily be 20 to 30 percent. Extinction by dust in the bulge of M31 may broaden and shift the intrinsic distribution of maximum nova magnitudes versus decay rates. We investigated this possibility by projecting Arp's and Rosino's novae onto a composite B - 6200A color map of M31's bulge. Thirty two of the 86 novae projected onto a smooth background with no underlying structure due to the presence of a dust cloud along the line of sight. The distribution of maximum magnitudes versus fade rates for these unreddened novae is indistinguishable from the distribution for the entire set of novae. It is concluded that novae suffer very little extinction from the filamentary and patchy distribution of dust seen in the bulge of M31. Time average B and H alpha nova luminosity functions are potentially powerful new ways to use novae as standard candles. Modern CCD observations and the photographic light curves of M31 novae found during the last 60 years were analyzed to show that these functions are power laws. Consequently, unless the eruption times for novae are known, the data cannot be used to obtain distances.

  15. NOVA, A BRIEF .....

    ERIC Educational Resources Information Center

    WHITING, RICHARD; AND OTHERS

    NOVA IS AN EXPERIMENTAL, 6-YEAR JUNIOR-SENIOR HIGH SCHOOL. ASPECTS OF THE PROGRAM INCLUDE THE TRIMESTER SYSTEM, THE CONTINUOUS PROGRESS CURRICULUM, TEAM TEACHING, A CLASS SCHEDULE OF FOUR 70-MINUTE PERIODS PER WEEK, THE USE OF DATA-PROCESSING EQUIPMENT, AND MODERN INSTRUCTIONAL AIDS. NOVA IS ORGANIZED CAMPUS-STYLE WITH INDIVIDUAL BUILDINGS DEVOTED…

  16. Nova-like variables

    NASA Technical Reports Server (NTRS)

    Ladous, Constanze

    1993-01-01

    On grounds of different observable characteristics five classes of nova-like objects are distinguished: the UX Ursae Majoris stars, the antidwarf novae, the DQ Herculis stars, the AM Herculis stars, and the AM Canum Venaticorum stars. Some objects have not been classified specifically. Nova-like stars share most observable features with dwarf novae, except for the outburst behavior. The understanding is that dwarf novae, UX Ursae Majoris stars, and anti-dwarf novae are basically the same sort of objects. The difference between them is that in UX Ursae Majoris stars the mass transfer through the accretion disc always is high so the disc is stationary all the time; in anti-dwarf novae for some reason the mass transfer occasionally drops considerably for some time, and in dwarf novae it is low enough for the disc to undergo semiperiodic changes between high and low accretion events. DQ Herculis stars are believed to possess weakly magnetic white dwarfs which disrupt the inner disc at some distance from the central star; the rotation of the white dwarf can be seen as an additional photometric period. In AM Herculis stars, a strongly magnetic white dwarf entirely prevents the formation of an accretion disk and at the same time locks the rotation of the white dwarf to the binary orbit. Finally, AM Canum Venaticorum stars are believed to be cataclysmic variables that consist of two white dwarf components.

  17. Nova AQL 1918 - A nude old nova

    NASA Astrophysics Data System (ADS)

    Selvelli, P. L.; Cassatella, A.

    IUE observations at high and low resolution of Nova Aql 1918 are studied. No evidence of outflow or nebular lines is found, which indicates that the shell ejected at the time of the outburst and surrounding the system for many years has disappeared. The ejection of the shell is shown to be a transient phenomenon during the life of the nova, and due to expansion at a rate of about 2 arcsec/yr, the density of the nebula has probably decreased so much that the nebula can now be considered to have vanished.

  18. ER Ursae Majoris: A dwarf nova with surprises

    NASA Astrophysics Data System (ADS)

    de Miguel, Enrique; Patterson, Joe; Kemp, Jonathan; Stein, William; Roberts, George; Campbell, T.; Hambsch, Franz-J.; Krajci, Tom; Dvorak, Shawn; Koff, Robert A.; Morelle, Etienne; Potter, Michael; Cejudo, David; Brady, Steve; Menzies, Kenneth

    2012-05-01

    ER Ursae Majoris is a relatively bright member of the SU UMa-type dwarf novae that undergoes frequent eruptions of amplitude ~2 mag every ~4 d. In addition to these ordinary dwarf-nova outbursts, ER UMa shows brighter eruptions (superoutbursts) lasting ~20 d with a recurrence time of ~44 d. As other members of the SU UMa class, ER UMa displays a characteristic periodic modulation (superhumps) in its light curve during the course of a superoutburst, the period being a few percent longer than the orbital period of the underlying binary system. A routine photometric patrol of ER UMa during its January 2011superoutburst became much more interesting after noticing the presence of an additional modulation in its light curve, with a period slightly shorter than the orbital period. Similar photometric waves (known as negative superhumps) have already been observed in other cataclysmic variables, mainly in nova-like systems, but only in a small handful of SU UMa-type stars during quiescence, and never before during a superoutburst. We report in this communication the results of a worldwide photometric campaign that was orchestrated right after the discovery of negative superhumps in ER UMa, and provide a thorough analysis of the data obtained from more than 10 stations of the Center of Backyard Astrophysics (CBA) network, which include more than 1000 hours of photometric data over a 4-month baseline on 2011, and a similar (still in progress) dense coverage in 2012.

  19. Light echoes - Novae

    NASA Technical Reports Server (NTRS)

    Schaefer, Bradley E.

    1988-01-01

    The sudden brilliance of a nova eruption will be reflected on surrounding dust grains to create a phantom nebula. Previous searches for these light echoes have used relatively short exposures with photograhic detectors. This paper reports on a search around eight recent novae with long exposures using a CCD camera. Despite an increase of sensitivity by over an order of magnitude, no light echoes were detected. It is found that the average grain density must be less than about 10 to the -9th per cu cm for distances from 0.1 pc to 1000 pc from the novae. The light echo around Nova Persei 1901 was caused by reflection off clouds with grain densities of several times 10 to the -9th per cu cm which are at distances between 0.1 pc and 10 pc. Echoes from dust in a circumstellar shell or ejected during a previous eruption will be effectively unobservable.

  20. Dust formation around novae

    SciTech Connect

    Johnson, D.J.

    1988-01-01

    This thesis examines the origin of the dust grains, thought to be a few tenths of a micron or larger in size, which can be found around some novae. Both nucleation and grain growth are treated. The problem is first examined in a limited way by studying grain growth and bypassing nucleation. It is shown that grains a few tenths of a micron in radius can form in geometrically thick, low density gas shells, but micron size particles would require much thinner shells. If the micron size dust exists, it suggests that a nova blows off a relatively thin shell of carbon-rich material which somehow stays thin (thickness << radius) even as it expands, or alternatively, that a nova blows off clumps of dense carbon-rich gas. The presence of larger micron size dust particles would therefore reveal something interesting about the nova eruption. The thesis then examines nucleation. It enumerates the processes which tend to prevent nucleation around a nova. The first obstacle is photoionization; if the nova's radiating temperature is two high the carbon is entirely ionized and nucleation is impossible. In the early stages of the eruption when the nova is relatively cool, 6-11 eV photons will disrupt small molecules, preventing nucleation. Nucleation might still be possible if the presence of hydrogen in the small molecules protects the carbon skeleton from disruption. A vibrationally excited molecule is more likely to lose a hydrogen atom than a more strongly bound carbon atom. Since nucleation appears improbable around an erupting nova, it is suggested that dust forms when the ejected material reaches the condensation radius and accretes on pre-existing nucleation sites.

  1. Nucleosynthesis in Novae

    NASA Astrophysics Data System (ADS)

    José, Jordi

    Remarkable progress in our understanding of nova outbursts has been achieved through combined efforts in photometry, spectroscopy and numerical simulations. According to the thermonuclear runaway model, novae are powered by thermonuclear explosions in the H-rich envelopes transferred from a low-mass stellar companion onto a close white dwarf star. Extensive numerical simulations have shown that the accreted envelopes attain peak temperatures ranging between 100 and 400 MK, for about several hundred seconds, hence allowing extensive nuclear processing which eventually shows up in the form of nucleosynthetic fingerprints in the ejecta. Indeed, it has been claimed that novae can play a key role in the enrichment of the interstellar medium through a number of intermediate-mass elements. This includes 17O, 15N, and 13C, plus a smaller contribution in a number of other species (A < 40), such as 7Li, 19F, or 26Al. At the turn of the XXI Century, classical novae entered the era of multidimensional models, which provide new insights into the physical mechanisms that drive mixing at the core-envelope interface. In this paper, we will present an overview on classical nova models, from the onset of accretion up to the explosion and ejection stages, with special emphasis on their gross observational properties and their associated nucleosynthesis. The impact of nuclear uncertainties on the final yields will be discussed.

  2. The Galactic Nova Rate Revisited

    NASA Astrophysics Data System (ADS)

    Shafter, A. W.

    2017-01-01

    Despite its fundamental importance, a reliable estimate of the Galactic nova rate has remained elusive. Here, the overall Galactic nova rate is estimated by extrapolating the observed rate for novae reaching m≤slant 2 to include the entire Galaxy using a two component disk plus bulge model for the distribution of stars in the Milky Way. The present analysis improves on previous work by considering important corrections for incompleteness in the observed rate of bright novae and by employing a Monte Carlo analysis to better estimate the uncertainty in the derived nova rates. Several models are considered to account for differences in the assumed properties of bulge and disk nova populations and in the absolute magnitude distribution. The simplest models, which assume uniform properties between bulge and disk novae, predict Galactic nova rates of ∼50 to in excess of 100 per year, depending on the assumed incompleteness at bright magnitudes. Models where the disk novae are assumed to be more luminous than bulge novae are explored, and predict nova rates up to 30% lower, in the range of ∼35 to ∼75 per year. An average of the most plausible models yields a rate of {50}-23+31 yr‑1, which is arguably the best estimate currently available for the nova rate in the Galaxy. Virtually all models produce rates that represent significant increases over recent estimates, and bring the Galactic nova rate into better agreement with that expected based on comparison with the latest results from extragalactic surveys.

  3. Nova in M31

    NASA Astrophysics Data System (ADS)

    Lang, F.; Lerchster, M.; Fliri, J.

    2006-05-01

    We report the discovery of a possible nova in M31 on a R band CCD image at JD 2453877.5 (2006, May 22.1 UT) with 18.7 mag (accuracy 0.1 mag). The image was obtained with the Wendelstein telescope (0.8 m, 1k x 1k CCD camera with 24mu sq. pixels). The position obtained for the nova candidate is RA(2000) = 00h 43m 11.81s, Dec(2000) = +41° 13' 44.7" with an accuracy of 0.1". At the position of the nova candidate no star brighter than 21.5 mag (1 sigma) was detected on 2006, May 12.2 UT on a Wendelstein R band image.

  4. Observations of Novae From ROAD

    NASA Astrophysics Data System (ADS)

    Hambsch, F.-J.

    2014-12-01

    The author discusses observations of galactic novae and some extragalactic supernovae from his remote observatory ROAD (Remote Observatory Atacama Desert) he commenced in August 2011 with Nova Lupi 2011 (PR Lup). The observed novae are mainly chosen according to AAVSO Alert Notices and AAVSO Special Notices as published on their website. Examples of dense observations of different novae are presented. The focus goes to the different behaviors of their light curves. It also demonstrates the capability of the remote observatory ROAD.

  5. School Psychology in Nova Scotia

    ERIC Educational Resources Information Center

    King, Sara; McGonnell, Melissa; Noyes, Amira

    2016-01-01

    Registration as a psychologist in Nova Scotia can be at the master's or doctoral level; however, the Nova Scotia Board of Examiners in Psychology has announced a move to the doctoral degree as the entry-level to practice. Many school psychologists in Nova Scotia practice at the master's level; therefore, this change could affect school psychology…

  6. School Psychology in Nova Scotia

    ERIC Educational Resources Information Center

    King, Sara; McGonnell, Melissa; Noyes, Amira

    2016-01-01

    Registration as a psychologist in Nova Scotia can be at the master's or doctoral level; however, the Nova Scotia Board of Examiners in Psychology has announced a move to the doctoral degree as the entry-level to practice. Many school psychologists in Nova Scotia practice at the master's level; therefore, this change could affect school psychology…

  7. NOVA HIGH SCHOOL--INTRODUCTION

    ERIC Educational Resources Information Center

    COGSWELL, JOHN F.

    AN OVERVIEW WAS PRESENTED OF THE ORGANIZATION AND OPERATION OF A NUMBER OF INNOVATIVE ASPECTS OF THE NOVA HIGH SCHOOL IN FORT LAUDERDALE, FLORIDA. NOVA IS PART OF A COMPLEX PLANNED TO INCLUDE GRADES K THROUGH 12. STUDENTS MUST APPLY TO ATTEND NOVA AND ARE SELECTED PRIMARILY ON THE RELATION OF STUDENT PERFORMANCE TO MEASURES OF APTITIDE. VOCATIONAL…

  8. Infrared spectroscopy of cataclysmic variables - III. Dwarf novae below the period gap and nova-like variables

    NASA Astrophysics Data System (ADS)

    Dhillon, V. S.; Littlefair, S. P.; Howell, S. B.; Ciardi, D. R.; Harrop-Allin, M. K.; Marsh, T. R.

    2000-06-01

    We present K-band spectra of the short-period dwarf novae YZ Cnc, LY Hya, BK Lyn, T Leo, SW UMa and WZ Sge, the nova-like variables DW UMa, V1315 Aql, RW Tri, VY Scl, UU Aqr and GP Com, and a series of field dwarf stars with spectral types ranging from K2 to M6. The spectra of the dwarf novae are dominated by emission lines of Hi and Hei. The large velocity and equivalent widths of these lines, in conjunction with the fact that the lines are double-peaked in the highest inclination systems, indicate an accretion disc origin. In the case of YZ Cnc and T Leo, for which we obtained time-resolved data covering a complete orbital cycle, the emission lines show modulations in their equivalent widths that are most probably associated with the bright spot (the region where the gas stream collides with the accretion disc). There are no clear detections of the secondary star in any of the dwarf novae below the period gap, yielding upper limits of 10-30per cent for the contribution of the secondary star to the observed K-band flux. In conjunction with the K-band magnitudes of the dwarf novae, we use the derived secondary star contributions to calculate lower limits to the distances to these systems. The spectra of the nova-like variables are dominated by broad, single-peaked emission lines of Hi and Hei - even the eclipsing systems we observed do not show the double-peaked profiles predicted by standard accretion disc theory. With the exception of RW Tri, which exhibits Nai, Cai and 12CO absorption features consistent with a M0V secondary contributing 65per cent of the observed K-band flux, we find no evidence for the secondary star in any of the nova-like variables. The implications of this result are discussed.

  9. NOVA HIGH SCHOOL.

    ERIC Educational Resources Information Center

    Broward County Schools, Fort Lauderdale, FL.

    NOVA HIGH SCHOOL OPENED IN SEPTEMBER 1963 AS A UNIT OF THE SOUTH FLORIDA EDUCATIONAL CENTER. IT IS EXPERIMENTAL IN CONCEPT, BUT NOT IN CURRICULUM. ITS CONSTRUCTION, FEATURES, EQUIPMENT, TEACHING AIDS, AND INSTRUCTIONAL METHODS HAVE BEEN TESTED AND PROVED IN OTHER SCHOOL SYSTEMS. ITS PHILOSOPHY REPRESENTS A RETURN TO FUNDAMENTAL EDUCATION, BUT ITS…

  10. SCIENCE AT NOVA.

    ERIC Educational Resources Information Center

    Broward County Schools, Fort Lauderdale, FL.

    THE SCIENCE PROGRAM AT NOVA HIGH SCHOOL IS STRUCTURED TO MEET THE NEEDS OF A SCIENTIFIC SOCIETY. THE JUNIOR HIGH PROGRAM EMPHASIZES THE ACCUMLATION, TABULATION, AND ANALYSIS OF DATA. THE SENIOR HIGH PROGRAM MAKES USE OF THESE PROCESSES IN THE INVESTIGATION OF VARIOUS SUBJECT AREAS. THE UNITS COMPOSING THE HIGH SCHOOL CURRICULUM ARE DESCRIBED. UNIT…

  11. SCIENCE AT NOVA.

    ERIC Educational Resources Information Center

    Broward County Schools, Fort Lauderdale, FL.

    THE SCIENCE PROGRAM AT NOVA HIGH SCHOOL IS STRUCTURED TO MEET THE NEEDS OF A SCIENTIFIC SOCIETY. THE JUNIOR HIGH PROGRAM EMPHASIZES THE ACCUMLATION, TABULATION, AND ANALYSIS OF DATA. THE SENIOR HIGH PROGRAM MAKES USE OF THESE PROCESSES IN THE INVESTIGATION OF VARIOUS SUBJECT AREAS. THE UNITS COMPOSING THE HIGH SCHOOL CURRICULUM ARE DESCRIBED. UNIT…

  12. Gamma Rays from Classical Novae

    NASA Technical Reports Server (NTRS)

    1997-01-01

    NASA at the University of Chicago, provided support for a program of theoretical research into the nature of the thermonuclear outbursts of the classical novae and their implications for gamma ray astronomy. In particular, problems which have been addressed include the role of convection in the earliest stages of nova runaway, the influence of opacity on the characteristics of novae, and the nucleosynthesis expected to accompany nova outbursts on massive Oxygen-Neon-Magnesium (ONeMg) white dwarfs. In the following report, I will identify several critical projects on which considerable progress has been achieved and provide brief summaries of the results obtained:(1) two dimensional simulation of nova runaway; (2) nucleosynthesis of nova modeling; and (3) a quasi-analytic study of nucleosynthesis in ONeMg novae.

  13. New Nova Candidates from the RSBE M31 Nova Survey

    NASA Astrophysics Data System (ADS)

    Lauber, Stephanie; Rector, Travis A.; Shafter, Allen W.

    2015-01-01

    Since 1995 the Kitt Peak National Observatory WIYN 0.9-m telescope has been used to monitor M31 for novae as part of the Research-Based Science Education Project (RBSE). The resulting images, which typically cover approximately the inner 20 arc min of M31, are taken through a broad-band H-alpha filter to isolate the strong H-alpha emission lines characteristic of novae shortly after eruption.We are in the process of reanalyzing the entire RBSE data set covering the period between September 1995 and August 2014 in order to produce an up-to-date list of novae from this survey. Here, we present coordinates and H-alpha magnitudes for 4 new nova discoveries not previous reported. Among the new nova discoveries, one system appears spatially coincident with M31N 1988-09a, and is thus a recurrent nova candidate.

  14. Nova in Puppis

    NASA Astrophysics Data System (ADS)

    Templeton, Matthew R.

    2007-11-01

    Nova Puppis 2007 was discovered visually by Alfredo Jose Serra Pereira, Carnaxide, Portugal, on November 14.23 UT at visual magnitude 7.0. The discovery was announced in IAU Circular No. 8895 (Daniel W. E. Green, Ed.). The nova is located at 08:16:17.99 -34:15:25.0 (J2000, J. Young and H. Rhoades, Table Mountain Observatory, near Wrightwood, CA). Nothing was visible down to magnitude 8 on November 6.23, 7.22, 8.23, 10.23, and 11.22 UT. Young reports that a red image of the field from the Digitized Sky Survey contains a point source at an approximate magnitude of 20. No spectra have yet been published. Please report observations to the AAVSO International Database as N PUP 2007.

  15. Nova Scorpii 2008

    NASA Astrophysics Data System (ADS)

    Templeton, Matthew R.

    2008-09-01

    Nova Sco 2008 was discovered by K. Nishiyama, Kurume, Fukuoka-ken, Japan, and F. Kabashima, Miyaki-cho, Saga-ken, Japan; Y. Sakurai, Mito, Ibaraki-ken, Japan; and Guoyou Sun, Qufu, Shandong, China, and Xing Gao, Urumqi, Xinjiang, China, on 2008 September 02.4594 UTC at magnitude 9.5 (unfiltered). This is a classical nova, as determined by low-resolution spectra by M. Fujii, Ibara, Okayama, Japan, and by H. Naito, Nishi-Harima Astron. Obs., on Sept 3.49 and Sept 5.47 UT, respectively. This object has been given the formal variable star designation V1309 Sco. Discovery information is from IAU Circular 8972, Daniel W.E. Green, editor. Observations should be submitted to the AAVSO International Database as V1309 SCO.

  16. Nova Lupi 2011

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2011-08-01

    Announcement of discovery of Nova Lupi 2011 = PNV J14542000-5505030. Discovered by Nicholas Brown (Quinns Rocks, Western Australia) on 2011 Aug. 4.73 UT at unfiltered mag=10.2 (tmax 400 film). Posted on the IAU Central Bureau for Astronomical Telegrams Transient Object Confirmation Page (TOCP) as PNV J14542000-5505030. Spectra obtained by Fred Walter (SUNY Stony Brook) 2011 August 9.0132 UT with the SMARTS 1.5m RC spectrograph at Cerro Tololo and reported in ATEL #3536 confirms that the object is an Fe II nova near maximum. Initially announced in [vsnet-alert 13560] (Nicholas Brown) and in AAVSO Special Notice #247 (Arne Henden). Finder charts with sequence may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details and observations.

  17. Chemistry in Novae

    NASA Astrophysics Data System (ADS)

    Rawlings, J. M. C.; Williams, D. A.

    It is shown that the 5 μm excess, which is attributed to CO in the ejecta of novae, can be modelled chemically. The principle problems involved in the modelling are: (1) the high ejecta temperature (≡104K), (2) the extremely high UV flux, and (3) the marginal self-shielding capability of H2. The authors find that the condition of H2 self-shielding alone is sufficient to allow rapid chemistry to proceed. Time-dependent chemistry calculations indicate that the chemistry is steered by the physics of the system.

  18. NOVA Fall 2002 Teacher's Guide.

    ERIC Educational Resources Information Center

    Ransick, Kristina; Rosene, Dale; Sammons, James; Turck, Mary

    This NOVA teacher's guide presents activities, information, and teaching ideas from the Public Broadcasting System's (PBS) NOVA television program series. Episodes include: (1) "Mysterious Life of Caves" which investigates the role microbes play in the creation of some limestone caves; (2) "Lost Roman Treasure" which follows…

  19. Nova Mus 2008 = QY Mus

    NASA Astrophysics Data System (ADS)

    Templeton, Matthew R.

    2008-10-01

    Nova Mus 2008 = QY Mus was discovered by William Liller, Vina del Mar, Chile, on 2008 September 28.998 UT at magnitude 8.6 (Tech Pan film + orange filter). The position is RA = 13h 16m 36.44s , Dec = -67d 36m 47.8s (from P. Nelson). This object was announced as a nova in IAU Circular 8990 (Daniel W.E. Green, editor). The nova classification was determined using low-resolution spectra by W. Liller indicating the presence of broad H-alpha lines at least 2300 angstroms wide. Several observers confirmed the nova and provided photometry. The position above was provided by Peter Nelson (Ellinbank, Vic., Aus.), and is averaged from four separate exposures (rms error approx. 0.4 arcseconds). The GCVS team have formally designated Nova Mus 2008 as QY MUS. Observations should be reported to the AAVSO International Database as QY MUS.

  20. Fritz Zwicky: Novae Become Supernovae

    NASA Astrophysics Data System (ADS)

    Koenig, T.

    2005-12-01

    The Swiss physicist Fritz Zwicky (1898-1974) dabbled in a plethora of disciplines, including astronomy and astrophysics. His dabblings were with vested interest and he has left quite an impact. His first great success was his nova research. In the early 1930s, while supermarkets and Superman were flying, he labelled the distinctly brighter nova Supernova. It had been believed that novae were the collision of two stars, but Zwicky came to recognize supernovae as a phenomenon quite distinct from novae. He and Walter Baade explained supernova by melding astronomy and physics and in this aim they created neutron stars, explained the origin of cosmic rays, initiated the first sky survey, and confirmed that a number of historical novae were indeed supernovae. This was truly an important work in the history of astrophysics.

  1. Recurrent Novae in M31

    NASA Astrophysics Data System (ADS)

    Shafter, A. W.; Henze, M.; Rector, T. A.; Schweizer, F.; Hornoch, K.; Orio, M.; Pietsch, W.; Darnley, M. J.; Williams, S. C.; Bode, M. F.; Bryan, J.

    2015-02-01

    The reported positions of 964 suspected nova eruptions in M31 recorded through the end of calendar year 2013 have been compared in order to identify recurrent nova (RN) candidates. To pass the initial screen and qualify as a RN candidate, two or more eruptions were required to be coincident within 0.‧1, although this criterion was relaxed to 0.‧15 for novae discovered on early photographic patrols. A total of 118 eruptions from 51 potential RN systems satisfied the screening criterion. To determine what fraction of these novae are indeed recurrent, the original plates and published images of the relevant eruptions have been carefully compared. This procedure has resulted in the elimination of 27 of the 51 progenitor candidates (61 eruptions) from further consideration as RNe, with another 8 systems (17 eruptions) deemed unlikely to be recurrent. Of the remaining 16 systems, 12 candidates (32 eruptions) were judged to be RNe, with an additional 4 systems (8 eruptions) being possibly recurrent. It is estimated that ∼4% of the nova eruptions seen in M31 over the past century are associated with RNe. A Monte Carlo analysis shows that the discovery efficiency for RNe may be as low as 10% that for novae in general, suggesting that as many as one in three nova eruptions observed in M31 arise from progenitor systems having recurrence times ≲ 100 yr. For plausible system parameters, it appears unlikely that RNe can provide a significant channel for the production of Type Ia supernovae.

  2. RECURRENT NOVAE IN M31

    SciTech Connect

    Shafter, A. W.; Henze, M.; Rector, T. A.; Schweizer, F.; Hornoch, K.; Orio, M.; Pietsch, W.; Darnley, M. J.; Williams, S. C.; Bode, M. F.; Bryan, J.

    2015-02-01

    The reported positions of 964 suspected nova eruptions in M31 recorded through the end of calendar year 2013 have been compared in order to identify recurrent nova (RN) candidates. To pass the initial screen and qualify as a RN candidate, two or more eruptions were required to be coincident within 0.′1, although this criterion was relaxed to 0.′15 for novae discovered on early photographic patrols. A total of 118 eruptions from 51 potential RN systems satisfied the screening criterion. To determine what fraction of these novae are indeed recurrent, the original plates and published images of the relevant eruptions have been carefully compared. This procedure has resulted in the elimination of 27 of the 51 progenitor candidates (61 eruptions) from further consideration as RNe, with another 8 systems (17 eruptions) deemed unlikely to be recurrent. Of the remaining 16 systems, 12 candidates (32 eruptions) were judged to be RNe, with an additional 4 systems (8 eruptions) being possibly recurrent. It is estimated that ∼4% of the nova eruptions seen in M31 over the past century are associated with RNe. A Monte Carlo analysis shows that the discovery efficiency for RNe may be as low as 10% that for novae in general, suggesting that as many as one in three nova eruptions observed in M31 arise from progenitor systems having recurrence times ≲100 yr. For plausible system parameters, it appears unlikely that RNe can provide a significant channel for the production of Type Ia supernovae.

  3. Olivier Chesneau's Work on Novae

    NASA Astrophysics Data System (ADS)

    Millour, F.; Lagadec, E.

    2015-12-01

    Olivier Chesneau founded a brand new field of observational astrophysics with his attempts to resolve the novae expanding fireball from the very first days of the explosion. With the images he could get, he showed that novae do indeed explode in an aspherical way, leading to a change of paradigm for the physics of these yet-poorly understood catastrophic systems. He also set the stage for a new way of estimating novae distances, by directly measuring the sky-size of the fireball and comparing it with spectroscopic scales, taking into account the tremendous effects of the fireball geometry.

  4. An observational study of quiescent novae

    NASA Astrophysics Data System (ADS)

    Dhillon, V. S.

    1990-01-01

    Quiescent novae are close binary stars which are characterised by the presence of Balmer and HeII emission lines in their optical spectra. In high-inclination systems, standard theory predicts that one should observe double-peaked emission line profiles which are eclipsed once every orbital period. However, the emission lines of eclipsing quiescent novae are single-peaked and uneclipsed, in obvious conflict with currently held beliefs on the nature of these systems. It is the purpose of this thesis to solve this long-standing problem and so arrive at a theoretical model for quiescent novae which is consistent with the observational evidence. The first part of the thesis sets the scene to the problem by presenting an overview of the conflicting observational and theoretical results. The second part then reports on a number of new observations obtained during the course of this work which have shed new light on the problem. The results of these new observations are presented in Part III of the thesis, where one chapter is devoted to each of the three objects studied (V1315 Aquilae, SW Sextantis and DW Ursae Majoris). The final part of the thesis is a discussion and comparison of the various results presented in Part III. Using these results, a series of observational constraints are defined which are then applied to a number of existing theoretical models. In the case of V1315 Aql and SW Sex, the very stringent set of constraints results in there being no single model capable of explaining the observed phenomena. DW UMa is even more enigmatic, appearing in a previously unseen low-state during which the mass transfer rate appears to have reduced dramatically and the optical spectra are dominated by Balmer emission from the inner face of the secondary star. The implications of these new observations for the wider field of cataclysmic variables are discussed, followed by a short summary of future work necessary to validate the origin, evolution and behaviour of the

  5. BK Lyncis: The Oldest Old Nova? or: Archaeo-Astronomy 101

    NASA Astrophysics Data System (ADS)

    Kemp, Jonathan; Patterson, Joe; de Miguel, Enrique; Roberts, George; Campbell, Tut; Hambsch, Franz-J.; Krajci, Tom; Dvorak, Shawn; Koff, Robert A.; Morell, Etienne; Potter, Michael; Cejudo, David; Ulowetz, Joe; Boyd, David; Sabo, Richard; Rock, John; Oksanen, Arto

    2012-05-01

    We summarize the results of a 20-year campaign to study the light curves of BK Lyncis, a nova-like star strangely located below the 2-3 hour orbital period gap in the family of cataclysmic variables. Two "superhumps" dominate the nightly light curves - with periods 4.6% longer, and 3.0% shorter, than Porb. The first appears to be associated with the star's brighter states (V~14), while the second appears to be present throughout and becomes very dominant in the low state (V~15.7). It's plausible that these arise, respectively, from a prograde apsidal precession and a retrograde nodal precession of the star's accretion disk. In 2011-2, the star's light curve became indistinguishable from that of a dwarf nova - in particular, that of the ER UMa subclass. No such transition has ever been observed in a cataclysmic variable. Reviewing all the star's oddities, we speculate: (a) BK Lyn is the remnant of the probable nova on 30 December 101, and (b) it has been fading ever since, but has taken ~2000 years for the accretion rate to drop sufficiently to permit dwarf-nova eruptions. If such behavior is common, it can explain two other puzzles of CV evolution. One: why the ER UMa class even exists (because all can be remnants of recent novae). And two: the relative space densities of short- and long-period CVs, and of known nova remnants (set by the durations of these transient phases).

  6. Argonne's Vilas Pol on NOVA!

    ScienceCinema

    None

    2016-07-12

    Can innovations in materials science help clean up our world? Argonne's material scientist Vilas Pol guest starred on NOVA's "Making Stuff: Cleaner," where David Pogue explored the rapidly-developing science and business of clean energy.

  7. Argonne's Vilas Pol on NOVA!

    SciTech Connect

    2011-01-01

    Can innovations in materials science help clean up our world? Argonne's material scientist Vilas Pol guest starred on NOVA's "Making Stuff: Cleaner," where David Pogue explored the rapidly-developing science and business of clean energy.

  8. BK Lyncis: the oldest old nova and a Bellwether for cataclysmic variable evolution

    NASA Astrophysics Data System (ADS)

    Patterson, Joseph; Uthas, Helena; Kemp, Jonathan; de Miguel, Enrique; Krajci, Thomas; Foote, Jerry; Hambsch, Franz-Josef; Campbell, Tut; Roberts, George; Cejudo, David; Dvorak, Shawn; Vanmunster, Tonny; Koff, Robert; Skillman, David; Harvey, David; Martin, Brian; Rock, John; Boyd, David; Oksanen, Arto; Morelle, Etienne; Ulowetz, Joseph; Kroes, Anthony; Sabo, Richard; Jensen, Lasse

    2013-09-01

    We summarize the results of a 20-yr campaign to study the light curves of BK Lyn, a nova-like star strangely located below the 2 to 3 h orbital-period gap in the family of cataclysmic variables (CVs). Two apparent superhumps dominate the nightly light curves, with periods 4.6 per cent longer, and 3.0 per cent shorter, than the orbital period. The first appears to be associated with the star's brighter states (V ˜ 14), while the second appears to be present throughout and becomes very dominant in the low state (V ˜ 15.7). It is plausible that these arise, respectively, from a prograde apsidal precession and a retrograde nodal precession of the star's accretion disc. Starting in the year 2005, the star's light curve became indistinguishable from that of a dwarf nova - in particular, that of the ER UMa subclass. No such clear transition has ever been observed in a CV before. Reviewing all the star's oddities, we speculate: (a) BK Lyn is the remnant of the probable nova on 101 December 30, and (b) it has been fading ever since, but it has taken ˜2000 yr for the accretion rate to drop sufficiently to permit dwarf-nova eruptions. If such behaviour is common, it can explain other puzzles of CV evolution. One: why the ER UMa class even exists (because all members can be remnants of recent novae). Two: why ER UMa stars and short-period nova-likes are rare (because their lifetimes, which are essentially cooling times, are short). Three: why short-period novae all decline to luminosity states far above their true quiescence (because they are just getting started in their post-nova cooling). Four: why the orbital periods, accretion rates and white dwarf temperatures of short-period CVs are somewhat too large to arise purely from the effects of gravitational radiation (because the unexpectedly long interval of enhanced post-nova brightness boosts the mean mass-transfer rate). And maybe even five: why very old, post-period-bounce CVs are hard to find (because the higher mass

  9. RZ Leonis Minoris bridging between ER Ursae Majoris-type dwarf nova and nova-like system

    NASA Astrophysics Data System (ADS)

    Kato, Taichi; Ishioka, Ryoko; Isogai, Keisuke; Kimura, Mariko; Imada, Akira; Miller, Ian; Masumoto, Kazunari; Nishino, Hirochika; Kojiguchi, Naoto; Kawabata, Miho; Sakai, Daisuke; Sugiura, Yuki; Furukawa, Hisami; Yamamura, Kenta; Kobayashi, Hiroshi; Matsumoto, Katsura; Wang, Shiang-Yu; Chou, Yi; Ngeow, Chow-Choong; Chen, Wen-Ping; Panwar, Neelam; Lin, Chi-Sheng; Hsiao, Hsiang-Yao; Guo, Jhen-Kuei; Lin, Chien-Cheng; Omarov, Chingis; Kusakin, Anatoly; Krugov, Maxim; Starkey, Donn R.; Pavlenko, Elena P.; Antonyuk, Kirill A.; Sosnjvskij, Aleksei A.; Antonyuk, Oksana I.; Pit, Nikolai V.; Baklanov, Alex V.; Babina, Julia V.; Itoh, Hiroshi; Padovan, Stefano; Akazawa, Hidehiko; Kafka, Stella; de Miguel, Enrique; Pickard, Roger D.; Kiyota, Seiichiro; Shugarov, Sergey Yu.; Chochol, Drahomir; Krushevska, Viktoriia; Sekeráš, Matej; Pikalova, Olga; Sabo, Richard; Dubovsky, Pavol A.; Kudzej, Igor; Ulowetz, Joseph; Dvorak, Shawn; Stone, Geoff; Tordai, Tamás; Dubois, Franky; Logie, Ludwig; Rau, Steve; Vanaverbeke, Siegfried; Vanmunster, Tonny; Oksanen, Arto; Maeda, Yutaka; Kasai, Kiyoshi; Katysheva, Natalia; Morelle, Etienne; Neustroev, Vitaly V.; Sjoberg, George

    2016-12-01

    We observed RZ LMi, which is renowned for its extremely short (˜19 d) supercycle and is a member of a small, unusual class of cataclysmic variables called ER UMa-type dwarf novae, in 2013 and 2016. In 2016, the supercycles of this object substantially lengthened in comparison to the previous measurements to 35, 32, and 60 d for three consecutive superoutbursts. We consider that the object virtually experienced a transition to the nova-like state (permanent superhumper). This observed behavior reproduced the prediction of the thermal-tidal instability model extremely well. We detected a precursor in the 2016 superoutburst and detected growing (stage A) superhumps with a mean period of 0.0602(1) d in 2016 and in 2013. Combined with the period of superhumps immediately after the superoutburst, the mass ratio is not as small as in WZ Sge-type dwarf novae, having orbital periods similar to RZ LMi. By using least absolute shrinkage and selection operator (Lasso) two-dimensional power spectra, we detected possible negative superhumps with a period of 0.05710(1) d. We estimated an orbital period of 0.05792 d, which suggests a mass ratio of 0.105(5). This relatively large mass ratio is even above that of ordinary SU UMa-type dwarf novae, and it is also possible that the exceptionally high mass-transfer rate in RZ LMi may be a result of a stripped secondary with an evolved core in a system evolving toward an AM CVn-type object.

  10. KQ Mon and the nature of the UX Ursa Majoris Nova-like variables

    NASA Technical Reports Server (NTRS)

    Sion, E. M.; Guinan, E. F.

    1983-01-01

    The UX Ursa Majoris stars form a group of nova-like variables with common photometric and spectroscopic properties. These objects appear to be related to the cataclysmic variables. However, there is no information that they have undergone major outbursts. The present investigation is concerned with a new object, KQ Mon, which has been included in a program of study conducted with the IUE satellite. A description of observations of KQ Mon is presented, and the relationship of this star to other UX UMa stars is examined. Attention is given to the nature of the UX Ursa Majoris stars. It is argued that the accretion rates of the UX UMa stars are higher than, for example, the dwarf novae during quiescence and that the higher accretion rates of the UX UMa stars are responsible for their lack of major outbursts.

  11. THE SHAPE OF LONG OUTBURSTS IN U GEM TYPE DWARF NOVAE FROM AAVSO DATA

    SciTech Connect

    Cannizzo, John K.

    2012-10-01

    We search the American Association of Variable Star Observers (AAVSO) archives of the two best-studied dwarf novae in an attempt to find light curves for long outbursts that are extremely well characterized. The systems are U Gem and SS Cyg. Our goal is to search for embedded precursors such as those that have been found recently in the high-fidelity Kepler data for superoutbursts (SOs) of some members of the SU UMa subclass of dwarf novae. For the vast majority of AAVSO data, the combination of low data cadence and large errors associated with individual measurements precludes one from making any strong statement about the shape of the long outbursts. However, for a small number of outbursts, extensive long-term monitoring with digital photometry yields high-fidelity light curves. We report the discovery of embedded precursors in two of three candidate long outbursts. This is the first time that such embedded precursors have been found in dwarf novae above the period gap in other than kepler data, and reinforces van Paradijs' finding that long outbursts in dwarf novae above the period gap and SOs in systems below the period gap constitute a unified class. The thermal-tidal instability to account for SOs in the SU UMa stars predicts embedded precursors only for short orbital period dwarf novae, therefore the presence of embedded precursors in long orbital period systems-U Gem and SS Cyg-argues for a more general mechanism to explain long outbursts.

  12. Ultraviolet studies of nova-like variables with the IUE

    NASA Technical Reports Server (NTRS)

    Guinan, E. F.

    1983-01-01

    KQ Mon is a new UX UMa-type nova-like variable. Optical spectra taken in 1978 reveal very shallow Balmer absorption lines and He I (wavelength 4471) absorption. There was no evidence of orbital variations but the appearance of the optical spectrum and the presence of low amplitude flickering suggested a strong similarity to CD-42 degrees 14462 (=V3885 Sgr) and other members of the UX UMa class. KQ Mon was observed at low dispersion with the IUE satellite. Six spectra taken with the short wavelength prime (SWP) camera are dominated by strong broad absorption lines due to N V, O I, Si III, Si IV, C IV, He II, N IV, and A1 III. There is little evidence of orbital phase modulation over the time baseline of the observations. Unlike UV observations of other UX UMa-type objects, KQ Mon exhibits no emission lines or P Cygni-type profiles and the velocity displacements appear to be smaller, suggesting the absence of a hot, high velocity wind characterizing other UX UMa stars. The relationship of KQ Mon to other UX UMa disk stars is discussed and a model is suggested to explain their observed properties and the lack of major outbursts.

  13. Nova LMC 1990 no. 1: The first extragalactic neon nova

    NASA Technical Reports Server (NTRS)

    Sonneborn, George; Shore, Steven N.; Starrfield, Sumner G.

    1990-01-01

    International Ultraviolet Explorer (IUE) observations of nova LMC (Large Magellanic Cloud) 1990 No. 1, the first neon (or ONeMg) nova observed outside the Galaxy are presented. The observations were obtained from 17 Jan. to Mar. 1990, with especially dense coverage during the first 25 days of the outburst. (The neon nova categorization is based on the detection of forbidden Ne 3-4 lines in optical spectra; the ultraviolet neon lines were not detected.) During the first 30 days of the outburst, the radiative losses were dominated by the N 5 delta 1240 and C 4 delta 1550 lines. The maximum ejection velocity was approximately 8000 km/s, based on the blue absorption edge of the C 4 P-Cygni profile. Early in the outburst of Nova LMC 1990 No. 1 the UV luminosity alone was approximately 3 times 10 to the 38th power erg/sec, implying that the bolometric luminosity was well in excess of the Eddington luminosity for a one solar mass object.

  14. Nova LMC 1990 no. 1: The first extragalactic neon nova

    NASA Technical Reports Server (NTRS)

    Sonneborn, George; Shore, Steven N.; Starrfield, Sumner G.

    1990-01-01

    International Ultraviolet Explorer (IUE) observations of nova LMC (Large Magellanic Cloud) 1990 No. 1, the first neon (or ONeMg) nova observed outside the Galaxy are presented. The observations were obtained from 17 Jan. to Mar. 1990, with especially dense coverage during the first 25 days of the outburst. (The neon nova categorization is based on the detection of forbidden Ne 3-4 lines in optical spectra; the ultraviolet neon lines were not detected.) During the first 30 days of the outburst, the radiative losses were dominated by the N 5 delta 1240 and C 4 delta 1550 lines. The maximum ejection velocity was approximately 8000 km/s, based on the blue absorption edge of the C 4 P-Cygni profile. Early in the outburst of Nova LMC 1990 No. 1 the UV luminosity alone was approximately 3 times 10 to the 38th power erg/sec, implying that the bolometric luminosity was well in excess of the Eddington luminosity for a one solar mass object.

  15. Observations of classical novae in outburst

    NASA Technical Reports Server (NTRS)

    Starrfield, S.; Stryker, L. L.; Sonneborn, G.; Sparks, Warren M.; Ferland, Gary; Wagner, R. M.; Williams, R. E.; Gehrz, Robert D.; Ney, Edward P.; Kenyon, Scott

    1988-01-01

    The IUE obtained ultraviolet data on novae in outburst. The characteristics of every one of the outbursts are different. Optical and infrared data on many of the same novae were also obtained. Three members of the carbon-oxygen class of novae are presented.

  16. Nova Superposed on Yavine Corona

    NASA Image and Video Library

    1998-06-04

    The view from NASA's Magellan spacecraft shows a 100-km-wide nova superposed on Yavine Corona. Coronae are roughly circular, volcanic features believed to form over hot upwellings of magma within the Venusian mantle. http://photojournal.jpl.nasa.gov/catalog/PIA00150

  17. NOVA Fall 1998 Teacher's Guide.

    ERIC Educational Resources Information Center

    Colombo, Luann

    This teacher's guide is designed to accompany the PBS television program "NOVA." Six science activities correspond to: (1) "Lost at Sea: The Search for Longitude,, which researches and charts the shortest course to circumnavigate the globe; (2) "Chasing El Nino," which formulates a question and designs an experiment to…

  18. An observational case against nova hibernation

    NASA Technical Reports Server (NTRS)

    Naylor, T.; Charles, P. A.; Mukai, K.; Evans, A.

    1992-01-01

    We use WHT spectroscopy and imaging to show that nova Vul 1670 (= CK Vul) has been incorrectly identified, and thus its luminosity cannot be used as evidence that novae fade into a 'hibernation' phase within 300 yr of their outbursts. INT spectroscopy is used to correct the magnitude of nova Sge 1783 (= WY Sge) for inclination, this result also implying that novae do not fade significantly. We therefore suggest that, while novae decline in the first 60 yr after outburst, thereafter their luminosity remains constant, and they never undergo a 'hibernation' phase. We show that this idea is consistent with the space density of novae and novalike variables, the outburst interval of SS Cyg and the current luminosities of old novae.

  19. AT Cnc: A SECOND DWARF NOVA WITH A CLASSICAL NOVA SHELL

    SciTech Connect

    Shara, Michael M.; Mizusawa, Trisha; Zurek, David; Wehinger, Peter; Martin, Christopher D.; Neill, James D.; Forster, Karl; Seibert, Mark

    2012-10-20

    We are systematically surveying all known and suspected Z Cam-type dwarf novae for classical nova shells. This survey is motivated by the discovery of the largest known classical nova shell, which surrounds the archetypal dwarf nova Z Camelopardalis. The Z Cam shell demonstrates that at least some dwarf novae must have undergone classical nova eruptions in the past, and that at least some classical novae become dwarf novae long after their nova thermonuclear outbursts, in accord with the hibernation scenario of cataclysmic binaries. Here we report the detection of a fragmented 'shell', 3 arcmin in diameter, surrounding the dwarf nova AT Cancri. This second discovery demonstrates that nova shells surrounding Z Cam-type dwarf novae cannot be very rare. The shell geometry is suggestive of bipolar, conical ejection seen nearly pole-on. A spectrum of the brightest AT Cnc shell knot is similar to that of the ejecta of the classical nova GK Per, and of Z Cam, dominated by [N II] emission. Galaxy Evolution Explorer FUV imagery reveals a similar-sized, FUV-emitting shell. We determine a distance of 460 pc to AT Cnc, and an upper limit to its ejecta mass of {approx}5 Multiplication-Sign 10{sup -5} M {sub Sun }, typical of classical novae.

  20. Far Ultraviolet Spectroscopy of Seven Nova-Like Variables

    NASA Astrophysics Data System (ADS)

    Mizusawa, Trisha; Merritt, Jason; Ballouz, Ronald-Louis; Bonaro, Michael; Foran, Sean; Plumberg, Christopher; Stewart, Heather; Wiley, Trayer; Sion, Edward M.

    2010-03-01

    We present the results of a multicomponent synthetic spectral analysis of the archival far ultraviolet spectra of several key nova-like variables including members of the SW Sex, RW Tri, UX UMa, and VY Scl subclasses: KR Aur, RW Tri, V825 Her, V795 Her, BP Lyn, V425 Cas, and HL Aqr. Accretion rates as well as the possible flux contribution of the accreting white dwarf are included in our analysis. Except for RW Tri, which has a reliable trigonometric parallax, we computed the distances to the nova-like systems using the method of Knigge. Our analysis of seven archival IUE spectra of RW Tri at its parallax distance of 341 pc consistently indicates a low mass (∼0.4 M⊙) white dwarf and an average accretion rate, . For KR Aur, we estimate that the white dwarf has Teff = 29,000 ± 2000 K, log g = 8.4, and contributes 18% of the far-UV flux, while an accretion disk with accretion rate at an inclination of 41° contributes the remainder. We find that an accretion disk dominates the far-UV spectrum of V425 Cas but a white dwarf contributes nonnegligibly with approximately 18% of the far-UV flux. For the two high state nova-likes, HL Aqr and V825 Her, their accretion disks totally dominate with and 3 × 10-9 M⊙ yr-1, respectively. For BP Lyn we find while for V795 Her, we find an accretion rate of . We discuss the implications of our results for the evolutionary status of nova-like variables.

  1. Identifying and quantifying recurrent novae masquerading as classical novae

    SciTech Connect

    Pagnotta, Ashley; Schaefer, Bradley E.

    2014-06-20

    Recurrent novae (RNe) are cataclysmic variables with two or more nova eruptions within a century. Classical novae (CNe) are similar systems with only one such eruption. Many of the so-called CNe are actually RNe for which only one eruption has been discovered. Since RNe are candidate Type Ia supernova progenitors, it is important to know whether there are enough in our Galaxy to provide the supernova rate, and therefore to know how many RNe are masquerading as CNe. To quantify this, we collected all available information on the light curves and spectra of a Galactic, time-limited sample of 237 CNe and the 10 known RNe, as well as exhaustive discovery efficiency records. We recognize RNe as having (1) outburst amplitude smaller than 14.5 – 4.5 × log (t {sub 3}), (2) orbital period >0.6 days, (3) infrared colors of J – H > 0.7 mag and H – K > 0.1 mag, (4) FWHM of Hα > 2000 km s{sup –1}, (5) high excitation lines, such as Fe X or He II near peak, (6) eruption light curves with a plateau, and (7) white dwarf mass greater than 1.2 M {sub ☉}. Using these criteria, we identify V1721 Aql, DE Cir, CP Cru, KT Eri, V838 Her, V2672 Oph, V4160 Sgr, V4643 Sgr, V4739 Sgr, and V477 Sct as strong RN candidates. We evaluate the RN fraction among the known CNe using three methods to get 24% ± 4%, 12% ± 3%, and 35% ± 3%. With roughly a quarter of the 394 known Galactic novae actually being RNe, there should be approximately a hundred such systems masquerading as CNe.

  2. Nova LMC 2005 - Nova in the Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2005-11-01

    AAVSO Alert Notice 330 announces the discovery of a nova in the Large Magellanic Cloud - Nova LMC 2005 - by William Liller (Vina del Mar, Chile) at magnitude 11.5 V (Tech Pan film, unfiltered, using a 0.2-m Schmidt camera) on 2005 November 26.164 UT. Peter Nelson (Ellinbank, Victoria, Australia) forwards the following position measured from a CCD image taken by him on November 27.5833 UT: R.A. = 05h 10m 32.68s (2000.0) Decl. = -69o 12' 35.7" (2000.0).Please note that this position is not the one given by B. Allen in IAU Circular 8635; that position is incorrect. A low-resolution spectrogram taken Nov. 28.28 UT by F. M. Walter (Stony Brook University), A. Pasten (CCTIO), and H. E. Bond (STScI) indicates a classical nova near maximum (IAU Circular 8635, ed. D.W.E. Green). Finder charts with sequence may be created using the AAVSO Variable Star Plotter (https://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details.

  3. Cerebral Aneurysms

    MedlinePlus

    ... cerebral aneurysm may be required to restore deteriorating respiration and reduce abnormally high pressure within the brain. ... cerebral aneurysm may be required to restore deteriorating respiration and reduce abnormally high pressure within the brain. ...

  4. Cerebral Palsy

    MedlinePlus

    ... ol (Spanish) Recommend on Facebook Tweet Share Compartir Cerebral palsy (CP) is a group of disorders that affect ... resource—it highlights the ADDM Network’s data on cerebral palsy in a way that is useful for stakeholders ...

  5. Cerebral Palsy

    MedlinePlus

    Cerebral palsy is a group of disorders that affect a person's ability to move and to maintain balance ... do not get worse over time. People with cerebral palsy may have difficulty walking. They may also have ...

  6. The NOvA Experiment

    NASA Astrophysics Data System (ADS)

    Habig, A.; NOvA Collaboration

    2012-08-01

    NOvA is an off-axis long-baseline neutrino experiment, looking for νe appearance in an upgraded NuMI beam of νμ to search for θ13 acting in subdominant νμ→νe transitions. As an appearance experiment, NOvA might also be sensitive to CP-violating δ and the neutrino mass hierarchy. To maximize sensitivity to the resulting ˜GeV electromagnetic showers, the 14 kton Far Detector is "totally active", comprised of liquid scintillator contained in 15.7 m long extruded PVC cells, with the scintillation light piped out in wavelength shifting fibers then digitized by avalanche photodiodes. Civil construction at the far detector site is underway, and the smaller near detector is being assembled at Fermilab.

  7. Nucleosynthesis and the nova outburst

    SciTech Connect

    Starrfield, S.; Truran, J.W.; Wiescher, M.; Sparks, W.M.

    1995-12-31

    A nova outburst is the consequence of the accretion of hydrogen rich material onto a white dwarf and it can be considered as the largest hydrogen bomb in the Universe. The fuel is supplied by a secondary star in a close binary system while the strong degeneracy of the massive white dwarf acts to contain the gas during the early stages of the explosion. The containment allows the temperature in the nuclear burning region to exceed 10{sup 8}K under all circumstances. As a result a major fraction of CNO nuclei in the envelope are transformed into {beta}{sup +}-unstable nuclei. We discuss the effects of these nuclei on the evolution. Recent observational studies have shown that there are two compositional classes of novae; one which occurs on carbon-oxygen white dwarfs, and a second class that occurs on oxygen-neon-magnesium white dwarfs. In this review we will concentrate on the latter explosions since they produce the most interesting nucleosynthesis. We report both on the results of new observational determinations of nova abundances and, in addition, new hydrodynamic calculations that examine the consequences of the accretion process on 1.0M{sub {circle_dot}}, 1.25M{sub {circle_dot}}, and 1.35M{sub {circle_dot}} white dwarfs. Our results show that novae can produce {sup 22}Na, {sup 26}Al, and other intermediate mass nuclei in interesting amounts. We will present the results of new calculations, done with updated nuclear reaction rates and opacities, which exhibit quantitative differences with respect to published work.

  8. Nucleosynthesis and the nova outburst

    NASA Technical Reports Server (NTRS)

    Starrfield, S.; Truran, J.W.; Wiescher, M.; Sparks, W.M.

    1995-01-01

    A nova outburst is the consequence of the accretion of hydrogen rich material onto a white dwarf and it can be considered as the largest hydrogen bomb in the Universe. The fuel is supplied by a secondary star in a close binary system while the strong degeneracy of the massive white dwarf acts to contain the gas during the early stages of the explosion. The containment allows the temperature in the nuclear burning region to exceed 10(sup 8)K under all circumstances. As a result a major fraction of CNO nuclei in the envelope are transformed into (beta)(sup +)-unstable nuclei. We discuss the effects of these nuclei on the evolution. Recent observational studies have shown that there are two compositional classes of novae; one which occurs on carbon-oxygen white dwarfs, and a second class that occurs on oxygen-neon-magnesium white dwarfs. In this review we will concentrate on the latter explosions since they produce the most interesting nucleosynthesis. We report both on the results of new observational determinations of nova abundances and, in addition, new hydrodynamic calculations that examine the consequences of the accretion process on 1.0M(sub (circle dot)), 1.25M(sub (circle dot)), and 1.35M(sub (circle dot)) white dwarfs. Our results show that novae can produce (sup 22)Na, (sup 26)Al, and other intermediate mass nuclei in interesting amounts. We will present the results of new calculations, done with updated nuclear reaction rates and opacities, which exhibit quantitative differences with respect to published work.

  9. Nucleosynthesis and the nova outburst

    NASA Technical Reports Server (NTRS)

    Starrfield, S.; Truran, J.W.; Wiescher, M.; Sparks, W.M.

    1995-01-01

    A nova outburst is the consequence of the accretion of hydrogen rich material onto a white dwarf and it can be considered as the largest hydrogen bomb in the Universe. The fuel is supplied by a secondary star in a close binary system while the strong degeneracy of the massive white dwarf acts to contain the gas during the early stages of the explosion. The containment allows the temperature in the nuclear burning region to exceed 10(sup 8)K under all circumstances. As a result a major fraction of CNO nuclei in the envelope are transformed into (beta)(sup +)-unstable nuclei. We discuss the effects of these nuclei on the evolution. Recent observational studies have shown that there are two compositional classes of novae; one which occurs on carbon-oxygen white dwarfs, and a second class that occurs on oxygen-neon-magnesium white dwarfs. In this review we will concentrate on the latter explosions since they produce the most interesting nucleosynthesis. We report both on the results of new observational determinations of nova abundances and, in addition, new hydrodynamic calculations that examine the consequences of the accretion process on 1.0M(sub (circle dot)), 1.25M(sub (circle dot)), and 1.35M(sub (circle dot)) white dwarfs. Our results show that novae can produce (sup 22)Na, (sup 26)Al, and other intermediate mass nuclei in interesting amounts. We will present the results of new calculations, done with updated nuclear reaction rates and opacities, which exhibit quantitative differences with respect to published work.

  10. The Shape of Long Outbursts in U Gem Type Dwarf Novae from AAVSO Data

    NASA Technical Reports Server (NTRS)

    Cannizzo, John K.

    2012-01-01

    We search the American Association of Variable Star Observers (AAVSO) archives of the two best studied dwarf novae in an attempt to find light curves for long out bursts that are extremely well-characterized. The systems are U Gem and S8 Cyg. Our goal is to search for embedded precursors such as those that have been found recently in the high fidelity Kepler data for superoutbursts of some members of the 8U UMa subclass of dwarf novae. For the vast majority of AAV80 data, the combination of low data cadence and large errors associated with individual measurements precludes one from making any strong statement about the shape of the long outbursts. However, for a small number of outbursts, extensive long term monitoring with digital photometry yields high fidelity light curves. We report the finding of embedded precursors in two of three candidate long outbursts. This reinforces van Paradijs' finding that long outbursts in dwarf novae above the period gap and superoutbursts in systems below the period gap constitute a unified class. The thermal-tidal instability to account for superoutbursts in the SU UMa stars predicts embedded precursors only for short orbital period dwarf novae, therefore the presence of embedded precursors in long orbital period systems - U Gem and SS Cyg - argues for a more general mechanism to explain long outbursts.

  11. The NOvA Data Acquisition System

    NASA Astrophysics Data System (ADS)

    Norman, A.

    2012-12-01

    The NOvA experiment is a long baseline neutrino experiment designed to make key measures to determine the neutrino mass hierarchy, neutrino mixing and CP violation in the neutrino sector. In order to make these measurements the NOvA collaboration has designed a highly distributed, synchronized, continuous digitization and readout system that is able to acquire and correlate data from the Fermilab accelerator complex, the NOvA near detector at Fermilab and the NOvA far detector which is located 810 km away at Ash River, MN. This system has unique properties that let it fully exploit the physics capabilities of the NOvA detector. This paper discusses the design of the NOvA DAQ system and its capabilities.

  12. NUCLEAR THERMOMETERS FOR CLASSICAL NOVAE

    SciTech Connect

    Downen, Lori N.; Iliadis, Christian; Jose, Jordi; Starrfield, Sumner

    2013-01-10

    Classical novae are stellar explosions occurring in binary systems, consisting of a white dwarf and a main-sequence companion. Thermonuclear runaways on the surface of massive white dwarfs, consisting of oxygen and neon, are believed to reach peak temperatures of several hundred million kelvin. These temperatures are strongly correlated with the underlying white dwarf mass. The observational counterparts of such models are likely associated with outbursts that show strong spectral lines of neon in their shells (neon novae). The goals of this work are to investigate how useful elemental abundances are for constraining the peak temperatures achieved during these outbursts and determine how robust 'nova thermometers' are with respect to uncertain nuclear physics input. We present updated observed abundances in neon novae and perform a series of hydrodynamic simulations for several white dwarf masses. We find that the most useful thermometers, N/O, N/Al, O/S, S/Al, O/Na, Na/Al, O/P, and P/Al, are those with the steepest monotonic dependence on peak temperature. The sensitivity of these thermometers to thermonuclear reaction rate variations is explored using post-processing nucleosynthesis simulations. The ratios N/O, N/Al, O/Na, and Na/Al are robust, meaning they are minimally affected by uncertain rates. However, their dependence on peak temperature is relatively weak. The ratios O/S, S/Al, O/P, and P/Al reveal strong dependences on temperature and the poorly known {sup 30}P(p, {gamma}){sup 31}S rate. We compare our model predictions to neon nova observations and obtain the following estimates for the underlying white dwarf masses: 1.34-1.35 M {sub Sun} (V838 Her), 1.18-1.21 M {sub Sun} (V382 Vel), {<=}1.3 M {sub Sun} (V693 CrA), {<=}1.2 M {sub Sun} (LMC 1990 no. 1), and {<=}1.2 M {sub Sun} (QU Vul).

  13. Observations of classical novae in outburst

    SciTech Connect

    Starrfield, S.; Stryker, L.L.; Sonneborn, G.; Sparks, W.M.; Ferland, G.; Wagner, R.M.; Williams, R.E.; Gehrz, R.D.; Ney, E.P.; Kenyon, S.

    1988-01-01

    Over the past 10 years the IUE Satellite has obtained ultraviolet data on a number of novae in outbursts and the characteristics of every one of the outbursts have been different. In addition, our group has also obtained optical and infrared data on many of the same novae. In this paper we present the data on three members of the carbon-oxygen class of novae. 6 refs., 5 figs.

  14. Searching for nova shells around cataclysmic variables

    NASA Astrophysics Data System (ADS)

    Sahman, D. I.; Dhillon, V. S.; Knigge, C.; Marsh, T. R.

    2015-08-01

    We present the results of a search for nova shells around 101 cataclysmic variables (CVs), using H α images taken with the 4.2-m William Herschel Telescope (WHT) and the 2.5-m Isaac Newton Telescope Photometric H α Survey of the Northern Galactic Plane (IPHAS). Both telescopes are located on La Palma. We concentrated our WHT search on nova-like variables, whilst our IPHAS search covered all CVs in the IPHAS footprint. We found one shell out of the 24 nova-like variables we examined. The newly discovered shell is around V1315 Aql and has a radius of ˜2.5 arcmin, indicative of a nova eruption approximately 120 yr ago. This result is consistent with the idea that the high mass-transfer rate exhibited by nova-like variables is due to enhanced irradiation of the secondary by the hot white dwarf following a recent nova eruption. The implications of our observations for the lifetime of the nova-like variable phase are discussed. We also examined four asynchronous polars, but found no new shells around any of them, so we are unable to confirm that a recent nova eruption is the cause of the asynchronicity in the white dwarf spin. We find tentative evidence of a faint shell around the dwarf nova V1363 Cyg. In addition, we find evidence for a light echo around the nova V2275 Cyg, which erupted in 2001, indicative of an earlier nova eruption ˜300 yr ago, making V2275 Cyg a possible recurrent nova.

  15. TOPICAL REVIEW: Nucleosynthesis in classical nova explosions

    NASA Astrophysics Data System (ADS)

    José, Jordi; Hernanz, Margarita

    2007-12-01

    Classical novae are fascinating stellar explosions at the crossroads of stellar astrophysics, nuclear physics, and cosmochemistry. In this review, we briefly summarize 30 years of nucleosynthesis studies, with special emphasis on recent advances in nova theory (including multidimensional models) as well as on experimental efforts to reduce nuclear uncertainties affecting critical reaction rates. Among the topics that are covered, we outline the interplay between nova outbursts and the galactic chemical abundances, the synthesis of radioactive nuclei of interest for γ-ray astronomy, such as 7Li, 22Na or 26Al, and the potential discovery of presolar meteoritic grains likely condensed in nova shells.

  16. Global Galactic Distribution of Classical Novae

    NASA Astrophysics Data System (ADS)

    Iyudin, A. F.; Schönfelder, V.; Bennett, K.; Diehl, R.; Hermsen, W.; Lichti, G. G.; Ryan, J.

    2002-11-01

    Classical novae are considered to be the major source of the ISM enrichment with the isotopes of 13C, 15N, and 22Na. The latter, radioactive 22Na, that decays producing penetrating 1.275 MeV γ-ray photon, could be very useful as a probe of the galactic global distribution of novae. It is expected that the accumulation of 22Na from the frequent novae in the bulge will lead to an observable extended emission. Additionally, a 22Na detection from the single nova can be used to verify predictions of the modern thermonuclear runaway theory (TNR) applied to classical novae. To gain a better insight into this problem we have used a two-way approach. Namely: (1) - we have studied the global galactic distribution of the 1.275 MeV γ-ray line emission assuming that it is mostly originates from decay of the novae-produced 22Na; and (2) - we pursued the 22Na line emission detection from recent individual novae. The combination of both approaches makes possible to tap rather uncertain galactic novae rate by comparing observations of the individual Galactic novae with the integrated 22Na line emission from the disk and/or bulge population. The COMPTEL telescope on board the Compton Gamma-Ray Observatory (CGRO), due to its combination of imaging and spectroscopic capabilities, is suitable to address the above ideas.

  17. Identification of Recurrent Novae in M31

    NASA Astrophysics Data System (ADS)

    Shafter, Allen W.; Rector, T. A.; Schweizer, F.; Bryan, J.

    2014-01-01

    Over roughly the past century a total of more than 900 optical transient events have been recorded in M31, the vast majority of which are believed to represent eruptions of classical novae. The impressive dataset of nova positions put together by Pietsch (http://www.mpe.mpg.de m31novae/opt/m31/) provides the opportunity to search for multiple nova outbursts from the same progenitor system, and thus to characterize the population of recurrent novae (RNe) in M31. In order to identify RNe candidates, we have searched for spatial near coincidences among the 945 recorded novae given in the Pietsch catalog through the end of August 2013. Given that the positions of many of the early novae are quite uncertain, we have set our initial screen to include nova pairs with nominal separations less than or equal to 6 arcsec. We have identified a total of 102 novae that pass this coarse screen. Of these, 78 novae form 39 pairs, 15 form five triples, four novae are part of a quad, and five novae form a quint. As demonstrated by Shafter, Rice and Daub (2009, presented at the "Wild Stars in the Old West II" conference, mintaka.sdsu.edu/faculty/shafter/extragalactic_novae/RNePoster4.pdf), the majority of the 102 novae surviving our initial screen are expected to be associated with chance positional near coincidences (especially near the nucleus), and are not RNe. To decide which candidates are indeed RNe, we have undertaken a study to locate the original discovery plates, CCD images or published finding charts, and to perform the necessary astrometry to identify which of our candidate RNe are chance positional coincidences, and which are RNe. For each candidate, we estimate the probability that the object is a chance positional coincidence as in Shafter et al. (2009). To date, we have been successful in identifying finding charts or original images for most of the candidates, and have found a total of 23 nova outbursts in M31 associated with 10 systems that are almost certainly RNe.

  18. Simulating Thermonuclear Runaway in Novae

    NASA Astrophysics Data System (ADS)

    Dursi, L. J.; Truran, J.; Zingale, M.; Calder, A. C.; Fryxell, B.; Olson, K.; Ricker, P.; Rosner, R.; Timmes, F. X.; Tufo, H. M.; MacNeice, P.

    2000-12-01

    A nova is a thought to result from a partially degenerate thermonuclear runaway on the surface of a white dwarf. Material from the underlying white dwarf must be dredged up into the atmosphere in order to produce an explosion with the observed energies; the carbon and oxygen serve as catalysts for the hydrogen burning, allowing the much more temperature-sensitive CNO burning to occur. In order to understand this dredge-up problem, we are running two different types of simulations. The first are large-scale simulations with the FLASH code (Fryxell et al., 2000), using a one-dimensional set of initial conditions of a nova about to undergo runaway created by Ami Glasner. These initial conditions have been used in previous multidimensional simulations (Glasner et al. 1997; Kercek et al. 1998), but these simulations have given widely different results because of different mixing behaviors in the two codes. Our set of simulations will shed some light on this discrepancy; since our code has adaptive mesh refinement (MacNeice et al., 2000), we can afford to highly refine the region of the star where the mixing occurs, without the cost of highly refining the entire region. Because these large-scale computations are extremely compute-intensive, they are not appropriate for broad exploration of initial conditions. To do this, we use a One-Dimensional Turbulence (ODT) model which has been used in astrophysical models previously (Niemeyer & Kerstein, 1997). This allows us to use ODT simulations of the nova as experiments to guide us to interesting regimes to study further with multidimensional FLASH code simulations. This work was supported in part by the Department of Energy Grant No. B341495 to the Center for Astrophysical Thermonuclear Flashes at the University of Chicago under the ASCI Strategic Alliances Program and by NASA/Goddard Space Flight Center

  19. Predicting a Luminous Red Nova

    NASA Astrophysics Data System (ADS)

    Van Noord, Daniel; Molnar, Larry; Kinemuchi, Karen; Steenwyk, Steven; Alexander, Cara; Spedden, Chris; Kobulnicky, Henry

    2016-05-01

    Luminous Red Novae (LRN) are rare transient events believed to be caused by the merger of a main sequence contact binary. Since the discovery of the prototype, V838 Mon, only a handful of LRN events have been observed. Tylenda et al. (2011) analyzed the OGLE data preceding the 2008 Novae of V1309 Sco and found that it exhibited a similar light curve to that of a contact binary with one interesting exception, the orbital period of V1309 Sco showed exponential period change going to zero. Unfortunately the system was discovered to be a binary after the merger, preventing any targeted observations to narrow down how the system entered this unusual state. However the extreme period change observed in V1309 Sco gives us a signature to look for in other contact binaries, allowing the discovery of merger candidates for follow up. We will present an analysis of light curves and spectra of KIC 9832227 (NSVS 5597755) that show it is a contact binary system with a negative period derivative that is becoming more extreme with time. These data span more than 15 years and are taken from the NSVS, ASAS, WASP, and Kepler surveys, with ongoing measurements from the Calvin College Observatory and the Apache Point Observatory. The ongoing period change observed in the system is consistent with the exponential model fit from V1309 Sco and the rate of period change has surpassed that of all other measured contact binaries with the exception of V1309 Sco. If the exponential period decay continues the system will likely merge between 2019 and 2022 resulting in a naked eye nova. If this event occurs, this star will present the unprecedented opportunity to study a LRN progenitor and to follow the evolution of the merger.

  20. Spectroscopy and photometry of the dwarf nova BZ Ursae Majoris and the CV linewidth/K, mass-ratio relation

    NASA Technical Reports Server (NTRS)

    Jurcevic, J. S.; Honeycutt, R. K.; Schlegel, E. M.; Webbink, R. F.

    1994-01-01

    Time-resolved spectroscopy of the dwarf nova BZ Ursae Majoris (BZ UMa) reveals periodic velocity variations in the hydrogen emission lines with P = 97.9 +/- 0.1 min and K = 73 +/- 6 km/s. CCD photometry over a 16-month interval shows three outbursts of about 4 mag with a mean separation of 181 days. The mean full width at half maximum (FWHM) for the hydrogen beta emission is large, prompting a recalibration of the FWHM/K vs. mass ratio relation, giving a mass ratio (M(sub RD)/M(sub WD)) of 0.20 for BZ UMa. The short period, long outburst interval, and small mass ratio support the suggestion of BZ UMa being in the SU Ursae Majoris subclass of dwarf novae.

  1. Novae a theoretical and observational study

    NASA Astrophysics Data System (ADS)

    Soraisam, Monika D.

    2016-02-01

    In this thesis, we present studies relating to novae that include both theoretical and ob- servational aspects. Being hosted by accreting white dwarfs (WDs), they have drawn attention in the context of the supernova Ia (SN Ia) progenitor problem. In the case of the nova explosion, the WD host is not disrupted. Instead, it continues to supply energy, even after the optical outbust, via stable nuclear burning of the remnant hydrogen envelope that survived the outburst. Accordingly, nova emission progresses toward the harder part of the electromagnetic spectrum, where it lasts longer than in the optical regime. As a consequence, novae are found to constitute the majority of the observed supersoft X-ray sources (SSSs). This is particularly well established for the galaxy M31. For high mass accretion rates in the unstable nuclear burning regime (or nova regime), there is evidence that significant mass accumulation by the WD is possible. This paved the way for SN Ia progenitor models in the single degenerate (SD) scenario involving novae. Based on the statistics of novae in M31, which is the most frequently used target for nova surveys, we investigate the role that novae may play in producing SNe Ia. Using multicycle nova evolution models and the observationally inferred nova rate in M31, we estimate the maximal SN Ia rate that novae can produce, assuming that all of the involved WDs reach the Chandrasekhar mass. Comparing this rate to the observationally inferred SN Ia rate for M31 constrains the contribution of the nova channel to the SN Ia rate to 2-7%. Additionally, we demonstrate that a more powerful diagnostic can be obtained from statistics of fast novae, which are characterized by decline times t2 10 days. Most novae resulting from a typical SD SN Ia progenitor accreting in the nova regime are fast. Specifically, as the WD in the nova grows in mass, it produces novae more frequently and with decreasing decline times. We therefore investigate how efficiently fast

  2. Nova pulse power design and operational experience

    SciTech Connect

    Whitham, K.; Larson, D.; Merritt, B.; Christie, D.

    1987-01-01

    Nova is a 100 TW Nd/sup + +/ solid state laser designed for experiments with laser fusion at Lawrence Livermore National Laboratory (LLNL). The pulsed power for Nova includes a 58 MJ capacitor bank driving 5336 flashlamps with millisecond pulses and subnanosecond high voltages for electro optics. This paper summarizes the pulsed power designs and the operational experience to date.

  3. Nova pulse power design and operational experience

    NASA Astrophysics Data System (ADS)

    Whitham, K.; Larson, D.; Merritt, B.; Christie, D.

    1987-01-01

    Nova is a 100 TW Nd++ solid state laser designed for experiments with laser fusion at Lawrence Livermore National Laboratory (LLNL). The pulsed power for Nova includes a 58 MJ capacitor bank driving 5336 flashlamps with millisecond pulses and subnanosecond high voltages for electro optics. This paper summarizes the pulsed power designs and the operational experience to date.

  4. Spectroscopy of novae -- a user's manual

    NASA Astrophysics Data System (ADS)

    Shore, Steven N.

    2012-09-01

    The spectroscopic development of classical novae is described as a narrative of the various stages of the outburst. The review highlights the multiwavelength aspects of the phenomenology and the recent developments related to structure, inhomogeneity, and dynamics of the ejecta. Special emphasis is placed on the distinct behavior of the symbiotic-like recurrent novae.

  5. Shear mixing in classical Novae

    NASA Astrophysics Data System (ADS)

    Alexakis, A.; Calder, A. C.; Dursi, L. J.; Times, F. X.; Truran, J. W.; Rosner, R.; Lamb, D. M.; Mignone, A.; Fryxel, B.; Zingale, M.; Olson, K.; Ricker, P.

    2003-03-01

    The mixing of white dwarf material with the accretion envelope in classical novae scenarios is essential for the later evolution and the outburst. One of the plausible mechanisms for the enrichment involves the coupling of large scale flows like convection or accretion with the breaking interfacial waves at the white dwarf surface. We examine how the interaction of accretion wind with a white dwarf surface can lead to a substantial C/O enrichment that can power a novae. We use the FLASH code to perform two and three dimensional simulations of wind driven gravity waves and investigate their growth and non-linear development for a variety of wind profiles. Our results show that even weak winds generate gravity waves through a resonant mechanism with the wind that grow nonlinear and break leading to spray formation and mixing. The total amount of white dwarf material mixed at late times, is shown to be proportional to the square of the maximum wind velocity, inversely proportional to gravity and independent of the functional form of the wind profile. This work has been supported by the DOE ASCI/Alliances program at the University of Chicago under grant No. B341495.

  6. Terra Nova Bay Polynya, Antarctica

    NASA Technical Reports Server (NTRS)

    2007-01-01

    In Terra Nova Bay, off the Scott Coast of Victoria Land, Antarctica, a large pocket of open water persists throughout most of the Southern Hemisphere winter, even while most of the rest of the Antarctic coastline is firmly embraced by the frozen Southern Ocean. This pocket of open water--a polynya--results from exceptionally strong winds that blow downslope from the Trans-Antarctic Mountains. These fierce katabatic winds drive the sea ice eastward. Since the dominant ice drift pattern in the area is northward, the Drygalski Ice Tongue prevents the bay from being re-populated with sea ice. This image of the Terra Nova Bay polynya was captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite on October 16, 2007. Sea ice sits over the Ross Sea like a cracked and crumbling windshield. Blue-tinged glaciers flow down from the Trans-Antarctic Mountains. Although glaciers can appear blue because of melt water, they can also get that tint when the wind scours and polishes the ice surface. Given the strength of the katabatic winds along this part of the Antarctic coast, it is likely that the blue color of these glaciers is a result of their having been swept clean of snow. The large image has a spatial resolution (level of detail) of 250 meters per pixel.

  7. Terra Nova Bay Polynya, Antarctica

    NASA Technical Reports Server (NTRS)

    2007-01-01

    In Terra Nova Bay, off the Scott Coast of Victoria Land, Antarctica, a large pocket of open water persists throughout most of the Southern Hemisphere winter, even while most of the rest of the Antarctic coastline is firmly embraced by the frozen Southern Ocean. This pocket of open water--a polynya--results from exceptionally strong winds that blow downslope from the Trans-Antarctic Mountains. These fierce katabatic winds drive the sea ice eastward. Since the dominant ice drift pattern in the area is northward, the Drygalski Ice Tongue prevents the bay from being re-populated with sea ice. This image of the Terra Nova Bay polynya was captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite on October 16, 2007. Sea ice sits over the Ross Sea like a cracked and crumbling windshield. Blue-tinged glaciers flow down from the Trans-Antarctic Mountains. Although glaciers can appear blue because of melt water, they can also get that tint when the wind scours and polishes the ice surface. Given the strength of the katabatic winds along this part of the Antarctic coast, it is likely that the blue color of these glaciers is a result of their having been swept clean of snow. The large image has a spatial resolution (level of detail) of 250 meters per pixel.

  8. BVRJK observations of Northern Hemisphere old novae

    NASA Technical Reports Server (NTRS)

    Szkody, Paula

    1994-01-01

    BVR photometry has been accomplished for 65 objects in the Duerbeck atlas along with J photometry of 52 and K of 30 objects. The (B - V), (V - R), and (V - J) colors are compiled with those available in the literature to assess the color change of novae as a function of time since outburst. Using available reddening values results in a list of 42 (B - V), 28 (V - R), and 38 (V - J) dereddened colors for novae that are from 1 to 319 years past outburst. The results indicate all the colors cluster about zero, with no obvious transition to red values as would be expected for novae undergoing a hibernation scenario. This indicates the accretion disk is sustained for at least 200 years after outburst. It is also apparent that red novae with giant secondaries and/or unusual properties readily stand out from the normal novae in color.

  9. ON THE PROGENITORS OF GALACTIC NOVAE

    SciTech Connect

    Darnley, M. J.; Bode, M. F.; Hounsell, R. A.; Ribeiro, V. A. R. M.; Williams, R. P.

    2012-02-10

    Of the approximately 400 known Galactic classical novae, only 10 of them, the recurrent novae, have been seen to erupt more than once. At least eight of these recurrents are known to harbor evolved secondary stars, rather than the main-sequence secondaries typical in classical novae. In this paper, we propose a new nova classification system, based solely on the evolutionary state of the secondary and not (like the current schemes) based on the properties of the outbursts. Using archival optical and near-infrared photometric observations of a sample of 38 quiescent Galactic novae we show that the evolutionary state of the secondary star in a quiescent system can be predicted and several objects are identified for follow-up observations: CI Aql, V2487 Oph, DI Lac, and EU Sct.

  10. Nova laser assurance-management system

    SciTech Connect

    Levy, A.J.

    1983-07-18

    In a well managed project, Quality Assurance is an integral part of the management activities performed on a daily basis. Management assures successful performance within budget and on schedule by using all the good business, scientific, engineering, quality assurance, and safety practices available. Quality assurance and safety practices employed on Nova are put in perspective by integrating them into the overall function of good project management. The Nova assurance management system was developed using the quality assurance (QA) approach first implemented at LLNL in early 1978. The LLNL QA program is described as an introduction to the Nova assurance management system. The Nova system is described pictorially through the Nova configuration, subsystems and major components, interjecting the QA techniques which are being pragmatically used to assure the successful completion of the project.

  11. BZ UMa and Var Her 04: Orphan TOADS

    NASA Astrophysics Data System (ADS)

    Price, A.; Howell, S.

    2005-05-01

    Both BZ UMa and Var Her 04 are cataclysmic variable stars without a home. Neither fit easily into current classification systems so may extend the population distribution of two unique CV types: UGWZ dwarf novae and intermediate polars. New outburst photometry and archival X-Ray data shed some new light on BZ UMa's high energy state and new spectral and IR observations from Spitzer of dust around the newly discovered cataclysmic variable Var Her 04 may help find it a home as well.

  12. One Thousand New Dwarf Novae from the OGLE Survey

    NASA Astrophysics Data System (ADS)

    Mróz, P.; Udalski, A.; Poleski, R.; Pietrukowicz, P.; Szymański, M. K.; Soszyński, I.; Wyrzykowski, Ł.; Ulaczyk, K.; Kozłowski, S.; Skowron, J.

    2015-12-01

    We present one of the largest collections of dwarf novae (DNe) containing 1091 objects that have been discovered in the long-term photometric data from the Optical Gravitational Lensing Experiment (OGLE) survey. They were found in the OGLE fields toward the Galactic bulge and the Magellanic Clouds. We analyze basic photometric properties of all systems and tentatively find a population of DNe from the Galactic bulge. We identify several dozen of WZ Sge-type DN candidates, including two with superhump periods longer than 0.09 d. Other interesting objects include SU UMa-type stars with "early" precursor outbursts or a Z Cam-type star showing outbursts during standstills. We also provide a list of DNe which will be observed during the K2 Campaign 9 microlensing experiment in 2016. Finally, we present the new OGLE-IV real-time data analysis system: CVOM, which has been designed to provide continuous real time photometric monitoring of selected CVs.

  13. Cerebral malaria

    PubMed Central

    Rénia, Laurent; Wu Howland, Shanshan; Claser, Carla; Charlotte Gruner, Anne; Suwanarusk, Rossarin; Hui Teo, Teck; Russell, Bruce; Ng, Lisa

    2012-01-01

    Cerebral malaria is the most severe pathology caused by the malaria parasite, Plasmodium falciparum. The pathogenic mechanisms leading to cerebral malaria are still poorly defined as studies have been hampered by limited accessibility to human tissues. Nevertheless, histopathology of post-mortem human tissues and mouse models of cerebral malaria have indicated involvement of the blood-brain barrier in cerebral malaria. In contrast to viruses and bacteria, malaria parasites do not infiltrate and infect the brain parenchyma. Instead, rupture of the blood-brain barrier occurs and may lead to hemorrhages resulting in neurological alterations. Here, we review the most recent findings from human studies and mouse models on the interactions of malaria parasites and the blood-brain barrier, shedding light on the pathogenesis of cerebral malaria, which may provide directions for possible interventions. PMID:22460644

  14. The NOvA Technical Design Report

    SciTech Connect

    Ayres, D.S.; Drake, G.R.; Goodman, M.C.; Grudzinski, J.J.; Guarino, V.J.; Talaga, R.L.; Zhao, A.; Stamoulis, P.; Stiliaris, E.; Tzanakos, G.; Zois, M.; /Athens U. /Caltech /UCLA /Fermilab /College de France /Harvard U. /Indiana U. /Lebedev Inst. /Michigan State U. /Minnesota U., Duluth /Minnesota U.

    2007-10-08

    Technical Design Report (TDR) describes the preliminary design of the NOvA accelerator upgrades, NOvA detectors, detector halls and detector sites. Compared to the March 2006 and November 2006 NOvA Conceptual Design Reports (CDR), critical value engineering studies have been completed and the alternatives still active in the CDR have been narrowed to achieve a preliminary technical design ready for a Critical Decision 2 review. Many aspects of NOvA described this TDR are complete to a level far beyond a preliminary design. In particular, the access road to the NOvA Far Detector site in Minnesota has an advanced technical design at a level appropriate for a Critical Decision 3a review. Several components of the accelerator upgrade and new neutrino detectors also have advanced technical designs appropriate for a Critical Decision 3a review. Chapter 1 is an Executive Summary with a short description of the NOvA project. Chapter 2 describes how the Fermilab NuMI beam will provide a narrow band beam of neutrinos for NOvA. Chapter 3 gives an updated overview of the scientific basis for the NOvA experiment, focusing on the primary goal to extend the search for {nu}{sub {mu}} {yields} {nu}{sub e} oscillations and measure the sin{sup 2}(2{theta}{sub 13}) parameter. This parameter has not been measured in any previous experiment and NOvA would extend the search by about an order of magnitude beyond the current limit. A secondary goal is to measure the dominant mode oscillation parameters, sin{sup 2}(2{theta}{sub 23}) and {Delta}m{sub 32}{sup 2} to a more precise level than previous experiments. Additional physics goals for NOvA are also discussed. Chapter 4 describes the Scientific Design Criteria which the Fermilab accelerator complex, NOvA detectors and NOvA detector sites must satisfy to meet the physics goals discussed in Chapter 3. Chapter 5 is an overview of the NOvA project. The changes in the design relative to the NOvA CDR are discussed. Chapter 6 summarizes the NOvA

  15. Circumstellar Dust in Symbiotic Novae

    NASA Astrophysics Data System (ADS)

    Jurkic, T.; Kotnik-Karuza, D.

    2015-12-01

    We present a model of inner dust regions around the cool Mira component of the two symbiotic novae, RR Tel and HM Sge, based on the near-IR photometry, ISO spectra and mid-IR interferometry. The dust properties were determined using the DUSTY code. A compact circumstellar silicate dust shell with inner dust shell temperatures between 900 K and 1300 K and of moderate optical depth can explain all the observations. RR Tel shows the presence of an equatorially enhanced dust density during minimum obscuration. Obscuration events are explained by an increase in optical depth caused by the newly condensed dust. The mass loss rates are significantly higher than in intermediate-period single Miras but in agreement with longer-period O-rich AGB stars.

  16. Nova laser alignment control system

    SciTech Connect

    Van Arsdall, P.J.; Holloway, F.W.; McGuigan, D.L.; Shelton, R.T.

    1984-03-29

    Alignment of the Nova laser requires control of hundreds of optical components in the ten beam paths. Extensive application of computer technology makes daily alignment practical. The control system is designed in a manner which provides both centralized and local manual operator controls integrated with automatic closed loop alignment. Menudriven operator consoles using high resolution color graphics displays overlaid with transport touch panels allow laser personnel to interact efficiently with the computer system. Automatic alignment is accomplished by using image analysis techniques to determine beam references points from video images acquired along the laser chain. A major goal of the design is to contribute substantially to rapid experimental turnaround and consistent alignment results. This paper describes the computer-based control structure and the software methods developed for aligning this large laser system.

  17. The INES Guide for Classical Novae

    NASA Astrophysics Data System (ADS)

    González-Riestra, R.; Cassatella, A.

    2002-11-01

    IUE ULDA/INES Access Guides have been published by ESA since 1989 with the purpose of facilitating the use of IUE data to scientists interested in a specific class of astronomical objects. We present here the ``INES Guide for Classical Novae'', in which we shall collect all the available IUE data for a total of 36 novae in outburst and 20 old novae. The Guide will include basic information about each object, observing logs, visual light curves, and representative high and low dispersion spectra.

  18. Nova V2214 Ophiuchi 1988 - A magnetic nova inside the period gap

    NASA Technical Reports Server (NTRS)

    Baptista, R.; Jablonski, F. J.; Cieslinski, D.; Steiner, J. E.

    1993-01-01

    The discovery of a coherent photometric modulation in Nova Oph 1988 with period 0.117515 +/- 0.000002 d, which is associated with the orbital period of the underlying binary, is reported. On the basis of photometric observations, it is concluded that Nova V2214 Oph 1988 is a magnetic nova with an orbital period inside the period gap. The inclusion of this system in the statistics of novae suggests that there is no period gap for novae and that there is a clear correlation between the occurrence of novae with short orbital periods and the presence of magnetic white dwarfs. It is suggested that funneling of the accretion flow onto the magnetic poles favors the conditions for a thermonuclear runaway, increasing the frequency of eruptions for magnetic systems.

  19. Recent progress in understanding the eruptions of classical novae

    SciTech Connect

    Shara, M.M.

    1989-01-01

    The physical processes generating nova eruptions are reviewed, along with the effects on nova eruptions of binary-system parameters such as the chemical composition or mass of the white dwarf and the mass accretion rate. Also considered are the possible metamorphosis from dwarf to classical novae and back again, X-ray and gamma-ray emission from novae, and the characteristics and distributions of novae in globular clusters and extragalactic systems. Limitations of the thermonuclear runaway model are discussed. 159 references.

  20. CCD observations of old nova fields

    NASA Technical Reports Server (NTRS)

    Downes, Ronald A.; Szkody, Paula

    1989-01-01

    The discovery of CK Vulpeculae (Nova 1670) has prompted a major review of ideas concerning the long-term development of novae. Unfortunately, there are very few recovered novae old enough to provide confirmation (or rejection) of the new 'hibernation' scenario. CCD images of seven old nova fields, and R band photometry for four fields, have been obtained in an attempt to recover these objects in quiescence. A strong candidate for U Leonis, and a possible counterpart for T Bootis, are found. For three other fields, weak candidates have been found. Finding charts and colors are presented for the seven fields observed. The R light curves of U Leo, indicating an orbital period of 192.5 or 385.0 min, are shown.

  1. CCD observations of old nova fields

    SciTech Connect

    Downes, R.A.; Szkody, P.; Washington Uni., Seattle )

    1989-06-01

    The discovery of CK Vulpeculae (Nova 1670) has prompted a major review of ideas concerning the long-term development of novae. Unfortunately, there are very few recovered novae old enough to provide confirmation (or rejection) of the new hibernation scenario. CCD images of seven old nova fields, and R band photometry for four fields, have been obtained in an attempt to recover these objects in quiescence. A strong candidate for U Leonis, and a possible counterpart for T Bootis, are found. For three other fields, weak candidates have been found. Finding charts and colors are presented for the seven fields observed. The R light curves of U Leo, indicating an orbital period of 192.5 or 385.0 min, are shown. 14 refs.

  2. Old Novae and the SW Sextantis Phenomenon

    NASA Astrophysics Data System (ADS)

    Schmidtobreick, L.; Tappert, C.

    2014-12-01

    From a large observing campaign, we found that nearly all non- or weakly magnetic cataclysmic variables (CVs) in the orbital period range between 2.8 and 4 hours are of SW Sex type and as such experience very high mass transfer rates. The exceptions seem to be some old novae that have periods around 3.5 h. Their spectra do not show the typical SW Sex characteristics but rather resemble those of dwarf novae with low mass transfer rates. The presence of old novae in this period range of SW Sex stars that do not follow the trend but show instead rather low mass transfer rates is interpreted as evidence for an effect of the nova eruption on the mass transfer rate of the underlying CV similar to the hibernation scenario.

  3. Copernicus observations of Nova Cygni 1975

    NASA Technical Reports Server (NTRS)

    Jenkins, E. B.; Snow, T. P.; Upson, W. L.; Anderson, R.; Starrfield, S. G.; Gallagher, J. S.; Friedjung, M.; Linsky, J. L.; Henry, R. C.; Moos, H. W.

    1977-01-01

    Near-ultraviolet radiation from Nova Cygni 1975 was detected by the Copernicus satellite on five occasions from 1975 September 1 to 1975 September 9. The nova was not seen in the UV after this date. The principal result was the observation of a broad emission feature from the Mg II doublet at 2800 A. The absence of strong UV radiation at shorter wavelengths suggests that these lines are produced by collisional excitation in the outer layers of an expanding shell with electron temperature of approximately 4000 K. The absence of observed emission lines from highly ionized species indicates that the amount of material with log T between 4.4 and 5.7 is less than 0.001 times that which produces the Mg II emission. The continuum flux in the near-UV decreased as the nova evolved, showing that the total luminosity decreased as the nova faded in the visible.

  4. Copernicus observations of Nova Cygni 1975

    NASA Technical Reports Server (NTRS)

    Jenkins, E. B.; Snow, T. P.; Upson, W. L.; Anderson, R.; Starrfield, S. G.; Gallagher, J. S.; Friedjung, M.; Linsky, J. L.; Henry, R. C.; Moos, H. W.

    1977-01-01

    Near-ultraviolet radiation from Nova Cygni 1975 was detected by the Copernicus satellite on five occasions from 1975 September 1 to 1975 September 9. The nova was not seen in the UV after this date. The principal result was the observation of a broad emission feature from the Mg II doublet at 2800 A. The absence of strong UV radiation at shorter wavelengths suggests that these lines are produced by collisional excitation in the outer layers of an expanding shell with electron temperature of approximately 4000 K. The absence of observed emission lines from highly ionized species indicates that the amount of material with log T between 4.4 and 5.7 is less than 0.001 times that which produces the Mg II emission. The continuum flux in the near-UV decreased as the nova evolved, showing that the total luminosity decreased as the nova faded in the visible.

  5. Pulse shaping on the Nova laser system

    SciTech Connect

    Lawson, J.K.; Speck, D.R.; Bibeau, C.; Weiland, T.L.

    1989-02-06

    Inertial confinement fusion requires temporally shaped pulses to achieve high gain efficiency. Recently, we demonstrated the ability to produce complex temporal pulse shapes at high power at 0.35 microns on the Nova laser system. 2 refs., 2 figs.

  6. Dust formation in Nova Del 2013

    NASA Astrophysics Data System (ADS)

    Shenavrin, V. I.; Taranova, O. G.; Tatarnikov, A. M.

    2013-09-01

    We present the result of the IR photometry of Nova Del 2013 obtained at the Crimean Station (Nauchny, Ukraine) of the Sternberg Astronomical Institute. JHKLM photometry was carried out with 125-cm telescope using a InSb-photometer on:

  7. CCD observations of old nova fields

    NASA Technical Reports Server (NTRS)

    Downes, Ronald A.; Szkody, Paula

    1989-01-01

    The discovery of CK Vulpeculae (Nova 1670) has prompted a major review of ideas concerning the long-term development of novae. Unfortunately, there are very few recovered novae old enough to provide confirmation (or rejection) of the new 'hibernation' scenario. CCD images of seven old nova fields, and R band photometry for four fields, have been obtained in an attempt to recover these objects in quiescence. A strong candidate for U Leonis, and a possible counterpart for T Bootis, are found. For three other fields, weak candidates have been found. Finding charts and colors are presented for the seven fields observed. The R light curves of U Leo, indicating an orbital period of 192.5 or 385.0 min, are shown.

  8. Rate of nova production in the Galaxy

    SciTech Connect

    Liller, W.; Mayer, B.

    1987-07-01

    The ongoing PROBLICOM program in the Southern Hemisphere now makes it possible to derive a reliable value for the overall production rate of Galactic novae. The results, 73 + or - 24/y, indicates that the Galaxy outproduces M 31 by a factor of two or three. It is estimated that the rate of supernova ejecta is one and a half orders of magnitude greater than that of novae in the Galaxy. 15 references.

  9. Cerebral Paragonimiasis.

    PubMed

    Miyazaki, I

    1975-01-01

    The first case of cerebral paragonimiasis was reported by Otani in Japan in 1887. This was nine years after Kerbert's discovery of the fluke in the lungs of Bengal tigers and seven years after a human pulmonary infection by the fluke was demonstrated by Baelz and Manson. The first case was a 26-year-old man who had been suffering from cough and hemosputum for one year. The patient developed convulsive seizures with subsequent coma and died. The postmortem examination showed cystic lesions in the right frontal and occipital lobes. An adult fluke was found in the occipital lesion and another was seen in a gross specimen of normal brain tissue around the affected occipital lobe. Two years after Otani's discovery, at autopsy a 29-year-old man with a history of Jacksonian seizure was reported as having cerebral paragonimiasis. Some time later, however, it was confirmed that the case was actually cerebral schistosomiasis japonica. Subsequently, cases of cerebral paragonimiasis were reported. However, the majority of these cases were not confirmed histologically. It was pointed out that some of these early cases were probably not Paragonimus infection. After World War II, reviews as well as case reports were published. Recently, investigations have been reported from Korea, with a clinicla study on 62 cases of cerebral paragonimiasis seen at the Neurology Department of the National Medical Center, Seoul, between 1958 and 1964. In 1971 Higashi described a statistical study on 105 cases of cerebral paragonimiasis that had been treated surgically in Japan.

  10. Novae Contribution to the Galactic Lithium Enhancement

    NASA Astrophysics Data System (ADS)

    Rukeya, Rejiefu; Lü, Guoliang; Wang, Zhaojun; Zhu, Chunhua

    2017-07-01

    We use the Modules for Experiments in Stellar Astrophysics (MESA) code to calculate the yields of {}7{Li} in the ejecta of classical novae, occurring on the surface of carbon-oxygen (CO) and oxygen-neon-magnesium (ONeMg) white dwarfs (WDs). Taking the masses and the mass accretion rates of WDs as input parameters, this article presents a grid showing the yield of {}7{Li} from classical novae, including a total of 79 models. Under similar input parameters, the {}7{Li} yields in our models are consistent with previous ones in the literature. {}7{Li} yields recently inferred spectroscopically from classical nova V1369 Cen are then compared with the theoretical values obtained in this work. Using the grid as its basis and population synthesis as its method, this paper estimates the amount of {}7{Li} produced by classical novae compared to the total {}7{Li} in the Galaxy. Our simulations suggest that novae can eject about {10}-9{{M}}⊙ of {}7{Li} every year. Hence, one may estimate that approximately 10% of {}7{Li} in the Galaxy originates from classical novae, which is significantly higher than the {}7{Li} produced by asymptotic giant branch stars.

  11. Gamma-ray novae: rare or nearby?

    NASA Astrophysics Data System (ADS)

    Morris, Paul J.; Cotter, Garret; Brown, Anthony M.; Chadwick, Paula M.

    2017-02-01

    Classical novae were revealed as a surprise source of γ-rays in Fermi Large Area Telescope (LAT) observations. During the first 8 yr since the LAT was launched, 6 novae in total have been detected to >5σ in γ-rays, in contrast to the 69 discovered optically in the same period. We attempt to resolve this discrepancy by assuming all novae are γ-ray emitters, and assigning peak 1 d fluxes based on a flat distribution of the known emitters to a simulated population. To determine optical parameters, the spatial distribution and magnitudes of bulge and disc novae in M31 are scaled to the Milky Way, which we approximate as a disc with a 20 kpc radius and elliptical bulge with semimajor axis 3 kpc and axis ratios 2:1 in the xy plane. We approximate Galactic reddening using a double exponential disc with vertical and radial scaleheights of rd = 5 kpc and zd = 0.2 kpc, and demonstrate that even such a rudimentary model can easily reproduce the observed fraction of γ-ray novae, implying that these apparently rare sources are in fact nearby and not intrinsically rare. We conclude that classical novae with mR ≤ 12 and within ≈ 8 kpc are likely to be discovered in γ-rays using the Fermi LAT.

  12. A nova outburst powered by shocks

    NASA Astrophysics Data System (ADS)

    Li, Kwan-Lok; Metzger, Brian D.; Chomiuk, Laura; Vurm, Indrek; Strader, Jay; Finzell, Thomas; Beloborodov, Andrei M.; Nelson, Thomas; Shappee, Benjamin J.; Kochanek, Christopher S.; Prieto, José L.; Kafka, Stella; Holoien, Thomas W.-S.; Thompson, Todd A.; Luckas, Paul J.; Itoh, Hiroshi

    2017-10-01

    Classical novae are runaway thermonuclear burning events on the surfaces of accreting white dwarfs in close binary star systems, sometimes appearing as new naked-eye sources in the night sky1. The standard model of novae predicts that their optical luminosity derives from energy released near the hot white dwarf, which is reprocessed through the ejected material2-5. Recent studies using the Fermi Large Area Telescope have shown that many classical novae are accompanied by gigaelectronvolt γ-ray emission6,7. This emission likely originates from strong shocks, providing new insights into the properties of nova outflows and allowing them to be used as laboratories for the study of the unknown efficiency of particle acceleration in shocks. Here, we report γ-ray and optical observations of the Milky Way nova ASASSN-16ma, which is among the brightest novae ever detected in γ-rays. The γ-ray and optical light curves show a remarkable correlation, implying that the majority of the optical light comes from reprocessed emission from shocks rather than the white dwarf8. The ratio of γ-ray to optical flux in ASASSN-16ma directly constrains the acceleration efficiency of non-thermal particles to be around 0.005, favouring hadronic models for the γ-ray emission9. The need to accelerate particles up to energies exceeding 100 gigaelectronvolts provides compelling evidence for magnetic field amplification in the shocks.

  13. X-ray Novae and Related Systems

    NASA Technical Reports Server (NTRS)

    Wheeler, J. Craig; Kim, Soonwook; Mineshige, Shin

    1992-01-01

    Accretion disk thermal instability models have been successful in accounting for the basic observations of dwarf novae and the steady behavior of nova-like systems. Models for the dwarf-nova like variability of the old nova and intermediate polar GK Per give good agreement with the burst amplitude, profile and recurrence time in the optical and UV. A month-long 'precursor plateau' in the UV is predicted for the expected 1992 outburst prior to the rise to maximum in the optical and UV. The models for the time scales of the outbursts and corresponding UV spectra at maximum are consistent with the inner edge of the accretion disk being essentially constant between quiescence and outburst and a factor of four larger than the co-rotation radius. These conclusions represent a challenge to the standard theory of magnetic accretion. Disk instability models have also given a good representation of the soft X-ray and optical outbursts of the X-ray novae A0620-00 and GS2000+25. Formation of coronae above the disk, heated by magneto-acoustic flux from the disk, may account for the temporal and spectral properties of the hard X-ray and gamma ray emission of related sources such as Cyg X-1, GS 2023+33 (V404 Cyg), IE 1740.7-2942 (the 'Galactic Center' Einstein Source), and GS 1124-683 (Nova Muscae).

  14. Circumstellar dust in symbiotic novae

    NASA Astrophysics Data System (ADS)

    Jurkic, Tomislav; Kotnik-Karuza, Dubravka

    2015-08-01

    Physical properties of the circumstellar dust and associated physical mechanisms play an important role in understanding evolution of symbiotic binaries. We present a model of inner dust regions around the cool Mira component of the two symbiotic novae, RR Tel and HM Sge, based on the long-term near-IR photometry, infrared ISO spectra and mid-IR interferometry. Pulsation properties and long-term variabilities were found from the near-IR light curves. The dust properties were determined using the DUSTY code which solves the radiative transfer. No changes in pulsational parameters were found, but a long-term variations with periods of 20-25 years have been detected which cannot be attributed to orbital motion.Circumstellar silicate dust shell with inner dust shell temperatures between 900 K and 1300 K and of moderate optical depth can explain all the observations. RR Tel showed the presence of an optically thin CS dust envelope and an optically thick dust region outside the line of sight, which was further supported by the detailed modelling using the 2D LELUYA code. Obscuration events in RR Tel were explained by an increase in optical depth caused by the newly condensed dust leading to the formation of a compact dust shell. HM Sge showed permanent obscuration and a presence of a compact dust shell with a variable optical depth. Scattering of the near-IR colours can be understood by a change in sublimation temperature caused by the Mira variability. Presence of large dust grains (up to 4 µm) suggests an increased grain growth in conditions of increased mass loss. The mass loss rates of up to 17·10-6 MSun/yr were significantly higher than in intermediate-period single Miras and in agreement with longer-period O-rich AGB stars.Despite the nova outburst, HM Sge remained enshrouded in dust with no significant dust destruction. The existence of unperturbed dust shell suggests a small influence of the hot component and strong dust shielding from the UV flux. By the use

  15. Measuring Cerebral Blood Flow in Moyamoya Angiopathy by Quantitative Magnetic Resonance Angiography Noninvasive Optimal Vessel Analysis.

    PubMed

    Khan, Nadia; Lober, Robert M; Ostergren, Lauren; Petralia, Jacob; Bell-Stephens, Teresa; Navarro, Ramon; Feroze, Abdullah; Steinberg, Gary K

    2017-02-14

    Moyamoya disease causes progressive occlusion of the supraclinoidal internal carotid artery, and middle, anterior, and less frequently the posterior cerebral arteries, carrying the risk of stroke. Blood flow is often partially reconstituted by compensatory moyamoya collaterals and sometimes the posterior circulation. Cerebral revascularization can further augment blood flow. These changes to blood flow within the cerebral vessels, however, are not well characterized. To evaluate blood flow changes resulting from the disease process and revascularization surgery using quantitative magnetic resonance angiography with noninvasive optimal vessel analysis (NOVA). We retrospectively analyzed 190 preoperative and postoperative imaging scans in 66 moyamoya patients after revascularization surgery. Images were analyzed for blood flow using NOVA and compared with preoperative angiographic staging and postoperative blood flow. Blood flow rates within superficial temporal artery grafts were compared based on angiographic evidence of patency. Diseased vessels had lower blood flow, correlating with angiographic staging. Flow in posterior cererbal and basilar arteries increased with disease severity, particularly when both the anterior and middle cerebral arteries were occluded. Basilar artery flow and ipsilateral internal carotid artery flow decreased after surgery. Flow rates were different between angiographically robust and poor direct bypass grafts, as well as between robust and patent grafts. Preoperative changes in cerebral vessel flow as measured by NOVA correlated with angiographic disease progression. NOVA demonstrated that preoperative augmentation of the posterior circulation decreased after surgery. This report is the first to quantify the shift in collateral supply from the posterior circulation to the bypass graft.

  16. Cerebral Palsy (For Parents)

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old Cerebral Palsy KidsHealth > For Parents > Cerebral Palsy A A A ... kids who are living with the condition. About Cerebral Palsy Cerebral palsy is one of the most common ...

  17. Cerebral palsy - resources

    MedlinePlus

    Resources - cerebral palsy ... The following organizations are good resources for information on cerebral palsy : National Institute of Neurological Disorders and Stroke -- www.ninds.nih.gov/disorders/cerebral_palsy/cerebral_palsy. ...

  18. Cerebral Palsy (For Teens)

    MedlinePlus

    ... Right Sport for You Healthy School Lunch Planner Cerebral Palsy KidsHealth > For Teens > Cerebral Palsy Print A A ... do just what everyone else does. What Is Cerebral Palsy? Cerebral palsy (CP) is a disorder of the ...

  19. Shortest recurrence periods of novae

    SciTech Connect

    Kato, Mariko; Saio, Hideyuki; Hachisu, Izumi; Nomoto, Ken'ichi

    2014-10-01

    Stimulated by the recent discovery of the 1 yr recurrence period nova M31N 2008-12a, we examined the shortest recurrence periods of hydrogen shell flashes on mass-accreting white dwarfs (WDs). We discuss the mechanism that yields a finite minimum recurrence period for a given WD mass. Calculating the unstable flashes for various WD masses and mass accretion rates, we identified a shortest recurrence period of about two months for a non-rotating 1.38 M {sub ☉} WD with a mass accretion rate of 3.6 × 10{sup –7} M {sub ☉} yr{sup –1}. A 1 yr recurrence period is realized for very massive (≳ 1.3 M {sub ☉}) WDs with very high accretion rates (≳ 1.5 × 10{sup –7} M {sub ☉} yr{sup –1}). We revised our stability limit of hydrogen shell burning, which will be useful for binary evolution calculations toward Type Ia supernovae.

  20. Models for various aspects of dwarf novae and nova-like stars

    NASA Technical Reports Server (NTRS)

    Ladous, Constanze

    1993-01-01

    The first attempts to explain the nature of dwarf novae were based on the assumption of single-star phenomena, in which emission lines were assumed to be caused by circumstellar gas shells. The outburst behavior was tentatively ascribed to the kind of (also not understood) mechanism leading to nova outbursts. The realization that some, and possibly all, dwarf novae and nova-like stars (and novae) are binaries eventually led to models which bore more and more similarities to the modern interpretation on the basis of the Roche model. Not all cataclysmic variables are known binaries. In fact, with respect to the entire number of known objects, the proven binaries are still the minority, but all the brightest variables are in fact known to binaries. Not a single system is known which exhibits the usual characteristics of a cataclysmic variable and at the same time can be declared with certainty to be a single star. Two systems are known, the dwarf nova EY Cyg and the recurrent nova V1017 Sgr, in which, in spite of intensive search, no radial velocity variations have been found; but they still exhibit composite spectra consisting of a bright continuum, an emission spectrum, and a cool absorption spectrum. If the Roche model is correct, it is to be expected that a small percentage of objects is viewed pole-on, so orbital motions do not make themselves felt as Doppler shifts of spectral lines. So even these two systems support the hypothesis that all cataclysmic variables (with the possible exception of symbiotic stars) are binaries. In cataclysmic variables, it seems that the brightness changes observed in dwarf novae and nova-like stars in the optical and the UV are due directly to changes in the accretion disks. The study and understanding of accretion disks in these systems can bear potentially valuable consequences for many other fields in astronomy. The observed spectra of dwarf novae and nova-like stars comprise a fairly large range: pure emission spectra, pure

  1. Cerebral palsy.

    PubMed

    Colver, Allan; Fairhurst, Charles; Pharoah, Peter O D

    2014-04-05

    The syndrome of cerebral palsy encompasses a large group of childhood movement and posture disorders. Severity, patterns of motor involvement, and associated impairments such as those of communication, intellectual ability, and epilepsy vary widely. Overall prevalence has remained stable in the past 40 years at 2-3·5 cases per 1000 livebirths, despite changes in antenatal and perinatal care. The few studies available from developing countries suggest prevalence of comparable magnitude. Cerebral palsy is a lifelong disorder; approaches to intervention, whether at an individual or environmental level, should recognise that quality of life and social participation throughout life are what individuals with cerebral palsy seek, not improved physical function for its own sake. In the past few years, the cerebral palsy community has learned that the evidence of benefit for the numerous drugs, surgery, and therapies used over previous decades is weak. Improved understanding of the role of multiple gestation in pathogenesis, of gene environment interaction, and how to influence brain plasticity could yield significant advances in treatment of the disorder. Reduction in the prevalence of post-neonatal cerebral palsy, especially in developing countries, should be possible through improved nutrition, infection control, and accident prevention. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Serendipitous discovery of a dwarf Nova in the Kepler field near the G dwarf KIC 5438845

    SciTech Connect

    Brown, Alexander; Ayres, Thomas R.; Neff, James E.; Wells, Mark A.; Kowalski, Adam; Berdyugina, Svetlana; Harper, Graham M.; Korhonen, Heidi; Piskunov, Nikolai; Saar, Steven; Walkowicz, Lucianne

    2015-02-01

    The Kepler satellite provides a unique window into stellar temporal variability by observing a wide variety of stars with multi-year, near-continuous, high precision, optical photometric time series. While most Kepler targets are faint stars with poorly known physical properties, many unexpected discoveries should result from a long photometric survey of such a large area of sky. During our Kepler Guest Observer programs that monitored late-type stars for starspot and flaring variability, we discovered a previously unknown dwarf nova that lies within a few arcseconds of the mid-G dwarf star KIC 5438845. This dwarf nova underwent nine outbursts over a 4 year time span. The two largest outbursts lasted ∼17–18 days and show strong modulations with a 110.8 minute period and a declining amplitude during the outburst decay phase. These properties are characteristic of an SU UMa-type cataclysmic variable. By analogy with other dwarf nova light curves, we associate the 110.8 minute (1.847 hr) period with the superhump period, close to but slightly longer than the orbital period of the binary. No precursor outbursts are seen before the super-outbursts and the overall super-outburst morphology corresponds to Osaki and Meyer “Case B” outbursts, which are initiated when the outer edge of the disk reaches the tidal truncation radius. “Case B” outbursts are rare within the Kepler light curves of dwarf novae. The dwarf nova is undergoing relatively slow mass transfer, as evidenced by the long intervals between outbursts, but the mass transfer rate appears to be steady, because the smaller “normal” outbursts show a strong correlation between the integrated outburst energy and the elapsed time since the previous outburst. At super-outburst maximum the system was at V ∼ 18, but in quiescence it is fainter than V ∼ 22, which will make any detailed quiescent follow-up of this system difficult.

  3. When does an old nova become a dwarf nova? Kinematics and age of the nova shell of the dwarf nova AT Cancri

    NASA Astrophysics Data System (ADS)

    Shara, Michael M.; Drissen, Laurent; Martin, Thomas; Alarie, Alexandre; Stephenson, F. Richard

    2017-02-01

    The Z Cam-type dwarf nova AT Cancri (AT Cnc) displays a classical nova (CN) shell, demonstrating that mass transfer in cataclysmic binaries decreases substantially after a CN eruption. The hibernation scenario of cataclysmic binaries predicts such a decrease, on a time-scale of a few centuries. In order to measure the time since AT Cnc's last CN eruption, we have measured the radial velocities of a hundred clumps in its ejecta with SITELLE, Canada-France-Hawaii Telescope's recently commissioned imaging Fourier transform spectrometer. These range from -455 to +490 km s-1. Coupled with the known distance to AT Cnc of 460 pc, the size of AT Cnc's shell, and a simple model of nova ejecta deceleration, we determine that the last CN eruption of this system occurred 330_{-90}^{+135} yr ago. This is the most rapid transition from a high mass-transfer rate, nova-like variable to a low mass-transfer rate, dwarf nova yet measured, and in accord with the hibernation scenario of cataclysmic binaries. We conclude by noting the similarity in the deduced outburst date (within a century of 1686 CE) of AT Cnc to a `guest star' reported in the constellation Cancer by Korean observers in 1645 CE.

  4. Convection and Mixing in Classical Novae Precursors

    NASA Astrophysics Data System (ADS)

    Dursi, L. J.; Calder, A. C.; Alexakis, A.; Truran, J. W.; Zingale, M.; Times, F. X.; Ricker, P. M.; Fryxell, B.; Olson, K.; Rosner, R.; MacNeice, P.

    2002-06-01

    To explain observed abundances from classical nova outbursts, and to help explain their energetics, nova models must incorporate a mechanism that will dredge up the heavier white dwarf material into the lighter accreted atmosphere. One proposed mechanism relies on the fluid motions from an early convective phase to do the mixing. We present recent work investigating two aspects of this mechanism. We examine results from two-dimensional simulations of classical nova precursor models that demonstrate the beginning of a convective phase during the `simmering' of a nova precursor. We use a new hydrostatic equilibrium hydrodynamics module recently developed for the adaptive-mesh code FLASH. The two-dimensional models are based on the one-dimensional models of Ami Glasner (Glasner et al. 1997), and were evolved with FLASH from a pre-convective state to the onset of convection. The onset of convection induces a velocity field near the C,O/H,He interface, which can then cause mixing through interactions with gravity waves. We show results from simulations of these wind-wave interactions, and estimate whether the `wind' caused by the convection could induce sufficient dredge-up to power a classical novae. This research has been supported by the US. Department of Energy under grant no. B341495 to the ASCI Flash Center at the University of Chicago

  5. Nova Discovery Efficiency 1890-2014; Only 43%±6% of the Brightest Nova Are Discovered

    NASA Astrophysics Data System (ADS)

    Schaefer, Bradley E.

    2014-06-01

    Galactic nova discovery has always been the domain of the best amateur astronomers, with the only substantial exception being the use of the Harvard plates from 1890-1947. (Modern CCD surveys have not produced any significant nova discoveries.) From 1890-1946, novae were discovered by gentlemen who deeply knew the stars in the sky and who checked for new stars on every clear night. This all changed when war surplus binoculars became commonly available, so the various organizations (e.g., AAVSO, BAA) instructed their hunters to use binoculars to regularly search small areas of the Milky Way. In the 1970s the hunters largely switched to blinking photographs, while they switched to CCD images in the 1990s, all exclusively in Milky Way regions. Currently, most hunters use 'go-to' scopes to look deeply only in the Milky Way, use weekly or monthly cadences, never go outside to look up at the light-polluted skies, and do not have the stars memorized at all. This situation is good for catching many faint novae, but is inefficient for catching the more isotropic and systematically-fast bright novae.I have made an exhaustive analysis of all known novae to isolate the effects on the relative discovery efficiency as a function of decade, the elongation from the Sun, the Moon's phase, the declination, the peak magnitude, and the duration of the peak. For example, the relative efficiency for novae south of declination -33° is 0.5 before 1953, 0.2 from 1953-1990, and 0.8 after 1990. My analysis gives the overall discovery efficiency to be 43%±6%, 30%, 22%, 12%, and 6% for novae peaking brighter than 2, 4, 6, 8, and 10 mag. Thus, the majority of first magnitude novae are being missed. The bright novae are lost because they are too close to the Sun, in the far south, and/or very fast. This is illustrated by the discovery rate for Vpeak<2 novae being once every five years before 1946, yet only one such nova (V1500 Cyg) has been seen in the last 68 years. A critical consequence of

  6. Recent developments on SU UMa stars - theory vs. observation

    NASA Astrophysics Data System (ADS)

    Cannizzo, John K.

    2015-01-01

    Kepler light curves of short period dwarf novae have resparked interest in the nature of superoutbursts and led to the question: Is the thermal-tidal instability needed, or can the plain vanilla version of the accretion disk limit cycle do the job all by itself? A detailed time-resolved study of an eclipsing SU UMa system during superoutburst onset should settle the question - if there is a dramatic contraction of the disk at superoutburst onset, Osaki's thermal-tidal model would be preferred; if not, the plain disk instability model would be sufficient. I will present recent results that support the contention by Osaki & Kato that the time varying negative superhump frequencies can be taken as a surrogate for the outer disk radius variations. Finally, it may be necessaryto look beyond the short period dwarf novae to gain perspective on the nature of embedded precursors in long outbursts.

  7. NOVA laser facility for inertial confinement fusion

    SciTech Connect

    Simmons, W.W.

    1983-11-30

    The NOVA laser consists of ten beams, capable of concentrating 100 to 150 kJ of energy (in 3 ns) and 100 to 150 TW of power (in 100 ps) on experimental targets by 1985. NOVA will also be capable of frequency converting the fundamental laser wavelength (1.05 ..mu..m) to its second (0.525 ..mu..m) or third (0.35 ..mu..m) harmonic. This additional capability (80 to 120 kJ at 0.525 ..mu..m, 40 to 70 kJ at 0.35 ..mu..m) was approved by the US Department of Energy (DOE) in April 1982. These shorter wavelengths are much more favorable for ICF target physics. Current construction status of the NOVA facility, intended for completion in the autumn of 1984, will be presented.

  8. The spatial distribution and population of novae in M31

    NASA Technical Reports Server (NTRS)

    Ciardullo, Robin; Ford, Holland C.; Neill, James D.; Jacoby, George H.; Shafter, Allen W.

    1987-01-01

    Results from an H-alpha survey for novae in the bulge of M31 are reported, and the spatial distribution of the nova population is analyzed. It is shown that in M31's central bulge the distribution of novae follows that of the light to within about 10 arcsec of the nucleus, refuting the notion that there is a nova 'hole' near the center of the galaxy. The Hubble-Arp nova sample is reanalyzed, concluding that the novae observed in the central 30 arcmin x 15 arcmin region belong almost exclusively to the bulge population. This result is compared to the observed cataclysmic variable distribution in the Galaxy, concluding that M31's spheroidal nova population is still compatible with the thin disk distribution of cataclysmic variables measured in the solar neighborhood. Possible explanations for the high specific nova rate of the bulge are discussed.

  9. Continuing spectroscopic monitoring of Nova Sct 2017 = ASASSN-17hx

    NASA Astrophysics Data System (ADS)

    Berardi, Paolo; Sims, Woody; Sollecchia, Umberto

    2017-07-01

    We report the results of low resolution spectroscopy of the classical nova Sct 2017 = ASASSN-17hx (Atel# 10523, #10524, #10527) as part of the continuing nova monitoring program by members of the ARAS group.

  10. AN EXTENDED GRID OF NOVA MODELS. III. VERY LUMINOUS, RED NOVAE

    SciTech Connect

    Shara, Michael M.; Zurek, David; Yaron, Ofer; Prialnik, Dina; Kovetz, Attay

    2010-12-10

    Extremely luminous, red eruptive variables like RV in M31 are being suggested as exemplars of a new class of astrophysical objects. Our greatly extended series of nova simulations shows that classical nova models can produce very red, luminous eruptions. In a poorly studied corner of three-dimensional nova parameter space (very cold, low-mass white dwarfs, accreting at very low rates) we find bona fide classical novae that are very luminous and red because they eject very slowly moving, massive envelopes. A crucial prediction of these nova models-in contrast to the predictions of merging star ('mergeburst') models-is that a hot remnant, the underlying white dwarf, will emerge after the massive ejected envelope has expanded enough to become optically thin. This blue remnant must fade on a timescale of decades-much faster than a 'mergeburst', which must fade on timescales of millennia or longer. Furthermore, the cooling nova white dwarf and its expanding ejecta must become redder in the years after eruption, while a contracting mergeburst must become hotter and bluer. We predict that red novae will always brighten to L {approx} 1000 L{sub sun} for about one year before rising to the maximum luminosity at L {approx} 10{sup 6}-10{sup 7} L{sub sun}. The maximum luminosity attainable by a nova is likely to be L {approx} 10{sup 7} L{sub sun}, corresponding to M {approx} -12. In an accompanying paper, we describe a fading, luminous blue candidate for the remnant of M31-RV; it is observed with the Hubble Space Telescope to be compatible only with the nova model.

  11. NUCLEAR MIXING METERS FOR CLASSICAL NOVAE

    SciTech Connect

    Kelly, Keegan J.; Iliadis, Christian; Downen, Lori; Champagne, Art; José, Jordi

    2013-11-10

    Classical novae are caused by mass transfer episodes from a main-sequence star onto a white dwarf via Roche lobe overflow. This material possesses angular momentum and forms an accretion disk around the white dwarf. Ultimately, a fraction of this material spirals in and piles up on the white dwarf surface under electron-degenerate conditions. The subsequently occurring thermonuclear runaway reaches hundreds of megakelvin and explosively ejects matter into the interstellar medium. The exact peak temperature strongly depends on the underlying white dwarf mass, the accreted mass and metallicity, and the initial white dwarf luminosity. Observations of elemental abundance enrichments in these classical nova events imply that the ejected matter consists not only of processed solar material from the main-sequence partner but also of material from the outer layers of the underlying white dwarf. This indicates that white dwarf and accreted matter mix prior to the thermonuclear runaway. The processes by which this mixing occurs require further investigation to be understood. In this work, we analyze elemental abundances ejected from hydrodynamic nova models in search of elemental abundance ratios that are useful indicators of the total amount of mixing. We identify the abundance ratios ΣCNO/H, Ne/H, Mg/H, Al/H, and Si/H as useful mixing meters in ONe novae. The impact of thermonuclear reaction rate uncertainties on the mixing meters is investigated using Monte Carlo post-processing network calculations with temperature-density evolutions of all mass zones computed by the hydrodynamic models. We find that the current uncertainties in the {sup 30}P(p, γ){sup 31}S rate influence the Si/H abundance ratio, but overall the mixing meters found here are robust against nuclear physics uncertainties. A comparison of our results with observations of ONe novae provides strong constraints for classical nova models.

  12. Cerebral Malaria.

    PubMed

    Marsden, P D; Bruce-Chwatt, L J

    1975-01-01

    Cerebral malaria is an acute diffuse encephalopathy associated only with Plasmodium falciparum. It is probably a consequence of the rapid proliferation of the parasites in the body of man in relation to red cell invasion, and results in stagnation of blood flow in cerebralcapillaries with thromobotic occlusion of large numbers of cerebral capillaries. The subsequent cerebral pathology is cerebral infarction with haemorrhage and cerebral oedema. The wide prevalence of P. falciparum in highly endemic areas results in daily challenges to patients from several infected mosquitoes. It is thus important to understand the characteristics of P. falciparum, since this is one of the most important protozoan parasites of man and severe infection from it constitutes one of the few real clinical emergencies in tropical medicine. One of the more important aspects of the practice of medicine in the tropics is to establish a good understanding of the pattern of medical practice in that area. This applies to malaria as well as to other diseases. The neophyte might be somewhat surprised to learn, for example that an experienced colleague who lives in a holoendemic malarious area such as West Africa, sees no cerebral malaria. But the explanation is simple when the doctor concerned has a practice which involves treating adults only. Cerebral malaria is rare in adults, because in highly endemic areas, by the age of 1 year most of the infants in a group under study have already experienced their first falciparum infection. By the time they reach adult life, they have a solid immunity against severe falciparum infections. In fact, "clinical malaria" could occur in such a group under only two circumstances: 1) in pregnancy, a patent infection with P. falciparum might develop, probably due to an IgG drain across the placenta to the foetus;2) in an individual who has constantly taken antimalarials and who may have an immunity at such a low level that when antimalarial therapy is interrupted

  13. The nova-like variable KQ Mon and the nature of the UX Ursa Majoris stars

    NASA Technical Reports Server (NTRS)

    Sion, E. M.; Guinan, E. F.

    1982-01-01

    The KQ Mon is a UX UMa type nova-like variable discovered by Howard Bond. Optical spectra taken by Bond in 1978 reveal very shallow Balmer absorption lines and He I absorption. Bond also did UBV and high speed photometry in 1978 and early 1981. There has been no evidence of orbital variations but the appearance of the optical spectrum and the presence of low amplitude flickering suggested a strong similarity to CD-42-14462 (=V3885 Sgr) and other members of the UX UMa class. Low dispersion observations of KQ Mon were made with the International Ultraviolet Explorer satellite. Six spectra taken with the shot wavelength prime camera are dominated by strong broad absorption lines due to N V, O I, Si III, Si IV, C IV, He II, N IV, and Al III. There is little evidence of orbital phase modulation over the time baseline of the observations. Unlike UV observations of other UX UMa type objects, KQ Mon exhibits no emission lines or P Cygni type profiles and the velocity displacements appear to be smaller, suggesting the absence of a hot, high velocity wind characterizing other UX UMa stars. The relationship of KQ Mon to other UX UMa disk stars is discussed and a model is suggested to explain their observed properties and the lack of major outbursts.

  14. Ultraviolet studies of nova-like variables with the IUE. Final report, April 1981-September 1983

    SciTech Connect

    Guinan, E.F.

    1983-09-01

    KQ Mon is a new UX UMa-type nova-like variable. Optical spectra taken in 1978 reveal very shallow Balmer absorption lines and He I (wavelength 4471) absorption. There was no evidence of orbital variations but the appearance of the optical spectrum and the presence of low amplitude flickering suggested a strong similarity to CD-42 degrees 14462 ( V3885 Sgr) and other members of the UX UMa class. KQ Mon was observed at low dispersion with the IUE satellite. Six spectra taken with the short wavelength prime (SWP) camera are dominated by strong broad absorption lines due to N V, O I, Si III, Si IV, C IV, He II, N IV, and A1 III. There is little evidence of orbital phase modulation over the time baseline of the observations. Unlike UV observations of other UX UMa-type objects, KQ Mon exhibits no emission lines or P Cygni-type profiles and the velocity displacements appear to be smaller, suggesting the absence of a hot, high velocity wind characterizing other UX UMa stars. The relationship of KQ Mon to other UX UMa disk stars is discussed and a model is suggested to explain their observed properties and the lack of major outbursts.

  15. The nova-like variable KQ Mon and the nature of the UX Ursa Majoris stars

    NASA Technical Reports Server (NTRS)

    Sion, E. M.; Guinan, E. F.

    1982-01-01

    The KQ Mon is a UX UMa type nova-like variable discovered by Howard Bond. Optical spectra taken by Bond in 1978 reveal very shallow Balmer absorption lines and He I absorption. Bond also did UBV and high speed photometry in 1978 and early 1981. There has been no evidence of orbital variations but the appearance of the optical spectrum and the presence of low amplitude flickering suggested a strong similarity to CD-42-14462 (=V3885 Sgr) and other members of the UX UMa class. Low dispersion observations of KQ Mon were made with the International Ultraviolet Explorer satellite. Six spectra taken with the shot wavelength prime camera are dominated by strong broad absorption lines due to N V, O I, Si III, Si IV, C IV, He II, N IV, and Al III. There is little evidence of orbital phase modulation over the time baseline of the observations. Unlike UV observations of other UX UMa type objects, KQ Mon exhibits no emission lines or P Cygni type profiles and the velocity displacements appear to be smaller, suggesting the absence of a hot, high velocity wind characterizing other UX UMa stars. The relationship of KQ Mon to other UX UMa disk stars is discussed and a model is suggested to explain their observed properties and the lack of major outbursts.

  16. PAH emission from Nova Cen 1986

    NASA Technical Reports Server (NTRS)

    Hyland, A. R. Harry; Mcgregor, P. J.

    1989-01-01

    The discovery of broad emission features between 3.2 and 3.6 microns were reported in the spectrum of Nova Cen 1986 (V842 Cen) some 300 days following outburst and remaining prominent for several months. The general characteristics of these features are similar to those attributed to polycyclic hydrocarbon (PAH) molecules in other dusty sources, although the relative strengths are different, and these observations provide the first clear evidence for molecular constituents other than graphite particles in the ejecta of novae.

  17. The spectral evolution of dwarf nova outbursts

    NASA Technical Reports Server (NTRS)

    Cannizzo, John K.; Kenyon, Scott J.

    1987-01-01

    The disk instability model for dwarf nova eruptions is investigated by computing the spectral development of the accretion disk through a complete limit cycle. Observed stellar spectra are used to model the radiation emitted by optically thick annuli within the disc. The general findings agree with those of Smak (1984) and Pringle et al. (1986). It is suggested that the 'dwarf nova oscillations' might be a source of information concerning the evolution of the inner disk and that detailed observations of this phenomenon can be used to test various outburst mechanisms.

  18. New results from NOvA

    NASA Astrophysics Data System (ADS)

    Vahle, P.; NOvA Collaboration

    2017-09-01

    The NOvA experiment at Fermilab uses a beam of neutrinos and two detectors separated by an 810 km baseline to observe muon neutrino disappearance and electron neutrino appearance. These measurements have the potential to reveal the remaining unknowns in neutrino oscillations, namely the mass hierarchy, the 23 octant, and perhaps even hint at the violation of CP in the neutrino sector. This paper describes the current status of the NOvA experiment and present results from two years of data taking, doubling the exposure of our initial results.

  19. Dust formation in Nova Cephei 2013

    NASA Astrophysics Data System (ADS)

    Ninan, J. P.; Ojha, D. K.; Ghosh, S. K.; Anupama, G. C.; Prabhu, T. P.; Bhatt, B. C.

    2013-08-01

    We report near-infrared K band photometry and spectroscopy of Nova Cephei 2013, discovered by K. Nishiyama and F. Kabashima on 2013 Feb 2.4 UT (cf. CBET #3397, ATel #4950, #4893, #5026). The observations were made using the 2-m Himalayan Chandra telescope (+TIFR Near Infrared Imager and Spectrometer, TIRSPEC) at the Indian Astronomical Observatory (IAO), Hanle (Ladakh). The estimated K band magnitudes of nova were: 2013 June 23 UT, 7.40 +/-0.02 and 2013 July 8 UT 7.84 +/- 0.02; the source brightness has therefore dimmed by 0.44 mag in K band during 16 days.

  20. Ultraviolet observations of LMC nova 1988

    NASA Technical Reports Server (NTRS)

    Starrfield, S.; Stryker, L. L.; Sonneborn, G.; Sparks, Warren M.; Sion, E. M.; Wagner, R. M.; Ferland, Gary; Gallagher, J. S.; Wade, R.; Williams, R. E.

    1988-01-01

    The IUE obtained ultraviolet spectra of a nova in an external galaxy. The spectral features do not seem unusual for a nova at maximum but it is hoped to be able to follow it for a long enough time to be able to study the high ionization lines that appear when the density drops to lower values (the nebular stage). A high dispersion spectrum was also obtained to assist in the line identification and to study the line of sight to the LMC 1 deg of arc away from SN 1987A.

  1. Ultraviolet observations of LMC nova 1988

    SciTech Connect

    Starrfield, S.; Stryker, L.L.; Sonneborn, G.; Sparks, W.M.; Sion, E.M.; Wagner, R.M.; Ferland, G.; Gallagher, J.S.; Wade, R.; Williams, R.E.; Heathcote, S.; Kenyon, S.; Shaviv, G.; Wehrse, R.; Hauschildt, P.; Truran, J.W.; Wu, C.C.; Gehrz, R.D.; Ney, E.P.

    1988-01-01

    This current bright novae was first detected in outburst on March 21, 1988. Its discovery has given us the opportunity of studying the first extragalactic nova in the ultraviolet and we have, therefore, obtained a number of LWP and SWP spectra when it was at maximum. We have also obtained a high dispersion LWP spectrum in order to study the ISM in the Large Magellanic Cloud on a slightly different line-of-sight from that analyzed using SN 1987A. 10 refs., 2 figs.

  2. Alignment of the NOvA Detectors

    NASA Astrophysics Data System (ADS)

    Bending, Sebastian; NOvA Collaboration

    2017-01-01

    NOvA is a long-baseline neutrino oscillation experiment intended to probe the neutrino mass hierarchy and provide constraints on CP violation in the neutrino sector. The experiment consists of a Near Detector at Fermilab and a Far Detector 810 km away at Ash River, Minnesota, both of which receive neutrinos from the NuMI beamline. The misalignment of elements within the detectors contributes to systematic uncertainties in NOvA measurements. A procedure to determine and correct for detector misalignments through the use of cosmic ray muon tracks will be presented.

  3. Nova in Centaurus - ASASSN-17gk

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2017-05-01

    AAVSO Alert Notice 578 announces the discovery of a galactic nova in Centaurus - ASASSN-17gk - by the ASAS-SN team at magnitude 10.9 V on 2017 May 17.28 UT. Spectroscopy indicating that ASASSN-17gk is a galactic nova was obtained by P. Luckas (International Centre for Radio Astronomy Research, Univ. Western Australia) on 2017 May 18.0598 UT (ATel #10399). Finder charts with sequence may be created using the AAVSO Variable Star Plotter (https://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details.

  4. Mix experiments with the NOVA laser

    SciTech Connect

    Rupert, V.C.; Kilkenny, J.D.; Skokowski, P.G.

    1988-10-01

    The NOVA mix experiments are designed to study mix between two dissimilar materials subjected to strong (M/approximately/50) shocks and variable accelerations in a direction normal to their common boundary. The main purpose of the experiments is to provide a data base with which predictive models can be compared and normalized. Together with shock tube experiments, which explore a different regime, the current NOVA tests investigate the shock induced source terms in our model and the evolution of both Rayleigh-Taylor stable and unstable interfaces. 3 refs., 9 figs.

  5. Terra Nova breaks new ground for alliances

    SciTech Connect

    Ghiselin, D.

    1996-08-01

    This paper reviews the development of alliances to help develop the Terra Nova oil and gas field in the offshore Atlantic areas of Canada. Largely attributed to BP, the strategic alliance concept got its start in the North Sea and on the North Slope of Alaska. BP saw it as the best way to take advantage of economy-of-scale, mitigate risk, and achieve outsourcing goals while retaining their core competencies. This paper reviews the methods of developing the alliances, the developing of a development plan for the Terra Nova field, and how the alliance plans to maximize the profittability of the operation for all involved.

  6. Nova Cephei 2014; Near-IR observations

    NASA Astrophysics Data System (ADS)

    Ashok, N. M.; Banerjee, D. P. K.; Venkataraman, V.; Joshi, Vishal

    2014-03-01

    Spectra of Nova Cephei 2014, discovered on 9 March 2014 (CBET 2825) were obtained on 13, 15 and 20 March at R ~ 1000 (0.85 to 2.4 micron range) with the 1.2m Mount Abu Telescope + the recently commissioned Near-Infrared Camera Spectrograph (NICS). The spectra show P Cygni features and are typical of the Fe II class of novae which in the NIR show prominent HI and OI lines but are distinguished from the He/N class by displaying numerous strong lines of Carbon (see Banerjee and Ashok, 2012, BASI, for the NIR templates of both classes).

  7. The Long-Term Behavior of Known & Suspected Novae

    NASA Astrophysics Data System (ADS)

    Pagnotta, A.

    2017-03-01

    The long-term evolution of classical novae is poorly understood. I discuss here an in-progress project designed to better understand the post-eruption behavior of novae and test the Hibernation theory of nova evolution. The project has two main parts: (1) a modern survey of Galactic nova magnitudes, and (2) construction of long-term light curves using primarily archival photographic plates.

  8. SN 2010U: A LUMINOUS NOVA IN NGC 4214

    SciTech Connect

    Humphreys, Roberta M.; Helton, L. Andrew; Prieto, Jose L.; Rosenfield, Philip; Williams, Benjamin; Murphy, Jeremiah; Dalcanton, Julianne; Gilbert, Karoline; Kochanek, Christopher S.; Stanek, K. Z.; Khan, Rubab; Szczygiel, Dorota; Mogren, Karen; Fesen, Robert A.; Milisavljevic, Dan

    2010-07-20

    The luminosity, light curve, post-maximum spectrum, and lack of a progenitor on deep pre-outburst images suggest that SN 2010U was a luminous, fast nova. Its outburst magnitude is consistent with that for a fast nova using the maximum magnitude-rate of decline relationship for classical novae.

  9. The benefit of amateur observations for research in dwarf novae

    NASA Technical Reports Server (NTRS)

    La Dous, Constanze

    1992-01-01

    Contributions of amateur astronomers to research on dwarf novae, which are based on carefully monitoring the outburst behavior of these objects, are reviewed. These contributions range from scheduling of observations to the observational basis for research on the dwarf nova outburst mechanism. It is suggested, that, with better equipment, observations of orbital light variations in dwarf novae might be performed by amateur astronomers.

  10. First optical candidate for a recovered classical nova in a globular cluster - Nova 1938 in M14

    NASA Technical Reports Server (NTRS)

    Shara, Michael M.; Potter, Michael; Moffat, Anthony F. J.; Hogg, Helen S.; Wehlau, Amelia

    1986-01-01

    U, B, V, R, and H-alpha CCD frames of the field of the nova which appeared in the globular cluster M14 in 1938 have been compared with the nova discovery images. On the basis of positional coincidence, brightness, and blue color, a candidate nova was identified and its right ascension and declination to within 1 arcsec each. Confirmation of the candidate and detailed study of the quiescent nova will probably require Hubble Space Telescope observations.

  11. Novae. Fermi establishes classical novae as a distinct class of gamma-ray sources.

    PubMed

    2014-08-01

    A classical nova results from runaway thermonuclear explosions on the surface of a white dwarf that accretes matter from a low-mass main-sequence stellar companion. In 2012 and 2013, three novae were detected in γ rays and stood in contrast to the first γ-ray-detected nova V407 Cygni 2010, which belongs to a rare class of symbiotic binary systems. Despite likely differences in the compositions and masses of their white dwarf progenitors, the three classical novae are similarly characterized as soft-spectrum transient γ-ray sources detected over 2- to 3-week durations. The γ-ray detections point to unexpected high-energy particle acceleration processes linked to the mass ejection from thermonuclear explosions in an unanticipated class of Galactic γ-ray sources.

  12. A near-infrared survey of old novae. I - The discovery of a candidate recurrent nova

    NASA Astrophysics Data System (ADS)

    Harrison, Thomas E.

    1992-12-01

    We report on a near-infrared survey of old novae in an attempt to discover previously unidentified members of the RS Oph family of recurrent novae. An RS Oph-type system contains a red giant, and is easily identified using infrared photometry. Two objects in our survey have infrared colors and luminosities that suggest that they may be recurrent novae: V723 Sco and AR Cir. We use a model of the Galaxy to rule out the possibility of source confusion in either case. The light curve of the 1952 outburst of V723 Sco was very similar to those of the other members of the RS Oph group of recurrent novae, and we conclude that it is a previously unidentified member of this family. The light curve of the 1906 outburst of AR Cir, however, more closely resembles those of the outbursts of symbiotic stars, and we classify it as such.

  13. NOVA making stuff: Season 2

    SciTech Connect

    Leombruni, Lisa; Paulsen, Christine Andrews

    2014-12-12

    Over the course of four weeks in fall 2013, 11.7 million Americans tuned in to PBS to follow host David Pogue as he led them in search of engineering and scientific breakthroughs poised to change our world. Levitating trains, quantum computers, robotic bees, and bomb-detecting plants—these were just a few of the cutting-edge innovations brought into the living rooms of families across the country in NOVA’s four-part series, Making Stuff: Faster, Wilder, Colder, and Safer. Each of the four one-hour programs gave viewers a behind-the-scenes look at novel technologies poised to change our world—showing them how basic research and scientific discovery can hold the keys to transforming how we live. Making Stuff Season 2 (MS2) combined true entertainment with educational value, creating a popular and engaging series that brought accessible science into the homes of millions. NOVA’s goal to engage the public with such technological innovation and basic research extended beyond the broadcast series, including a variety of online, educational, and promotional activities: original online science reporting, web-only short-form videos, a new online quiz-game, social media engagement and promotion, an educational outreach “toolkit” for science educators to create their own “makerspaces,” an online community of practice, a series of nationwide Innovation Cafés, educator professional development, a suite of teacher resources, an “Idealab,” participation in national conferences, and specialized station relation and marketing. A summative evaluation of the MS2 project indicates that overall, these activities helped make a significant impact on the viewers, users, and participants that NOVA reached. The final evaluation conducted by Concord Evaluation Group (CEG) confidently concluded that the broadcast, website, and outreach activities were successful at achieving the project’s intended impacts. CEG reported that the MS2 series and website content were

  14. Supernova hydrodynamicas experiments using the Nova laser

    SciTech Connect

    Remington, B.A.; Glendinning, S.G.; Estabrook, K.

    1997-07-01

    We are developing experiments using the Nova laser to investigate (1) compressible nonlinear hydrodynamic mixing relevant to the first few hours of the supernova (SN) explosion and (2) ejecta-ambient plasma interactions relevant to the early SN remnant phase. The experiments and astrophysical implications are discussed.

  15. Clinical and laboratory features of Nocardia nova.

    PubMed Central

    Wallace, R J; Brown, B A; Tsukamura, M; Brown, J M; Onyi, G O

    1991-01-01

    Recent studies have shown that Nocardia asteroides isolates have five major antibiotic resistance patterns; one of these patterns identifies isolates of Nocardia farcinica. In the current study, we investigated a second pattern characterized by susceptibility to ampicillin and erythromycin. This pattern was seen in 17% of 223 clinical isolates identified by standard techniques as N. asteroides and associated with diseases typical for nocardiae. Biochemically, isolates with this drug pattern were relatively homogeneous and identical to the type strain and previous descriptions of Nocardia nova. The strains studied were unique among nocardiae in having both alpha- and beta-esterase activity (85 and 95%, respectively). However, the arylsulfatase activity at 14 days (75%) and antimicrobial susceptibility patterns, including susceptibility to erythromycin (100%), were the only routinely available methods that would separate N. nova strains from other members of N. asteroides. N. asteroides should be considered a complex because current clinical identification schemes include isolates of N. farcinica and N. nova and may well include additional species. This is the first detailed description of N. nova as a pathogen in humans. PMID:1774244

  16. NOVA[R] Spring 2001 Teacher's Guide.

    ERIC Educational Resources Information Center

    WGBH-TV, Boston, MA.

    This teacher's guide is designed to accompany the PBS television program "NOVA" and features six activities. "Sultan's Lost Treasure" presents the attempts of an archaeologist and his team to salvage an ancient ship wreck. "Vanished!" investigates what happened to the Stardust airliner in 1947 which disappeared during…

  17. Nova Scotia. Reference Series No. 32.

    ERIC Educational Resources Information Center

    Department of External Affairs, Ottawa (Ontario).

    This booklet, one of a series featuring the Canadian provinces, presents a brief overview of Nova Scotia and is suitable for teacher reference or student reading. Separate sections discuss the geography and climate, history, economic development, fishing, agriculture, forestry, mining, manufacturing, energy, education, arts and culture, and…

  18. The NOvA simulation chain

    DOE PAGES

    Aurisano, A.; Backhouse, C.; Hatcher, R.; ...

    2015-12-23

    The NOvA experiment is a two-detector, long-baseline neutrino experiment operating in the recently upgraded NuMI muon neutrino beam. Simulating neutrino interactions and backgrounds requires many steps including: the simulation of the neutrino beam flux using FLUKA and the FLUGG interface, cosmic ray generation using CRY, neutrino interaction modeling using GENIE, and a simulation of the energy deposited in the detector using GEANT4. To shorten generation time, the modeling of detector-specific aspects, such as photon transport, detector and electronics noise, and readout electronics, employs custom, parameterized simulation applications. We will describe the NOvA simulation chain, and present details on the techniquesmore » used in modeling photon transport near the ends of cells, and in developing a novel data-driven noise simulation. Due to the high intensity of the NuMI beam, the Near Detector samples a high rate of muons originating in the surrounding rock. In addition, due to its location on the surface at Ash River, MN, the Far Detector collects a large rate ((˜) 140 kHz) of cosmic muons. Furthermore, we will discuss the methods used in NOvA for overlaying rock muons and cosmic ray muons with simulated neutrino interactions and show how realistically the final simulation reproduces the preliminary NOvA data.« less

  19. The Expanding Fireball of Nova Delphini 2013

    DTIC Science & Technology

    2014-10-26

    A classical nova occurs when material accreting onto the surface of a white dwarf in a close binary system ignites in a thermonuclear runaway...explosion could be intrinsically bipolar, resulting from a localized ignition on the surface of the white dwarf or as a consequence of rotational

  20. Models of classical and recurrent novae

    NASA Technical Reports Server (NTRS)

    Friedjung, Michael; Duerbeck, Hilmar W.

    1993-01-01

    The behavior of novae may be divided roughly into two separate stages: quiescence and outburst. However, at closer inspection, both stages cannot be separated. It should be attempted to explain features in both stages with a similar model. Various simple models to explain the observed light and spectral observations during post optical maximum activity are conceivable. In instantaneous ejection models, all or nearly all material is ejected in a time that is short compared with the duration of post optical maximum activity. Instantaneous ejection type 1 models are those where the ejected material is in a fairly thin shell, the thickness of which remains small. In the instantaneous ejection type 2 model ('Hubble Flow'), a thick envelope is ejected instantaneously. This envelope remains thick as different parts have different velocities. Continued ejection models emphasize the importance of winds from the nova after optical maximum. Ejection is supposed to occur from one of the components of the central binary, and one can imagine a general swelling of one of the components, so that something resembling a normal, almost stationary, stellar photosphere is observed after optical maximum. The observed characteristics of recurrent novae in general are rather different from those of classical novae, thus, models for these stars need not be the same.

  1. Nova Scotia. Reference Series No. 32.

    ERIC Educational Resources Information Center

    Department of External Affairs, Ottawa (Ontario).

    This booklet, one of a series featuring the Canadian provinces, presents a brief overview of Nova Scotia and is suitable for teacher reference or student reading. Separate sections discuss the geography and climate, history, economic development, fishing, agriculture, forestry, mining, manufacturing, energy, education, arts and culture, and…

  2. Hydrodynamic studies of the nova outburst

    SciTech Connect

    Starrfield, S.

    1980-01-01

    Hydrostatic studies have shown that a thermonuclear runaway will occur in the hydrogen-rich material accumulated on the surface of a degenerate star. Results of earlier studies are used to obtain models for calculations which show that the resulting thermonuclear runaway produces a nova outburst; the characteristics of this outburst depending on the carbon-oxygen abundance in the envelope. (GHT)

  3. Status of the NOvA experiment

    SciTech Connect

    Plunkett, Robert; /Fermilab

    2007-12-01

    The NOvA experiment, using the existing NuMI beamline, is planned for construction at Ash River, Minnesota. The experiment will provide a measurement of, or strong limit on the neutrino mixing angle {theta}{sub 13}, and for sufficiently strong mixing, establish the hierarchy of the neutrino masses.

  4. NEVEC: the NOVA ESO VLTI Expertise Center

    NASA Astrophysics Data System (ADS)

    Le Poole, Rudolf S.; Miley, George; Jaffe, Walter; Glindemann, Andreas; Bakker, Eric J.; Waters, Rens; Roettgering, Huub J. A.; Cotton, Bill; Percheron, Isabelle; Meisner, Jeffrey A.; de Jong, Jeroen; D'Arcio, Luigi; Heijligers, Bjoern

    2003-02-01

    The start of NEVEC was initiated by the opportunity in the Netherlands to reinstate instrumental efforts in astronomy through a funding program for 'Top Research Schools,’ which brought about the creation of NOVA. The fact that considerable experience exists in Radio Astronomical imaging through interferometry (the Westerbork Synthesis Radio Telescope started in 1970), and the relatively small size at the time of ESO's VLTI Team made it opportune to aim for a win-win situation through collaboration. So presently an MOU between ESO and NOVA is in force, which stipulates that 10 out of the 18 man-years funded by NOVA for NEVEC until 2005 [new personnel, in university setting (Leiden) but on project money] shall be used on tasks that are mutually agreed between NOVA and ESO. The tasks presently are found in the domain of observing modes, calibration and modeling, as well as contributing to the commissioning of new instruments and thinking about future instruments. Another task, outside these 10 FTE, has been the data handling and analysis software for MIDI, and again contributing to its commissioning. Delivery of the first operational version in Heidelberg has just taken place (summer 2002) contributing to the successful Preliminary Acceptance in Europe for MIDI on September 10, 2002. The actual state of 'products and deliveries' and the future outlook are reviewed.

  5. NOVA[R] Spring 2002 Teacher's Guide.

    ERIC Educational Resources Information Center

    Armstrong, Peter; Ransick, Kristi; Rosene, Dale; Sammons, James

    The guide presents lesson plans from "NOVA" which targets middle school and junior high school students and meet the National Science Education Standards. Lessons include: (1) "Neanderthals on Trial"; (2) "Fireworks"; (3) "Secrets, Lies and Atomic Spies"; (4) "Bioterror"; (5) "The Missing…

  6. Nova Sct 2009 (V496 Sct)

    NASA Astrophysics Data System (ADS)

    Templeton, Matthew R.

    2009-11-01

    As initially announced in CBET 2008 (Daniel W. E. Green, ed.) and AAVSO Special Notice #176 (M. Templeton), and expanded on in IAU Circular No. 9093 (Green, ed.), Nova Scutum 2009 (V496 Sct) was discovered by H. Nishimura (Miyawaki, Kakegawa, Japan) on 2009 November 8.370 UT at unfiltered CCD magnitude of 8.8, using 120-mm camera lens, derived by S. Nakano (Sumoto, Japan) from Nishimura's discovery images. RA: 18:43:45.57 , Dec: -7:36:42.0 (equinox 2000.0) from E. Guido and G. Sostero. Spectroscopy by F. Teyssier (Rouen, France); D. Balam (NRCC) and G. Sarty (U. Sask.); and U. Munari et al. (INA-Padova & the Asiago Novae and Symbiotic Stars Collaboration) confirm the object as a nova, with emission lines showing P Cygni profiles. Munari et al. show the presence of FeII, indicating a nova of the Fe II-type. Observations should be reported to the AAVSO International Database as V496 SCO.

  7. Nova pulse power system description and status

    SciTech Connect

    Holloway, R.W.; Whitham, K.; Merritt, B.T.; Gritton, D.G.; Oicles, J.A.

    1981-06-01

    The Nova laser system is designed to produce critical data in the nation's inertial confinement fusion effort. It is the world's largest peak power laser and presents various unique pulse power problems. In this paper, pulse power systems for this laser are described, the evolutionary points from prior systems are pointed out, and the current status of the hardware is given.

  8. The expanding fireball of Nova Delphini 2013.

    PubMed

    Schaefer, G H; ten Brummelaar, T; Gies, D R; Farrington, C D; Kloppenborg, B; Chesneau, O; Monnier, J D; Ridgway, S T; Scott, N; Tallon-Bosc, I; McAlister, H A; Boyajian, T; Maestro, V; Mourard, D; Meilland, A; Nardetto, N; Stee, P; Sturmann, J; Vargas, N; Baron, F; Ireland, M; Baines, E K; Che, X; Jones, J; Richardson, N D; Roettenbacher, R M; Sturmann, L; Turner, N H; Tuthill, P; van Belle, G; von Braun, K; Zavala, R T; Banerjee, D P K; Ashok, N M; Joshi, V; Becker, J; Muirhead, P S

    2014-11-13

    A classical nova occurs when material accreting onto the surface of a white dwarf in a close binary system ignites in a thermonuclear runaway. Complex structures observed in the ejecta at late stages could result from interactions with the companion during the common-envelope phase. Alternatively, the explosion could be intrinsically bipolar, resulting from a localized ignition on the surface of the white dwarf or as a consequence of rotational distortion. Studying the structure of novae during the earliest phases is challenging because of the high spatial resolution needed to measure their small sizes. Here we report near-infrared interferometric measurements of the angular size of Nova Delphini 2013, starting one day after the explosion and continuing with extensive time coverage during the first 43 days. Changes in the apparent expansion rate can be explained by an explosion model consisting of an optically thick core surrounded by a diffuse envelope. The optical depth of the ejected material changes as it expands. We detect an ellipticity in the light distribution, suggesting a prolate or bipolar structure that develops as early as the second day. Combining the angular expansion rate with radial velocity measurements, we derive a geometric distance to the nova of 4.54 ± 0.59 kiloparsecs from the Sun.

  9. NOVA[R] Fall 2001 Teacher's Guide.

    ERIC Educational Resources Information Center

    WGBH-TV, Boston, MA.

    This teacher guide includes activity information for the program NOVA, Fall 2001. Background for each activity is provided along with its correlation to the national science standards. Activities include: (1) "Search for a Safe Cigarette"; (2) "18 Ways To Make a Baby"; (3) "Secrets of Mind"; (4) "Neanderthals on…

  10. NOvA: Exploring Neutrino Mysteries

    ScienceCinema

    Vahle, Tricia; Messier, Mark

    2016-07-12

    Neutrinos are a mystery to physicists. They exist in three different flavors and mass states and may be able to give hints about the origins of the matter-dominated universe. A new long-baseline experiment led by Fermilab called NOvA may provide some answers.

  11. Numerical modelling of the classical nova outburst

    SciTech Connect

    Kutter, G.S.; Sparks, W.M.

    1987-01-01

    We describe a mechanism that promises to explain how nova outbursts take place on white dwarf of 1 Msub solar or less and for accretion rates of 4 x 10/sup -10/ Msub solar yr/sup -1/ or greater. 7 refs.

  12. The Dwarf Novae Ty Psc and V436 Cen During Quiescence: Exposed White Dwarfs?

    NASA Astrophysics Data System (ADS)

    Nadalin, I.; Sion, E. M.

    2000-12-01

    The dwarf novae TY Psc and V436 Cen are SU UMa systems with very similar orbital periods, similar recurrence times for normal outbursts ( 23 days) and superoutbursts ( ~ 340 days) and nearly identical outburst amplitudes. We have applied the Massa-Fitzpatrick (2000) flux calibration correction to the archival IUE NEWSIPS SWP spectra of these two systems, obtained during dwarf nova quiescence. We have carried out high gravity model atmosphere using the codes TLUSTY195, SYNSPEC42, ROTIN and accretion disk synthetic spectra from the grid of Wade and Hubeny (1998). We present our results on the physical properties of the underlying white dwarf accreters, including temperature, gravity, chemical abundances estimates, and the accretion rate during quiescence. We discuss our results in the context of the overall picture of accretion physics in dwarf novae and the effects of accretion on the white dwarf. This research was supported in part by NSF grant AST 99-01955, NASA ADP grant NAG5-8388 and by summer research funding from the NASA- Delaware Space Grant Colleges Consortium.

  13. Cerebral malaria

    PubMed Central

    Newton, C.; Hien, T. T.; White, N.

    2000-01-01

    Cerebral malaria may be the most common non-traumatic encephalopathy in the world. The pathogenesis is heterogenous and the neurological complications are often part of a multisystem dysfunction. The clinical presentation and pathophysiology differs between adults and children. Recent studies have elucidated the molecular mechanisms of pathogenesis and raised possible interventions. Antimalarial drugs, however, remain the only intervention that unequivocally affects outcome, although increasing resistance to the established antimalarial drugs is of grave concern. Artemisinin derivatives have made an impact on treatment, but other drugs may be required. With appropriate antimalarial drugs, the prognosis of cerebral malaria often depends on the management of other complications—for example, renal failure and acidosis. Neurological sequelae are increasingly recognised, but further research on the pathogenesis of coma and neurological damage is required to develop other ancillary treatments.

 PMID:10990500

  14. THE DWARF NOVA OUTBURSTS OF NOVA HER 1960 (=V446 HER)

    SciTech Connect

    Honeycutt, R. K.; Robertson, J. W.; Kafka, S. E-mail: jrobertson@atu.edu

    2011-04-15

    V446 Her is the best example of an old nova which has developed dwarf nova (DN) eruptions in the post-nova state. We report on observed properties of the long-term light curve of V446 Her, using photometry over 19 years. Yearly averages of the outburst (OB) magnitudes show a decline of {approx}0.013 mag yr{sup -1}, consistent with the decline of other post-novae that do not have DN OBs. Previous suggestions of bimodal distributions of the amplitudes and widths of the OBs are confirmed. The OBs occur at a mean spacing of 18 days but the range of spacings is large (13-30 days). From simulations of DN OBs, it has been predicted that the OB spacing in V446 Her will increase as M-dot from the red dwarf companion slowly falls following the nova; however, the large intrinsic scatter in the spacings serves to hide any evidence of this effect. We do find a systematic change in the OB pattern in which the brighter, wider type of OBs disappeared after late 2003, and this phenomenon is suggested to be due to falling M-dot following the nova.

  15. Explosive lithium production in the classical nova V339 Del (Nova Delphini 2013).

    PubMed

    Tajitsu, Akito; Sadakane, Kozo; Naito, Hiroyuki; Arai, Akira; Aoki, Wako

    2015-02-19

    The origin of lithium (Li) and its production process have long been uncertain. Li could be produced by Big Bang nucleosynthesis, interactions of energetic cosmic rays with interstellar matter, evolved low-mass stars, novae, and supernova explosions. Chemical evolution models and observed stellar Li abundances suggest that at least half the Li may have been produced in red giants, asymptotic giant branch (AGB) stars, and novae. No direct evidence, however, for the supply of Li from evolved stellar objects to the Galactic medium has hitherto been found. Here we report the detection of highly blue-shifted resonance lines of the singly ionized radioactive isotope of beryllium, (7)Be, in the near-ultraviolet spectra of the classical nova V339 Del (Nova Delphini 2013) 38 to 48 days after the explosion. (7)Be decays to form (7)Li within a short time (half-life of 53.22 days). The (7)Be was created during the nova explosion via the alpha-capture reaction (3)He(α,γ)(7)Be (ref. 5). This result supports the theoretical prediction that a significant amount of (7)Li is produced in classical nova explosions.

  16. The NOvA software testing framework

    NASA Astrophysics Data System (ADS)

    Tamsett, M.; C Group

    2015-12-01

    The NOvA experiment at Fermilab is a long-baseline neutrino experiment designed to study vε appearance in a vμ beam. NOvA has already produced more than one million Monte Carlo and detector generated files amounting to more than 1 PB in size. This data is divided between a number of parallel streams such as far and near detector beam spills, cosmic ray backgrounds, a number of data-driven triggers and over 20 different Monte Carlo configurations. Each of these data streams must be processed through the appropriate steps of the rapidly evolving, multi-tiered, interdependent NOvA software framework. In total there are greater than 12 individual software tiers, each of which performs a different function and can be configured differently depending on the input stream. In order to regularly test and validate that all of these software stages are working correctly NOvA has designed a powerful, modular testing framework that enables detailed validation and benchmarking to be performed in a fast, efficient and accessible way with minimal expert knowledge. The core of this system is a novel series of python modules which wrap, monitor and handle the underlying C++ software framework and then report the results to a slick front-end web-based interface. This interface utilises modern, cross-platform, visualisation libraries to render the test results in a meaningful way. They are fast and flexible, allowing for the easy addition of new tests and datasets. In total upwards of 14 individual streams are regularly tested amounting to over 70 individual software processes, producing over 25 GB of output files. The rigour enforced through this flexible testing framework enables NOvA to rapidly verify configurations, results and software and thus ensure that data is available for physics analysis in a timely and robust manner.

  17. ToO IRS Observations of Novae

    NASA Astrophysics Data System (ADS)

    Woodward, Charles; Black, John; Bode, Michael; Evans, Aneuryn; Geballe, Thomas; Gehrz, Robert; Greenhouse, Matthew; Hauschildt, Peter; Helton, Andrew; Krautter, Joachim; Liller, William; Lyke, James; Lynch, David; Rudy, Richard; Salama, Alberto; Schwarz, Greg; Shore, Steve; Starrfield, Sumner; Truran, Jim; Vanlandingham, Karen; Wagner, R. Mark

    2006-05-01

    Stars are the engines of energy production and chemical evolution in our Universe. They deposit radiative and mechanical energy into their environments and enrich the ambient interstellar medium with elements synthesized in their interiors and dust grains condensed in their atmospheres. Classical novae (CN) contribute to this cycle of chemical enrichment through explosive nucleosynthesis and the violent ejection of material dredged from the white dwarf progenitor and mixed with the accreted surface layers. Using Spitzer (+IRS), we propose a 25.8 hrs no-impact ToO program to study (in temporal detail) the evolutionary stages of CN by targeting 4 Galactic and 2 Magellanic Cloud (MC) novae. Spitzer is a unique facility that enables us to investigate aspects of the CN phenomenon including the in situ formation and astromineralogy of nova dust, the elemental abundances resulting from thermonuclear runaway, the correlation of ejecta masses with progenitor type, the bolometric luminosities of the outburst, and the kinematics and structure of the ejected envelopes. Synoptic, high signal-to-noise IRS spectra permit: 1) determination of the grain size distribution and mineral composition of nova dust; 2) estimation of chemical abundances of nova ejecta from coronal and other emission line spectroscopy; 3) measurement of the density and masses of the ejecta; 4) characterization of the geometry and structure of ejected shells at early stages during which the initial mixing of the chemical abundances can be studied in detail; and 5) exploration of the characteristics of CN in low metallicity systems (MC) at mid- to far-IR wavelengths. Observations of CN with Spitzer will be complemented by extensive ground-based, as well as space-based (e.g., Chandra, Swift, XMM-Newton), DDT and ToO programs led by team CoIs.

  18. Cerebral Palsy (For Parents)

    MedlinePlus

    ... 10 Tips for Parents Healthy Habits for TV, Video Games, and the Internet Cerebral ... cerebral Cerebral palsy (CP) is a disorder that affects muscle tone, movement, and motor skills (the ability to move in a coordinated and ...

  19. Far Ultraviolet Spectroscopy of Three Long Period Nova-Like Variables, V363 Aur, AC Cnc and RZ Gru

    NASA Astrophysics Data System (ADS)

    Bisol, Alexandra; Sion, E. M.

    2011-01-01

    We have selected three nova-like variables: V363 Aur, RZ Gru and AC Cnc, all of which are UX UMa types, having similar orbital periods well beyond the 3 to 4 hour range where most nova-likes are found. All should have very similar secondary stars given the fact that they their physical parameters are so similar. V363 Aur is a bona fide SW Sex star, and AC Cnc is a probable one, while RZ Gru is not a member of the SW Sex subclass. Our objective is to carry out the first synthetic spectral analysis of far ultraviolet spectra of the three systems using state-of-the-art models both of accretion disks and photospheres. Therefore we shall compare the distances we obtain from the best fitting synthetic spectral models to other distance estimates in the literature. We present model-derived accretion rates and distances for all three systems. The FUV flux range of RZ Gru and V363 Aur is dominated by radiation from an optically thick, steady state, accretion but for AC Cnc, we find that a hot white dwarf accounts for 70% of the FUV flux. We compare the FUV characteristics and physical properties of these three long period nova-like systems to the properties of other nova-likes at shorter periods. This work was supported in part by NSF grant AST0807892 to Villanova University.

  20. The awakening of a classical nova from hibernation

    NASA Astrophysics Data System (ADS)

    Mróz, Przemek; Udalski, Andrzej; Pietrukowicz, Paweł; Szymański, Michał K.; Soszyński, Igor; Wyrzykowski, Łukasz; Poleski, Radosław; Kozłowski, Szymon; Skowron, Jan; Ulaczyk, Krzysztof; Skowron, Dorota; Pawlak, Michał

    2016-09-01

    Cataclysmic variable stars—novae, dwarf novae, and nova-likes—are close binary systems consisting of a white dwarf star (the primary) that is accreting matter from a low-mass companion star (the secondary). From time to time such systems undergo large-amplitude brightenings. The most spectacular eruptions, with a ten-thousandfold increase in brightness, occur in classical novae and are caused by a thermonuclear runaway on the surface of the white dwarf. Such eruptions are thought to recur on timescales of ten thousand to a million years. In between, the system’s properties depend primarily on the mass-transfer rate: if it is lower than a billionth of a solar mass per year, the accretion becomes unstable and the matter is dumped onto the white dwarf during quasi-periodic dwarf nova outbursts. The hibernation hypothesis predicts that nova eruptions strongly affect the mass-transfer rate in the binary, keeping it high for centuries after the event. Subsequently, the mass-transfer rate should significantly decrease for a thousand to a million years, starting the hibernation phase. After that the nova awakes again—with accretion returning to the pre-eruption level and leading to a new nova explosion. The hibernation model predicts cyclical evolution of cataclysmic variables through phases of high and low mass-transfer. The theory gained some support from the discovery of ancient nova shells around the dwarf novae Z Camelopardalis and AT Cancri, but direct evidence for considerable mass-transfer changes prior, during and after nova eruptions has not hitherto been found. Here we report long-term observations of the classical nova V1213 Cen (Nova Centauri 2009) covering its pre- and post-eruption phases and precisely documenting its evolution. Within the six years before the explosion, the system revealed dwarf nova outbursts indicative of a low mass-transfer rate. The post-nova is two orders of magnitude brighter than the pre-nova at minimum light with no trace of

  1. The awakening of a classical nova from hibernation.

    PubMed

    Mróz, Przemek; Udalski, Andrzej; Pietrukowicz, Paweł; Szymański, Michał K; Soszyński, Igor; Wyrzykowski, Łukasz; Poleski, Radosław; Kozłowski, Szymon; Skowron, Jan; Ulaczyk, Krzysztof; Skowron, Dorota; Pawlak, Michał

    2016-09-29

    Cataclysmic variable stars-novae, dwarf novae, and nova-likes-are close binary systems consisting of a white dwarf star (the primary) that is accreting matter from a low-mass companion star (the secondary). From time to time such systems undergo large-amplitude brightenings. The most spectacular eruptions, with a ten-thousandfold increase in brightness, occur in classical novae and are caused by a thermonuclear runaway on the surface of the white dwarf. Such eruptions are thought to recur on timescales of ten thousand to a million years. In between, the system's properties depend primarily on the mass-transfer rate: if it is lower than a billionth of a solar mass per year, the accretion becomes unstable and the matter is dumped onto the white dwarf during quasi-periodic dwarf nova outbursts. The hibernation hypothesis predicts that nova eruptions strongly affect the mass-transfer rate in the binary, keeping it high for centuries after the event. Subsequently, the mass-transfer rate should significantly decrease for a thousand to a million years, starting the hibernation phase. After that the nova awakes again-with accretion returning to the pre-eruption level and leading to a new nova explosion. The hibernation model predicts cyclical evolution of cataclysmic variables through phases of high and low mass-transfer. The theory gained some support from the discovery of ancient nova shells around the dwarf novae Z Camelopardalis and AT Cancri, but direct evidence for considerable mass-transfer changes prior, during and after nova eruptions has not hitherto been found. Here we report long-term observations of the classical nova V1213 Cen (Nova Centauri 2009) covering its pre- and post-eruption phases and precisely documenting its evolution. Within the six years before the explosion, the system revealed dwarf nova outbursts indicative of a low mass-transfer rate. The post-nova is two orders of magnitude brighter than the pre-nova at minimum light with no trace of dwarf

  2. Progress in Modeling Classical Nova Outbursts

    NASA Astrophysics Data System (ADS)

    Calder, A. C.; Alexakis, A.; Dursi, L. J.; Mignone, A.; Timmes, F. X.; Truran, J. W.; Rosner, R.; Lamb, D. Q.; Brown, E.; Fryxell, B.; Zingale, M.; Ricker, P.; Olson, K.

    2003-03-01

    We report on progress in modeling many facets of Classical Novae. These include magnetohydrodynamical simulations of the accretion phase (for the case of magnetic white dwarfs) and hydrodynamical simulations of the mixing of white dwarf material into the hydrogen-rich envelope by resonant gravity wave breaking at the surface of the white dwarf (See also Alexakis, et al.). We also report on initial efforts at the development of a sub-grid enrichment model based on these results as well as results of one-dimensional simulations with mixing length convection of the enrichment process exploring the long-term behavior of the enriched region. Finally, we present two-dimensional simulations of the onset and development of convection in nova precursor models and during the runaway. This work was supported by the DOE ASCI/Alliances program at the University of Chicago under grant No. B341495.

  3. Status of the NOvA Experiment

    NASA Astrophysics Data System (ADS)

    Perevalov, Denis

    2012-08-01

    NOvA is an off-axis long baseline neutrino experiment searching for νμ → νe oscillations using an upgraded NuMI neutrino beam from Fermilab, Batavia, IL. The main physics goal is a measurement or strong limit on the neutrino mixing angle θ13. For sufficiently large values of θ13, NOvA will also be sensitive to measuring CP violation and establishing the neutrino masses hierarchy. A large 14 kton Far detector, comprised of liquid scintillator contained in extruded PVC cells, will also provide an opportunity for other non-accelerator physics searches. While civil construction at the far detector is underway, a smaller prototype near detector has been assembled at Fermilab and is being studied.

  4. Strong earthquakes, novae and cosmic ray environment

    NASA Technical Reports Server (NTRS)

    Yu, Z. D.

    1985-01-01

    Observations about the relationship between seismic activity and astronomical phenomena are discussed. First, after investigating the seismic data (magnitude 7.0 and over) with the method of superposed epochs it is found that world seismicity evidently increased after the occurring of novae with apparent magnitude brighter than 2.2. Second, a great many earthquakes of magnitude 7.0 and over occurred in the 13th month after two of the largest ground level solar cosmic ray events (GLEs). The causes of three high level phenomena of global seismic activity in 1918-1965 can be related to these, and it is suggested that according to the information of large GLE or bright nova predictions of the times of global intense seismic activity can be made.

  5. Tycho Brahe and the Nova of 1572

    NASA Astrophysics Data System (ADS)

    Gingerich, O.

    2005-12-01

    The brilliant Nova of 1572 marked the beginning of the end of Aristotelian cosmology and provided the defining moment when the young Tycho Brahe became a professional astronomer. He received more than a ton of gold from the Danish king to build his Uraniborg Observatory. His instruments, the finest produced in the pre-telescopic age, enabled him to establish that both the nova and the Comet of 1577 lay beyond the moon, contrary to Aristotle's teaching. His major attempt to establish the distance to Mars (in order to distinguish between the Ptolemaic and Copernican cosmologies) failed, but left in its wake a magnificently accurate set of data that enabled Kepler to make the greatest advance in celestial mechanics since Copernicus himself.

  6. Discovery of an eclipsing dwarf nova in the ancient nova shell Te 11

    NASA Astrophysics Data System (ADS)

    Miszalski, Brent; Woudt, P. A.; Littlefair, S. P.; Warner, B.; Boffin, H. M. J.; Corradi, R. L. M.; Jones, D.; Motsoaledi, M.; Rodríguez-Gil, P.; Sabin, L.; Santander-García, M.

    2016-02-01

    We report on the discovery of an eclipsing dwarf nova (DN) inside the peculiar, bilobed nebula Te 11. Modelling of high-speed photometry of the eclipse finds the accreting white dwarf to have a mass 1.18 M⊙ and temperature 13 kK. The donor spectral type of M2.5 results in a distance of 330 pc, colocated with Barnard's loop at the edge of the Orion-Eridanus superbubble. The perplexing morphology and observed bow shock of the slowly expanding nebula may be explained by strong interactions with the dense interstellar medium in this region. We match the DN to the historic nova of 483 CE in Orion and postulate that the nebula is the remnant of this eruption. This connection supports the millennia time-scale of the post-nova transition from high to low mass-transfer rates. Te 11 constitutes an important benchmark system for CV and nova studies as the only eclipsing binary out of just three DNe with nova shells.

  7. A wave model for dwarf novae

    NASA Technical Reports Server (NTRS)

    Sparks, W. M.; Kutter, G. S.

    1980-01-01

    The rapid coherent oscillation during a dwarf nova outburst is attributed to an accretion-driven wave going around the white dwarf component of the binary system. The increase and decrease in the period of this oscillation is due to the change in the velocity of the wave as it is first being driven and then damped. Qualitatively, a large number of observations can be explained with such a model. The beginnings of a mathematical representation of this model are developed.

  8. Swift observations of Nova Scuti 2017

    NASA Astrophysics Data System (ADS)

    Kuin, N. P. M.; Page, K. L.; Williams, S. C.; Darnley, M. J.; Nelson, T. J.; Osborne, J.

    2017-08-01

    Nova Sct 2017 (ASASSN-17hx/ASASSN-17ib) went into eruption on 2017-06-19.41 (hereafter taken as Day 0), as reported on the ASAS SN transient page (see also ATEL #10523,#10524) Spectroscopic confirmation (ATEL #10527,#10542) observed emission in H and He I, and in N II as well as Fe II. The ASASSN light curve data show a peak of V = 8.75 on 2017, July 30, day 40.867.

  9. Testing Coordinate Frame Transformations NOVAS vs SOFA

    DTIC Science & Technology

    2010-07-14

    2 International Earth Rotation and Reference Systems Service (IERS) Fortran modules is independent of SOFA although both software libraries include...code that is similar to two .3 The document SOFA Tools for Earth Attitude (IAU 2009b), also known as the “SOFA Cookbook,” contains several Fortran...out in both NOVAS and SOFA. NU2000A and iau2000a (Fortran and C, respectively), which evaluate the full 1,365-term IAU 2000A nutation series in

  10. Mechanical construction of the 22 Nova laser

    SciTech Connect

    Hurley, C.A.; Frick, F.A.; Patton, H.G.; Bradley, G.; Martos, A.

    1983-11-22

    The Nova laser system for Inertial Confinement Fusion studies at Lawrence Livermore National Laboratory is under construction and will be completed October 1984 with first operations scheduled for 1985. This system is the largest precision opto-mechanical engineering system ever built. Major engineering and subsystems are mechanical, optical, and electrical power. A series of system technologies include alignment, diagnostics, target, frequency conversion, and controls. This paper will only discuss the mechanical system.

  11. Introduction to the Nova technical contract

    SciTech Connect

    Lindl, J.D.; Kilkenny, J.D.

    1996-06-01

    The 1990 National Academy of Sciences (NAS) final report recommended proceeding with the construction of a 1-to 2-MJ Nd-doped glass laser designed to achieve ignition in the laboratory (a laser originally called the Nova Upgrade, but now called the National Ignition Facility, or NIF, and envisioned as a national user facility). As a prerequisite, the report recommended completion of a series of target physics objectives on the Nova laser in use at the Lawrence Livermore National Laboratory (LLNL). Meeting these objectives, which were called the Nova Technical Contract (NTC), would demonstrate (the Academy committee believed) that the physics of ignition targets was understood well enough that the laser requirements could be accurately specified. Completion of the NTC objectives was given the highest priority (it was Recommendation 1.1) in the NAS report. The NAS committee also recommended a concentrated effort on advanced target design for ignition. As recommended in the report, completion of these objectives has been the joint responsibility of LLNL and the Los Alamos National Laboratory. Most of the articles in this issue of the ICF Quarterly were written jointly by scientists from both institutions. The original NTC objectives have been largely met. This Introduction summarizes those objectives and their motivation in the context of the requirements for ignition.

  12. Low Mach Number Simulations of Classical Novae

    NASA Astrophysics Data System (ADS)

    Krueger, Brendan K.; Calder, A. C.; Zingale, M.; Almgren, A. S.; Bell, J. B.; Nonaka, A.

    2012-01-01

    Classical novae are thermonuclear explosions in the accreted layer on the surface of a white dwarf star. The manner in which convective flow interacts with the underlying white dwarf plays a critical role in determining the composition of the accreted layer and the energy release in the outburst. Studies of these complex reactive flows are typically limited by the available computing technology. I am applying a new low Mach number simulation code, MAESTRO, to study classical novae. MAESTRO filters out acoustic waves, allowing much larger time steps without restricting temperature or density perturbations, which in turn enables simulations of much longer time scales. With this unique tool, I have been exploring the development of convection and subsequent mixing in classical novae and their impact on the overall evolution of the outburst. I will present results from multidimensional simulations and quantify the character of the convection and mixing. This work was supported by NASA under grant No. NNX09AD19G and LLNL under contract B59328.

  13. Integration of the Super Nova early warning system with the NOvA Trigger

    SciTech Connect

    Habig, Alec; Zirnstein, Jan

    2015-12-23

    The NOvA experiment, with a baseline of 810km, samples Fermilab’s upgraded NuMI beam with a Near Detector on-site and a Far Detector (FD) at Ash River, MN, to observe oscillations of muon neutrinos. The 344,064 liquid scintillator-filled cells of the 14 kton FD provide high granularity of a large detector mass and enable us to also study non-accelerator based neutrinos with our Data Driven Trigger framework. This paper will focus on the real time integration of the SNEWS with the NOvA Trigger where we have set up an XML-RPC based messaging system to inject the SNEWS signal directly into our trigger. In conclusion, this presents a departure from the E-Mail based notification mechanism used by SNEWS in the past and allows NOvA more control over propagation and transmission timing.

  14. Integration of the Super Nova early warning system with the NOvA Trigger

    DOE PAGES

    Habig, Alec; Zirnstein, Jan

    2015-12-23

    The NOvA experiment, with a baseline of 810km, samples Fermilab’s upgraded NuMI beam with a Near Detector on-site and a Far Detector (FD) at Ash River, MN, to observe oscillations of muon neutrinos. The 344,064 liquid scintillator-filled cells of the 14 kton FD provide high granularity of a large detector mass and enable us to also study non-accelerator based neutrinos with our Data Driven Trigger framework. This paper will focus on the real time integration of the SNEWS with the NOvA Trigger where we have set up an XML-RPC based messaging system to inject the SNEWS signal directly into ourmore » trigger. In conclusion, this presents a departure from the E-Mail based notification mechanism used by SNEWS in the past and allows NOvA more control over propagation and transmission timing.« less

  15. Integration of the Super Nova Early Warning System with the NOvA Trigger

    NASA Astrophysics Data System (ADS)

    Habig, Alec; Zirnstein, Jan

    2015-12-01

    The NOvA experiment, with a baseline of 810km, samples Fermilab's upgraded NuMI beam with a Near Detector on-site and a Far Detector (FD) at Ash River, MN, to observe oscillations of muon neutrinos. The 344,064 liquid scintillator-filled cells of the 14kton FD provide high granularity of a large detector mass and enable us to also study non-accelerator based neutrinos with our Data Driven Trigger framework. This paper will focus on the real time integration of the SNEWS with the NOvA Trigger where we have set up an XML-RPC based messaging system to inject the SNEWS signal directly into our trigger. This presents a departure from the E-Mail based notification mechanism used by SNEWS in the past and allows NOvA more control over propagation and transmission timing.

  16. Extinction, ejecta masses, and radial velocities of novae

    NASA Technical Reports Server (NTRS)

    Williams, Robert E.

    1994-01-01

    Interstellar reddening is determined for a number of recent novae based upon emission-line ratios which are generally observable using CCDs. Large values of extinction are found for most systems, possibly indicative of an intrinsic component of reddening in postoutburst novae. The unusual characteristics of the (O I) lines in novae, which are strong and optically thick, require a large population of very dense globules which are the likely sites of dust formation. These pyroclasts must be ejected from the white dwarf. The total mass of the neutral gas in the globules in some of the objects is substantially larger than the masses normally derived for the ionized ejecta of novae. The distribution of radial velocities of Galactic novae in the Tololo sample, although uncertain, shows an asymmetry in having predominantly negative values. Either high internal absorption in the expanding ejecta skews the emission lines to bluer wavelengths, or most of the novae are moving out from the center of the Galaxy.

  17. Extinction, ejecta masses, and radial velocities of novae

    NASA Technical Reports Server (NTRS)

    Williams, Robert E.

    1994-01-01

    Interstellar reddening is determined for a number of recent novae based upon emission-line ratios which are generally observable using CCDs. Large values of extinction are found for most systems, possibly indicative of an intrinsic component of reddening in postoutburst novae. The unusual characteristics of the (O I) lines in novae, which are strong and optically thick, require a large population of very dense globules which are the likely sites of dust formation. These pyroclasts must be ejected from the white dwarf. The total mass of the neutral gas in the globules in some of the objects is substantially larger than the masses normally derived for the ionized ejecta of novae. The distribution of radial velocities of Galactic novae in the Tololo sample, although uncertain, shows an asymmetry in having predominantly negative values. Either high internal absorption in the expanding ejecta skews the emission lines to bluer wavelengths, or most of the novae are moving out from the center of the Galaxy.

  18. NovaNet Student Outcomes, 2001-2002.

    ERIC Educational Resources Information Center

    Harlow, Kristin; Baenen, Nancy

    NovaNet is an individualized, computer-based instruction program that is used in the Wake County Public School System (WCPSS), North Carolina, for high school course credit, remediation, and enrichment. NovaNet was first used in WCPSS in 1996, and in 1999 WCPSS received a 3-year federal grant to expand the use of NovaNET to all high schools. In…

  19. A SPITZER SURVEY OF NOVAE IN M31

    SciTech Connect

    Shafter, A. W.; Rubin, M.; Bode, M. F.; Darnley, M. J.; Misselt, K. A.; Hornoch, K.

    2011-01-20

    We report the results of the first infrared survey of novae in M31. Both photometric and spectroscopic observations of a sample of 10 novae (M31N 2006-09c, 2006-10a, 2006-10b, 2006-11a, 2007-07f, 2007-08a, 2007-08d, 2007-10a, 2007-11d, and 2007-11e) were obtained with the Spitzer Space Telescope. The observations, which were obtained between {approx}3 and {approx}7 months after discovery, revealed evidence for dust formation in two of the novae: M31N 2006-10a and (possibly) 2007-07f, and [Ne II] 12.8 {mu}m line emission in a third (2007-11e). The Spitzer observations were supplemented with ground-based optical photometric and spectroscopic data that were used to determine the speed classes and spectroscopic types of the novae. After including data for dust-forming Galactic novae, we show that dust formation timescales are correlated with nova speed class in that dust typically forms earlier in faster novae. Our failure to detect the signature of dust formation in most of our M31 sample is likely a result of the relatively long delay between nova eruption and our Spitzer observations. The two novae for which we found evidence of dust formation were the two 'slowest' novae in our sample. Finally, as expected, we found that the majority of the novae in our sample belong to the Fe II spectroscopic class, with only one clear example of the He/N class (M31N 2006-10b). Typical of an He/N system, M31N 2006-10b was the fastest nova in our sample, not detected with the IRS, and just barely detected in three of the IRAC bands when it was observed {approx}4 months after eruption.

  20. The UBV Color Evolution of Classical Novae. I. Nova-giant Sequence in the Color-Color Diagram

    NASA Astrophysics Data System (ADS)

    Hachisu, Izumi; Kato, Mariko

    2014-04-01

    We identified a general course of classical nova outbursts in the B - V versus U - B color-color diagram. It is reported that novae show spectra similar to those of A-F supergiants near optical light maximum. However, they do not follow the supergiant sequence in the color-color diagram, neither the blackbody nor the main-sequence sequence. Instead, we found that novae evolve along a new sequence in the pre-maximum and near-maximum phases, which we call "the nova-giant sequence." This sequence is parallel to but Δ(U - B) ≈ -0.2 mag bluer than the supergiant sequence. This is because the mass of a nova envelope is much (~10-4 times) less than that of a normal supergiant. After optical maximum, its color quickly evolves back blueward along the same nova-giant sequence and reaches the point of free-free emission (B - V = -0.03, U - B = -0.97), which coincides with the intersection of the blackbody sequence and the nova-giant sequence, and remains there for a while. Then the color evolves leftward (blueward in B - V but almost constant in U - B), owing mainly to the development of strong emission lines. This is the general course of nova outbursts in the color-color diagram, which was deduced from eight well-observed novae in various speed classes. For a nova with unknown extinction, we can determine a reliable value of the color excess by matching the observed track of the target nova with this general course. This is a new and convenient method for obtaining the color excesses of classical novae. Using this method, we redetermined the color excesses of 20 well-observed novae. The obtained color excesses are in reasonable agreement with the previous results, which in turn support the idea of our general track of nova outbursts. Additionally, we estimated the absolute V magnitudes of about 30 novae using a method for time-stretching nova light curves to analyze the distance-reddening relations of the novae.

  1. The UBV color evolution of classical novae. I. Nova-giant sequence in the color-color diagram

    SciTech Connect

    Hachisu, Izumi; Kato, Mariko E-mail: mariko@educ.cc.keio.ac.jp

    2014-04-20

    We identified a general course of classical nova outbursts in the B – V versus U – B color-color diagram. It is reported that novae show spectra similar to those of A-F supergiants near optical light maximum. However, they do not follow the supergiant sequence in the color-color diagram, neither the blackbody nor the main-sequence sequence. Instead, we found that novae evolve along a new sequence in the pre-maximum and near-maximum phases, which we call 'the nova-giant sequence'. This sequence is parallel to but Δ(U – B) ≈ –0.2 mag bluer than the supergiant sequence. This is because the mass of a nova envelope is much (∼10{sup –4} times) less than that of a normal supergiant. After optical maximum, its color quickly evolves back blueward along the same nova-giant sequence and reaches the point of free-free emission (B – V = –0.03, U – B = –0.97), which coincides with the intersection of the blackbody sequence and the nova-giant sequence, and remains there for a while. Then the color evolves leftward (blueward in B – V but almost constant in U – B), owing mainly to the development of strong emission lines. This is the general course of nova outbursts in the color-color diagram, which was deduced from eight well-observed novae in various speed classes. For a nova with unknown extinction, we can determine a reliable value of the color excess by matching the observed track of the target nova with this general course. This is a new and convenient method for obtaining the color excesses of classical novae. Using this method, we redetermined the color excesses of 20 well-observed novae. The obtained color excesses are in reasonable agreement with the previous results, which in turn support the idea of our general track of nova outbursts. Additionally, we estimated the absolute V magnitudes of about 30 novae using a method for time-stretching nova light curves to analyze the distance-reddening relations of the novae.

  2. [Cerebral palsy].

    PubMed

    Malagón Valdez, Jorge

    2007-01-01

    The term cerebral palsy (CP), is used for a great number of clinical neurological syndromes. The syndromes are characterized by having a common cause, motor defects. It is important, because they can cause a brain damage by presenting motor defects and some associated deficiencies, such as mental deficiency, epilepsy, language and visual defects and pseudobulbar paralysis, with the non-evolving fact. Some authors prefer using terms such as "non-evolving encephalopathies". In the treatment the utility of prevention programs of early stimulation and special rehabilitation methods, and treatment of associated deficiencies such as epilepsy, mental deficiency, language, audition and visual problems, and the attention deficit improve the prognosis in an important way. The prognosis depends on the severity of the disease and the associated manifestations.

  3. Nova M33N 2012-10a

    NASA Astrophysics Data System (ADS)

    Alothman, Nourah

    In this thesis I present a study and measurement of a Nova in M33 galaxy type N 2012-10a (which is type of binary star) using data that were collected by the ROTSE IIIb robotic telescope and another observatory. I study the fundamental properties of the light curve and determined the brightness and the velocity of this type of nova. I analyzed the spectra that were measured by the Hobby-Eberly Telescope (HET) at the McDonald Observatory. In addition, I compared this type of nova to other types of Novae.

  4. Recent progress in understanding the eruptions of classical novae

    NASA Technical Reports Server (NTRS)

    Shara, Michael M.

    1988-01-01

    Dramatic progress has occurred in the last two decades in understanding the physical processes and events leading up to, and transpiring during the eruption of a classical nova. The mechanism whereby a white dwarf accreting hydrogen-rich matter from a low-mass main-sequence companion produces a nova eruption has been understood since 1970. The mass-transferring binary stellar configuration leads inexorably to thermonuclear runaways detected at distances of megaparsecs. Summarized here are the efforts of many researchers in understanding the physical processes which generate nova eruptions; the effects upon nova eruptions of different binary-system parameters (e.g., chemical composition or mass of the white dwarf, different mass accretion rates); the possible metamorphosis from dwarf to classical novae and back again; and observational diagnostics of novae, including x ray and gamma ray emission, and the characteristics and distributions of novae in globular clusters and in extragalactic systems. While the thermonuclear-runaway model remains the successful cornerstone of nova simulation, it is now clear that a wide variety of physical processes, and three-dimensional hydrodynamic simulations, will be needed to explain the rich spectrum of behavior observed in erupting novae.

  5. Search for X-ray emission from Nova Cygni 1975

    NASA Technical Reports Server (NTRS)

    Hoffman, J. A.; Lewin, W. H. G.; Brecher, K.; Buff, J.; Clark, G. W.; Joss, P. C.; Matilsky, T.

    1976-01-01

    A search for X-rays from Nova Cygni 1975 was carried out before, during, and after the time of optical maximum. No X-rays were detected over the spectral range 0.1-50 keV. On the basis of these results a strong upper limit of .0001 has been placed on the ratio of X-ray to optical luminosity for this nova, consistent with effective temperatures of about 10,000 K. If Nova Cygni 1975 is a virgin nova, its low mass exchange rate would imply that any associated X-ray emission would not be detectable by present techniques.

  6. Recent progress in understanding the eruptions of classical novae

    SciTech Connect

    Shara, M.M.

    1988-10-01

    Dramatic progress has occurred in the last two decades in understanding the physical processes and events leading up to, and transpiring during the eruption of a classical nova. The mechanism whereby a white dwarf accreting hydrogen-rich matter from a low-mass main-sequence companion produces a nova eruption has been understood since 1970. The mass-transferring binary stellar configuration leads inexorably to thermonuclear runaways detected at distances of megaparsecs. Summarized here are the efforts of many researchers in understanding the physical processes which generate nova eruptions; the effects upon nova eruptions of different binary-system parameters (e.g., chemical composition or mass of the white dwarf, different mass accretion rates); the possible metamorphosis from dwarf to classical novae and back again; and observational diagnostics of novae, including x ray and gamma ray emission, and the characteristics and distributions of novae in globular clusters and in extragalactic systems. While the thermonuclear-runaway model remains the successful cornerstone of nova simulation, it is now clear that a wide variety of physical processes, and three-dimensional hydrodynamic simulations, will be needed to explain the rich spectrum of behavior observed in erupting novae.

  7. Monitoring of Northern dwarf novae for radio jets campaign

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2014-10-01

    Ms. Deanne Coppejans (PhD candidate, Radboud University Nijmegen (Netherlands) and University of Cape Town) and colleagues have requested AAVSO observer assistance in monitoring nine Northern dwarf novae in support of their campaign to observe them in outburst with the Very Large Array (VLA) to search for radio jets. They will observe 5 targets from the following list: U Gem*, EX Dra, Z Cam*, RX And*, EM Cyg, AB Dra, SY Cnc, SU UMa*, and YZ Cnc*. Stars with an asterisk (*) will be given higher priority. The campaign will begin now, starting with monitoring of RX And and EM Cyg, and run through September 2015, or until all five VLA triggers have been used. This campaign is similar to previous AAVSO campaigns, namely the 2007 campaign to monitor a sample of 10 dwarf novae (AAVSO Alert Notice 345), which resulted in the first detection of a radio jet in a dwarf nova system (Koerding et al. 2008, Science, 320, 1318), and the ones carried out at the request of Dr. James Miller-Jones and colleagues on SS Cyg in 2010-2011 (AAVSO Special Notices #204, #206, Alert Notice 445). The latter resulted in an accurate distance determination to SS Cyg, thereby reconciling its behavior with our understanding of accretion disc theory in accreting compact objects (Miller-Jones et al. 2013, Science, 340, 950). Ms. Coppejans writes: "The relation between accretion and outflow is one of the basic problems in modern astrophysics. It has long been thought that CVs are the only accreting systems that do not produce jets, and this notion has even been used to constrain jet models. However, there are now some indications that CVs do show jets, possibly allowing a universal link between accretion and ejection. Radio observations provide the best unambiguous tracer of the corresponding jet or directed outflow, but there are only two clear detections. By observing a more extensive sample of cataclysmic variables in outburst we will determine the existence of jets or other outflows in these

  8. Expanded Very Large Array Nova Project Observations of the Classical Nova V1723 Aquilae

    NASA Astrophysics Data System (ADS)

    Krauss, Miriam I.; Chomiuk, Laura; Rupen, Michael; Roy, Nirupam; Mioduszewski, Amy J.; Sokoloski, J. L.; Nelson, Thomas; Mukai, Koji; Bode, M. F.; Eyres, S. P. S.; O'Brien, T. J.

    2011-09-01

    We present radio light curves and spectra of the classical nova V1723 Aql obtained with the Expanded Very Large Array (EVLA). This is the first paper to showcase results from the EVLA Nova Project, which comprises a team of observers and theorists utilizing the greatly enhanced sensitivity and frequency coverage of EVLA radio observations, along with observations at other wavelengths, to reach a deeper understanding of the energetics, morphology, and temporal characteristics of nova explosions. Our observations of V1723 Aql span 1-37 GHz in frequency, and we report on data from 14 to 175 days following the time of the nova explosion. The broad frequency coverage and frequent monitoring show that the radio behavior of V1723 Aql does not follow the classic Hubble-flow model of homologous spherically expanding thermal ejecta. The spectra are always at least partially optically thin, and the flux rises on faster timescales than can be reproduced with linear expansion. Therefore, any description of the underlying physical processes must go beyond this simple picture. The unusual spectral properties and light curve evolution might be explained by multiple emitting regions or shocked material. Indeed, X-ray observations from Swift reveal that shocks are likely present.

  9. Expanded Very Large Array Nova Project Observations of the Classical NovaV1723 Aquilae

    NASA Technical Reports Server (NTRS)

    Krauss, Miriam I.; Chomiuk, Laura; Rupen, Michael; Roy, Nirupam; Mioduszewski, Amy J.; Sokoloski, J. L.; Nelson, Thomas; Mukai, Koji; Bode, M. F.; Eyres, S. P. S.; hide

    2011-01-01

    We present radio light curves and spectra of the classical nova VI723 Aql obtained with the Expanded Very Large Array (EVLA). This is the first paper to showcase results from the EVLA Nova Project, which comprises a team of observers and theorists utilizing the greatly enhanced sensitivity and frequency coverage of EVLA radio observations, along with observations at other wavelengths, to reach a deeper understanding of the energetics, morphology, and temporal characteristics of nova explosions. Our observations of VI723 Aql span 1-37 GHz in frequency, and we report on data from 14 to 175 days following the time of the nova explosion. The broad frequency coverage and frequent monitoring show that the radio behavior of VI723 Aql does not follow the classic Hubble-flow model of homologous spherically expanding thermal ejecta. The spectra are always at least partially optically thin, and the flux rises on faster timescales than can be reproduced with linear expansion. Therefore, any description of the underlying physical processes must go beyond this simple picture. The unusual spectral properties and light curve evolution might be explained by multiple emitting regions or shocked material. Indeed, X-ray observations from Swift reveal that shocks are likely present.

  10. Unusual ``Stunted'' Outbursts in Old Novae and Nova-Like Cataclysmic Variables

    NASA Astrophysics Data System (ADS)

    Honeycutt, R. K.; Robertson, J. W.; Turner, G. W.

    1998-06-01

    Outbursts averaging 0.6 mag in amplitude and 10 days in width are described in five old novae and nova-like cataclysmic variables: UU Aqr, Q Cyg, CP Lac, X Ser, and RW Sex. These stars are thought to be high mass transfer rate systems for which the accretion disk is expected to be stable against the thermal instability responsible for dwarf nova outbursts. The widths and spacings of these events are similar to those of dwarf nova eruptions, but the amplitudes are significantly smaller, or ``stunted.'' The outbursts are sometimes accompanied by dips. These dips have amplitudes that are similar to the outbursts' but have shapes that scatter significantly more than the shapes of the outbursts. The outbursts and dips sometimes occur as pairs and are sometimes isolated. We are not able at this time to determine a single common mechanism for this behavior, or even to conclude that some mechanisms are preferred. Rather, we characterize these phenomena with regard to outburst shapes and frequency of occurrence and explore a range of possible causes, including truncated disks, mass transfer modulations, and Z Camelopardalis type behavior. Arguments are assembled for and against such possible mechanisms, and key observations are suggested. It appears unlikely that accretion disk instabilities are the single common cause of these phenomena, and we are left with either a combination of accretion disk and mass transfer events or a situation in which mass transfer events are somehow responsible for all these varied behaviors.

  11. Discovery of a Probable Nova in M81 and Photometry of Three M81 Novae

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Errmann, R.; Carlisle, Ch.; Vaduvescu, O.

    2015-02-01

    We report the discovery of a probable nova in M81 on a co-added 1600-s narrow-band H-alpha CCD image taken with the 2.5-m Isaac Newton Telescope (INT) + WFC at La Palma under ~1.6" seeing on 2015 Jan.

  12. CURious Variables Experiment (CURVE): CCD photometry of active dwarf nova DI Ursae Majoris

    NASA Astrophysics Data System (ADS)

    Rutkowski, A.; Olech, A.; Wiśniewski, M.; Pietrukowicz, P.; Pala, J.; Poleski, R.

    2009-04-01

    Context: We report an analysis of photometric behaviour of DI UMa, an extremely active dwarf nova. The observational campaign (completed in 2007) covers five superoutbursts and four normal outbursts. Aims: We examined principal parameters of the system to understand peculiarities of DI UMa, and other active cataclysmic variables. Methods: Based on precise photometric measurements, temporal light curve behaviour, O-C analysis, and power spectrum analysis, we investigated physical parameters of the system. Results: We found that the period of the supercycle now equals 31.45 ± 0.3 days. Observations during superoutbursts infer that the period of superhumps equals P_sh = 0.055318(11) days (79.66± 0.02 min). During quiescence, the light curve reveals a modulation of period P_orb = 0.054579(6) days (78.59 ± 0.01 min), which we interpret as the orbital period of the binary system. The values obtained allowed us to determine a fractional period excess of 1.35% ± 0.02%, which is surprisingly small compared to the usual value for dwarf novae (2%-5%). A detailed O-C analysis was performed for two superoutbursts with the most comprehensive coverage. In both cases, we detected an increase in the superhump period with a mean rate of dot P/P_sh = 4.4(1.0)× 10-5. Conclusions: Based on these measurements, we confirm that DI UMa is probably a period bouncer, an old system that reached its period minimum a long time ago, has a secondary that became a degenerate brown dwarf, the entire system evolving now toward longer periods. DI UMa is an extremely interesting object because we know only one more active ER UMa star with similar characteristics (IX Dra). Photometric data are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/497/437

  13. Recurrent Nova U Scorpii in outburst

    NASA Astrophysics Data System (ADS)

    Templeton, Matthew R.; Schaefer, Bradley E.

    2010-01-01

    The outburst is announced of the recurrent nova U Sco at magnitude V=8.05 on 2010 January 28.4385 UT, according to observations by Barbara G. Harris, New Smyrna Beach, FL, USA. The outburst was confirmed by Shawn Dvorak, Clermont, FL, USA, who estimated it at V~8.8 at Jan 28.4743. Prior to outburst, U Scorpii was measured at V=18.2 on Jan 27.4501 (Harris), and estimated at m(vis) <16.5 on January 27.6271 (Mike Linnolt, Hoolehua, HI, USA). Observations in the AAVSO International Database show that the last outburst of U Sco occurred on 1999 February 25, when the star reached visual magnitude 7.5. U Sco is an extremely fast nova, and will reach maximum and decline by one magnitude within one day. Visual, CCD, and PEP observations are urgently requested, including unfiltered CCD time series. Please obtain S/N of at least 50 for all instrumental photometry. Observers are asked to use filters when performing single-measure photometry, but unfiltered time series is also requested beginning immediately and continuing for the next month. The AAVSO has been participating in a campaign on U Sco by request of Dr. Bradley Schaefer (LSU; see AAVSO Alert Notice 367). This nova outburst will be observed by several ground- and space-based observatories world-wide, and your observations are urgently requested to provide the overall, long-term optical light curve of U Sco. Finder charts with sequence may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details.

  14. Dwarf nova outbursts in intermediate polars

    NASA Astrophysics Data System (ADS)

    Hameury, J.-M.; Lasota, J.-P.

    2017-06-01

    Context. The disc instability model (DIM) has been very successful in explaining the dwarf nova outbursts observed in cataclysmic variables. When, as in intermediate polars, the accreting white dwarf is magnetised, the disc is truncated at the magnetospheric radius, but for mass-transfer rates corresponding to the thermal-viscous instability such systems should still exhibit dwarf-nova outbursts. Yet, the majority of intermediate polars, in which the magnetic field is not large enough to completely disrupt the accretion disc, seem to be stable, and the rare observed outbursts, in particular in systems with long orbital periods, are much shorter than normal dwarf-nova outbursts. Aims: We investigate the predictions of the disc instability model for intermediate polars in order to determine which of the observed properties of these systems can be explained by the DIM. Methods: We use our numerical code for the time evolution of accretion discs, modified to include the effects of the magnetic field, with constant or variable mass transfer from the secondary star. Results: We show that intermediate polars have mass transfer low enough and magnetic fields large enough to keep the accretion disc stable on the cold equilibrium branch. We show that the infrequent and short outbursts observed in long-period systems, such as, for example, TV Col, cannot be attributed to the thermal-viscous instability of the accretion disc, but instead have to be triggered by an enhanced mass-transfer from the secondary, or, more likely, by some instability coupling the white dwarf magnetic field with that generated by the magnetorotational instability operating in the accretion disc. Longer outbursts (a few days) could result from the disc instability.

  15. V4743 Sgr, a magnetic nova?

    NASA Astrophysics Data System (ADS)

    Zemko, P.; Orio, M.; Mukai, K.; Bianchini, A.; Ciroi, S.; Cracco, V.

    2016-08-01

    Two XMM-Newton observations of Nova V4743 Sgr (Nova Sgr 2002) were performed shortly after it returned to quiescence, 2 and 3.5 yr after the explosion. The X-ray light curves revealed a modulation with a frequency of ≃0.75 mHz, indicating that V4743 Sgr is most probably an intermediate polar (IP). The X-ray spectra have characteristics in common with known IPs, with a hard thermal plasma component that can be fitted only assuming a partially covering absorber. In 2004, the X-ray spectrum had also a supersoft blackbody-like component, whose temperature was close to that of the white dwarf (WD) in the supersoft X-ray phase following the outburst, but with flux by at least two orders of magnitude lower. In quiescent IPs, a soft X-ray flux component originates at times in the polar regions irradiated by an accretion column, but the supersoft component of V4743 Sgr disappeared in 2006, indicating a possible origin different from accretion. We suggest that it may have been due to an atmospheric temperature gradient on the WD surface, or to continuing localized thermonuclear burning at the bottom of the envelope, before complete turn-off. An optical spectrum obtained with Southern African Large Telescope (SALT) 11.5 yr after the outburst showed a prominent He II λ4686 line and the Bowen blend, which reveal a very hot region, but with peak temperature shifted to the ultraviolet range. V4743 Sgr is the third post-outburst nova and IP candidate showing a low-luminosity supersoft component in the X-ray flux a few years after the outburst.

  16. Review of the classical nova outburst

    SciTech Connect

    Starrfield, S.; Sparks, W.M.

    1986-06-01

    Observational studies have not only identified a new class of novae but theoretical simulations of this class have been found to be in excellent agreement with the observations. This new class consists of outbursts occurring on ONeMg white dwarfs in close binar systems in contrast to the other outbursts which are occurring on CO white dwarfs. We also review the effects of the ..beta../sup +/-unstable nuclei and show how their presence has a major effect on the evolution. 77 refs.

  17. New nova candidate in M81

    NASA Astrophysics Data System (ADS)

    Henze, M.; Sala, G.; Jose, J.; Figueira, J.; Hernanz, M.

    2016-06-01

    We report the discovery of a new nova candidate in the M81 galaxy on 16x200s stacked R filter CCD images, obtained with the 80 cm Ritchey-Chretien F/9.6 Joan Oro telescope at Observatori Astronomic del Montsec, owned by the Catalan Government and operated by the Institut d'Estudis Espacials de Catalunya, Spain, using a Finger Lakes PL4240-1-BI CCD Camera (with a Class 1 Basic Broadband coated 2k x 2k chip with 13.5 microns sq. pixels).

  18. New optical nova in M 31

    NASA Astrophysics Data System (ADS)

    Henze, M.; Pietsch, W.; Burwitz, V.; Hatzidimitriou, D.; Reig, P.; Primak, N.; Papamastorakis, G.

    2008-10-01

    We report the discovery of a new nova in M 31 on four consecutive dithered stacked R filter CCD images, obtained on 2008 Oct 18.91, with the 1.3m Ritchey Chretien f/7.5 telescope at Skinakas Observatory, Crete, Greece, using an Andor DZ436-BV CCD Camera (with a Marconi 2k x 2k chip with 13.5µm sq. pixels). The R magnitude of the object was 18.3. The object is already visible on several earlier R images obtained with the same telescope and camera.

  19. New optical nova candidate in M 31

    NASA Astrophysics Data System (ADS)

    Podigachoski, P.; Henze, M.; Pietsch, W.; Burwitz, V.; Papamastorakis, G.; Reig, P.; Strigachev, A.

    2009-10-01

    We report the discovery of a new nova candidate in M 31 on three consecutive dithered stacked CCD images, obtained on 2009 Oct 9.08, with the 1.3m Ritchey Chretien f/7.5 telescope at Skinakas Observatory, Crete, Greece, using an Andor DZ436-BV CCD Camera (with a Marconi 2k x 2k chip with 13.5 microns sq. pixels) and a broad (75Å) H-alpha filter. The object is clearly visible on the three individual images and one additional image taken at Oct 9.12.

  20. Optical Nova Candidate in M31

    NASA Astrophysics Data System (ADS)

    Hatzidimitriou, D.; Burwitz, V.; Pietsch, W.; Strigachev, A.; Reig, P.; Papamastorakis, I.

    2007-09-01

    We report the discovery of a possible nova in M31 on four consecutive dithered stacked R filter CCD images, obtained on 2007 September 02.09, with the 1.3m Ritchey Chretien f/7.5 telescope at Skinakas Observatory, Crete, Greece, using an Andor DZ436-BV CCD Camera (with a Marconi 2k x 2k chip with 13.5µm sq. pixels). The R magnitude of the object was 18.1. On 2007 September 03.09, the object was again detected with the same instrument setup, with an R magnitude of 18.2.

  1. A new optical Nova in M31

    NASA Astrophysics Data System (ADS)

    Pietsch, W.; Burwitz, V.; Hatzidimitriou, D.; Steinle, H.; Slowikowska, A.; Stefanescu, A.; Reig, P.; Papamastorakis, G.; Cikota, S.; Cikota, A.; Sanchez, S.; Haberl, F.; Sala, G.; Greiner, J.

    2007-07-01

    We report the discovery of an optical nova in M31 at RA(2000) = 00h 42m 59.49s , Dec(2000) = +41° 15' 06.5" with an accuracy of 0.2". The observations were obtained at the 1.3m Ritchey Chretien f/7.5 telescope at Skinakas Observatory, Crete, Greece, using an Andor DZ436-BV CCD Camera (with a Marconi 2k x 2k chip with 13.5µm sq. pixels). The observations were taken through a Johnson standard R filter (4*100 s stacked) and a broad H- alpha filter (3*300 s stacked).

  2. New optical nova candidate in M 31

    NASA Astrophysics Data System (ADS)

    Pietsch, W.; Kaduk, F.; Henze, M.; Burwitz, V.; Papamastorakis, G.; Reig, P.; Strigachev, A.

    2009-08-01

    We report the discovery of a new nova candidate in M 31 on three consecutive dithered stacked CCD images, obtained on 2009 Aug 4.03, with the 1.3m Ritchey Chretien f/7.5 telescope at Skinakas Observatory, Crete, Greece, using an Andor DZ436-BV CCD Camera (with a Marconi 2k x 2k chip with 13.5 microns sq. pixels) and a broad (75Å) H-alpha filter. The object is clearly visible on the three individual images.

  3. A new optical Nova in M31

    NASA Astrophysics Data System (ADS)

    Burwitz, V.; Hatzidimitriou, D.; Stefanescu, A.; Steinle, H.; Pietsch, W.; Manousakis, A.; Reig, P.; Papamastorakis, G.; Cikota, S.; Cikota, A.; Sanchez, S.

    2007-07-01

    We report the discovery of a optical nova in M31 on four consecutive dithered R filter CCD images obtained on (2007 July 19.00741, 19.00890, 19.01041, 19.01193, with corresponding R magnitudes of 18.8, 18.7, 18.8, 18.5) obtained at the 1.3m Ritchey Chretien f/7.5 telescope at Skinakas Observatory, Crete, Greece, using an Andor DZ436-BV CCD Camera (with a Marconi 2k x 2k chip with 13.5µm sq. pixels).

  4. UBVJHKLM photometry of Nova Del 2013

    NASA Astrophysics Data System (ADS)

    Burlak, A. M.; Shenavrin, I. V.; Tatarnikov, M. A.; Tatarnikova, A. A.

    2013-08-01

    We present the results of the optical and IR photometry of Nova Del 2013 obtained at the Crimean Station (Nauchny, Ukraine) of the Sternberg Astronomical Institute. UBV photometry was carried out with 60-cm Zeiss telescope using a photoelectric photometer on August 15.94 UT: U=4.54+/-0.02, B=5.07+/-0.01, V=5.05+/-0.01; on August 16.80 UT: U=4.54+/-0.01, B=4.85+/-0.02, V=4.68+/-0.01; on August 16.86 UT: U=4.66+/-0.01, B=4.92+/-0.01, V=4.73+/-0.01.

  5. Supernova hydrodynamics experiments using the Nova laser

    SciTech Connect

    Remington, B.A.; Glendinning, S.G.; Estabrook, K.; Wallace, R.J.; Rubenchik, A.; Kane, J.; Arnett, D.; Drake, R.P.; McCray, R.

    1997-04-01

    We are developing experiments using the Nova laser to investigate two areas of physics relevant to core-collapse supernovae (SN): (1) compressible nonlinear hydrodynamic mixing and (2) radiative shock hydrodynamics. In the former, we are examining the differences between the 2D and 3D evolution of the Rayleigh-Taylor instability, an issue critical to the observables emerging from SN in the first year after exploding. In the latter, we are investigating the evolution of a colliding plasma system relevant to the ejecta-stellar wind interactions of the early stages of SN remnant formation. The experiments and astrophysical implications are discussed.

  6. Superhumps in Cataclysmic Binaries. XXIV. Twenty More Dwarf Novae

    NASA Astrophysics Data System (ADS)

    Patterson, Joseph; Thorstensen, John R.; Kemp, Jonathan; Skillman, David R.; Vanmunster, Tonny; Harvey, David A.; Fried, Robert A.; Jensen, Lasse; Cook, Lewis M.; Rea, Robert; Monard, Berto; McCormick, Jennie; Velthuis, Fred; Walker, Stan; Martin, Brian; Bolt, Greg; Pavlenko, Elena; O'Donoghue, Darragh; Gunn, Jerry; Novák, Rudolf; Masi, Gianluca; Garradd, Gordon; Butterworth, Neil; Krajci, Thomas; Foote, Jerry; Beshore, Edward

    2003-11-01

    We report precise measures of the orbital and superhump period in 20 more dwarf novae. For 10 stars, we report new and confirmed spectroscopic periods-signifying the orbital period Po-as well as the superhump period Psh. These are GX Cas, HO Del, HS Vir, BC UMa, RZ Leo, KV Dra, KS UMa, TU Crt, QW Ser, and RZ Sge. For the remaining 10, we report a medley of Po and Psh measurements from photometry; most are new, with some confirmations of previous values. These are KV And, LL And, WX Cet, MM Hya, AO Oct, V2051 Oph, NY Ser, KK Tel, HV Vir, and RX J1155.4-5641. Periods, as usual, can be measured to high accuracy, and these are of special interest since they carry dynamical information about the binary. We still have not quite learned how to read the music, but a few things are clear. The fractional superhump excess ɛ[=(Psh-Po)/Po] varies smoothly with Po. The scatter of the points about that smooth curve is quite low, and can be used to limit the intrinsic scatter in M1, the white dwarf mass, and the mass-radius relation of the secondary. The dispersion in M1 does not exceed 24%, and the secondary-star radii scatter by no more than 11% from a fixed mass-radius relation. For the well-behaved part of ɛ(Po) space, we estimate from superhump theory that the secondaries are 18%+/-6% larger than theoretical ZAMS stars. This affects some other testable predictions about the secondaries: at a fixed Po, it suggests that the secondaries are (compared with ZAMS predictions) 40%+/-14% less massive, 12%+/-4% smaller, 19%+/-6% cooler, and less luminous by a factor of 2.5(7). The presence of a well-defined mass-radius relation, reflected in a well-defined ɛ(Po) relation, strongly limits effects of nuclear evolution in the secondaries.

  7. UBVRI Polarimetry of Nova Sgr 2015#2

    NASA Astrophysics Data System (ADS)

    Muneer, S.; Anupama, G. C.; Raveendran, A. V.; Muniyandi, A.; Baskar, R.

    2015-03-01

    We report here the first polarimetric observations of Nova Sgr 2015#2 (PNV J18365700-2855420). The linear polarization observations of the nova in UBVRI spectral bands were obtained during 16-22 March 2015 with a two beam, multichannel polarimeter attached to the 1-m Carl-Zeiss telescope at the Vainu Bappu Observatory, Kavalur, India.

  8. Results of Statewide TerraNova Testing, Fall 1998.

    ERIC Educational Resources Information Center

    La Marca, Paul M.

    This summary provides key findings about state, district, and school level performance on the TerraNova examinations (CTB/McGraw Hill) in Nevada in 1998-1999. The TerraNova tests are used to assess students in grades 4, 8, and 10 as stipulated by Nevada law. Within this summary, a description of performance as measured by national percentile…

  9. Nova Scotia NewStart, Inc.; Annual Report, 1969.

    ERIC Educational Resources Information Center

    Nova Scotia NewStart, Inc., Yarmouth.

    Focusing on efforts at human resource development among unemployed and/or disadvantaged Nova Scotia adults (especially those in economically depressed areas), the present annual report reviews Nova Scotia NewStart activities begun in 1968 and carried over into 1969, as well as those designed and initiated in 1969 or planned for initiation in 1970.…

  10. Independent Discovery of an Apparent Nova in M81

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Kucakova, H.; Vrastil, J.; Williams, S. C.; Henze, M.; Meusinger, H.; Pohl, C.; Darnley, M. J.; Kaur, A.; Hartmann, D. H.; Sala, G.; Jose, J.; Figueira, J.; Sin, P.; Hernanz, M.; Shafter, A. W.

    2017-02-01

    The M81 nova monitoring collaboration reports the independent discovery of an apparent nova in M81 on a co-added 3510-s unfiltered CCD frame taken on 2017 Feb. 24.119 UT with the 0.65-m telescope at Ondrejov.

  11. Independent Discovery of an Apparent Nova in M81

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Kucakova, H.; Williams, S. C.; Henze, M.; Darnley, M. J.; Kaur, A.; Hartmann, D. H.; Sala, G.; Jose, J.; Figueira, J.; Sin, P.; Hernanz, M.; Shafter, A. W.; Meusinger, H.

    2017-02-01

    The M81 nova monitoring collaboration reports the independent discovery of an apparent nova in M81 on a co-added 5400-s unfiltered CCD frame taken on 2017 Feb. 19.962 UT with the 0.65-m telescope at Ondrejov (OND).

  12. Discovery of a nova candidate in M81

    NASA Astrophysics Data System (ADS)

    Williams, S. C.; Hornoch, K.; Kucakova, H.; Henze, M.; Darnley, M. J.; Kaur, A.; Hartmann, D. H.; Sala, G.; Jose, J.; Figueira, J.; Sin, P.; Hernanz, M.; Shafter, A. W.; Meusinger, H.

    2017-02-01

    The M81 nova monitoring collaboration reports the discovery of a new nova candidate in M81. The candidate was discovered at a H & alpha; magnitude of 20.6 & pm;0.2 on 2017-02-08.05 UT, with the 2-m Liverpool Telescope.

  13. Discovery of a Probable Nova in M81

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Henze, M.; Vrastil, J.; Kucakova, H.; Meusinger, H.; Pohl, C.; Williams, S. C.; Darnley, M. J.; Kaur, A.; Hartmann, D. H.; Sala, G.; Jose, J.; Figueira, J.; Sin, P.; Hernanz, M.; Shafter, A. W.

    2017-02-01

    The M81 nova monitoring collaboration reports the discovery of a probable nova in M81 on a co-added 1800-s unfiltered CCD frame taken on 2017 Feb. 26.928 UT with the 0.65-m telescope at Ondrejov (OND).

  14. Discovery of two Probable Novae in M81

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Kucakova, H.; Henze, M.; Sala, G.; Jose, J.; Figueira, J.; Sin, P.; Hernanz, M.; Williams, S. C.; Meusinger, H.; Darnley, M. J.; Kaur, A.; Hartmann, D. H.; Shafter, A. W.

    2017-09-01

    The M81 nova monitoring collaboration reports the discovery of two probable novae in M81 on a co-added 2700-s unfiltered CCD frame taken on 2017 Sep. 18.129 UT with the 0.65-m telescope at Ondrejov (OND).

  15. V390 Nor = Nova Normae 2007

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2007-06-01

    Nova Normae 2007 was discovered photographically by William Liller on June 15.086 UT at magnitude 9.4. Precise position measured by G. Bolt from his unfiltered CCD image of June 16.7 UT: 16:32:11.51 -45:09:13.4 (2000.0). Giorgio Di Scala reported to the AAVSO that a low-resolution spectrum indicates a nova a week or so after outburst, with strong H-alpha emission. E. Kazarovets, Sternberg Astronomical Institute, reports that N Nor 07 has been assigned the name V390 Nor. Discovery originally announced in IAU Central Bureau Electronic Telegram 982 (Daniel W. E. Green) and AAVSO Special Notice #49 (Arne Henden). Information in this Alert Notice was received at AAVSO from William Liller, Giorgio Di Scala, or via IAU Circular No. 8850, ed. Daniel W. E. Green. A chart for V390 Nor is available via the Variable Star Plotter (VSP). Go to: http://www.aavso.org/observing/charts/vsp/ and enter the name V390 NOR.

  16. Quark nova model for fast radio bursts

    NASA Astrophysics Data System (ADS)

    Shand, Zachary; Ouyed, Amir; Koning, Nico; Ouyed, Rachid

    2016-05-01

    Fast radio bursts (FRBs) are puzzling, millisecond, energetic radio transients with no discernible source; observations show no counterparts in other frequency bands. The birth of a quark star from a parent neutron star experiencing a quark nova - previously thought undetectable when born in isolation - provides a natural explanation for the emission characteristics of FRBs. The generation of unstable r-process elements in the quark nova ejecta provides millisecond exponential injection of electrons into the surrounding strong magnetic field at the parent neutron star's light cylinder via β-decay. This radio synchrotron emission has a total duration of hundreds of milliseconds and matches the observed spectrum while reducing the inferred dispersion measure by approximately 200 cm-3 pc. The model allows indirect measurement of neutron star magnetic fields and periods in addition to providing astronomical measurements of β-decay chains of unstable neutron rich nuclei. Using this model, we can calculate expected FRB average energies (˜ 1041 erg) and spectral shapes, and provide a theoretical framework for determining distances.

  17. SALT observations of southern post-novae

    NASA Astrophysics Data System (ADS)

    Tomov, T.; Swierczynski, E.; Mikolajewski, M.; Ilkiewicz, K.

    2015-04-01

    Aims: We report on recent optical observations of the stellar and the nebular remnants of 22 southern post-novae. Methods: In this study, for each of our targets, we obtained and analysed long-slit spectra in the spectral range 3500-6600 Å and in Hα+[N ii] narrow-band images. Results: The changes in the emission lines' equivalent widths with the time since the outburst agree with earlier published results of other authors. We estimated an average value α = 2.37 for the exponent of the power law fitted to the post-novae continua. Our observations clearly show the two-component structure of the V842 Cen expanding nebulae, owing to the different velocities of the ejected matter. We discovered an expanding shell around V382 Vel with an outer diameter of about 12″. Based on observations made with the Southern African Large Telescope (SALT).The spectra as FITS files are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/576/A119

  18. Novae - The study of the reactive flow

    NASA Astrophysics Data System (ADS)

    Glasner, S. A.; Truran, J. W.

    2012-02-01

    There is a wide consensus in the astrophysics community that the mechanism underlying the observed Classical Nova eruptions is a surface thermonuclear runaway. We start this short review with the main observational facts that lead to the theoretical model of a thermonuclear runaway that takes place in an accreted hydrogen rich envelope placed on top of a cool degenerate core of a white dwarf. According to the theory, the accreted envelope becomes unstable to convection days to weeks prior to the runaway. During the extreme stages of the runaway itself, when the burning is most efficient, the envelope is fully convective. Therefore, the elements processed under such extreme conditions are lifted to the outermost regions of the star. A significant fraction of the envelope is ejected during the outburst. The complicated combination of hydrodynamic instabilities and explosive hydrogen burning, close to the surface of the star, gives us a unique opportunity to study this complex reactive flow. The range of core masses, core temperatures and accretion rates introduce a whole range of burning temperatures and densities. Following the description of the "standard" cases, we then focus on rare, but still possible, portions of the relevant parameter space, in which "breakout" of the traditional CNO cycle can occur and lead to heavy element enrichment patterns caused only by breakout burning. We conclude our review with the main challenges that nova theorists face today, with special emphasis on problems related to the nucleosynthesis issues.

  19. Developing beam phasing on the Nova laser

    SciTech Connect

    Ehrlich, R.B.; Amendt, P.A.; Dixit, S.N.; Hammel, B.A.; Kalantar, D.H.; Pennington, D.M.; Weiland, T.L.

    1997-03-10

    We are presently adding the capability to irradiate indirectly-driven Nova targets with two rings of illumination inside each end of the hohlraum for studies of time-dependent second Legendre (P2) and time- integrated fourth Legendre (P4) flux asymmetry control. The rings will be formed with specially designed kinoform phase plates (KPPs), which will direct each half of each beam into two separate rings that are nearly uniform azimuthally. The timing and temporal pulse shape of the outer rings will be controlled independently from those of the inner rings, allowing for phasing of the pulse shapes to control time dependent asymmetry. Modifications to the incident beam diagnostics (IBDS) will enable us to verify that acceptable levels of power balance among the contributing segments of each ring have been achieved on each shot. Current techniques for precision beam pointing and timing are expected to be sufficiently accurate for these experiments. We present a design for an affordable retrofit to achieve beam phasing on Nova, results of a simplified demonstration, and calculations highlighting the anticipated benefits.

  20. Optical components for the Nova laser

    SciTech Connect

    Wallerstein, E.P.; Baker, P.C.; Brown, N.J.

    1982-05-17

    In addition to its other characteristics, the Nova Laser Fusion facility may well be the largest precision optical project ever undertaken. Moreover, during the course of construction, concurrent research and development has been successfully conducted, and has resulted in significant advances in various technical areas, including manufacturing efficiency. Although assembly of the first two beams of Nova is just commencing, the optical production, including construction of the special facilities required for many of the components, has been underway for over three years, and many phases of the optical manufacturing program for the first 10 beams will be completed within the next two years. On the other hand, new requirements for second and third harmonic generation have created the need to initiate new research and development. This work has been accomplished through the enormous cooperation DOE/LLNL has received from commercial industry on this project. In many cases, industry, where much of the optical component research and development and virtually all of the manufacturing is being done, has made substantial investment of its own funds in facilities, equipment, and research and development, in addition to those supplied by DOE/LLNL.

  1. Study of the nova-produced 22Na with COMPTEL

    NASA Astrophysics Data System (ADS)

    Iyudin, A. F.; Diehl, R.; Lichti, G. G.; Schönfelder, V.; Strong, A. W.; Bennett, K.; Winkler, C.; Bloemen, H.; Hermsen, W.; Ryan, J.

    2001-09-01

    After 9 years of the Compton Mission (CGRO), the COMPTEL telescope continues to improve the level of sensitivity towards about 10-5 photons/(cm2s) in line emission around 1 MeV. Classical novae provide an environment in which hydrogen-burning reactions proceed on CNO and heavier nuclei at high temperatures. For such conditions astrophysically significant fluxes of the 22Na γ-ray line at 1.275 MeV are expected from the nearby nova. We have analyzed measurements of 22Na line emission from several recent novae, including nova V382 Vel, the brightest neon-type nova in the last 25 years, to gain more insight into sodium production in the Galaxy.

  2. Population of post-nova supersoft X-ray sources

    NASA Astrophysics Data System (ADS)

    Soraisam, Monika D.; Gilfanov, Marat; Wolf, William M.; Bildsten, Lars

    2016-01-01

    Novae undergo a supersoft X-ray phase of varying duration after the optical outburst. Such transient post-nova supersoft X-ray sources (SSSs) are the majority of the observed SSSs in M31. In this paper, we use the post-nova evolutionary models of Wolf et al. to compute the expected population of post-nova SSSs in M31. We predict that depending on the assumptions about the white dwarf (WD) mass distribution in novae, at any instant there are about 250-600 post-nova SSSs in M31 with (unabsorbed) 0.2-1.0 keV luminosity Lx ≥ 1036 erg s-1. Their combined unabsorbed luminosity is of the order of ˜1039 erg s-1. Their luminosity distribution shows significant steepening around log (Lx) ˜ 37.7-38 and becomes zero at Lx ≈ 2 × 1038 erg s-1, the maximum Lx achieved in the post-nova evolutionary tracks. Their effective temperature distribution has a roughly power-law shape with differential slope of ≈4-6 up to the maximum temperature of Teff ≈ 1.5 × 106 K. We compare our predictions with the results of the XMM-Newton monitoring of the central field of M31 between 2006 and 2009. The predicted number of post-nova SSSs exceeds the observed number by a factor of ≈2-5, depending on the assumed WD mass distribution in novae. This is good agreement, considering the number and magnitude of uncertainties involved in calculations of the post-nova evolutionary models and their X-ray output. Furthermore, only a moderate circumstellar absorption, with hydrogen column density of the order of ˜1021 cm-2, will remove the discrepancy.

  3. United Cerebral Palsy

    MedlinePlus

    ... stay up to date with everything UCP! Affiliate Network UCP affiliates provide services and support on a ... with Cerebral Palsy and other disabilities and their networks. Individuals with cerebral palsy and other disabilities deserve ...

  4. Cerebral Palsy (For Kids)

    MedlinePlus

    ... Emergency Room? What Happens in the Operating Room? Cerebral Palsy KidsHealth > For Kids > Cerebral Palsy A A A ... the things that kids do every day. What's CP? Some kids with CP use wheelchairs and others ...

  5. Observations and simulations of nova Vul 1984 no. 2: A nova with ejecta rich in oxygen, neon, and magnesium

    NASA Technical Reports Server (NTRS)

    Starrfield, S.; Sonneborn, G.; Stryker, L. L.; Sparks, Warren M.; Truran, James W.; Ferland, Gary; Wagner, R. M.; Gallagher, J. S.; Wade, R.; Williams, R. E.

    1988-01-01

    Nova Vul 1984 no. 2 was observed with IUE from Dec. 1984 through Nov. 1987. The spectra are characterized by strong lines from Mg, Ne, C, Si, O, N, and other elements. Data obtained in the ultraviolet, infrared, and optical show that this nova is ejecting material rich in oxygen, neon, and magnesium.

  6. THE NOVA SHELL AND EVOLUTION OF THE RECURRENT NOVA T PYXIDIS

    SciTech Connect

    Schaefer, Bradley E.; Pagnotta, Ashley; Shara, Michael M.

    2010-01-01

    T Pyxidis (T Pyx) is the prototypical recurrent nova (RN), with five eruptions from 1890 to 1967 and a mysterious nova shell. We report new observations of the nova shell with the Hubble Space Telescope (HST) in the year 2007, which provides a long time baseline to compare with HST images from 1994 and 1995. We find that the knots in the nova shell are expanding with velocities ranging from roughly 500 km s{sup -1} to 715 km s{sup -1}, assuming a distance of 3500 pc. The fractional expansion of the knots is constant, which implies no significant deceleration of the knots, which must have been ejected by an eruption close to the year 1866. We see knots that have turned on after 1995; this shows that the knots are powered by shocks from the collision of the '1866' ejecta with fast ejecta from later RN eruptions. We derive that the '1866' ejecta has a total mass of approx10{sup -4.5} M {sub sun}, which with the low ejection velocity shows that the '1866' event was an ordinary nova eruption, not an RN eruption. This also implies that the accretion rate before the ordinary nova event must have been low (around the 4 x 10{sup -11} M{sub sun} yr{sup -1} expected for gravitational radiation alone), and that the matter accumulated on the surface of the white dwarf for approx750,000 years. The current accretion rate (>10{sup -8} M{sub sun} yr{sup -1}) is approx1000x higher than expected for a system below the period gap, with the plausible reason being that the '1866' event started a continuing supersoft source that drives the accretion. The accretion rate has been declining since before the 1890 eruption, with the current rate being only 3% of its earlier value. The decline in the observed accretion rate shows that the supersoft source is not self-sustaining; we calculate that the accretion in T Pyx will effectively stop in upcoming decades. With this, T Pyx will enter a state of hibernation lasting for an estimated 2,600,000 years before gravitational radiation brings the

  7. Curious Variables Experiment (CURVE). CCD Photometry of Dwarf Nova V660 Herculis

    NASA Astrophysics Data System (ADS)

    Olech, A.; Zloczewski, K.; Cook, L. M.; Mularczyk, K.; Kedzierski, P.; Wisniewski, M.

    2005-06-01

    We report extensive photometry of the dwarf nova V660 Her. During our campaign, lasting from August 2003 to November 2004, we recorded one bright eruption which turned out to be a superoutburst lasting about 15 days and having amplitude of approx 4.5 mag. Clear superhumps with a mean period of P_sh=0.080924(18) days (116.53+/-0.03 min) were present during all nights of the superoutburst. The period of the superhumps was not stable and in the interval covered by our observations it decreased with a rate of dot P/P_sh=-4.0(1.4) times 10^-5. Based on our data and the known orbital period of the binary we calculate the period excess of 3.4\\+/-0.1%, which is typical for an SU UMa star at this orbital period. This value indicates that the mass ratio of the system is q=0.154.

  8. Dwarf nova-type cataclysmic variable stars are significant radio emitters

    NASA Astrophysics Data System (ADS)

    Coppejans, Deanne L.; Körding, Elmar G.; Miller-Jones, James C. A.; Rupen, Michael P.; Sivakoff, Gregory R.; Knigge, Christian; Groot, Paul J.; Woudt, Patrick A.; Waagen, Elizabeth O.; Templeton, Matthew

    2016-12-01

    We present 8-12 GHz radio light curves of five dwarf nova (DN) type cataclysmic variable stars (CVs) in outburst (RX And, U Gem, and Z Cam), or superoutburst (SU UMa and YZ Cnc), increasing the number of radio-detected DN by a factor of 2. The observed radio emission was variable on time-scales of minutes to days, and we argue that it is likely to be synchrotron emission. This sample shows no correlation between the radio luminosity and optical luminosity, orbital period, CV class, or outburst type; however, higher cadence observations are necessary to test this, as the measured luminosity is dependent on the timing of the observations in these variable objects. The observations show that the previously detected radio emission from SS Cyg is not unique in type, luminosity (in the plateau phase of the outburst), or variability time-scales. Our results prove that DN, as a class, are radio emitters in outburst.

  9. Cerebral Palsy (For Kids)

    MedlinePlus

    ... CPR: A Real Lifesaver Kids Talk About: Coaches Cerebral Palsy KidsHealth > For Kids > Cerebral Palsy Print A A A What's in this article? ... the first word you spoke? For kids with cerebral palsy, called CP for short, taking a first step ...

  10. Aging and Cerebral Palsy.

    ERIC Educational Resources Information Center

    Networker, 1993

    1993-01-01

    This special edition of "The Networker" contains several articles focusing on aging and cerebral palsy (CP). "Aging and Cerebral Palsy: Pathways to Successful Aging" (Jenny C. Overeynder) reports on the National Invitational Colloquium on Aging and Cerebral Palsy held in April 1993. "Observations from an Observer" (Kathleen K. Barrett) describes…

  11. An X-ray source associated with a Vista Variables Survey nova candidate nova

    NASA Astrophysics Data System (ADS)

    Orio, M.; Mukai, K.; Valle, M. Della

    2016-02-01

    We report that one of the ten Galactic transients proposed to be novae, discovered in the Vista-Variables-Via Lactea (VVV) Survey disk area by Saito et al. (ATel 8602), VVV-NOV-13, is spatially coincident with a faint, hard X-ray source observed in 2011 June 16 and 17 for 19700 s in a survey of the NORMA spiral arm with the Chandra ACIS-I camera (P.I.

  12. Very high-energy γ -ray observations of novae and dwarf novae with the MAGIC telescopes

    DOE PAGES

    Ahnen, M. L.

    2015-10-01

    In the last five years the Fermi Large Area Telescope (LAT) instrument detected GeV γ-ray emission from five novae. The GeV emission can be interpreted in terms of an inverse Compton process of electrons accelerated in a shock. In this case it is expected that protons in the same conditions can be accelerated to much higher energies. Consequently they may produce a second component in the γ-ray spectrum at TeV energies.

  13. Laying the foundation for a digital Nova Scotia

    NASA Astrophysics Data System (ADS)

    Bond, J.

    2016-04-01

    In 2013, the Province of Nova Scotia began an effort to modernize its coordinate referencing infrastructure known as the Nova Scotia Coordinate Referencing System (NSCRS). At that time, 8, active GPS stations were installed in southwest Nova Scotia to evaluate the technology's ability to address the Province's coordinate referencing needs. The success of the test phase helped build a business case to implement the technology across the entire Province. It is anticipated that by the end of 2015, 40 active GPS stations will be in place across Nova Scotia. This infrastructure, known as the Nova Scotia Active Control Stations (NSACS) network, will allow for instantaneous, centimetre level positioning across the Province. Originally designed to address the needs of the surveying community, the technology has also proven to have applications in mapping, machine automation, agriculture, navigation, emergency response, earthquake detection and other areas. In the foreseeable future, all spatial data sets captured in Nova Scotia will be either directly or indirectly derived from the NSACS network. The technology will promote high accuracy and homogenous spatial data sets across the Province. The technology behind the NSACS and the development of the system are described. Examples of how the technology is contributing to a digital Nova Scotia are presented. Future applications of the technology are also considered.

  14. Nova is an old hand at big deals in Alberta

    SciTech Connect

    Sutherland, J.

    1980-09-10

    Nova, an Alberta Corporation, formerly Alberta Gas Trunk Line Co. Ltd., and Shell Canada Resources Ltd. will build a 600 million lb/yr styrene plant near Edmonton, Alberta. For feedstock, 5000 bbl/day of benzene will come from a $350 million, 100,000 bbl/day refinery that will be built by Shell at Edmonton. Husky Oil Ltd., which is controlled by Nova, will take a 40% equity in the refinery. According to Nova, which has a monopoly on gas transmission in Alberta, continued collaboration with Shell could lead to the spending of an additional $2 billion in the next few years. Dow Chemical of Canada Ltd. and Nova will put together an ethane extraction system in Alberta which will feed their jointly owned 1.2 billion lb/yr ethylene plant near Red Deer, Alberta. Dow uses the entire output of the ethylene plant at its recently completed Fort Saskatchewan, Alberta, complex. Alberta Gas Ethylene Co. Ltd., a Nova subsidiary, has begun work on a second 1.2 billion lb/yr ethylene unit scheduled for completion in early 1984, and will soon start work on a third ethylene unit at Red Deer. According to J. Sutherland (Nova, Alberta Corp.), Nova is rapidly expanding its ethylene capacity because, for at least a certain period of time, world-scale plants using Alberta natural gas will be very competitive.

  15. CLIP Identifies Nova-Regulated RNA Networks in the Brain

    NASA Astrophysics Data System (ADS)

    Ule, Jernej; Jensen, Kirk B.; Ruggiu, Matteo; Mele, Aldo; Ule, Aljaž; Darnell, Robert B.

    2003-11-01

    Nova proteins are neuron-specific antigens targeted in paraneoplastic opsoclonus myoclonus ataxia (POMA), an autoimmune neurologic disease characterized by abnormal motor inhibition. Nova proteins regulate neuronal pre-messenger RNA splicing by directly binding to RNA. To identify Nova RNA targets, we developed a method to purify protein-RNA complexes from mouse brain with the use of ultraviolet cross-linking and immunoprecipitation (CLIP). Thirty-four transcripts were identified multiple times by Nova CLIP. Three-quarters of these encode proteins that function at the neuronal synapse, and one-third are involved in neuronal inhibition. Splicing targets confirmed in Nova-/- mice include c-Jun N-terminal kinase 2, neogenin, and gephyrin; the latter encodes a protein that clusters inhibitory γ-aminobutyric acid and glycine receptors, two previously identified Nova splicing targets. Thus, CLIP reveals that Nova coordinately regulates a biologically coherent set of RNAs encoding multiple components of the inhibitory synapse, an observation that may relate to the cause of abnormal motor inhibition in POMA.

  16. Non-Detection of Nova Shells Around Asynchronous Polars

    NASA Astrophysics Data System (ADS)

    Pagnotta, Ashley; Zurek, David

    2016-01-01

    Asynchronous polars (APs) are accreting white dwarfs (WDs) that have different WD and orbital angular velocities, unlike the rest of the known polars, which rotate synchronously (i.e., their WD and orbital angular velocities are the same). Past nova eruptions are the predicted cause of the asynchronicity, in part due to the fact that one of the APs, V1500 Cyg, was observed to undergo a nova eruption in 1975. We used the SALT 10m-class telescope and the MDM 2.4m Hiltner telescope to search for nova shells around three of the remaining four APs (V1432 Aql, BY Cam, and CD Ind) as well as one Intermediate Polar with a high asynchronicity (EX Hya). We found no evidence of nova shells in any of our images. We therefore cannot say that any of the systems besides V1500 Cyg had nova eruptions, but because not all post-nova systems have detectable shells, we also cannot exclude the possibility of a nova eruption occurring in any of these systems and knocking the rotation out of sync.

  17. OGLE ATLAS OF CLASSICAL NOVAE. II. MAGELLANIC CLOUDS

    SciTech Connect

    Mróz, P.; Udalski, A.; Poleski, R.; Soszyński, I.; Szymański, M. K.; Pietrzyński, G.; Wyrzykowski, Ł.; Ulaczyk, K.; Kozłowski, S.; Pietrukowicz, P.; Skowron, J.

    2016-01-15

    The population of classical novae in the Magellanic Clouds was poorly known because of a lack of systematic studies. There were some suggestions that nova rates per unit mass in the Magellanic Clouds were higher than in any other galaxy. Here, we present an analysis of data collected over 16 years by the OGLE survey with the aim of characterizing the nova population in the Clouds. We found 20 eruptions of novae, half of which are new discoveries. We robustly measure nova rates of 2.4 ± 0.8 yr{sup −1} (LMC) and 0.9 ± 0.4 yr{sup −1} (SMC) and confirm that the K-band luminosity-specific nova rates in both Clouds are 2–3 times higher than in other galaxies. This can be explained by the star formation history in the Magellanic Clouds, specifically the re-ignition of the star formation rate a few Gyr ago. We also present the discovery of the intriguing system OGLE-MBR133.25.1160, which mimics recurrent nova eruptions.

  18. A FORCAST Mid-IR Study of the Classical Nova V1369 Cen (Nova Centauri 2013)

    NASA Astrophysics Data System (ADS)

    Helton, L.

    2014-10-01

    The Galactic cycle of chemical evolution depends on the redistribution into the ambient interstellar medium (ISM) of elements synthesized by thermonuclear processes. Classical novae (CNe) contribute to this cycle by deposition into the ISM of gas enriched through explosive nucleosynthesis and dust grains condensed in their ejecta providing the material from which the next generation of stars and planets grow. We propose to observe the nova V1369 Cen (Nova Centauri 2013) in the mid-IR with FORCAST to determine the ejecta mass, the degree of elemental enrichment in the ejecta, the dust grain mineralogy, and the processes of dust grain growth and destruction. FORCAST observations fulfill these goals by providing high S/N data in which we can 1.) measure H recombination, nebular, and coronal emission lines necessary to determine ejecta abundances and masses; 2.) measure prominent dust features from silicates and polycyclic aromatic hydrocarbons to track dust condensation, mass, grain size distribution, and processing; and 3.) estimate the energy budget of the eruption providing insight into the underlying white dwarf and the eruption's contribution to the energy budget of the ISM. These observations will complement our extensive, on-going Chandra, Swift, and ground based optical and near-IR observing programs.

  19. HYDROGEN BURNING ON ACCRETING WHITE DWARFS: STABILITY, RECURRENT NOVAE, AND THE POST-NOVA SUPERSOFT PHASE

    SciTech Connect

    Wolf, William M.; Bildsten, Lars; Brooks, Jared; Paxton, Bill

    2013-11-10

    We examine the properties of white dwarfs (WDs) accreting hydrogen-rich matter in and near the stable burning regime of accretion rates as modeled by time-dependent calculations done with Modules for Experiments in Stellar Astrophysics (MESA). We report the stability boundary for WDs of masses between 0.51 M{sub ☉} and 1.34 M{sub ☉} as found via time-dependent calculations. We also examine recurrent novae that are accreting at rates close to, but below, the stable burning limit and report their recurrence times. Our dense grid in accretion rates finds the expected minimum possible recurrence times as a function of the WD mass. This enables inferences to be made about the minimum WD mass possible to reach a specific recurrence time. We compare our computational models of post-outburst novae to the stably burning WDs and explicitly calculate the duration and effective temperature (T{sub eff}) of the post-nova WD in the supersoft phase. We agree with the measured turnoff time-T{sub eff} relation in M31 by Henze and collaborators, infer WD masses in the 1.0-1.3 M{sub ☉} range, and predict ejection masses consistent with those observed. We close by commenting on the importance of the hot helium layer generated by stable or unstable hydrogen burning for the short- and long-term evolution of accreting WDs.

  20. Polarimetry of the Nova V339 Del

    NASA Astrophysics Data System (ADS)

    Shakhovskoy, D. N.; Antonyuk, K. A.; Belan, S. P.

    2017-03-01

    Polarimetric UBVRI observations of the Nova V339 Del during the 5-108 days following the maximum of the outburst of 2013 reveal a variability in the degree of linear polarization with an amplitude of about 0.2%. The character of the variability in the polarization parameters during the period up to 30 days after the maximum is indicative of a nonspherical diffuse shell, with a geometry that is more likely bipolar than disk-shaped. In the early nebular stage (30-100 days after the maximum) a variability in the position angle of the intrinsic polarization was observed that suggests that the shape of the shell deviates from axial symmetry.

  1. TIDAL NOVAE IN COMPACT BINARY WHITE DWARFS

    SciTech Connect

    Fuller, Jim; Lai Dong

    2012-09-01

    Compact binary white dwarfs (WDs) undergoing orbital decay due to gravitational radiation can experience significant tidal heating prior to merger. In these WDs, the dominant tidal effect involves the excitation of outgoing gravity waves in the inner stellar envelope and the dissipation of these waves in the outer envelope. As the binary orbit decays, the WDs are synchronized from outside in (with the envelope synchronized first, followed by the core). We examine the deposition of tidal heat in the envelope of a carbon-oxygen WD and study how such tidal heating affects the structure and evolution of the WD. We show that significant tidal heating can occur in the star's degenerate hydrogen layer. This layer heats up faster than it cools, triggering runaway nuclear fusion. Such 'tidal novae' may occur in all WD binaries containing a CO WD, at orbital periods between 5 minutes and 20 minutes, and precede the final merger by 10{sup 5}-10{sup 6} years.

  2. Supernova hydrodynamics experiments using the Nova laser*

    NASA Astrophysics Data System (ADS)

    Remington, B. A.; Glendinning, S. G.; Estabrook, K. G.; London, R. A.; Wallace, R. J.; Kane, J.; Arnett, D.; Drake, R. P.; Liang, E.; McCray, R.; Rubenchik, A.

    1997-04-01

    We are developing experiments using the Nova laser [1,2] to investigate two areas of physics relevant to core-collapse supernovae (SN): compressible nonlinear hydrodynamic mixing and (2) radiative shock hydrodynamics. In the former, we are examining the differences between the 2D and 3D evolution of the Rayleigh-Taylor instability, an issue critical to the observables emerging from SN in the first year after exploding. In the latter, we are investigating the evolution of a colliding plasma system relevant to the ejecta-stellar wind interactions of the early stages of SN remnant formation. The experiments and astrophysical implications will be discussed. *Work performed under the auspices of the U.S. Department of Energy by the Lawrence Livermore National Laboratory under contract number W-7405-ENG-48. [1] J. Kane et al., in press, Astrophys. J. Lett. (March-April, 1997). [2] B.A. Remington et al., in press, Phys. Plasmas (May, 1997).

  3. New optical nova candidate in M 31

    NASA Astrophysics Data System (ADS)

    Henze, M.; Pietsch, W.; Burwitz, V.; Hatzidimitriou, D.; Reig, P.; Primak, N.; Papamastorakis, G.; Updike, A.; Hartmann, D. H.; Milne, P.; Williams, G.

    2008-07-01

    We report the discovery of a possible nova in M 31 on four consecutive dithered stacked 100s R filter CCD images, obtained on 2008 July 06.04, with the 1.3m Ritchey Chretien f/7.5 telescope at Skinakas Observatory, Crete, Greece, using an Andor DZ436-BV CCD Camera (with a Marconi 2k x 2k chip with 13.5μm sq. pixels). The R magnitude of the object was 18.7. The object is already visible with a magnitude of 18.3 on a 12*60s stacked R filter CCD image obtained with the robotic 60cm telescope with an E2V CCD (2kx2k) of the Livermore Optical Transient Imaging System (Super-LOTIS, located at Steward Observatory, Kitt Peak, Arizona, USA) on 2008 June 30.45.

  4. Time resolved side scatter diagnostics at NOVA

    SciTech Connect

    Kyrala, G.A.; Evans, S.C.; Jimerson, J.R.; Fernandez, J.C.

    1996-06-01

    Side scattering of the radiation during the interaction of a laser beam with the long scale length plasma in hohlraum is a difficult problem of relevance to the viability of ICF. It is important to measure the absolute amount of the laser side scatter as well as the angular distribution of that scatter. The OSA diagnostics has been implemented on NOVA to measure these quantities. We have implemented a fiber-optically coupled streak camera to measure the temporally and angularly resolved side scatter radiation at 351 nm at 9 different angles. Filtered PIN diodes were positioned at 31 various angles in the E-field planed and B-field plane of the incident probe beam to sample and measure the scattered radiation at the 351 nm wavelength of the probe. The diode data was used to calibrate the Brillouin power received by the 9 strategically located fiber optic channels. This presentation will describe the OSA and associated diagnostics.

  5. Event Reconstruction Techniques in NOvA

    NASA Astrophysics Data System (ADS)

    Baird, M.; Bian, J.; Messier, M.; Niner, E.; Rocco, D.; Sachdev, K.

    2015-12-01

    The NOvA experiment is a long-baseline neutrino oscillation experiment utilizing the NuMI beam generated at Fermilab. The experiment will measure the oscillations within a muon neutrino beam in a 300 ton Near Detector located underground at Fermilab and a functionally-identical 14 kiloton Far Detector placed 810 km away. The detectors are liquid scintillator tracking calorimeters with a fine-grained cellular structure that provides a wealth of information for separating the different particle track and shower topologies. Each detector has its own challenges with the Near Detector seeing multiple overlapping neutrino interactions in each event and the Far Detector having a large background of cosmic rays due to being located on the surface. A series of pattern recognition techniques have been developed to go from event records, to spatially and temporally separating individual interactions, to vertexing and tracking, and particle identification. This combination of methods to achieve the full event reconstruction will be discussed.

  6. Classical Rayleigh Taylor experiments on Nova

    SciTech Connect

    Budil, K.S.; Remington, B.A.; Peyser, T.A.

    1995-07-01

    The evolution of the Rayleigh-Taylor (RT) instability in a compressible medium was investigated both at an accelerating embedded interface and at the ablation front in a new series of experiments on Nova. The x-ray drive generated in a hohlraum ablatively accelerated a planar target consisting of a doped plastic pusher which was in some cases backed by a higher density titanium payload. Both target types were diagnosed by face-on and side-on radiography. Experiments have been done with a variety of wavelengths and initial amplitudes. In the case where the perturbed RT-unstable embedded interface is isolated from the ablation front, short wavelength perturbations are observed to grow strongly. When the perturbation is at the ablation front, the short wavelengths are observed to be severely stabilized.

  7. Eclipse Mapping Experiments in Dwarf Novae Outbursts

    NASA Astrophysics Data System (ADS)

    Borges, B. W.; Baptista, R.

    2006-06-01

    In this work, we report the eclipse mapping analysis of CCD photometric data of two short period dwarf novae - V4140 Sgr (Borges & Baptista 2005) and HT Cas (Borges, Baptista & Catalán, in preparation) - during observed outburst events. The analysis of the observations of V4140 Sgr, done between 1991 and 2001, reveals that the object was in the decline from an outburst in 1992 and again in outburst in 2001. A distance of d = 170+/-30 pc is obtained from a method similar to that used to constrain the distance to open clusters. From this distance, disc radial brightness temperature distributions are determined, and the disc temperatures remain below the critical effective temperature T_{crit} at all disc radii during the outburst. The distributions in quiescence and in outburst are significantly different from those of other dwarf novae of similar orbital period. These results cannot be explained within the framework of the disc instability model and the small amplitude outbursts of V4140 Sgr can be due bursts of enhanced mass transfer rate from the secondary star. Our HT Cas data consist of V and R CCD photometric observations done in 2005 November with the 0.95-m James Gregory Telescope (JGT) and cover a outburst cycle. We used the entropy associated to the eclipse maps to obtain the semi-opening disc angle α evolution throught the outburst. The obtained angles are systematically lower than those obtained by Ioannou et al. (1999) and we can conclude that the outburst radial profiles must be flatter than the the T ∝ r^{-3/4} law of steady state dics, against the expectations of the disc instability model. Our intensity radial distributions presents the same ``outside-in'' outburst behavior as obtained by the referred author.

  8. 15 CFR 904.101 - Notice of violation and assessment (NOVA).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... (NOVA). 904.101 Section 904.101 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign... REGULATIONS CIVIL PROCEDURES Civil Penalties § 904.101 Notice of violation and assessment (NOVA). (a) A NOVA will be issued by NOAA and served upon the respondent(s). The NOVA will contain: (1) A...

  9. 15 CFR 904.101 - Notice of violation and assessment (NOVA).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... (NOVA). 904.101 Section 904.101 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign... REGULATIONS CIVIL PROCEDURES Civil Penalties § 904.101 Notice of violation and assessment (NOVA). (a) A NOVA will be issued by NOAA and served upon the respondent(s). The NOVA will contain: (1) A...

  10. 15 CFR 904.101 - Notice of violation and assessment (NOVA).

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... (NOVA). 904.101 Section 904.101 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign... REGULATIONS CIVIL PROCEDURES Civil Penalties § 904.101 Notice of violation and assessment (NOVA). (a) A NOVA will be issued by NOAA and served upon the respondent(s). The NOVA will contain: (1) A...

  11. 15 CFR 904.101 - Notice of violation and assessment (NOVA).

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... (NOVA). 904.101 Section 904.101 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign... REGULATIONS CIVIL PROCEDURES Civil Penalties § 904.101 Notice of violation and assessment (NOVA). (a) A NOVA will be issued by NOAA and served upon the respondent(s). The NOVA will contain: (1) A...

  12. 15 CFR 904.101 - Notice of violation and assessment (NOVA).

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... (NOVA). 904.101 Section 904.101 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign... REGULATIONS CIVIL PROCEDURES Civil Penalties § 904.101 Notice of violation and assessment (NOVA). (a) A NOVA will be issued by NOAA and served upon the respondent(s). The NOVA will contain: (1) A...

  13. Observations and simulations of recurrent novae: U Sco and V394 CrA

    NASA Technical Reports Server (NTRS)

    Starrfield, S.; Sonneborn, G.; Sparks, Warren M.; Shaviv, G.; Williams, R. E.; Heathcote, S.; Ferland, Gary; Gehrz, Robert D.; Ney, Edward P.; Kenyon, Scott

    1988-01-01

    Observations and analysis of the Aug. 1987 outburst of the recurrent nova V394 CrA are presented. This nova is extremely fast and its outburst characteristics closely resemble those of the recurrent nova U Sco. Hydrodynamic simulations of the outbursts of recurrent novae were performed. Results as applied to the outbursts of V394 CrA and U Sco are summarized.

  14. 78 FR 53493 - Presidential Permits: NOVA Chemicals Inc. Line 20 Facilities

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-29

    ... Presidential Permits: NOVA Chemicals Inc. Line 20 Facilities August 21, 2013. AGENCY: Department of State. ACTION: Notice of Issuance of a Presidential Permit for NOVA Chemicals Inc. Line 20 Facilities. SUMMARY: The Department of State issued a Presidential Permit to NOVA Chemicals Inc. (``NOVA Inc.'') on August...

  15. The UBV Color Evolution of Classical Novae. II. Color-Magnitude Diagram

    NASA Astrophysics Data System (ADS)

    Hachisu, Izumi; Kato, Mariko

    2016-04-01

    We have examined the outburst tracks of 40 novae in the color-magnitude diagram (intrinsic B - V color versus absolute V magnitude). After reaching the optical maximum, each nova generally evolves toward blue from the upper right to the lower left and then turns back toward the right. The 40 tracks are categorized into one of six templates: very fast nova V1500 Cyg fast novae V1668 Cyg, V1974 Cyg, and LV Vul moderately fast nova FH Ser and very slow nova PU Vul. These templates are located from the left (blue) to the right (red) in this order, depending on the envelope mass and nova speed class. A bluer nova has a less massive envelope and faster nova speed class. In novae with multiple peaks, the track of the first decay is more red than that of the second (or third) decay, because a large part of the envelope mass had already been ejected during the first peak. Thus, our newly obtained tracks in the color-magnitude diagram provide useful information to understand the physics of classical novae. We also found that the absolute magnitude at the beginning of the nebular phase is almost similar among various novae. We are able to determine the absolute magnitude (or distance modulus) by fitting the track of a target nova to the same classification of a nova with a known distance. This method for determining nova distance has been applied to some recurrent novae, and their distances have been recalculated.

  16. The analysis of spectra of novae taken near maximum

    NASA Technical Reports Server (NTRS)

    Stryker, L. L.; Hestand, J.; Starrfield, S.; Wehrse, R.; Hauschildt, P.; Spies, W.; Baschek, B.; Shaviv, G.

    1988-01-01

    A project to analyze ultraviolet spectra of novae obtained at or near maximum optical light is presented. These spectra are characterized by a relatively cool continuum with superimposed permitted emission lines from ions such as Fe II, Mg II, and Si II. Spectra obtained late in the outburst show only emission lines from highly ionized species and in many cases these are forbidden lines. The ultraviolet data will be used with calculations of spherical, expanding, stellar atmospheres for novae to determine elemental abundances by spectral line synthesis. This method is extremely sensitive to the abundances and completely independent of the nebular analyses usually used to obtain novae abundances.

  17. Pre-Discovery Detections of the Nova Delphini Outburst

    NASA Astrophysics Data System (ADS)

    Wren, J.; Vestrand, T. W.; Wozniak, P.; Davis, H

    2013-08-01

    Three RAPTOR full-sky persistent monitors located in Los Alamos, NM, and Maui, HI, detected the emergence of Nova Delphini 2013 (CBET #3628) at magnitude 10.1 at 6:58 UT on 14 Aug, 2013. Our photometry of the nova shows a rapid rise to approximately magnitude 8.5 by 8 UT and then a more gradual rise to approximately magnitude 7.5 by 14 UT (the time of discovery by Koichi Itagaki). Our full-sky persistent monitors imaged the nova every 10s during this time period, a total of about 2500 photometric measurements before 14 UT.

  18. Liquid Scintillator Production for the NOvA Experiment

    DOE PAGES

    Mufson, S.; Baugh, B.; Bower, C.; ...

    2015-04-15

    The NOvA collaboration blended and delivered 8.8 kt (2.72M gal) of liquid scintillator as the active detector medium to its near and far detectors. The composition of this scintillator was specifically developed to satisfy NOvA's performance requirements. A rigorous set of quality control procedures was put in place to verify that the incoming components and the blended scintillator met these requirements. The scintillator was blended commercially in Hammond, IN. The scintillator was shipped to the NOvA detectors using dedicated stainless steel tanker trailers cleaned to food grade.

  19. Microstructures of Rare Silicate Stardust from Nova and Supernovae

    NASA Technical Reports Server (NTRS)

    Nguyen, A. N.; Keller, L. P.; Rahman, Z.; Messenger, S

    2011-01-01

    Most silicate stardust analyzed in the laboratory and observed around stellar environments derives from O-rich red giant and AGB stars [1,2]. Supernova (SN) silicates and oxides are comparatively rare, and fewer than 10 grains from no-va or binary star systems have been identified to date. Very little is known about dust formation in these stellar environments. Mineralogical studies of only three O-rich SN [3-5] and no nova grains have been performed. Here we report the microstructure and chemical makeup of two SN silicates and one nova grain.

  20. Spectropolarimetry of Nova Cygni 1992: Evidence for an asymmetric geometry

    NASA Technical Reports Server (NTRS)

    Bjorkman, K. S.; Johansen, K. A.; Nordsieck, K. H.; Gallagher, J. S.; Barger, A. J.

    1994-01-01

    We present the first study of the spectropolarimetric evolution of a fast neon nova from outburst through the decline of the light curve, showing the initial presence and gradual disappearance of intrinsic linear polarization. The observations of Nova Cygni 1992 were obtained at the Pine Bluff Observatory of the University of Wisconsin from 1992 March through 1993 May. The emission lines and the continuum show quite different linear polarization behaviors, with the line emission essentially unpolarized and the continuum showing intrinsic polarization. The data provide evidence for an asymmetric geometry in the initial explosion and evidence for clumping in the subsequent nova ejecta.

  1. THE BEHAVIOR OF NOVAE LIGHT CURVES BEFORE ERUPTION

    SciTech Connect

    Collazzi, Andrew C.; Schaefer, Bradley E.; Xiao Limin; Pagnotta, Ashley; Kroll, Peter; Loechel, Klaus; Henden, Arne A.

    2009-12-15

    In 1975, E. R. Robinson conducted the hallmark study of the behavior of classical nova light curves before eruption, and this work has now become part of the standard knowledge of novae. He made three points: 5 out of 11 novae showed pre-eruption rises in the years before eruption, one nova (V446 Her) showed drastic changes in the variability across eruptions, and all but one of the novae (excepting BT Mon) have the same quiescent magnitudes before and after the outburst. This work has not been tested since it came out. We have now tested these results by going back to the original archival photographic plates and measuring large numbers of pre-eruption magnitudes for many novae using comparison stars on a modern magnitude scale. We find in particular that four out of five claimed pre-eruption rises are due to simple mistakes in the old literature, that V446 Her has the same amplitude of variations across its 1960 eruption, and that BT Mon has essentially unchanged brightness across its 1939 eruption. Out of 22 nova eruptions, we find two confirmed cases of significant pre-eruption rises (for V533 Her and V1500 Cyg), while T CrB has a deep pre-eruption dip. These events are a challenge to theorists. We find no significant cases of changes in variability across 27 nova eruptions beyond what is expected due to the usual fluctuations seen in novae away from eruptions. For 30 classical novae plus 19 eruptions from 6 recurrent novae, we find that the average change in magnitude from before the eruption to long after the eruption is 0.0 mag. However, we do find five novae (V723 Cas, V1500 Cyg, V1974 Cyg, V4633 Sgr, and RW UMi) that have significantly large changes, in that the post-eruption quiescent brightness level is over ten times brighter than the pre-eruption level. These large post-eruption brightenings are another challenge to theorists.

  2. The Behavior of Novae Light Curves Before Eruption

    NASA Astrophysics Data System (ADS)

    Collazzi, Andrew C.; Schaefer, Bradley E.; Xiao, Limin; Pagnotta, Ashley; Kroll, Peter; Löchel, Klaus; Henden, Arne A.

    2009-12-01

    In 1975, E. R. Robinson conducted the hallmark study of the behavior of classical nova light curves before eruption, and this work has now become part of the standard knowledge of novae. He made three points: 5 out of 11 novae showed pre-eruption rises in the years before eruption, one nova (V446 Her) showed drastic changes in the variability across eruptions, and all but one of the novae (excepting BT Mon) have the same quiescent magnitudes before and after the outburst. This work has not been tested since it came out. We have now tested these results by going back to the original archival photographic plates and measuring large numbers of pre-eruption magnitudes for many novae using comparison stars on a modern magnitude scale. We find in particular that four out of five claimed pre-eruption rises are due to simple mistakes in the old literature, that V446 Her has the same amplitude of variations across its 1960 eruption, and that BT Mon has essentially unchanged brightness across its 1939 eruption. Out of 22 nova eruptions, we find two confirmed cases of significant pre-eruption rises (for V533 Her and V1500 Cyg), while T CrB has a deep pre-eruption dip. These events are a challenge to theorists. We find no significant cases of changes in variability across 27 nova eruptions beyond what is expected due to the usual fluctuations seen in novae away from eruptions. For 30 classical novae plus 19 eruptions from 6 recurrent novae, we find that the average change in magnitude from before the eruption to long after the eruption is 0.0 mag. However, we do find five novae (V723 Cas, V1500 Cyg, V1974 Cyg, V4633 Sgr, and RW UMi) that have significantly large changes, in that the post-eruption quiescent brightness level is over ten times brighter than the pre-eruption level. These large post-eruption brightenings are another challenge to theorists.

  3. SOFIA: A Promising Resource for Future Nova Studies

    NASA Astrophysics Data System (ADS)

    Helton, L. A.; Sofia Science Team

    2014-12-01

    The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a 2.5-m telescope carried on board a Boeing 747-SP aircraft. Optimized for observations from infrared through sub-mm wavelengths, SOFIA observes from an altitude of 37,000 - 45,000 feet, above 99% of the atmospheric water vapor. The Observatory's complement of instruments possesses a broad range of capabilities, many of which are especially well suited for observations of classical novae, recurrent novae, and other cataclysmic variables. Here we present a selection of the instruments available on board SOFIA that may prove to be very useful for future novae studies.

  4. Liquid scintillator production for the NOvA experiment

    NASA Astrophysics Data System (ADS)

    Mufson, S.; Baugh, B.; Bower, C.; Coan, T. E.; Cooper, J.; Corwin, L.; Karty, J. A.; Mason, P.; Messier, M. D.; Pla-Dalmau, A.; Proudfoot, M.

    2015-11-01

    The NOvA collaboration blended and delivered 8.8 kt (2.72M gal) of liquid scintillator as the active detector medium to its near and far detectors. The composition of this scintillator was specifically developed to satisfy NOvA's performance requirements. A rigorous set of quality control procedures was put in place to verify that the incoming components and the blended scintillator met these requirements. The scintillator was blended commercially in Hammond, IN. The scintillator was shipped to the NOvA detectors using dedicated stainless steel tanker trailers cleaned to food grade.

  5. Current results of the NOvA experiment

    NASA Astrophysics Data System (ADS)

    Kolupaeva, Liudmila

    2016-10-01

    NOvA is a long baseline neutrino oscillation experiment at Fermi National Accelerator Laboratory, USA. It is one of the so-called "off-beam-axis" experiments with two highly active detectors separated by 810 km of Earth's crust. Both detectors are identical and consist of PVC cells filled with a liquid scintillator. The NOvA collaboration has already published its first results for muon neutrino disappearance [1] and electron neutrino appearance [2] mode with data collected between July 2013 and March 2015. This talk is devoted to a discussion on NOvA's first results.

  6. Neutrino Physics in the NOvA Experiment

    SciTech Connect

    Sanchez, Mayly

    2016-09-19

    The objective of the experimental neutrino physics program at ISU is to contribute to the NOvA experiment in order to enable the measurement of the unknown neutrino parameters: the CP violation phase and the mass hierarchy. In the Summer of 2015, the NOvA Collaboration released results from the first year of data collected by the experiment. The ISU group played an important role in various aspects of these results including authoring one of the two resulting publications. During this project period and with the support of this grant the PI and her group made leading contributions both in data analysis and operations to the NOvA experiment.

  7. E2000 + 223 - A newly discovered old nova?

    NASA Astrophysics Data System (ADS)

    Takalo, L. O.; Nousek, J. A.

    1985-06-01

    The X-ray source, E2000 + 223, serendipitously discovered by the Einstein Observatory, has been tentatively identified with an old nova shell. Spectroscopic observations of the diffuse optical counterpart show a heavily reddened continuum with bright forbidden S II emission lines at double lambda 6716, 6732. Radio observations at the VLA show a weak (about 1.2 mJy) extended radio source, with a nonthermal spectrum, concident with the optical emission. The observations can be best explained by assuming the object is an old nova which erupted sometime in the eighteenth or nineteenth century, similar to GK Per (Nova 1901) but at a distance of 1.4 kpc.

  8. E2000 + 223 - A newly discovered old nova?

    NASA Technical Reports Server (NTRS)

    Takalo, L. O.; Nousek, J. A.

    1985-01-01

    The X-ray source, E2000 + 223, serendipitously discovered by the Einstein Observatory, has been tentatively identified with an old nova shell. Spectroscopic observations of the diffuse optical counterpart show a heavily reddened continuum with bright forbidden S II emission lines at double lambda 6716, 6732. Radio observations at the VLA show a weak (about 1.2 mJy) extended radio source, with a nonthermal spectrum, concident with the optical emission. The observations can be best explained by assuming the object is an old nova which erupted sometime in the eighteenth or nineteenth century, similar to GK Per (Nova 1901) but at a distance of 1.4 kpc.

  9. The Nova Outburst: Thermonuclear Runaways on Degenerated Dwarfs

    SciTech Connect

    Starrfield, S.; Truran, J.W.; Sparks, W.M.

    1999-07-08

    Observational and theoretical studies of the outbursts of classical novae have provided critical insights into a broad range of astrophysical phenomena. Thermonuclear runaways (TNRs) in accreted hydrogen-rich envelopes on the white dwarf (WD) components of close binary systems constitute not only the outburst mechanism for a classical nova explosion, but also the recurrent novae and a fraction of the symbiotic novae explosions. Studies of the general characteristics of these explosions, both in our own galaxy and in neighboring galaxies of varying metallicity, can teach us about binary stellar evolution, while studies of the evolution of nova binary systems can constrain models for the (as yet unidentified) progenitors of Type Ia supernovae. Further, the empirical relation between the peak luminosity of a nova and the rate of decline, which presents a challenge to theoretical models, allows novae to be utilized as standard candles for distance determinations out to the Virgo Cluster. E xtensive studies of novae with IUE and the resulting abundance determinations have revealed the existence of oxygen-neon white dwarfs in some systems. The high levels of enrichment of novae ejecta in elements ranging from carbon to sulfur confirm that there is significant dredge-up of matter from the core of the underlying white dwarf and enable novae to contribute to the chemical enrichment of the interstellar medium. Observations of the epoch of dust formation in the expanding shells of novae allow important constraints to be placed on the dust formation process and confirm that graphite, SiC, and SiO{sub 2} grains are formed by the outburst. It is possible that grains from novae were injected into the pre-solar nebula and can be identified with some of the pre-solar grains or ''stardust'' found in meteorites. Finally, g-ray observations during the first several years of their outburst, using the next generation of satellite observatories, could confirm

  10. Distributed computer control system in the Nova Laser Fusion Test Facility

    SciTech Connect

    Not Available

    1985-09-01

    The EE Technical Review has two purposes - to inform readers of various activities within the Electronics Engineering Department and to promote the exchange of ideas. The articles, by design, are brief summaries of EE work. The articles included in this report are as follows: Overview - Nova Control System; Centralized Computer-Based Controls for the Nova Laser Facility; Nova Pulse-Power Control System; Nova Laser Alignment Control System; Nova Beam Diagnostic System; Nova Target-Diagnostics Control System; and Nova Shot Scheduler. The 7 papers are individually abstracted.

  11. Backyard Research on Cataclysmic Variables by a Consortium of Professional and Amateur Astronomers: DV UMa-A Case Study

    NASA Astrophysics Data System (ADS)

    Vanmunster, T.

    2006-06-01

    The Center for Backyard Astrophysics (CBA) is a multi-longitude network of small photometric telescopes, owned by talented amateurs, who study periodic phenomena in Cataclysmic Variables (CVs). The CBA is among the leading examples of successful partnerships between professional and amateur enthusiasts, producing vast amounts of high-quality variable star data. This poster paper highlights observational CBA results obtained on DV UMa, a most interesting eclipsing UGSU-type dwarf nova, that has been intensively monitored during its April 1997 superoutburst.

  12. A Hubble Space Telescope survey for novae in M87.I. light and color curves, spatial distributions, and the nova rate

    DOE PAGES

    Shara, Michael M.; Doyle, Trisha F.; Lauer, Tod R.; ...

    2016-11-08

    The Hubble Space Telescope has imaged the central part of M87 over a 10 week span, leading to the discovery of 32 classical novae (CNe) and nine fainter, likely very slow, and/or symbiotic novae. In this first paper of a series, we present the M87 nova finder charts, and the light and color curves of the novae. We demonstrate that the rise and decline times, and the colors of M87 novae are uncorrelated with each other and with position in the galaxy. The spatial distribution of the M87 novae follows the light of the galaxy, suggesting that novae accreted by M87 during cannibalistic episodes are well-mixed. Conservatively using only the 32 brightest CNe we derive a nova rate for M87:more » $${363}_{-45}^{+33}$$ novae yr–1. We also derive the luminosity-specific classical nova rate for this galaxy, which is $${7.88}_{-2.6}^{+2.3}\\,{\\mathrm{yr}}^{-1}/{10}^{10}\\,{L}_{\\odot }{,}_{K}$$. Both rates are 3–4 times higher than those reported for M87 in the past, and similarly higher than those reported for all other galaxies. As a result, we suggest that most previous ground-based surveys for novae in external galaxies, including M87, miss most faint, fast novae, and almost all slow novae near the centers of galaxies.« less

  13. A Hubble Space Telescope survey for novae in M87.I. light and color curves, spatial distributions, and the nova rate

    SciTech Connect

    Shara, Michael M.; Doyle, Trisha F.; Lauer, Tod R.; Zurek, David; Neill, J. D.; Madrid, Juan P.; Mikołajewska, Joanna; Welch, D. L.; Baltz, Edward A.

    2016-11-08

    The Hubble Space Telescope has imaged the central part of M87 over a 10 week span, leading to the discovery of 32 classical novae (CNe) and nine fainter, likely very slow, and/or symbiotic novae. In this first paper of a series, we present the M87 nova finder charts, and the light and color curves of the novae. We demonstrate that the rise and decline times, and the colors of M87 novae are uncorrelated with each other and with position in the galaxy. The spatial distribution of the M87 novae follows the light of the galaxy, suggesting that novae accreted by M87 during cannibalistic episodes are well-mixed. Conservatively using only the 32 brightest CNe we derive a nova rate for M87: ${363}_{-45}^{+33}$ novae yr–1. We also derive the luminosity-specific classical nova rate for this galaxy, which is ${7.88}_{-2.6}^{+2.3}\\,{\\mathrm{yr}}^{-1}/{10}^{10}\\,{L}_{\\odot }{,}_{K}$. Both rates are 3–4 times higher than those reported for M87 in the past, and similarly higher than those reported for all other galaxies. As a result, we suggest that most previous ground-based surveys for novae in external galaxies, including M87, miss most faint, fast novae, and almost all slow novae near the centers of galaxies.

  14. Summary of Stimulated Raman Scattering Experiments in the Nova Air-Path and Projected Nova and Nova II System Performance Limits

    SciTech Connect

    Henesian, M; Swift, C D; Murray, J R

    2007-07-17

    The authors present the results of high intensity beam propagation experiments conducted with the Nova laser system to investigate the occurrence of stimulated rotational Raman scattering (SRRS) from atmospheric nitrogen in the beam path. Enclosed is a preprint entitled ''Stimulated Rotational Raman Scattering in Nitrogen in Long Air Paths'' that they have published in the November issue of Optics Letters. The physics issues associated with SRRS are discussed at length in the preprint. The small signal steady-state SRRS gain coefficient that they determined from threshold measurements is in excellent agreement with recent direct SRRS gain measurements by Bischel, et al., at SRI, and is in good agreement with early gain estimates from Averbakh, et al., in the Soviet Union. Consequently, they have a high degree of confidence in the gain coefficient. In addition, threshold SRRS experiments on the long air-path Nova II system are in substantial agreement with the earlier Nova experiments. Nova and Nova II system performance limitations were not critically addressed in the publication so they shall discuss these issues in this paper.

  15. Ocean and Coastal Acidification off New England and Nova Scotia

    EPA Science Inventory

    New England coastal and adjacent Nova Scotia shelf waters have a reduced buffering capacity because of significant freshwater input, making the region’s waters potentially more vulnerable to coastal acidification. Nutrient loading and heavy precipitation events further acid...

  16. Confirmation of nova M31 2009-08d

    NASA Astrophysics Data System (ADS)

    Rodríguez-Gil, P.; Ferrando, R.; Rodríguez, D.; Bode, M. F.; Huxor, A.; Giles, P.; Mackey, D.

    2009-08-01

    We confirm the nova nature of the possible nova M31 2009-08d, discovered by Rafael Ferrando on UT 2009 Aug 15.0950 (discovery image at http://www.pla-de-arguines.com/NOVA-M31D.jpg) . Koichi Itagaki reported the same discovery on UT 2009 Aug 15.981 (http://www.supernovae.net/novae.html ). A single, filterless image of 20-s exposure time taken on UT 2009 Aug 18.1430 with the ACAM imager/spectrograph on the 4.2m William Herschel Telescope (La Palma) reveals the object at coordinates RA=00h44m09.91s, Dec= +41d48m51.0s (J2000), as reported.

  17. The likely progenitor of Nova ASASSN-16ra

    NASA Astrophysics Data System (ADS)

    Ferreira, T. S.; Saito, R. K.

    2017-09-01

    Jayasinghe et. al. (ATel #10740) recently reported on the detection of a likely Galactic Nova in the Milky Way disk, confirmed by spectroscopic observations at SOAR Telescope (Chomiuk et al. 2017, ATel #10764).

  18. A Comprehensive Review of Nova-Like Variable Stars

    NASA Astrophysics Data System (ADS)

    Sion, Edward

    2016-07-01

    A comprehensive review of nova-like variable stars of the VY Sculptoris and UX Ursa Majoris subtypes is presented. All that has been learned, up to the present time, from observations in the X-ray, far ultraviolet, optical and infrared bandpasses will be discussed. Spectroscopic analyses of high optical brightness states and low optical brightness states of nova-like variables will be summarized. The application of standard and non-standard accretion disk models as well as boundary layer structure will be discussed. The results of searches for nova shells, the evolutionary state of nova-likes as well as new spectroscopic results on BZ Cam (the bow shock CV) and BB Dor will also be included. This work is supported by NASA ADP grants NNX13AF12G and NNX13AF11G to Villanova University.

  19. Faint Object Camera observations of a globular cluster nova field

    NASA Technical Reports Server (NTRS)

    Margon, Bruce; Anderson, Scott F.; Downes, Ronald A.; Bohlin, Ralph C.; Jakobsen, Peter

    1991-01-01

    The Faint Object Camera onboard Hubble Space Telescope has obtained U and B images of the field of Nova Ophiuchi 1938 in the globular cluster M14 (NGC 6402). The candidate for the quiescent nova suggested by Shara et al. (1986) is clearly resolved into at least six separate images, probably all stellar, in a region of 0.5 arcsec. Although two of these objects are intriguing as they are somewhat ultraviolet, the actual nova counterpart remains ambiguous, as none of the images in the field has a marked UV excess. Many stars within the 1.4 arcsec (2 sigma) uncertainty of the nova outburst position are viable counterparts if only astrometric criteria are used for selection. The 11 x 11 arcsec frames easily resolve several hundred stars in modest exposures, implying that HST even in its current optical configuration will be unique for studies of very crowded fields at moderate (B = 22) limiting magnitudes.

  20. Ultraviolet spectroscopy of the recurrent nova U Scorpii during outburst

    NASA Technical Reports Server (NTRS)

    Williams, R. E.; Sparks, W. M.; Gallagher, J. S.; Ney, E. P.; Starrfield, S. G.; Truran, J. W.

    1981-01-01

    Observations of the recurrent nova U Sco during the 1979 outburst are presented, and the spectral evolution is found to differ from that of other recurrent novas. Spectra are dominated by emission lines, and the strong forbidden-line emission characteristic is conspicuously absent. A method to determine masses of nova shells is outlined, and an analysis of the emission lines shows an enrichment in N relative to C and O, and that the nova ejecta are rich in He relative to H. Optical spectra of U Sco obtained following its return to quiescence show predominantly He II emission lines, which suggests an enrichment of the preoutburst gas in He, and thus the presence of a highly evolved companion.

  1. WHT, DIPOL-2 polarimetry of Nova Sgr 2015b

    NASA Astrophysics Data System (ADS)

    Harvey, Eamonn; Berdyugin, Andrei; Redman, Matt

    2015-09-01

    We report polarimetry data from three nights observing of Nova Sgr 2015b (also PNV J18365700-2855420 or V5668 Sgr) with the William Herschel Telescope in the BVR passbands using the DIPOL-2 instrument.

  2. Ocean and Coastal Acidification off New England and Nova Scotia

    EPA Science Inventory

    New England coastal and adjacent Nova Scotia shelf waters have a reduced buffering capacity because of significant freshwater input, making the region’s waters potentially more vulnerable to coastal acidification. Nutrient loading and heavy precipitation events further acid...

  3. Faint Object Camera observations of a globular cluster nova field

    NASA Technical Reports Server (NTRS)

    Margon, Bruce; Anderson, Scott F.; Downes, Ronald A.; Bohlin, Ralph C.; Jakobsen, Peter

    1991-01-01

    The Faint Object Camera onboard Hubble Space Telescope has obtained U and B images of the field of Nova Ophiuchi 1938 in the globular cluster M14 (NGC 6402). The candidate for the quiescent nova suggested by Shara et al. (1986) is clearly resolved into at least six separate images, probably all stellar, in a region of 0.5 arcsec. Although two of these objects are intriguing as they are somewhat ultraviolet, the actual nova counterpart remains ambiguous, as none of the images in the field has a marked UV excess. Many stars within the 1.4 arcsec (2 sigma) uncertainty of the nova outburst position are viable counterparts if only astrometric criteria are used for selection. The 11 x 11 arcsec frames easily resolve several hundred stars in modest exposures, implying that HST even in its current optical configuration will be unique for studies of very crowded fields at moderate (B = 22) limiting magnitudes.

  4. Optical observations of KT Eri = Nova Eridani 2009

    NASA Astrophysics Data System (ADS)

    Ragan, E.; Brozek, T.; Suchomska, K.; Skalbania, A.; Konorski, P.; Galan, C.; Swierczynski, E.; Tomov, T.; Mikolajewski, M.; Wychudzki, P.

    2009-12-01

    We report on optical observations of Nova Eri 2009 obtained at the Nicolaus Copernicus University Observatory (Torun, Poland) and the Olsztyn Planetarium and Astronomical Observatory. Using a 60 cm Cassegrain telescope (Torun) and a 25 cm Schmidt-Cassegrain telescope (Olsztyn) we estimated the V brightness of the Nova to ~8.30+/-0.04 mag and ~8.59+/-0.01 mag on Nov. 27.00 UT and Nov. 27.91 UT.

  5. Synthesis of C-rich dust in CO nova outbursts

    NASA Astrophysics Data System (ADS)

    José, Jordi; Halabi, Ghina M.; El Eid, Mounib F.

    2016-09-01

    Context. Classical novae are thermonuclear explosions that take place in the envelopes of accreting white dwarfs in stellar binary systems. The material transferred onto the white dwarf piles up under degenerate conditions, driving a thermonuclear runaway. In these outbursts, about 10-7-10-3 M⊙, enriched in CNO and sometimes other intermediate-mass elements (e.g., Ne, Na, Mg, or Al for ONe novae) are ejected into the interstellar medium. The large concentrations of metals spectroscopically inferred in the nova ejecta reveal that the solar-like material transferred from the secondary mixes with the outermost layers of the underlying white dwarf. Aims: Most theoretical models of nova outbursts reported to date yield, on average, outflows characterized by O > C, from which, in principle, only oxidized condensates (e.g., O-rich grains) would be expected. Methods: To specifically address whether CO novae can actually produce C-rich dust, six different hydrodynamic nova models have been evolved, from accretion to the expansion and ejection stages, with different choices for the composition of the substrate with which the solar-like accreted material mixes. Updated chemical profiles inside the H-exhausted core have been used, based on stellar evolution calculations for a progenitor of 8 M⊙ through H- and He-burning phases. Results: We show that these profiles lead to C-rich ejecta after the nova outburst. This extends the possible contribution of novae to the inventory of presolar grains identified in meteorites, particularly in a number of carbonaceous phases (i.e., nanodiamonds, silicon carbides, and graphites).

  6. AAS Nova and Astrobites: Making current astronomy research accessible

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna; Astrobites Team

    2016-10-01

    AAS Nova and Astrobites are two resources available for astronomers, astronomy students, and astronomy enthusiasts to keep up with some of the most recent research published across the field of astronomy. Both supported by the AAS, these two daily astrophysical literature blogs provide accessible summaries of recent publications on the arXiv and in AAS journals. We present the goals, content, and readership of AAS Nova and Astrobites, and discuss how they might be used as tools in the undergraduate classroom.

  7. X-ray Grating Observations of Recent Recurrent Novae

    NASA Astrophysics Data System (ADS)

    Orio, Marina; Behar, Ehud; Gallagher, J.; Bianchini, A.; Chiosi, E.; Luna, J.; Nelson, T.; Rauch, T.

    2013-01-01

    Two recurrent novae (RNe) that do not host red giants were observed in outburst at the beginning of 2009 and 2010, respectively. The first nova was LMC 2009a, and the second one was U Scorpii. Nova LMC 2009a was a relatively slow RN, and it was quite luminous both at optical and X-ray wavelengths. U Sco is the fastest nova ever recorded. Its supersoft X-ray phase started a couple of weeks after optical maximum and lasted for about a month, while for Nova LMC 2009a this phase started four months after maximum and lasted for 5 months. For both novae, the first X-ray spectrum taken while the luminous supersoft X-ray source was beginning to emerge is remarkably similar with broad and prominent emission lines of nitrogen and carbon accounting for at least 30% of the X-ray flux. Blue-shifted absorption and red-shifted emission form apparent P-Cyg profiles. We attribute the emission features to the ejecta and show evidence that they are largely due to collisional ionization. In the case of U Sco the absorption lines were embedded in the emission features after the first observation. We find evidence that in U Scorpii we were observing the Thomson reflected spectrum at a distance of ~= 3 R⊙ from the white dwarf rather than the atmosphere itself. For both novae, the peak temperature was remarkably high, probably close to 900,000 K for U Sco, and about 600,000 K for Nova LMC 2009a. We suggest that these two objects represent different stages of RNe secular evolution.

  8. Hot Spot Manifestation in Eclipsing Dwarf Nova HT Cassiopeiae

    NASA Astrophysics Data System (ADS)

    Bąkowska, K.; Olech, A.

    2014-09-01

    We report the detection of a hot spot in the light curves of the eclipsing dwarf nova HT Cas during its superoutburst in 2010 November. Analysis of the eight reconstructed light curves of the hot spot eclipses showed directly that the brightness of the hot spot was changing significantly during the superoutburst. Thereby, detected hot spot manifestation in HT Cas is the newest observational evidence for the EMT model for dwarf novae.

  9. Discovery of two nova candidates in M81

    NASA Astrophysics Data System (ADS)

    Williams, S. C.; Hornoch, K.; Kucakova, H.; Henze, M.; Darnley, M. J.; Meusinger, H.; Kaur, A.; Hartmann, D. H.; Sala, G.; Jose, J.; Figueira, J.; Hernanz, M.; Shafter, A. W.

    2017-05-01

    The M81 nova monitoring collaboration reports the discovery of two M81 nova candidates in H & alpha; imaging from the 2-m Liverpool Telescope (LT). The first, M81N 2017-05a, was discovered on 2017-05-03.89 UT at RA = 9h55m24.61s, Dec. = +69 & deg;06'59.1" (J2000, 1 & sigma; error 0.2").

  10. Near-infrared photometric observations of Nova Ophiuchi 2012

    NASA Astrophysics Data System (ADS)

    Raj, Ashish; Ashok, N. M.; Banerjee, D. P. K.; Raman, V. Venkata

    2012-04-01

    Ashish Raj, N. M. Ashok, D. P. K. Banerjee and V. Venkata Raman, Physical Research Laboratory, report near-infrared J-, H-, and K-band photometry of the Nova Oph 2012 (cf. CBET 3072, 3081) obtained with the Mt. Abu 1.2-m telescope (+PRL Near-Infrared NICMOS3 Imager/Spectrometer). The preliminary reduction of these Mt. Abu observations, of Mar. 29, 31 and Apr. 2, 3 UT shows the brightening of the nova in the JHK bands.

  11. The nova rate in the elliptical component of NGC 5128

    NASA Technical Reports Server (NTRS)

    Ciardullo, Robin; Tamblyn, Peter; Jacoby, George H.; Ford, Holland C.; Williams, R. E.

    1990-01-01

    The results are presented of a five year nova survey of NGC 5128 performed with an H-alpha filter at the prime focus of the CTIO 4 m telescope. In all, 16 novae were detected, of which 12 are members of a statistically complete and homogeneous sample unaffected by the absorption lane of the galaxy. When normalized to B luminosity, the nova rate in the elliptical component of NGC 5128 is 2.7 + or - 1.0 times less than that observed in the bulge of M31. However, when normalized in the infrared K bandpass, the two nova rates are identical, and comparable to that measured in the Large Magellanic Cloud. These data suggest that (1) the percentage of binary stars is approximately constant over a large range of star-forming environments, (2) the nova rate in our own galaxy is between 11 and 46/yr, and (3) nova rates are not strongly affected by tidal captures in bright globular clusters.

  12. Atypical dust species in the ejecta of classical novae

    NASA Astrophysics Data System (ADS)

    Helton, L. A.; Evans, A.; Woodward, C. E.; Gehrz, R. D.

    2011-03-01

    A classical nova outburst arises from a thermonuclear runaway in the hydrogen-rich material accreted onto the surface of a white dwarf in a binary system. These explosions can produce copious amounts of heavy element enriched material that are ejected violently into the surrounding interstellar medium. In some novae, conditions in the ejecta are suitable for the formation of dust of various compositions, including silicates, amorphous carbon, silicon carbide, and hydrocarbons. Multiple dust grain types are sometimes produced in the same system. CO formation in novae may not reach saturation, thus invalidating the usual paradigm in which the C:O ratio determines the dust species. A few novae, such as V705 Cas and DZ Cru, have exhibited emission features near 6, 8, and 11 μmthat are similar to "Unidentified Infrared" (UIR) features, but with significant differences in position and band structure. Here, we present Spitzer IRS spectra of two recent dusty novae, V2361 Cyg and V2362 Cyg, that harbor similar peculiar emission structures superimposed on features arising from carbonaceous grains. In other astronomical objects, such as star forming regions and young stellar objects, emission peaks at 6.2, 7.7, and 11.3 μmhave been associated with polycyclic aromatic hydrocarbon (PAH) complexes. We suggest that hydrogenated amorphous carbon (HAC) may be the source of these features in novae based upon the spectral behavior of the emission features and the conditions under which the dust formed.

  13. Novae as a Class of Transient X-ray Sources

    NASA Technical Reports Server (NTRS)

    Mukai, K.; Orio, M.; Valle, M. Della

    2007-01-01

    Motivated by the recently discovered class of faint (10(exp 34)-10(exp 35) ergs/s) X-ray transients in the Galactic Center region, we investigate the 2-10 keV properties of classical and recurrent novae. Existing data are consistent with the idea that all classical novae are transient X-ray sources with durations of months to years and peak luminosities in the 10(exp 34)-10(exp 35)ergs/s range. This makes classical novae a viable candidate class for the faint Galactic Center transients. We estimate the rate of classical novae within a 15 arcmin radius region centered on the Galactic Center (roughly the field of view of XMM-Newton observations centered on Sgr A*) to be approx.0.1 per year. Therefore, it is plausible that some of the Galactic Center transients that have been announced to date are unrecognized classical novae. The continuing monitoring of the Galactic Center region carried out by Chandra and XMM-Newton may therefore provide a new method to detect classical novae in this crowded and obscured region, an

  14. Detecting Nova Shells around known Cataclysmic Variable systems

    NASA Astrophysics Data System (ADS)

    Xhakaj, Enia; Kupfer, Thomas; Prince, Thomas A.

    2017-01-01

    Nova shells are hydrogen-rich nebulae around Cataclysmic Variables that are created when a Nova outburst takes place. Learning more about Nova shells can help us get a better understanding of the long-term evolution of white dwarfs in active Cataclysmic Variables. In this project, we present the search for Nova shells around 1700 Cataclysmic Variables, using Hα images from the Palomar Transient Factory (PTF) survey. The PTF Hα survey started in 2009 using the 48’’ Oschin telescope at Palomar Observatory and is the first of its type covering the whole northern hemisphere while reaching 18 mags in 60 seconds of exposure. We concentrated our search on the IAU catalogue of Historical Novae, as well as on the SDSS and the Ritter-Kolb catalogue of Cataclysmic Variables. We numerically analyzed radial profiles centered on the target sources to search for excess emission potentially associated with the shells. Out of 1700 Cataclysmic Variables present in these catalogues, we detected 25 Nova shells, out of which 20 are not observed before.

  15. Evolution of Nova-Dependent Splicing Regulation in the Brain

    PubMed Central

    Živin, Marko; Darnell, Robert B

    2007-01-01

    A large number of alternative exons are spliced with tissue-specific patterns, but little is known about how such patterns have evolved. Here, we study the conservation of the neuron-specific splicing factors Nova1 and Nova2 and of the alternatively spliced exons they regulate in mouse brain. Whereas Nova RNA binding domains are 94% identical across vertebrate species, Nova-dependent splicing silencer and enhancer elements (YCAY clusters) show much greater divergence, as less than 50% of mouse YCAY clusters are conserved at orthologous positions in the zebrafish genome. To study the relation between the evolution of tissue-specific splicing and YCAY clusters, we compared the brain-specific splicing of Nova-regulated exons in zebrafish, chicken, and mouse. The presence of YCAY clusters in lower vertebrates invariably predicted conservation of brain-specific splicing across species, whereas their absence in lower vertebrates correlated with a loss of alternative splicing. We hypothesize that evolution of Nova-regulated splicing in higher vertebrates proceeds mainly through changes in cis-acting elements, that tissue-specific splicing might in some cases evolve in a single step corresponding to evolution of a YCAY cluster, and that the conservation level of YCAY clusters relates to the functions encoded by the regulated RNAs. PMID:17937501

  16. Diabetes Care Program of Nova Scotia: Celebrating 25 Years of Improving Diabetes Care in Nova Scotia.

    PubMed

    Payne, Jennifer I; Dunbar, Margaret J; Talbot, Pamela; Tan, Meng H

    2017-08-16

    The Diabetes Care Program of Nova Scotia (DCPNS)'s mission is "to improve, through leadership and partnerships, the health of Nova Scotians living with, affected by, or at risk of developing diabetes." Working together with local, provincial and national partners, the DCPNS has improved and standardized diabetes care in Nova Scotia over the past 25 years by developing and deploying a resourceful and collaborative program model. This article describes the model and highlights its key achievements. With balanced representation from frontline providers through to senior decision makers in health care, the DCPNS works across the age continuum, supporting the implementation of national clinical practice guidelines and, when necessary, developing provincial guidelines to meet local needs. The development and implementation of standardized documentation and data collection tools in all diabetes centres created a robust opportunity for the development and expansion of the DCPNS registry. This registry provides useful clinical and statistical information to staff, providers within the circle of care, management and senior leadership. Data are used to support individual care, program planning, quality improvement and business planning at both the local and the provincial levels. The DCPNS supports the sharing of new knowledge and advances through continuous education for providers. The DCPNS's ability to engage diabetes educators and key physician champions has ensured balanced perspectives in the creation of tools and resources that can be effective in real-world practice. The DCPNS has evolved to become an illustrative example of the chronic care model in action. Copyright © 2017 Diabetes Canada. Published by Elsevier Inc. All rights reserved.

  17. [Reversible cerebral vasoconstriction syndrome].

    PubMed

    Laakso, Elina; Pekkola, Johanna; Soinne, Lauri; Putaala, Jukka

    2014-01-01

    Reversible cerebral vasoconstriction syndrome (RCVS) is increasingly recognized. The condition is characterized by multifocal vasoconstriction lesions in cerebral arteries. Headache is the central symptom, with an acute onset and paroxysmal occurrence. Some of the patients develop intracranial hemorrhage, ischemic disturbance of the cerebral circulation, hypertensive encephalopathy (PRES) or epileptic seizures as complications. The disease is most common in middle-aged women. Most patients have an underlying predisposing factor, most commonly vasoactive medications, drugs or puerperium. There is no evidence-based practice.

  18. Another neon nova - Early infrared photometry and spectroscopy of Nova Cygni 1992

    NASA Technical Reports Server (NTRS)

    Hayward, T. L.; Gehrz, R. D.; Miles, J. W.; Houck, J. R.

    1992-01-01

    Infrared photometry and spectrophotometry of Nova Cygni 1992 taken within 54 days of its eruption show a strong 12.8-micron Ne II forbidden emission line as well as hydrogen recombination lines. Spectra with lambda/Delta lambda of about 2000 resolve the Ne II forbidden and 12.37-micron Hu-alpha lines with about 2200 km/s (FWHM). The Ne II forbidden line shows multiple velocity components. The amount of forbidden Ne II required to produce the observed emission feature exceeds the solar abundance of neon by at least a factor of 4.

  19. [Pedagogical Professional Development of Medical Teachers: The Experience of NOVA Medical School / Universidade Nova de Lisboa].

    PubMed

    Marques, Joana; Rosado-Pinto, Patrícia

    2017-03-31

    To be a college teacher requires a permanent effort in developing specific competencies, namely in the pedagogical domain. This paper aims both to describe the pedagogical professional development program offered by the Medical Education Office of NOVA Medical School of Universidade Nova de Lisboa and to analyse its role in the enhancement of reflection around curriculum and teaching practice. Description of the pedagogical programme offered between 2010 and 2016. We focused the analysis on different kinds of data - opinions of the participants in the training programme (questionnaire before and after the training); pedagogical products elaborated by the participants in the programme - design of lessons, modules or curricular units; questionnaire sent in 2016 to NOVA Medical School teachers responsible for the curricular units, about the contribution of their disciplines to the accomplishment of the core learning outcomes of the NOVA Medical School medical graduates. The pedagogical training needs identified by the teachers focused mainly on improving practice, critically analysing the curriculum and sharing experiences. Globally the training programme was deeply appreciated and considered very good by 97% of the participants. The lesson plans delivered showed that the teachers were able to integrate and apply the concepts developed during the training. The answers from the 46 faculty responsible for the curricular units (the majority of them had attended the Medical Education Office training programme) highlighted their capacity to critically approach content and pedagogical strategies within their disciplines as well as their contribution to the main goals of the medical curriculum. The results underlined the importance of a pedagogical training focused on the critical analysis of curriculum and pedagogical practice. On the other hand, the pedagogical products analyzed revealed great mastery by teachers of the content and pedagogical strategies present in the

  20. Another neon nova - Early infrared photometry and spectroscopy of Nova Cygni 1992

    NASA Technical Reports Server (NTRS)

    Hayward, T. L.; Gehrz, R. D.; Miles, J. W.; Houck, J. R.

    1992-01-01

    Infrared photometry and spectrophotometry of Nova Cygni 1992 taken within 54 days of its eruption show a strong 12.8-micron Ne II forbidden emission line as well as hydrogen recombination lines. Spectra with lambda/Delta lambda of about 2000 resolve the Ne II forbidden and 12.37-micron Hu-alpha lines with about 2200 km/s (FWHM). The Ne II forbidden line shows multiple velocity components. The amount of forbidden Ne II required to produce the observed emission feature exceeds the solar abundance of neon by at least a factor of 4.

  1. Two new, bright optical nova candidates in M 31 including one possible recurrent nova

    NASA Astrophysics Data System (ADS)

    Henze, M.; Burwitz, V.; Pietsch, W.; Hatzidimitriou, D.; Reig, P.; Primak, N.; Papamastorakis, G.

    2008-08-01

    We report the discovery of two new, bright possible novae in M 31 on dithered stacked R filter CCD images, obtained on 2008 August 09, with the 1.3m Ritchey Chretien f/7.5 telescope at Skinakas Observatory, Crete, Greece, using an Andor DZ436-BV CCD Camera (with a Marconi 2k x 2k chip with 13.5µm sq. pixels). The first object is visible in two different pointings of four images taken on 2008 August 09.96 and three images taken on 2008 August 09.97, respectively.

  2. ARAS Optical Spectroscopy of Classical Nova ASASSN-16ig (Nova Sgr 2016 no. 2)

    NASA Astrophysics Data System (ADS)

    Garde, Olivier; Charbonnel, Stephane; Du, Pascal Le

    2016-08-01

    We obtained a series of optical of the classical nova ASASSN-16ig in Sagittarius (N Sgr 2016 no. 2) (see ATels #9375, #9343, #9352, #9359, CBET 4295, 4299) with a LISA spectrograph plus ATIK414EX CCD using a C14 at Obs. Hautes Provence on Aug. 13.83 UT and 14.49 UT with total exposures of about 6000 sec each at a resolution of around 700 covering the interval 4000 - 7550 A with sufficient S/N ratio ( > 10). The spectra on both days are show the early optically thick "Fe curtain" stage of the ejecta expansion with the usual low ionization spectrum.

  3. Observations and simulations of Nova Vul 1984 No. 2: A nova with ejecta rich in oxygen, neon, and magnesium

    SciTech Connect

    Starrfield, S.; Sonneborn, G.; Stryker, L.L.; Sparks, W.M.; Truran, J.W.; Ferland, G.; Wagner, R.M.; Gallagher, J.S.; Wade, R.; Williams, R.E.; Kenyon, S.; Shaviv, G.; Wu, C.C.; Gehrz, R.D.; Ney, E.P.

    1988-01-01

    Nova Vul 1984 /number sign/2 has been observed with the IUE Satellite from December 1984 through November 1987 and we expect to be able to observe it with the IUE Satellite for at least another two years. These spectra are characterized by strong lines from Mg, Ne, C, Si, O, N, and other elements. Data obtained in the ultraviolet, infrared, and optical show that this nova is ejecting material rich in oxygen, neon, and magnesium. 16 refs., 5 figs., 1 tab.

  4. Statins and cerebral hemodynamics

    PubMed Central

    Giannopoulos, Sotirios; Katsanos, Aristeidis H; Tsivgoulis, Georgios; Marshall, Randolph S

    2012-01-01

    HMG-CoA reductase inhibitors (statins) are associated with improved stroke outcome. This observation has been attributed in part to the palliative effect of statins on cerebral hemodynamics and cerebral autoregulation (CA), which are mediated mainly through the upregulation of endothelium nitric oxide synthase (eNOS). Several animal studies indicate that statin pretreatment enhances cerebral blood flow after ischemic stroke, although this finding is not further supported in clinical settings. Cerebral vasomotor reactivity, however, is significantly improved after long-term statin administration in most patients with severe small vessel disease, aneurysmal subarachnoid hemorrhage, or impaired baseline CA. PMID:22929438

  5. Nucleosynthesis in the Classical Nova Outburst

    NASA Astrophysics Data System (ADS)

    Starrfield, Sumner

    2010-02-01

    Classical Novae are the consequences of the accretion of hydrogen-rich material onto white dwarfs in close binary stellar systems. They are the third largest stellar explosions that occur in a galaxy after Gamma-ray Bursts and Supernovae but are far more common. They are well studied in the Solar neighborhood and in nearby galaxies so that a large number now have measured chemical abundances of their ejected gases. Of importance to this meeting, our simulations show that the temperatures reached in the explosions sample the same conditions as realized in terrestrial laboratory measurements; therefore, no extrapolations are necessary. As a result, we have been doing new calculations that test the effects of new reaction rates on predictions of the observed properties of the outburst. We will show the results of these simulations and, in addition, the effects of including reaction rates that were not previously included in the calculations. We will also show how the evolution and properties of the explosion depends on the initial assumed composition of the accreting material and the characteristics of the white dwarf. Finally, the connection with Supernovae of Type Ia, the explosions currently being used the study the evolution of the universe, is that they are thought to be the consequences of the accretion of helium rich material onto a white dwarf. The results of new simulations of these events will be presented. )

  6. Supernova hydrodynamics experiments on the Nova laser

    NASA Astrophysics Data System (ADS)

    Kane, J.; Arnett, D.; Remington, B. A.; Glendinning, S. G.; Rubenchik, A.; Drake, R. P.; Fryxell, B. A.; Muller, E.

    1997-12-01

    The critical roles of hydrodynamic instabilities in SN 1987A and in ICF are well known; 2D-3D differences are important in both areas. In a continuing project at Lawrence Livermore National Laboratory (LLNL), the Nova Laser is being used in scaled laboratory experiments of hydrodynamic mixing under supernova-relevant conditions. Numerical simulations of the experiments are being done, using LLNL hydro codes, and astrophysics codes used to model supernovae. Initial investigations with two-layer planar packages having 2D sinusoidal interface perturbations are described in Ap.J. 478, L75 (1997). Early-time simulations done with the LLNL 1D radiation transport code HYADES are mapped into the 2D LLNL code CALE and into the multi-D supernova code PROMETHEUS. Work is underway on experiments comparing interface instability growth produced by 2D sinusoidal versus 3D cross-hatch and axisymmetric cylindrical perturbations. Results of the simulations will be presented and compared with experiment. Implications for interpreting supernova observations and for supernova modelling will be discussed. * Work performed under the auspices of the U.S. Department of Energy by the Lawrence Livermore National Laboratory under contract number W-7405-ENG-48.

  7. Supernova experiments on the Nova Laser

    SciTech Connect

    Kane, J.; Arnett, D.; Remington, B.A.; Glendinning, S.G.; Wallace, R.; Rubenchik, A.; Fryxell, B.A.

    1997-12-02

    Supernova (SN) 1987A focused attention on the critical role of hydrodynamic instabilities in the evolution of supernovae. To test the modeling of these instabilities, we are developing laboratory experiments of hydrodynamic mixing under conditions relevant to supernovae. Initial results were reported in [l]. The Nova laser is used to generate a 10-15 Mbar shock at the interface of a two-layer planar target, which triggers perturbation growth, due to the Richtmyer-Meshkov and Rayleigh-Taylor instabilities as the interface decelerates. This resembles the hydrodynamics of the He-H interface of a Type II supernova at intermediate times, up to a few x10{sup 3} s. The experiment is modeled using the hydrodynamics codes HYADES and CALE, and the supernova code PROMETHEUS. Results of the experiments and simulations are presented. New analysis of the bubble velocity is presented, as well as a study of 2D vs. 3D difference in growth at the He-H interface of SN 1987A.

  8. Supernova Experiments on the Nova Laser

    SciTech Connect

    Kane, J.; Arnett, D.; Remington, B. A.; Glendinning, S. G.; Bazan, G.; Drake, R. P.; Fryxell, B. A.

    2000-04-01

    Supernova (SN) 1987A focused attention on the critical role of hydrodynamic instabilities in the evolution of supernovae. To test the modeling of these instabilities, we are developing laboratory experiments of hydrodynamic mixing under conditions relevant to supernovae. Initial results were reported by Kane et al. in a recent paper. The Nova laser is used to generate a 10-15 Mbar shock at the interface of a two-layer planar target, which triggers perturbation growth, due to the Richtmeyer-Meshkov instability, and to the Rayleigh-Taylor instability as the interface decelerates. This resembles the hydrodynamics of the He-H interface of a Type II supernova at intermediate times, up to a few times 10{sup 3} s. The experiment is modeled using the hydrodynamics codes HYADES and CALE, and the supernova code PROMETHEUS. Results of the experiments and simulations are presented. We also present new analysis of the bubble velocity, a study of two-dimensional versus three-dimensional difference in growth at the He-H interface of SN 1987A, and designs for two-dimensional versus three-dimensional hydro experiments. (c) 2000 The American Astronomical Society.

  9. T Pyxidis: death by a thousand novae

    NASA Astrophysics Data System (ADS)

    Patterson, Joseph; Oksanen, Arto; Kemp, Jonathan; Monard, Berto; Rea, Robert; Hambsch, Franz-Josef; McCormick, Jennie; Nelson, Peter; Allen, William; Krajci, Thomas; Lowther, Simon; Dvorak, Shawn; Borgman, Jordan; Richards, Thomas; Myers, Gordon; Harlingten, Caisey; Bolt, Greg

    2017-04-01

    We report a 20-yr campaign to track the 1.8 h photometric (and orbital) wave in the recurrent nova T Pyxidis. Before and after the 2011 eruption, the period increased on a time-scale P/dot{P} = 3 × 105 yr. This suggests a mass transfer rate in quiescence of ˜10-7 M⊙ yr-1, in substantial agreement with the accretion rate based on the star's luminosity. During the eruption itself, a rapid period increase of 0.0054(7) per cent occurred. This is probably a measure of the mass ejected in the outburst. For a plausible choice of binary parameters, that mass is at least 3 × 10-5 M⊙, and probably more. This represents >300 yr of accretion at the pre-outburst rate, but the time between outbursts was only 45 yr. Thus, the erupting white dwarf (WD) seems to have ejected at least six times more mass than it accreted. If this eruption is typical, the WD must be eroding, rather than growing, in mass. Unless the present series of eruptions is a short-lived episode, the binary dynamics will evaporate the secondary in ˜105 yr. This could be a major channel by which short-period cataclysmic variables are removed from the population.

  10. Uma Krishnaswami and International Imaginings

    ERIC Educational Resources Information Center

    Aldama, Frederick Luis

    2006-01-01

    This article presents an interview with South Asian children's book and young adult fiction writer, Uma Krishnaswami. The interviewer states that "in all her creative endeavors Uma's keen sense of detail, narrative voice, and characterization complicate and humanize portrayals of multicultural peoples worldwide." In this interview, Krishnaswami…

  11. NOVA2-mediated RNA regulation is required for axonal pathfinding during development

    PubMed Central

    Saito, Yuhki; Miranda-Rottmann, Soledad; Ruggiu, Matteo; Park, Christopher Y; Fak, John J; Zhong, Ru; Duncan, Jeremy S; Fabella, Brian A; Junge, Harald J; Chen, Zhe; Araya, Roberto; Fritzsch, Bernd; Hudspeth, A J; Darnell, Robert B

    2016-01-01

    The neuron specific RNA-binding proteins NOVA1 and NOVA2 are highly homologous alternative splicing regulators. NOVA proteins regulate at least 700 alternative splicing events in vivo, yet relatively little is known about the biologic consequences of NOVA action and in particular about functional differences between NOVA1 and NOVA2. Transcriptome-wide searches for isoform-specific functions, using NOVA1 and NOVA2 specific HITS-CLIP and RNA-seq data from mouse cortex lacking either NOVA isoform, reveals that NOVA2 uniquely regulates alternative splicing events of a series of axon guidance related genes during cortical development. Corresponding axonal pathfinding defects were specific to NOVA2 deficiency: Nova2-/- but not Nova1-/- mice had agenesis of the corpus callosum, and axonal outgrowth defects specific to ventral motoneuron axons and efferent innervation of the cochlea. Thus we have discovered that NOVA2 uniquely regulates alternative splicing of a coordinate set of transcripts encoding key components in cortical, brainstem and spinal axon guidance/outgrowth pathways during neural differentiation, with severe functional consequences in vivo. DOI: http://dx.doi.org/10.7554/eLife.14371.001 PMID:27223325

  12. Cerebral Asymmetries and Reading Acquisition

    ERIC Educational Resources Information Center

    Pirozzolo, Francis J.

    1978-01-01

    Reviewed are historical developments regarding the concepts of cerebral localization, and analyzed are implications of current research on the role of the cerebral hemispheres in reading disorders. (CL)

  13. Outburst of the recurrent nova V745 Sco

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2014-02-01

    The outburst of the recurrent nova V745 Sco (Nova Sco 1937) by Rod Stubbings (Tetoora Road, VIC, Australia) at visual magnitude 9.0 on 2014 February 6.694 UT is reported. This recurrent nova is fading quickly. Follow-up observations of all types (visual, CCD, DSLR) are strongly encouraged, as is spectroscopy; fast time-series of this nova may be useful to detect possible flaring activity as was observed during the outburst of U Scorpii in 2010. Coincident time-series by multiple observers would be most useful for such a study, with a V-filter being preferred. Observations reported to the AAVSO International Database show V745 Sco at visual mag. 10.2 on 2014 Feb. 07.85833 UT (A. Pearce, Nedlands, W. Australia). Finder charts with sequence may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. Previous outbursts occurred in 1937 and 1989. The 1937 outburst was detected in 1958 (in decline at magnitude 11.0 on 1937 May 11.1 UT; outburst had occurred within the previous 19 days) by Lukas Plaut on plates taken by Hendrik van Gent at the Leiden Observatory; the object was announced as Nova Sco 1937 and later assigned the GCVS name V745 Sco. The 1989 outburst was detected on 1989 August 1.55 UT by Mati Morel (MMAT, Thornton, NSW, Australia) at visual magnitude 10.4 and in decline. Dr. Bradley Schaefer (Louisiana State University) reports (2010ApJS..187..275S) in his comprehensive analysis of the 10 known galactic recurrent novae (including V745 Sco) that the median interval between recurrent novae outbursts is 24 years. The interval since the 1989 outburst of V745 Sco is 24.10 years. See the Alert Notice for additional visual and multicolor photometry and for more details.

  14. STUDIES IN CEREBRAL METABOLISM

    PubMed Central

    Gordan, Gilbert S.; Adams, John E.; Bentinck, Richard C.; Eisenberg, Eugene; Harper, Harold; Hobson, Quentin J. G.

    1953-01-01

    In numerous clinical observations, it has been noted that steroid hormones have effects upon the central nervous system. Earlier interpretations of this relationship were largely speculative until newer methods permitted quantitation of actions of hormones and hormonal deficiencies on cerebral metabolism. The present studies indicate that certain steroids which affect behavior also influence cerebral metabolism. PMID:13019600

  15. Reversible cerebral vasoconstriction syndrome.

    PubMed

    Lee, R; Ramadan, H; Bamford, J

    2013-01-01

    Reversible cerebral vasoconstriction syndrome (RCVS) is an underdiagnosed condition which usually presents as severe headache with or without neurological deficit. We report the case of a 55-year-old woman who presented with headache and multifocal intracerebral haemorrhage. We review the literature regarding the presentation, pathophysiology and management of RCVS and discuss how to differentiate it from cerebral vasculitis.

  16. Cerebral Palsy (CP) Quiz

    MedlinePlus

    ... SSI file Error processing SSI file Pop Quiz: Cerebral Palsy Language: English Español (Spanish) Recommend on Facebook Tweet ... Sandy is the parent of a child with cerebral palsy and the Board President of Gio’s Garden , a ...

  17. KIC 9832227: a red nova precursor

    NASA Astrophysics Data System (ADS)

    Molnar, Lawrence A.; Van Noord, Daniel; Kinemuchi, Karen; Smolinski, Jason P.; Alexander, Cara E.; Kobulnicky, Henry A.; Cook, Evan M.; Jang, Byoungchan; Steenwyk, Steven D.

    2017-01-01

    Molnar et al. (2015) suggested that KIC 9832227 is a contact binary star in its final years before merging and producing a red nova eruption. Analysis of light curves spanning 1999 to 2014 showed a negative time derivative and second derivative of the orbital period. The timing data were found to be well fit by the empirical exponential formula that Tylenda et al. (2011) used to describe preoutburst data of V1309 Sco. While it could not be concluded that this was the correct interpretation of the data, the prediction made for the near future was specific and falsifiable. We will present light curve data from 2015-2016 which is consistent with the extrapolation of the previous fit. As predicted, the period derivative now exceeds the range measured for other contact systems. Reanalysis of the Kepler spacecraft timing data shows a low amplitude modulation consistent with a third star with an orbital period of 1.7 y and msin i = 0.11 solar masses. We will also present spectroscopic data that show the signature of both binary components. These data rule out the presence of any additional main sequence stars with mass greater than 0.4 solar masses. Based on an updated fit to the exponential formula, we now estimate the time of merger to be the year 2022.2 with a random uncertainty of 0.6 years. These results greatly strengthen the original suggestion. The system presents an unprecedented opportunity to study the mechanism of stellar merger through targeted observations of a precursor. Molnar, L. et al. (2015), AAS Meeting #225, id.415.05. Tylenda, R., et al. (2011), AA, 528, A114.

  18. The Nova-like star RW Sextantis

    NASA Astrophysics Data System (ADS)

    Stokes, S. J.; Evans, J. M.; Bianchini, A.; Canterna, R.

    2000-12-01

    We have analyzed 17 medium resolution spectra of RW Sex taken in 1988 at La Silla in the spectral range is 4000-5000 Å with a dispersion of 60 Å/mm and spectral resolution of about 2 Å/pixel. The mean spectrum of the object shows the continuum energy distribution slightly brighter and steeper than that observed by Beuermann, Stasiewski and Schwope (1992). In both cases the slope seems to be steeper that the λ -2.33 power law predicted for standard accretion discs (see Warner 1995). This might be due to uncertain flux calibration or to the dramatic intrinsic variability of this nova-like system (Honeycutt et al. 1998). Like in Beuerman et al.'s, the hydrogen and the HeI lines appear in absorption with superimposed central emission components. Relatively weak emissions from HeII at λ λ 4542,4686 and the blend CIII+NIII at λ4640 -50 are also seen. The peaks of the narrow emissions components of Hβ , HeIλ4471 and HeIλ4922 have been measured using Gaussian fittings. The new ephemeris are: T0(HJD) = 2446486.5061 +/- 0.0010 + 0.245064 +/- 0.000004 The radial velocity curve produced by the absorption components of the hydrogen and the HeI lines are in antiphase with respect to that produced by the emission cores. The amplitudes of all the radial velocity curves are consistent with those shown by Beuermann, Stasiewski and Schwope (1992). According to these authors the absorption lines are produced in the optically thick accretion disc while the narrow emissions arise from the heated atmosphere of the secondary. We fail however to detect the broad emission components observed by these authors and attributed to the hot disc corona. This point should deserve future investigation.

  19. Na-22 decay gamma rays from classical novae

    NASA Technical Reports Server (NTRS)

    Truran, James W.

    1993-01-01

    NASA Grant NAG 5-1565 has provided support for a program of theoretical research in nuclear astrophysics and related areas, focusing upon the possibility of detecting gamma rays from nearby novae. Particular attention has been given to the evaluation of the theoretical expectations for gamma ray emission from four possible sources: (1) the positron decays of the unstable CNO and fluorine isotopes that are transported to the surface regions of the envelope in the earliest stages of the outbursts; (2) Be-7 decay gamma rays, (3) Na-22 decay gamma rays released in the later stages of the outbursts; and (4) Al-26 decay gamma rays from novae and their possible contribution to Galactic emission. The critical questions of (1) the frequency of occurrence of ONeMg-enriched novae; (2) the expected Galactic distribution of the novae that produce 26Al; and (3) the nature of the observed soft X-ray emission from classical novae, have also been addressed. Considerable progress in research has been achieved on many of these fronts. Brief summaries of the results of several research projects are presented.

  20. Having a Blast with Chandra Observations of Novae

    NASA Astrophysics Data System (ADS)

    Drake, Jeremy J.

    2010-03-01

    Chandra and XMM-Newton are revolutionizing our understanding of the X-ray behaviour of nova explosions. High resolution grating spectra of bright novae in outburst have provided remarkable new insights into the nature of the explosions themselves, and the physical state and chemical composition of the residual "supersoft sources" that emerge from within an expanding shell of ejecta. I will describe the results of some detailed Chandra observations that reveal early phase hard X-ray emission that is not yet understood, supersoft source spectra that exhibit unexpected, wild variations and blue-shifted signatures of outflow, and spectra enabling detailed dissection of a momentum-conserving blast wave. Building an understanding of the surprisingly diverse X-ray behaviour of novae witnessed to date will require future concerted Chandra and XMM-Newton campaigns to catch bright events with gratings while we can. The recurrent nova U Sco represents perhaps the next great opportunity as the nova world waits with bated breath for its next, now slightly overdue, explosion.

  1. Observations and predictions of EUV emission from classical novae

    SciTech Connect

    Starrfield, S.; Truran, J.W.; Sparks, W.M.; Krautter, J.

    1989-01-01

    Theoretical modeling of novae in outburst predicts that they should be active emitters of radiation both in the EUV and soft X-ray wavelengths twice during the outburst. The first time is very early in the outburst when only an all sky survey can detect them. This period lasts only a few hours. They again become bright EUV and soft X-ray emitters late in the outburst when the remnant object becomes very hot and is still luminous. The predictions imply both that a nova can remain very hot for months to years and that the peak temperature at this time strongly depends upon the mass of the white dwarf. It is important to observe novae at these late times because a measurement of both the flux and temperature can provide information about the mass of the white dwarf, the tun-off time scale, and the energy budget of the outburst. We review the existing observations of novae in late stages of their outburst and present some newly obtained data for GQ Mus 1983. We then provide results of new hydrodynamic simulations of novae in outburst and compare the predictions to the observations. 43 refs., 6 figs.

  2. π0 mass reconstruction in NOvA Far Detector.

    NASA Astrophysics Data System (ADS)

    Edayath, Sijith

    2017-01-01

    NOvA is a long-baseline neutrino oscillation experiment with functionally identical, segmented, tracking calorimeter Near and Far detectors. The detectors lie 14.6 mrad off-axis from the Fermilab NuMI beam, with a well-defined peak in neutrino energy at 2 GeV. The absolute calibration of the energy scale of the detectors is a major systematic uncertainty in long-baseline oscillation search in NOvA. Neutrino detectors make use of some standard candles for absolute energy calibration. Stopping muon energy distributions, Michel electron energy distributions, and invariant π0 mass are among them. In this talk, we cover NOvA's use of a new method to identify π0 with cosmic origins in the NOvA Far Detector. We employ a computer vision based particle identifier using convolutional neural networks (CVN) to identify π0s, complementing an existing strategy to identify π0 from the neutrino beam using more traditional methods in the Near Detector. Registered for PhD at Cochin University of Science and Technology, India and doing research in NOvA experiment at Fermilab.

  3. Evaluating local food programs: the case of Select Nova Scotia.

    PubMed

    Knight, Andrew J

    2013-02-01

    This study evaluated the effectiveness of the buy local food program Select Nova Scotia; a government program with the goal to increase awareness and consumption of Nova Scotia produced and processed agri-food products by Nova Scotians and visitors. The evaluation methodology was based on prior evaluation resources and local food consumer research. Data were gathered through a web panel survey; 877 respondents completed the survey in June 2010. The results suggest that the program is reaching a wider audience than just those predisposed to local food initiatives. In addition, awareness of Select Nova was related to perceptions of local benefits and barriers, as well as purchase motivation and behavior. Respondents who were aware of Select Nova Scotia rated societal benefits as more important and viewed location and price as less of a barrier; they were also more likely to be highly motivated to purchase local foods. This study also informs results found in previous consumer research studies and identifies marketing opportunities to enhance the effectiveness of local food programs. The results suggest that societal benefits might be used as a way to differentiate products with similar attributes. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. A Hubble Space Telescope survey for Novae in M87. II. Snuffing out the maximum magnitude–rate of decline relation for novae as a non-standard candle, and a prediction of the existence of ultrafast novae

    DOE PAGES

    Shara, Michael M.; Doyle, Trisha; Lauer, Tod R.; ...

    2017-04-20

    The extensive grid of numerical simulations of nova eruptions first predicted that some classical novae might significantly deviate from the Maximum Magnitude–Rate of Decline (MMRD) relation, which purports to characterize novae as standard candles. Kasliwal et al. have announced the observational detection of a new class of faint, fast classical novae in the Andromeda galaxy. These objects deviate strongly from the MMRD relationship, as predicted by Yaron et al. Recently, Shara et al. reported the first detections of faint, fast novae in M87. These previously overlooked objects are as common in the giant elliptical galaxy M87 as they are inmore » the giant spiral M31; they comprise about 40% of all classical nova eruptions and greatly increase the observational scatter in the MMRD relation. We use the extensive grid of the nova simulations of Yaron et al. to identify the underlying causes of the existence of faint, fast novae. These are systems that have accreted, and can thus eject, only very low-mass envelopes, of the order of 10–7–10–8 M ⊙, on massive white dwarfs. Such binaries include, but are not limited to, the recurrent novae. As a result, these same models predict the existence of ultrafast novae that display decline times, t 2, to be as short as five hours. We outline a strategy for their future detection.« less

  5. 'GrepNova': a tool for amateur supernova hunting

    NASA Astrophysics Data System (ADS)

    Ford, D.

    2011-12-01

    This paper presents 'GrepNova'a software package which assists amateur supernova hunters by allowing new observations of galaxies to be compared against historical library images in a highly automated fashion. As each new observation is imported, 'GrepNova' automatically identifies a suitable comparison image and rotates it into a common orientation with the new image. The pair can then be blinked on the computer's display to allow a rapid visual search to be made for stars in outburst. 'GrepNova' has been in use by Tom Boles at his observatory in Coddenham, Suffolk since 2005 August, where it has assisted in the discovery of 50 supernovae up to 2011 October.

  6. Nova outbursts in the case of mild hibernation

    SciTech Connect

    Livio, M.; Shankar, A.; Truran, J.W.

    1988-02-01

    The necessary conditions for the production of strong thermonuclear runaways in the hibernation scenario are identified and explored. It is found that a reduction in the accretion rate by a factor of about 100, for a period longer than a few thousand years, is generally sufficient to ensure nova-type outbursts, even in the presence of rather high preoutburst accretion rates. Nova outbursts can be obtained under mild hibernation conditions on 1 solar mass white dwarfs as well as on very massive ones. A reduction in the accretion rate by a factor of 10 only is insufficient to produce a nova outburst, if the preoutburst accretion rate is as high as 10 to the -8th solar mass/yr. 28 references.

  7. Ultrastructure of extrusomes in hypotrichous ciliate Pseudourostyla nova

    NASA Astrophysics Data System (ADS)

    Zhou, Yao; Wang, Zhengjun; Zhang, Jun; Gu, Fukang

    2011-01-01

    The ultrastructure of extrusomes of the hypotrichous ciliate Pseudourostyla nova was observed in scanning and transmission electron microscopy and enzyme-cytochemistry. The results show that the distribution, morphological characteristics, morphogenesis process, and extrusive process of the extrusomes in P. nova are different from the trichocysts in Paramecium, suggesting that the extrusomes of P. nova can respond to environmental stimuli, play an important role in the defense of this species, and cannot be regarded as "trichocysts". The results also suggest that the extrusomes might be originated from the Golgi apparatus and mature in the cytoplasm; after the extrusion of mature extrusomes, the residual substance might be reabsorbed and reused by the ciliate cell via food vacuoles, and take part in material recycling of the cell.

  8. Model Atmospheres for Novae in Outburst: Summary of Research

    NASA Technical Reports Server (NTRS)

    Hauschildt, Peter H.

    1999-01-01

    This paper presents a final report and summary of research on Model Atmospheres for Novae in Outburst. Some of the topics include: 1) Detailed NLTE (non-local thermodynamic equilibrium) Model Atmospheres for Novae during Outburst: II. Modeling optical and ultraviolet observations of Nova LMC 1988 #1; 2) A Non-LTE Line-Blanketed Stellar Atmosphere Model of the Early B Giant epsilon CMa; 3) Spectroscopy of Low Metallicity Stellar atmospheres; 4) Infrared Colors at the Stellar/Substellar Boundary; 5) On the abundance of Lithium in T CrB; 6) Numerical Solution of the Expanding Stellar Atmosphere Problem; and 7) The NextGen Model Atmosphere grid for 3000 less than or equal to T (sub eff) less than or equal to 10000K.

  9. First Neutrino Oscillation Results from the NOvA experiment

    SciTech Connect

    Sachdev, Kanika

    2016-11-29

    NOvA is a long-baseline neutrino oscillation experiment on the NuMI muon neutrino beam at Fermilab. It consists of two functionally identical, nearly fully-active liquid-scintillator tracking calorimeters. The Near Detector (ND) at Fermilab is used to study the neutrino beam spectrum and composition before oscillations occur. The Far Detector in northern Minnesota, 810 km away, observes the oscillated beam and is used to extract the oscillation parameters. NOvA is designed to observe oscillations in two channels: disappearance channel ( ν μ → ν μ ) and ν e appearance channel ( ν μ → ν e ). This paper reports the measurements of both these channels based on the first NOvA data taken from February 16, 2014 till May 15, 2015

  10. Multi-Dimensional Modeling of Nova with Realistic Nuclear Physics

    SciTech Connect

    Zingale, M; Hoffman, R D

    2011-01-27

    This contract covered the period from 03/09/2010 to 09/30/2010. Over this period, we adapted the low Mach number hydrodynamics code MAESTRO to perform simulations of novae. A nova is the thermonuclear runaway of an accreted hydrogen layer on the surface of a white dwarf. As the accreted layer grows in mass, the temperature and density at the base increase to the point where hydrogen fusion can begin by the CNO cycle - a burning process that uses carbon, nitrogen, and oxygen to complete the fusion of four hydrogen nuclei into one helium-4 nucleus. At this point, we are running initial models of nova, exploring the details of the convection. In the follow-on contract to this one, we will continue this investigation.

  11. Discovery of Explosive Lithium Production in Classical Novae

    NASA Astrophysics Data System (ADS)

    Tajitsu, Akito; Sadakane, Kozo; Naito, Hiroyuki; Arai, Akira; Kawakita, Hideyo; Aoki, Wako

    The origin of lithium (Li) and its production process have long been an unsettled question in cosmology and astrophysics. Chemical evolution models and observed stellar Li abundances suggest that at least half of the present Li abundance may have been produced in red giants, asymptotic giant branch (AGB) stars, and novae. However, no direct evidence for the supply of Li from evolved stellar o bjects to the Galactic medium has been found until we reported the detection of a radioactive isotope of beryllium, 7Be, in the post-outburst UV spectra of the classical novae — V339 Del, V5668 Sgr, and V2944 Oph. 7Be decays to form 7Li within a short period of time. These findings strongly suggest that the explosive production of 7Li via the reaction 3He(α , γ )7Be and subsequent decay to 7Li occurs frequently among classical novae and contributes to the process of the Galactic Li enrichment.

  12. Soft x-ray emission from classical novae in outburst

    SciTech Connect

    Starrfield, S. Arizona State Univ., Tempe, AZ . Dept. of Physics and Astronomy); Truran, J.W. . Dept. of Astronomy); Sparks, W.M. ); Krautter, J. ); MacDonald, J. . Dept. of Physics and Ast

    1989-01-01

    Theoretical modeling of novae in outburst predicts that they should be active emitters of radiation at soft x-ray wavelengths twice during their outburst. The first time occurs very early in the outburst when only a very sensitive all sky survey will be able to detect them. This period lasts only a few hours for the very fastest novae. They again become bright in x-rays late in the outburst when the remnant object becomes very hot and is still luminous. Both simulations and observations show that novae can remain very hot for months to years. It is important to observe them at these late times because a measurement both of the flux and temperature can provide information about the mass of the white dwarf, the turn-off time scale, and the energy budget of the outburst. 8 refs., 2 figs.

  13. Nova-1: The newest Transit satellite - A status report

    NASA Astrophysics Data System (ADS)

    Eisner, A.; Yionoulis, S. M.; Platt, J. A.; Jenkins, R. E.; Ray, J. C.; Pryor, L. L.

    Four of the five satellites of the Navy Navigation Satellite System (Transit) which are currently in orbit were designed in 1963 and have been in continuous service for the last 7-14 years. Nova-1 as the newest addition to Transit was launched on May 14, 1981. Nova-1 has a number of new features. One of these features is the single-axis DIScos COmpensation System (DISCOS) which continuously compensates for atmospheric drag and solar radiation perturbations to the along-track motion of the spacecraft.The Incrementally Programmable Synthesizer (IPS) represents a high-precision, digitally-controlled frequency device which is employed to adjust the high quality master oscillator operating frequency of the spacecraft to a precise 'constant' desired frequency. Attention is given to Nova-1 objectives and accomplishments.

  14. Nova Cephei 2014 = TCP J20542386+6017077

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2014-03-01

    Details of discovery of Nova Cephei 2014 (TCP J20542386+6017077) and procedures for observing and reporting observations are announced. Discovered by Koichi Nishiyama (Kurume, Japan) and Fujio Kabashima (Miyaki, Japan) at unfiltered CCD magnitude 11.7 on 2014 Mar. 8.792 UT. Coordinates: R.A. 20 54 23.75 Dec. +60 17 06.9 (2000.0). Nova Cep 2014 is a highly reddened classical Fe II-type nova near maximum, per low-resolution spectra obtained by U. Munari et al. on 2014 Mar. 9.792 UT. Announced in IAU CBAT CBET 3825 (D. W. E. Green, ed.). Finder charts with sequence may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details and observations.

  15. High Energy Neutrino Physics with NOvA

    SciTech Connect

    Coan, Thomas

    2016-09-09

    Knowledge of the position of energy deposition in “hit” detector cells of the NOvA neutrino detector is required by algorithms for pattern reconstruction and particle identification necessary to interpret the raw data. To increase the accuracy of this process, the majority of NOvA's 350 000 far detector cell shapes, including distortions, were measured as they were constructed. Using a special laser scanning system installed at the site of the NOvA far detector in Ash River, MN, we completed algorithmic development and measured shape parameters for the far detector. The algorithm and the measurements are “published” in NOνA’s document database (doc #10389, “Cell Center Finder for the NOνA Far Detector Modules”).

  16. Nova V2362 Cygni (Nova Cygni 2006): Spitzer, Swift, and Ground-Based Spectral Evolution

    NASA Technical Reports Server (NTRS)

    Lynch, David K.; Venturini, Catherine C.; Mazuk, S.; Woodward, Charles; Gehrz, Robert; Rayner, John; Helton, L.A.; Ness, Jan-Uwe; Starrfield, Sumner; Rudy, Richard J.; Russell, Ray W.; Osborne, Julian P.; Page, Kim; Pearson, Richard; Wagner, R. Mark; Puetter, Richard C.; Perry, Raleigh B.; Schwarz, Greg; Vanlandingham, Karen; Black, John; Bode, Michael; Evans, Aneurin; Geballe, Thomas; Greenhouse, Matthew; Hauschildt, Peter

    2008-01-01

    Nova V2362 Cygni has undergone a number of very unusual changes. Ground-based spectroscopy initially revealed a normal sequence of events: the object faded and its near-infrared emission lines gradually shifted to higher excitation conditions until about day 100 when the optical fading reversed and the object slowly brightened. This was accompanied by a rise in the Swift X-ray telescope flux and a sudden shift in excitation of the visible and IR spectrum back to low levels. The new lower excitation spectrum revealed broad line widths and many P-Cygni profiles, all indicative of the ejection of a second shell. Eventually, dust formed, the X-ray brightness -- apparently unaffected by dust formation -- peaked and then declined, and the object faded at all wavelengths. The Spitzer dust spectra revealed a number of solid-state emission features that, at this time, are not identified.

  17. Nova V2362 Cygni (Nova Cygni 2006): Spitzer, Swift, and Ground-Based Spectral Evolution

    NASA Technical Reports Server (NTRS)

    Lynch, David K.; Venturini, Catherine C.; Mazuk, S.; Woodward, Charles; Gehrz, Robert; Rayner, John; Helton, L.A.; Ness, Jan-Uwe; Starrfield, Sumner; Rudy, Richard J.; hide

    2008-01-01

    Nova V2362 Cygni has undergone a number of very unusual changes. Ground-based spectroscopy initially revealed a normal sequence of events: the object faded and its near-infrared emission lines gradually shifted to higher excitation conditions until about day 100 when the optical fading reversed and the object slowly brightened. This was accompanied by a rise in the Swift X-ray telescope flux and a sudden shift in excitation of the visible and IR spectrum back to low levels. The new lower excitation spectrum revealed broad line widths and many P-Cygni profiles, all indicative of the ejection of a second shell. Eventually, dust formed, the X-ray brightness -- apparently unaffected by dust formation -- peaked and then declined, and the object faded at all wavelengths. The Spitzer dust spectra revealed a number of solid-state emission features that, at this time, are not identified.

  18. On the decay of outbursts in dwarf novae nad X-ray novae

    NASA Technical Reports Server (NTRS)

    Cannizzo, John K.

    1994-01-01

    We perform computations using a time-dependent model for the accretion disk limit-cycle mechanism to examine the decay of the optical light following the peak of a dwarf nova outburst. We present the results of a parameter study of the physical input variables which affect the decay rate. In the model, the decay is brought about by a cooling transition front which begins at large radii in the disk and moves inward. The nature of the decay is strongly influenced by the radial dependence of the accretion disk viscosity parameter alpha. To obtain exponential decays for typical dwarf nova parameters, we require alpha proportional to r(exp epsilon(sub 0)), where epsilon(sub 0) approximately = 0.3-0.4. The exact value of epsilon(sub 0) which produces exponential decays depends on factors such as the mass of the accreting star and the inner radius of the accretion disk. Therefore, the observed ubiquity of exponential decays in two different types of systems (dwarf novae and X-ray novae) leads us to believe that alpha is an unnatural scaling for the viscosity. The physics of the cooling transition front must be self-regulating in that the timescale (-parital derivative of lnSigma(r)/partial derivative +)(exp -1) (where Sigma is the surface density) for mass extraction across the front remains constant. This may be consistent with a scaling alpha proportional to (h/r)(exp n), where h is the local disk semi-thickness and n approximately 1-2. As regards the speed of the cooling front, we find v(sub F)(r) proportional to r(exp p), where p approximately 3 at large radii, with an abrupt transition to p approximately 0 at some smaller radius. The r(exp 3) dependence is much steeper than has been found by previous workers and appears to result from the strong variation of specific heat within the cooling front when the front resides at a large radius in the disk. The outflow of disk material across the cooling front causes a significant departure of dln T(sub dff0/dln r from the

  19. Let's Set the Record Straight: A Case for Nova University's External Doctorate in Education

    ERIC Educational Resources Information Center

    Mitchell, Donald P.

    1974-01-01

    The director of Nova University's national Ed.D. program for educational leaders assails Richard Morland and Phi Delta Kappan magazine for publishing material that questioned Nova's external degrees. (Author)

  20. The geographic accessibility of pharmacies in Nova Scotia

    PubMed Central

    Heard, Deborah; Fisher, Judith; Douillard, Jay; Muzika, Greg; Sketris, Ingrid S.

    2013-01-01

    Introduction: Geographic proximity is an important component of access to primary care and the pharmaceutical services of community pharmacies. Variations in access to primary care have been found between rural and urban areas in Canadian and international jurisdictions. We studied access to community pharmacies in the province of Nova Scotia. Methods: We used information on the locations of 297 community pharmacies operating in Nova Scotia in June 2011. Population estimates at the census block level and network analysis were used to study the number of Nova Scotia residents living within 800 m (walking) and 2 km and 5 km (driving) distances of a pharmacy. We then simulated the impact of pharmacy closures on geographic access in urban and rural areas. Results: We found that 40.3% of Nova Scotia residents lived within walking distance of a pharmacy; 62.6% and 78.8% lived within 2 km and 5 km, respectively. Differences between urban and rural areas were pronounced: 99.2% of urban residents lived within 5 km of a pharmacy compared with 53.3% of rural residents. Simulated pharmacy closures had a greater impact on geographic access to community pharmacies in rural areas than urban areas. Conclusion: The majority of Nova Scotia residents lived within walking or short driving distance of at least 1 community pharmacy. While overall geographic access appears to be lower than in the province of Ontario, the difference appears to be largely driven by the higher proportion of rural dwellers in Nova Scotia. Further studies should examine how geographic proximity to pharmacies influences patients’ access to traditional and specialized pharmacy services, as well as health outcomes and adherence to therapy. Can Pharm J 2013;146:39-46. PMID:23795168

  1. The spectroscopic evolution of the γ-ray emitting classical nova Nova Mon 2012. I. Implications for the ONe subclass of classical novae

    NASA Astrophysics Data System (ADS)

    Shore, S. N.; De Gennaro Aquino, I.; Schwarz, G. J.; Augusteijn, T.; Cheung, C. C.; Walter, F. M.; Starrfield, S.

    2013-05-01

    Aims: Among the classical novae, the ONe subgroup, distinguished by their large overabundance of neon, are thought to occur on the most massive white dwarfs. Nova Mon 2012 was the first classical nova to be detected as a high energy γ-ray transient, by Fermi-LAT, before its optical discovery. The first optical spectra obtained about 55 days after γ-ray peak, were strikingly similar to the ONe class after the transition to the nebular (optically thin) spectrum. The current paper presents our subsequent optical and ultraviolet observations. Methods: A time sequence of optical echelle spectra (3700-7400 Å) with the Nordic Optical Telescope (NOT) began on 2012 Aug. 16, immediately following the optical announcement, and are continuing. The nova was observed almost simultaneously with the NOT on 2012 Nov. 21, with the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope at medium echelle resolution (1150-3050 Å) on Nov. 20, and with the CHIRON CTIO/SMARTS echelle spectrograph at medium resolution (4500-8900 Å) on Nov. 22. We used plasma diagnostics (e.g. [O III] and Hβ line flux) to constrain electron densities and temperatures, and the filling factor, for the ejecta. Using Monte Carlo modeling, we derived the structure from comparisons to the optical and ultraviolet line profiles. We also compared observed fluxes for Nova Mon 2012 with those predicted by photoionization modeling with Cloudy using element abundances derived for other ONe novae, the parameters derived from the line profile modeling and multiwavelength continuum measurements. Results: Nova Mon 2012 is confirmed as an ONe nova first observed spectroscopically in the nebular stage. We derive an extinction of E(B - V) = 0.85 ± 0.05 and hydrogen column density NH ≈ 5 × 1021 cm-2. The corrected continuum luminosity is nearly the same in the entire observed energy range compared to V1974 Cyg, V382 Mon, and Nova LMC 2000 at the same epoch after outburst. The distance, about 3

  2. PU Vulpeculae: an eclipsing symbiotic nova.

    NASA Astrophysics Data System (ADS)

    Nussbaumer, H.; Vogel, M.

    1996-03-01

    A series of IUE observation from 1992 to 1995 has definitely established PU Vul as an eclipsing binary. The outburst of this symbiotic nova began in 1977. An extended fading in 1980 gave rise to various interpretations, the eclipse scenario being one of them, dust formation being another. From AFOEV and AAVSO observations we find a period of 4900+/-100days, or 13.42+/-0.27years. An eclipsing object of such a long period signifies that we see the binary system at an orbital inclination close to 90deg. ESO observations in the near infrared give an orbital velocity of 4.7km/s and a mass function of m_f_=~0.05. Assuming a white dwarf mass between 0.4Msun_ and 0.5Msun_ gives for the red giant 0.7<=M/Msun_<=1.1. From the length of the eclipse the radius of the red giant is determined as R_giant_>=82Rsun_. We discuss IUE, HST and ground based observations of PU Vulpeculae before and during its second observed eclipse of the hot component by the cool giant which lasted from 1993 to 1995, mid-eclipse was in April 1994. Line profiles, particularly those taken by HST, allow a neat distinction between narrow nebular lines and broader wind lines which prove the existence of a fast wind from the hot star in the binary system of v=~1000km/s. That wind has relatively high densities (N_e_>10^12^cm^-3^) and is optically thick to radiation at λ<228A. Nebular lines have half widths corresponding to v=~70km/s. During the 1994 eclipse the more highly ionized lines were strongly eclipsed, whereas the lowly ionized nebular lines were hardly affected. This proves that the lowly ionized nebular lines are emitted in a very extended region, and not only close to the cool giant. From 1990 to 1994 relative C/N/O abundances of the nebular and wind emission regions have not changed beyond observational uncertainties.

  3. Nova V2467 Cyg as possible intermediate polar

    NASA Astrophysics Data System (ADS)

    Swierczynski, E.; Ragan, E.; Galan, C.; Mikolajewski, M.

    2008-09-01

    We report the results of 8 nights of unfiltered and RI band CCD photometry of the fast nova V2467Cyg (Nova Cyg 2007). The observations were carried out from 26 June to 8 July 2008 with the 60cm Cassegrain telescope of the Nicolaus Copernicus University Observatory (Torun, Poland). In total we collected 5683 frames during about 20 hours of observations. The magnitudes estimated on July 25.94 UT were B=16.10, V=14.71, R=14.19, I=13.67.

  4. Optical photometry and spectroscopy of Nova Del 2013

    NASA Astrophysics Data System (ADS)

    Tomov, T.; Ilkiewicz, K.; Swierczynski, E.; Belcheva, M.; Dimitrov, D.

    2013-08-01

    We report optical BV photometry and spectroscopy of Nova Del 2013, carried out between August 14.88 UT and August 15.08 UT. Using a 60 cm Cassegrain telescope at the Nicolaus Copernicus University Observatory (Torun, Poland) we estimated the V brightness of the Nova to be 6.31+/-0.02 mag and 6.18+/-0.03 mag on Aug. 14.94 UT and Aug. 15.02 UT respectively. HD 194113 (F2, V=8.00 mag) was used as a comparison star.

  5. Nova Scotia: late career nurse and new graduate transition.

    PubMed

    Bellefontaine, Pat; Eden, Valerie

    2012-03-01

    Addressing Canada's growing shortage of nurses requires effective strategies for their education, retention and recruitment. Although Nova Scotia produces more than 250 registered nurses and 125 licensed practical nurses each year, some 20% of these graduates leave the province to work elsewhere. The Nova Scotia Research to Action project focused on three retention and recruitment projects: (a) a new-nurse graduate orientation/transition framework, (b) guidelines for nursing mentorship and (c) an online employment tool to assist in the hiring of new nurse graduates. Project partners continue to work collaboratively to advance these provincial initiatives.

  6. First Radio Detections of Nova V5588 Sgr

    NASA Astrophysics Data System (ADS)

    Krauss, M. I.; Chomiuk, L.; Sokoloski, J. L.; Rupen, M. P.; Mioduszewski, A. J.; Roy, N.; O'Brien, T. J.; Bode, M. F.; Eyres, S. P. S.

    2011-06-01

    The EVLA Nova Team reports the first radio detections of the classical nova V5588 Sgr (IAUC #9203, CBET #2707) with the EVLA. The flux densities were 49.3 ± 9.1 microJy at 5.0 GHz and 69.0 ± 7.5 microJy at 6.8 GHz on 2011 May 15.4, and 394 ± 55 microJy at 33.1 GHz on May 14.5. The spectral index α was 1.1 ± 0.1 (where Sν ∝ ν α), suggesting partially optically thick thermal emission.

  7. Nova Sagittarii 2012 No. 5 = PSN J18193700-1907400

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2012-07-01

    Nova Sagittarii 2012 No. 5 = PSN J18193700-1907400 was discovered by Tadashi Kojima (Tsumagoi, Agatsuma-gun, Gunma-ken, Japan) (reported by S. Nakano (Sumoto, Japan) at mag 12.6 on two frames using a Canon EOS 40D camera (+ 150-mm f/2.8 lens) on 2012 July 16.512 UT. Coordinates (2000.0) R.A. 18 19 37.0 Decl. -19 07 40. Spectra confirm it as a Fe II-type nova close to maximum brightness and as being affected by large interstellar reddening. Details are in IAU CBET 3182 and CBET 3184. Report observations to the AAVSO International Database.

  8. NOVA: A new multi-level logic simulator

    NASA Technical Reports Server (NTRS)

    Miles, L.; Prins, P.; Cameron, K.; Shovic, J.

    1990-01-01

    A new logic simulator that was developed at the NASA Space Engineering Research Center for VLSI Design was described. The simulator is multi-level, being able to simulate from the switch level through the functional model level. NOVA is currently in the Beta test phase and was used to simulate chips designed for the NASA Space Station and the Explorer missions. A new algorithm was devised to simulate bi-directional pass transistors and a preliminary version of the algorithm is presented. The usage of functional models in NOVA is also described and performance figures are presented.

  9. Bipolar gas outflow from the nova V458 Vul

    NASA Astrophysics Data System (ADS)

    Goranskij, V. P.; Barsukova, E. A.; Fatkhullin, T. A.

    2010-06-01

    Classical nova V458 Vul (N Vul 2007 No.1) was detected as a supersoft X-ray source by the Swift XRT (ATel#1246, #1603). This star is interesting with its spectral class change: features of Fe II class nova completely changed by features of He/N class in the SSS phase (T.N. Tarasova, IBVS No.5807). We performed spectral observations of V458 Vul with the Russian 6-m telescope BTA and spectral camera SCORPIO on 2010 June 9.84 UT.

  10. The Orbital Period of the Classical Nova V458 Vul

    NASA Astrophysics Data System (ADS)

    Goranskij, V. P.; Metlova, N. V.; Barsukova, E. A.; Burenkov, A. N.; Soloviev, V. Ya.

    2008-07-01

    Classical nova V458 Vul (N Vul 2007 No.1) was detected as a supersoft X-ray source (SSS) by the Swift XRT several times in the time range between 2007 October 18 and 2008 June 18 (J. Drake et al., ATel #1246 and #1603). Our V photometry shows the plateau in the light curve continued since January till June 2008. This feature accompanies usually the SSS phases in some classical novae. The fragmentary monitoring during plateau shows night- to-night variability with the amplitudes between 1.2 and 0.4 mag and rapid variability by 0.1 mag in the time scale of an hour.

  11. Nova in Scorpius - PNV J16521887-3754189

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2017-02-01

    Announces the discovery of Nova Sco 2017(PNV J16521887-3754189) [V1657 Sco] by Hideo Nishimura (Shizuoka-ken, Japan) at unfiltered CCD magnitude 11.7 on 2017 February 1.862 UT. Spectroscopy indicating that PNV J16521887-3754189 is an He/N nova was obtained 2017 February 12.3 UT by J. Strader (Michigan State Univ.) et al. (ATel #10071). Finder charts with sequence may be created using the AAVSO Variable Star Plotter (https://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details.

  12. Nova in Ophiuchus - TCP J17394608-2457555

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2017-05-01

    AAVSO Alert Notice 576 announces the discovery of a galactic nova in Ophiuchus, TCP J17394608-2457555, by Koichi Itagaki (Yamagata, Japan) at unfiltered CCD magnitude 13.6 on 2017 May 08.7511 UT. Spectroscopy indicating that TCP J17394608-2457555 is an FeII nova (highly reddened) was obtained 2017 May 11.15 UT by S. C. Wiliams (Lancaster) and M. J. Darnley (LJMU) (ATel #10366). Finder charts with sequence may be created using the AAVSO Variable Star Plotter (https://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details.

  13. A Hubble Space Telescope Survey for Novae in M87. I. Light and Color Curves, Spatial Distributions, and the Nova Rate

    NASA Astrophysics Data System (ADS)

    Shara, Michael M.; Doyle, Trisha F.; Lauer, Tod R.; Zurek, David; Neill, J. D.; Madrid, Juan P.; Mikołajewska, Joanna; Welch, D. L.; Baltz, Edward A.

    2016-11-01

    The Hubble Space Telescope has imaged the central part of M87 over a 10 week span, leading to the discovery of 32 classical novae (CNe) and nine fainter, likely very slow, and/or symbiotic novae. In this first paper of a series, we present the M87 nova finder charts, and the light and color curves of the novae. We demonstrate that the rise and decline times, and the colors of M87 novae are uncorrelated with each other and with position in the galaxy. The spatial distribution of the M87 novae follows the light of the galaxy, suggesting that novae accreted by M87 during cannibalistic episodes are well-mixed. Conservatively using only the 32 brightest CNe we derive a nova rate for M87: {363}-45+33 novae yr-1. We also derive the luminosity-specific classical nova rate for this galaxy, which is {7.88}-2.6+2.3 {{yr}}-1/{10}10 {L}⊙ {,}K. Both rates are 3-4 times higher than those reported for M87 in the past, and similarly higher than those reported for all other galaxies. We suggest that most previous ground-based surveys for novae in external galaxies, including M87, miss most faint, fast novae, and almost all slow novae near the centers of galaxies. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555.

  14. The neon nova. II - Condensation of silicate grains in the ejecta of Nova Vulpeculae 1984 number 2

    NASA Astrophysics Data System (ADS)

    Gehrz, R. D.; Grasdalen, G. L.; Greenhouse, M.; Hackwell, J. A.; Hayward, T.; Bentley, A. F.

    1986-09-01

    Infrared photometry of Nova Vulpeculae 1984 number 2 (NV2) from 2.3 to 19.5 microns during May 14, 1985 to March 31, 1986 shows that silicate grains had condensed and grown in the nova ejecta by August 23, 1985, 240 days after the eruption. A relative overabundance of oxygen in the nova shell seems indicated. Forbidden 12.8-micron Ne II forbidden line emission was a factor of about 41 above the continuum at a spectral resolution of 67 on day 240; the line persisted through day 461. The anomalous chemical composition of NV2's ejecta supports recent suggestions that ONeMg white dwarfs (evolved from 8-12 solar-mass progenitor stars) are accreting matter in binary systems.

  15. 15 CFR 904.102 - Procedures upon receipt of a NOVA.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 15 Commerce and Foreign Trade 3 2014-01-01 2014-01-01 false Procedures upon receipt of a NOVA. 904... PROCEDURES Civil Penalties § 904.102 Procedures upon receipt of a NOVA. (a) The respondent has 30 days from receipt of the NOVA in which to respond. During this time the respondent may: (1) Accept the penalty...

  16. 15 CFR 904.102 - Procedures upon receipt of a NOVA.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Procedures upon receipt of a NOVA. 904... PROCEDURES Civil Penalties § 904.102 Procedures upon receipt of a NOVA. (a) The respondent has 30 days from receipt of the NOVA in which to respond. During this time the respondent may: (1) Accept the penalty...

  17. 15 CFR 719.8 - Filing and service of papers other than the NOVA.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... than the NOVA. 719.8 Section 719.8 Commerce and Foreign Trade Regulations Relating to Commerce and... CONVENTION REGULATIONS ENFORCEMENT § 719.8 Filing and service of papers other than the NOVA. (a) Filing. All... address set forth in the NOVA, or such other place as the ALJ may designate. Filing by United States...

  18. 15 CFR 719.8 - Filing and service of papers other than the NOVA.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... than the NOVA. 719.8 Section 719.8 Commerce and Foreign Trade Regulations Relating to Commerce and... CONVENTION REGULATIONS ENFORCEMENT § 719.8 Filing and service of papers other than the NOVA. (a) Filing. All... address set forth in the NOVA, or such other place as the ALJ may designate. Filing by United States...

  19. 15 CFR 904.102 - Procedures upon receipt of a NOVA.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 15 Commerce and Foreign Trade 3 2012-01-01 2012-01-01 false Procedures upon receipt of a NOVA. 904... PROCEDURES Civil Penalties § 904.102 Procedures upon receipt of a NOVA. (a) The respondent has 30 days from receipt of the NOVA in which to respond. During this time the respondent may: (1) Accept the penalty...

  20. 15 CFR 719.8 - Filing and service of papers other than the NOVA.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... than the NOVA. 719.8 Section 719.8 Commerce and Foreign Trade Regulations Relating to Commerce and... CONVENTION REGULATIONS ENFORCEMENT § 719.8 Filing and service of papers other than the NOVA. (a) Filing. All... address set forth in the NOVA, or such other place as the ALJ may designate. Filing by United States...

  1. 15 CFR 904.102 - Procedures upon receipt of a NOVA.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 3 2011-01-01 2011-01-01 false Procedures upon receipt of a NOVA. 904... PROCEDURES Civil Penalties § 904.102 Procedures upon receipt of a NOVA. (a) The respondent has 30 days from receipt of the NOVA in which to respond. During this time the respondent may: (1) Accept the penalty...

  2. 15 CFR 904.102 - Procedures upon receipt of a NOVA.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 15 Commerce and Foreign Trade 3 2013-01-01 2013-01-01 false Procedures upon receipt of a NOVA. 904... PROCEDURES Civil Penalties § 904.102 Procedures upon receipt of a NOVA. (a) The respondent has 30 days from receipt of the NOVA in which to respond. During this time the respondent may: (1) Accept the penalty...

  3. NovaNET User Manual for C-Router Instructors. Second Edition Revised.

    ERIC Educational Resources Information Center

    Fortner, Monica B.; Davis, Dennis M.

    The NovaNET computer system is a mainframe system with a large network of users sharing the same computer. This manual is intended to teach instructors how to use the NovaNET system to deliver instruction to their students. The manual is divided into four main sections, each of which teaches a group of skills needed by NovaNET instructors. The…

  4. NovaNET User Manual for C-Router Instructors. Second Edition Revised.

    ERIC Educational Resources Information Center

    Fortner, Monica B.; Davis, Dennis M.

    The NovaNET computer system is a mainframe system with a large network of users sharing the same computer. This manual is intended to teach instructors how to use the NovaNET system to deliver instruction to their students. The manual is divided into four main sections, each of which teaches a group of skills needed by NovaNET instructors. The…

  5. Cerebral Cavernous Malformations (CCM)

    MedlinePlus

    ... Contact Registry Interest Form Contact Us | Login Disorder Definitions Learn More > Disorder Definitions Cerebral Cavernous Malformations (CCM) ... until it is too late to salvage vision. Routine screening is very important, even if there are ...

  6. Cerebral Aneurysms Fact Sheet

    MedlinePlus

    ... Caregiver Education » Fact Sheets Cerebral Aneurysms Fact Sheet Table of Contents (click to jump to sections) What ... Information Page NINDS Epilepsy Information Page NINDS Familial Periodic Paralyses Information Page NINDS Farber's Disease Information Page ...

  7. Acquired Cerebral Trauma: Epilogue.

    ERIC Educational Resources Information Center

    Bigler, Erin D., Ed.

    1988-01-01

    The article summarizes a series of articles concerning acquired cerebral trauma. Reviewed are technological advances, treatment, assessment, potential innovative therapies, long-term outcome, family impact of chronic brain injury, and prevention. (DB)

  8. Cerebral amyloid angiopathy

    MedlinePlus

    ... 911) if you have sudden loss of movement , sensation, vision, or speech. Alternative Names Amyloidosis - cerebral; CAA; Congophilic angiopathy Images Amyloidosis on the fingers Arteries of the brain References Kase CS, Shoamanesh A. Intracerebral hemorrhage. In: Daroff ...

  9. Nanomedicine in cerebral palsy

    PubMed Central

    Balakrishnan, Bindu; Nance, Elizabeth; Johnston, Michael V; Kannan, Rangaramanujam; Kannan, Sujatha

    2013-01-01

    Cerebral palsy is a chronic childhood disorder that can have diverse etiologies. Injury to the developing brain that occurs either in utero or soon after birth can result in the motor, sensory, and cognitive deficits seen in cerebral palsy. Although the etiologies for cerebral palsy are variable, neuroinflammation plays a key role in the pathophysiology of the brain injury irrespective of the etiology. Currently, there is no effective cure for cerebral palsy. Nanomedicine offers a new frontier in the development of therapies for prevention and treatment of brain injury resulting in cerebral palsy. Nanomaterials such as dendrimers provide opportunities for the targeted delivery of multiple drugs that can mitigate several pathways involved in injury and can be delivered specifically to the cells that are responsible for neuroinflammation and injury. These materials also offer the opportunity to deliver agents that would promote repair and regeneration in the brain, resulting not only in attenuation of injury, but also enabling normal growth. In this review, the current advances in nanotechnology for treatment of brain injury are discussed with specific relevance to cerebral palsy. Future directions that would facilitate clinical translation in neonates and children are also addressed. PMID:24204146

  10. Nanomedicine in cerebral palsy.

    PubMed

    Balakrishnan, Bindu; Nance, Elizabeth; Johnston, Michael V; Kannan, Rangaramanujam; Kannan, Sujatha

    2013-01-01

    Cerebral palsy is a chronic childhood disorder that can have diverse etiologies. Injury to the developing brain that occurs either in utero or soon after birth can result in the motor, sensory, and cognitive deficits seen in cerebral palsy. Although the etiologies for cerebral palsy are variable, neuroinflammation plays a key role in the pathophysiology of the brain injury irrespective of the etiology. Currently, there is no effective cure for cerebral palsy. Nanomedicine offers a new frontier in the development of therapies for prevention and treatment of brain injury resulting in cerebral palsy. Nanomaterials such as dendrimers provide opportunities for the targeted delivery of multiple drugs that can mitigate several pathways involved in injury and can be delivered specifically to the cells that are responsible for neuroinflammation and injury. These materials also offer the opportunity to deliver agents that would promote repair and regeneration in the brain, resulting not only in attenuation of injury, but also enabling normal growth. In this review, the current advances in nanotechnology for treatment of brain injury are discussed with specific relevance to cerebral palsy. Future directions that would facilitate clinical translation in neonates and children are also addressed.

  11. The Formation of Cataclysmic Variables: The Influence of Nova Eruptions

    NASA Astrophysics Data System (ADS)

    Nelemans, G.; Siess, L.; Repetto, S.; Toonen, S.; Phinney, E. S.

    2016-01-01

    The theoretical and observed populations of pre-cataclysmic variables are dominated by systems with low-mass white dwarfs (WDs), while the WD masses in cataclysmic variables (CVs) are typically high. In addition, the space density of CVs is found to be significantly lower than in the theoretical models. We investigate the influence of nova outbursts on the formation and initial evolution of CVs. In particular, we calculate the stability of the mass transfer in the case where all of the material accreted on the WD is lost in classical novae and part of the energy to eject the material comes from a common-envelope-like interaction with the companion. In addition, we study the effect of an asymmetry in the mass ejection that may lead to small eccentricities in the orbit. We find that a common-envelope-like ejection significantly decreases the stability of the mass transfer, particularly for low-mass WDs. Similarly, the influence of asymmetric mass loss can be important for short-period systems and even more so for low-mass WDs; however, this influence likely disappears long before the next nova outburst due to orbital circularization. In both cases the mass-transfer rates increase, which may lead to observable (and perhaps already observed) consequences for systems that do survive to become CVs. However, a more detailed investigation of the interaction between nova ejecta and the companion and the evolution of slightly eccentric CVs is needed before definite conclusions can be drawn.

  12. 3D Hydrodynamic Simulation of Classical Novae Explosions

    NASA Astrophysics Data System (ADS)

    Kendrick, Coleman J.

    2015-01-01

    This project investigates the formation and lifecycle of classical novae and determines how parameters such as: white dwarf mass, star mass and separation affect the evolution of the rotating binary system. These parameters affect the accretion rate, frequency of the nova explosions and light curves. Each particle in the simulation represents a volume of hydrogen gas and are initialized randomly in the outer shell of the companion star. The forces on each particle include: gravity, centrifugal, coriolis, friction, and Langevin. The friction and Langevin forces are used to model the viscosity and internal pressure of the gas. A velocity Verlet method with a one second time step is used to compute velocities and positions of the particles. A new particle recycling method was developed which was critical for computing an accurate and stable accretion rate and keeping the particle count reasonable. I used C++ and OpenCL to create my simulations and ran them on two Nvidia GTX580s. My simulations used up to 1 million particles and required up to 10 hours to complete. My simulation results for novae U Scorpii and DD Circinus are consistent with professional hydrodynamic simulations and observed experimental data (light curves and outburst frequencies). When the white dwarf mass is increased, the time between explosions decreases dramatically. My model was used to make the first prediction for the next outburst of nova DD Circinus. My simulations also show that the companion star blocks the expanding gas shell leading to an asymmetrical expanding shell.

  13. Non-LTE model atmosphere analysis of Nova Cygni 1992

    NASA Technical Reports Server (NTRS)

    Hauschildt, P. H.; Starrfield, S.; Austin, S.; Wagner, R. M.; Shore, S. N.; Sonneborn, G.

    1994-01-01

    We use spherically symmetric non-local thermodynamic equilibrium (non-LTE), line-blanketed, expanding model atmospheres to analyze the International Ultraviolet Explorer (IUE) and optical spectra of Nova Cygni 1992 during the early phases of its outburst. We find that the first IUE spectrum obtained just after discovery on 1992 February 20, is best reproduced by a model atmosphere with a steep density gradient and homologous expansion, whereas the IUE and optical spectra obtained on February 24 show an extended, optically thick, wind structure. Therefore, we distinguish two phases of the early evolution of the nova photosphere: the initial, rapid, 'fireball' phase and the subsequent, much longer, optically thick 'wind' phase. The importance of line-blanketing in nova spectra is demonstrated. Our preliminary abundance analysis implies that hydrogen is depeleted in the ejecta, corresponding to abundance enhancements of Fe by a factor of approximately 2 and of CNO by more than a factor of 10 when compared to solar abundances. The synthetic spectra reproduce both the observed pseudo-continua as well as most of the observed features from the UV to the optical spectral range and demonstrate the importance of obtaining nearly simultaneous UV and optical spectra for performing accurate analyses of expanding stellar atmospheres (for both novae and supernovae).

  14. The γ-ray sources in classical novae

    NASA Astrophysics Data System (ADS)

    Sun, Weichao; Zhu, Chunhua; Wang, Zhaojun; Lü, Guoliang

    2016-08-01

    The interaction between novae ejecta and accretion disks or circumbinary (CB) disks surrounding nova systems based on the diffusive shock acceleration (DSA) mechanism are investigated. Results suggest that interaction between the novae ejecta and CB disks most probably produce γ-rays. Both leptonic and hadronic scenarios can feasibly produce γ-rays in CB disks. A grid is calculated in order to discuss the γ-ray sources in classical novae (CNe), and results indicated that the mass of a white dwarf and the orbit period in CNe can greatly affect the production of γ-rays. According to the proposed grid and synthesis population method, it is estimated that the percentage of CNe that can produce γ-rays ranges from approximately 0.17 % to 51 % for leptonic scenarios when the magnetic field strength in the shock region ranges from 0.005 G to 0.02 G. The occurrence rate of γ-ray CNe ranges from approximately 1 yr^{-1} to 27 yr^{-1} in the galaxy. The corresponding percentage ranges from approximately 64 % to 97 % in hadronic scenarios, while the occurrence rate of γ-ray CNe ranges from approximately 35 yr^{-1} to 52 yr^{-1} in the galaxy.

  15. The political economy of wilderness designation in Nova Scotia

    Treesearch

    Glyn Bissix; Leah Levac; Peter Horvath

    2002-01-01

    This paper traces the various policy stimuli shaping the development of the Nova Scotia Wilderness Areas Protection Act (December, 1998). It does so by examining international, national, provincial, and local influences on wilderness designation, legislative structure, and implementation issues that influenced, or are likely to influence, wilderness area management. By...

  16. ToO Galactic Nova -- Michelle ``Quick Response''

    NASA Astrophysics Data System (ADS)

    Helton, L. Andrew; Woodward, Chick; Evans, Nye; Geballe, Tom; Spitzer Nova Team

    2006-08-01

    Stars are the engines of energy production and chemical evolution in our Universe, depositing radiative and mechanical energy into their environments and enriching the ambient ISM with elements synthesized in their interiors and dust grains condensed in their atmospheres. Classical novae (CN) contribute to this cycle of chemical enrichment through explosive nucleosynthesis and the violent ejection of material dredged from the white dwarf progenitor and mixed with the accreted surface layers. We propose to obtain mid-IR spectra of a new galactic CN in outburst to investigate aspects of the CN phenomenon including the in situ formation and mineralogy of nova dust and the elemental abundances resulting from thermonuclear runaway. Synoptic, high S/N Michelle spectra permit: 1) determination of the grain size distribution and mineral composition of nova dust; 2) estimation of chemical abundances of nova ejecta from coronal and other emission line spectroscopy; and 3) measurement of the density and masses of the ejecta. This Gemini `Target of Opportunity' initiative (trigger K=5- 8 mag, assuming adequate PWFS guide stars exist) complements our extensive Spitzer, Chandra, Swift, XMM-Newton CN DDT/ToO programs.

  17. Synoptic Mid-IR Spectra ToO Novae

    NASA Astrophysics Data System (ADS)

    Helton, L. Andrew; Woodward, Chick; Evans, Nye; Geballe, Tom; Spitzer Nova Team

    2007-02-01

    Stars are the engines of energy production and chemical evolution in our Universe, depositing radiative and mechanical energy into their environments and enriching the ambient ISM with elements synthesized in their interiors and dust grains condensed in their atmospheres. Classical novae (CN) contribute to this cycle of chemical enrichment through explosive nucleosynthesis and the violent ejection of material dredged from the white dwarf progenitor and mixed with the accreted surface layers. We propose to obtain mid-IR spectra of a new galactic CN in outburst to investigate aspects of the CN phenomenon including the in situ formation and mineralogy of nova dust and the elemental abundances resulting from thermonuclear runaway. Synoptic, high S/N Michelle spectra permit: 1) determination of the grain size distribution and mineral composition of nova dust; 2) estimation of chemical abundances of nova ejecta from coronal and other emission line spectroscopy; and 3) measurement of the density and masses of the ejecta. This Gemini `Target of Opportunity' initiative (trigger K=5- 8 mag, assuming adequate PWFS guide stars exist) complements our extensive Spitzer, Chandra, Swift, XMM-Newton CN DDT/ToO programs.

  18. Initiation of Convection in a Classical Nova Precursor

    NASA Astrophysics Data System (ADS)

    Dursi, L. J.; Calder, A. C.; Ricker, P. M.; Truran, J. W.; Zingale, M.; Fryxell, B.; Olson, K.; Rosner, R.; Timmes, F. X.; Tufo, H.; MacNeice, P.

    2001-12-01

    Classical Novae result from the explosive thermonuclear burning of material accreted from a companion star onto the surface of a white dwarf. Observed abundances and explosion energies estimated from observations indicate that there must be significant mixing of the heavier material of the white dwarf (C/O) into the lighter accreted material (H/He). Accordingly, nova models must incorporate a mechanism that will dredge up the heavier white dwarf material, and fluid motions from an early convection phase is one proposed mechanism. We present results from two-dimensional simulations of classical nova precursor models that demonstrate the beginning of a convective phase during the `simmering' of a Nova precursor. We use a new hydrostatic equilibrium hydrodynamics module recently developed for the adaptive-mesh code FLASH. The two-dimensional models are based on the one-dimensional models of Ami Glasner (Glasner et al. 1997), and were evolved with FLASH from a pre-convective state to the onset of convection. In addition, we present the details of the hydrostatic equilibrium module and the hydrostatic boundary conditions used in the simulations. This research has been supported by the U.S. Department of Energy under grant no. B341495 to the ASCI Flash Center at the University of Chicago.

  19. Character Sets for PLATO/NovaNET: An Expository Catalog.

    ERIC Educational Resources Information Center

    Gilpin, John B.

    The PLATO and NovaNET computer-based instructional systems use a fixed system character set ("normal font") and an author-definable character set ("alternate font"). The alternate font lets the author construct his own symbols and bitmapped pictures. This expository catalog allows users to determine quickly (1) whether there is…

  20. High Speed Photometry and Spectroscopy of Novae at Quiescence

    NASA Astrophysics Data System (ADS)

    Egan, J. M.; Woudt, P. A.; Warner, B.; Williams, R. E.; Steeghs, D. T. H.; Ribeiro, V. A. R. M.

    2014-12-01

    We present spectroscopy of Nova Velorum 1999 (V382 Vel) and Nova Sagittarii 1936c (V630 Sgr) obtained with the Southern African Large Telescope in May and July 2012 as part of our ongoing observing campaign of old novae. The SALT spectrum of V382 Vel is dominated by broad Hα emission associated with the nova shell. The other Balmer lines in the spectrum are narrower and single-peaked, with Hβ at similar line strength as He II 4686Å. The SALT spectrum of V630 Sgr is dominated by He II 4686Å, emission lines are double-peaked (except the lines of the He II Pickering series) and show clear variations in multiple spectra obtained over one-quarter of the binary orbit. Additional high speed photometry of V382 Vel has been obtained in 2012 using the new SHOC photometer of the South African Astronomical Observatory. It shows the emergence of large amplitude quasi-periodic variability with periodicities around ˜ 30 minutes, not seen previously.

  1. Development of the Hα profile in Nova Del 2013

    NASA Astrophysics Data System (ADS)

    Storrs, Alex; Mahmoudian, T.

    2014-01-01

    We report observations of the Hα profile of Nova Del 2013, with resolving power R = 3000. Starting in late August the expected P Cygni profile (blueshifted absorption) was observed. Beginning in September a redshifted absorption appears and strengthens through the month. We will report observations through fall and discuss possible causes of these features.

  2. Epidemiology of Lyme Disease, Nova Scotia, Canada, 2002–2013

    PubMed Central

    Johnston, B. Lynn; Schleihauf, Emily; Mask, Angela; Haldane, David; Drebot, Michael; Baikie, Maureen; Cole, Teri J.; Fleming, Sarah; Gould, Richard; Lindsay, Robbin

    2015-01-01

    Ixodes scapularis ticks, which transmit Borrelia burgdorferi, the causative agent of Lyme disease (LD), are endemic to at least 6 regions of Nova Scotia, Canada. To assess the epidemiology and prevalence of LD in Nova Scotia, we analyzed data from 329 persons with LD reported in Nova Scotia during 2002–2013. Most patients reported symptoms of early localized infection with rash (89.7%), influenza-like illness (69.6%), or both; clinician-diagnosed erythema migrans was documented for 53.2%. In a separate serosurvey, of 1,855 serum samples screened for antibodies to B. burgdorferi, 2 were borderline positive (both with an indeterminate IgG on Western blot), resulting in an estimated seroprevalence of 0.14% (95% CI 0.02%–0.51%). Although LD incidence in Nova Scotia has risen sharply since 2002 and is the highest in Canada (16/100,000 population in 2013), the estimated number of residents with evidence of infection is low, and risk is localized to currently identified LD-endemic regions. PMID:26401788

  3. Discovery of a Probable Nova in M31

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Kucakova, H.

    2017-03-01

    We report the discovery of a probable nova in M31 on a co-added 900-s R-band CCD frame taken on 2017 Mar. 1.754 UT with the 0.65-m telescope at Ondrejov. The object designated PNV J00430201+4113190 is located at R.A. = 0h43m02s.01, Decl.

  4. Grassroots Response to HIV/AIDS in Nova Scotia

    ERIC Educational Resources Information Center

    Plumb, Donovan

    2005-01-01

    This chapter describes how by adopting a cultural theory of learning, members of a community-based research team deepened their understanding of the nature, pervasiveness, and contribution of everyday learning processes of people affected by HIV/AIDS in Nova Scotia, Canada.

  5. NOvA: Building a Next Generation Neutrino Experiment

    ScienceCinema

    Perko, John; Williams, Ron; Miller, Bill

    2016-07-12

    The NOvA neutrino experiment is searching for the answers to some of the most fundamental questions of the universe. This video documents how collaboration between government research institutions like Fermilab, academia and industry can create one of the largest neutrino detectors in the world.

  6. Discovery of a Possible Nova in M31

    NASA Astrophysics Data System (ADS)

    Maehara, Hiroyuki

    2016-11-01

    We report the discovery of a possible nova in M31 on V-band CCD images taken on 2016-11-12.372 UT with the 1.05-m Schmidt telescope and KWFC (Sako et al. 2012, SPIE, 8446, 84466L) at Kiso Observatory, the University of Tokyo.

  7. A SHORT DESCRIPTION OF THE PLAN OF NOVA HIGH SCHOOL.

    ERIC Educational Resources Information Center

    HIERS, NAN

    THE NOVA HIGH SCHOOL IS AN EDUCATIONAL EXPERIMENT TO MAKE LEARNING AND ACHIEVEMENT INTERESTING, CHALLENGING, AND EXCITING TO THE STUDENT. THE PROGRAM IS BASED ON THE CONCEPT OF INDIVIDUAL PROGRESS WITH EMPHASIS ON QUALITY EDUCATION. FEATURES OF THE SCHOOL ENVIRONMENT INCLUDE AIR-CONDITIONING, CARPETING, MULTIPURPOSE CLASSROOMS, INDIVIDUAL STUDY…

  8. Hydrodynamic studies of oxygen, neon, and magnesium novae

    NASA Technical Reports Server (NTRS)

    Starrfield, Sumner; Sparks, W. M.; Truran, J. W.

    1987-01-01

    Results are presented from recent theoretical studies that have examined the properties of nova outbursts on ONeMg white dwarfs. These outbursts are much more violent and occur much more frequently than outbursts on CO white dwarfs. Hydrodynamic simulations of both kinds of outbursts are in excellent agreement with the observations.

  9. Maria Helena Novaes--Creative Person, Creative Life

    ERIC Educational Resources Information Center

    de Alencar, Eunice M. L. Soriano

    2014-01-01

    This article describes the characteristics and accomplishments of Maria Helena Novaes, one of the most creative school psychologists of Brazil. It identifies the people who influenced her and some of the factors that may have contributed to her achievements and rise to eminence. It highlights the numerous opportunities she received during her life…

  10. Grassroots Response to HIV/AIDS in Nova Scotia

    ERIC Educational Resources Information Center

    Plumb, Donovan

    2005-01-01

    This chapter describes how by adopting a cultural theory of learning, members of a community-based research team deepened their understanding of the nature, pervasiveness, and contribution of everyday learning processes of people affected by HIV/AIDS in Nova Scotia, Canada.

  11. Discovery of a Probable Nova in M31

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Kucakova, H.

    2017-08-01

    We report the discovery of a probable nova in M31 on a co-added 1350-s R-band CCD frame taken on 2017 Aug. 3.840 UT with the 0.65-m telescope at Ondrejov. The object designated PNV J00423895+4115171 is located at R.A. = 0h42m38s.95, Decl.

  12. Fotometria col filtro LPR alla nova V5668 SGR

    NASA Astrophysics Data System (ADS)

    Sigismondi, Costantino

    2016-09-01

    The nova SGR 2015 no. 2 or V5668 SGR was visually observed with the LPR filter to evaluate the OIII emission. The contributions of B, V, R and Visual components to the LPR magnitude are modeled and compared with the observations in scotopic vision.

  13. Non-LTE model atmosphere analysis of Nova Cygni 1992

    NASA Technical Reports Server (NTRS)

    Hauschildt, P. H.; Starrfield, S.; Austin, S.; Wagner, R. M.; Shore, S. N.; Sonneborn, G.

    1994-01-01

    We use spherically symmetric non-local thermodynamic equilibrium (non-LTE), line-blanketed, expanding model atmospheres to analyze the International Ultraviolet Explorer (IUE) and optical spectra of Nova Cygni 1992 during the early phases of its outburst. We find that the first IUE spectrum obtained just after discovery on 1992 February 20, is best reproduced by a model atmosphere with a steep density gradient and homologous expansion, whereas the IUE and optical spectra obtained on February 24 show an extended, optically thick, wind structure. Therefore, we distinguish two phases of the early evolution of the nova photosphere: the initial, rapid, 'fireball' phase and the subsequent, much longer, optically thick 'wind' phase. The importance of line-blanketing in nova spectra is demonstrated. Our preliminary abundance analysis implies that hydrogen is depeleted in the ejecta, corresponding to abundance enhancements of Fe by a factor of approximately 2 and of CNO by more than a factor of 10 when compared to solar abundances. The synthetic spectra reproduce both the observed pseudo-continua as well as most of the observed features from the UV to the optical spectral range and demonstrate the importance of obtaining nearly simultaneous UV and optical spectra for performing accurate analyses of expanding stellar atmospheres (for both novae and supernovae).

  14. Maria Helena Novaes--Creative Person, Creative Life

    ERIC Educational Resources Information Center

    de Alencar, Eunice M. L. Soriano

    2014-01-01

    This article describes the characteristics and accomplishments of Maria Helena Novaes, one of the most creative school psychologists of Brazil. It identifies the people who influenced her and some of the factors that may have contributed to her achievements and rise to eminence. It highlights the numerous opportunities she received during her life…

  15. Hydrodynamic studies of oxygen, neon, and magnesium novae

    NASA Technical Reports Server (NTRS)

    Starrfield, Sumner; Sparks, W. M.; Truran, J. W.

    1987-01-01

    Results are presented from recent theoretical studies that have examined the properties of nova outbursts on ONeMg white dwarfs. These outbursts are much more violent and occur much more frequently than outbursts on CO white dwarfs. Hydrodynamic simulations of both kinds of outbursts are in excellent agreement with the observations.

  16. H-alpha confirmation of novae in M31

    NASA Astrophysics Data System (ADS)

    Ovcharov, E.; Nikolov, G.; Kostov, A.; Bozhilov, V.; Minev, M.; Valcheva, A.; Nedialkov, P.

    2015-08-01

    We report H-alpha and BR-band photometry of three objects in M31, suspected as novae. The objects are: PNV J00420640+4108211 = 2015-03a? (ATel# 7189), 2015-07c? (ATel# 7795, ATel #7818) and TCP J00401150+4042199 = 2015-07e? (ATel #7834).

  17. Late stages in the evolution of classical novae

    NASA Technical Reports Server (NTRS)

    Starrfield, S.; Krautter, J.; Sonneborn, G.; Shore, S. N.; Wagner, R. M.; Austin, S.; Saizar, P.; Ferland, G.; Wade, R.; Gehrz, R. D.

    1990-01-01

    We have begun a study of the long term evolution of novae in outburst in order to determine the means by which they return in quiescence when nuclear burning has ended. This project involves both IUE and optical observations and theoretical predictions. Recently, in the initial observational part of this project, we have obtained IUE Short Wavelength Prime (SWP) spectra of GQ Mus 1983 and QU Vul 1984. Each spectrum was a 16 hour exposure using a combined US1 plus Vilspa shift. No novae have been studied in the UV for as long as QU Vul and GQ Mus and observations of their spectral evolution are providing unique data on the turn-off time scale. We have also obtained the spectra of old novae from the IUE archives in order to compare and contrast the existing spectra with those of GQ Mus and Qu Vul. The theoretical prediction is that a nova should be very hot just before turnoff but x ray observations from EXOSAT do not confirm this prediction.

  18. Optical and ultraviolet observations of nova Vul 1987

    NASA Technical Reports Server (NTRS)

    Starrfield, S.; Stryker, L. L.; Sonneborn, G.; Sparks, Warren M.; Wagner, R. M.; Ferland, Gary; Gallagher, J. S.; Wade, R.; Williams, R. E.; Gehrz, Robert D.

    1988-01-01

    The outburst for a nova discovered in Nov. 1987 and followed since then is summarized. Although it was possible to observe it with the IUE at maximum, its ultraviolet energy faded rapidly, and after the first 2 weeks it was impossible to observe it at IUE wavelengths. It is observed to form a thick dust shell and is in the nebular stage.

  19. The Present Status of the Antigonish Movement in Nova Scotia.

    ERIC Educational Resources Information Center

    Sowder, Ellie Mae

    A comprehensive case study is presented of the Antigonish Movement in eastern Nova Scotia. Originally founded to combat poverty and exploitation, it has functioned since 1929 under the extension department of St. Francis Xavier University, Antigonish. The Movement brought education into the lives of ordinary working people and introduced group…

  20. Nova Lup 2016 during the X-ray decay phase

    NASA Astrophysics Data System (ADS)

    Orio, Marina; Beardmore, Andrew; Page, Kim; Osborne, Julian

    2017-09-01

    Nova Lup 2016 (ASASSN-16kt; see ATel #9538, #9539, #8550, #9554, #9587, #9594 and #9644) has been regularly monitored with Swift since the observations published in ATel #10632 that revealed a luminous supersoft X-ray source with a peak XRT count rate of 61.1(+-)0.1 cts/s on 2017/2/22.

  1. The Present Status of the Antigonish Movement in Nova Scotia.

    ERIC Educational Resources Information Center

    Sowder, Ellie Mae

    A comprehensive case study is presented of the Antigonish Movement in eastern Nova Scotia. Originally founded to combat poverty and exploitation, it has functioned since 1929 under the extension department of St. Francis Xavier University, Antigonish. The Movement brought education into the lives of ordinary working people and introduced group…

  2. Near infrared monitoring observations of Nova T Pyxidis

    NASA Astrophysics Data System (ADS)

    Varricatt, W. P.; Carroll, T.; Ehle, J.; Wold, T.

    2012-09-01

    T Pyxidis is a recurrent nova, the latest outburst of which was discovered on 2011 April 14 (Waagan, E.; Linnolt, M.; Pearce, A. 2011, IAUC, 9205, 1), nearly 50 years after its previous outburst (see Evans, A. et al. 2012, MNRAS, 424, L69).

  3. Discovery of a Probable Nova in M31

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Fatka, P.

    2017-06-01

    We report the discovery of a probable nova in M31 on a co-added 990-s R-band CCD frame taken on 2017 Jun. 29.984 UT with the 0.65-m telescope at Ondrejov. The object designated PNV J00425962+4121290 is located at R.A. = 0h42m59s.62, Decl.

  4. Discovery of a Possible Nova in M31

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Wolf, M.

    2016-10-01

    We report the discovery of a possible nova in M31 on a co-added 1080-s R-band CCD frame taken on 2016 Oct. 7.758 UT with the 0.65-m telescope at Ondrejov. The object designated PNV J00420668+4105113 is located at R.A. = 0h42m06s.68, Decl.

  5. Cambridge Health's outreach earns alliance an AHA NOVA Award.

    PubMed

    Rees, Tom

    2005-01-01

    Cambridge Health Alliance, (CHA), Somerville, Mass., has been named for one of the five NOVA Awards given this year by the American Hospital Association. It is recognized for leading a program to improve community health by extending help to low-income and uninsured children and adults, as well as to the chronically ill and racial and ethnic minorities.

  6. Discovery of a Probable Nova in M33

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Vaduvescu, O.; Tudor, V.

    2014-08-01

    We report the discovery of a probable nova in M33 on co-added 960-s narrow-band H-alpha and 480-s R-band CCD images taken with the 2.5-m Isaac Newton Telescope (INT) + WFC at La Palma under ~1.1" seeing on 2014 July 29.206 and 29.222 UT, respectively.

  7. Discovery of a Probable Nova in M81

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Vaduvescu, O.; Mocnik, T.

    2014-09-01

    We report the discovery of a probable nova in M81 on a co-added 1440-s narrow-band H-alpha CCD image taken with the 2.5-m Isaac Newton Telescope (INT) + WFC at La Palma under ~2.2" seeing on 2014 Sep.

  8. Discovery of an Apparent Nova in M81

    NASA Astrophysics Data System (ADS)

    Hornoch, K.; Alfaro, M. Diaz; Ordonez-Etxeberria, I.; Vaduvescu, O.

    2015-01-01

    We report the discovery of an apparent nova in M81 on a co-added 1600-s narrow-band H-alpha CCD image taken with the 2.5-m Isaac Newton Telescope (INT) + WFC at La Palma under ~2.4" seeing on 2015 Jan. 15.126 UT.

  9. NOvA: Building a Next Generation Neutrino Experiment

    SciTech Connect

    Perko, John; Williams, Ron; Miller, Bill

    2013-12-05

    The NOvA neutrino experiment is searching for the answers to some of the most fundamental questions of the universe. This video documents how collaboration between government research institutions like Fermilab, academia and industry can create one of the largest neutrino detectors in the world.

  10. UK Nova/Supernova Patrol - the first 25 years

    NASA Astrophysics Data System (ADS)

    Hurst, G. M.

    2003-06-01

    The text of the Presidential Address delivered at 23 Savile Row, London W1 on 2002 October 30. The challenge of this Presidential Address is to compress the events of the first 25 years of the UK Nova/Supernova Patrol into a talk lasting for about an hour. When the patrol began as a formal search programme all that time ago, I had no idea just how much would be achieved and I feel quite humble in presenting the results as the coordinator when the real work has been carried out by all those dedicated observers over the years, whether looking for novae with binoculars or those now employing the latest technology to detect extragalactic supernovae. I will describe how and why the patrol started in 1976, including earlier events that persuaded key individuals that the time had come for a team approach to searching for novae. The aims of the patrol will be discussed and how these have changed over the years, which has necessitated some rethinking of the techniques employed. Naturally the patrol discoveries will be discussed in detail, but also the vital follow-up work on novae and supernovae, such as light curve analysis, which can produce valuable scientific information for the professional community. Indeed the patrol's work has generated excellent professional-amateur liaison as each side has helped the other to increase our understanding of these somewhat elusive objects, which suddenly burst into view in the night sky.

  11. MN Draconis: a peculiar, active dwarf nova in the period gap

    NASA Astrophysics Data System (ADS)

    Bąkowska, K.; Olech, A.; Pospieszyński, R.; Świerczyński, E.; Martinelli, F.; Rutkowski, A.; Koff, R.; Drozd, K.; Butkiewicz-Bąk, M.; Kankiewicz, P.

    2017-07-01

    Context. We present results of an extensive world-wide observing campaign of MN Draconis. Aims: MN Draconis is a poorly known active dwarf nova in the period gap and is one of only two known cases of period-gap SU UMa objects showing negative superhumps. The photometric behaviour of MN Draconis poses a challenge for existing models of the superhump and superoutburst mechanisms. Therefore, a thorough investigation of peculiar systems like MN Draconis is crucial for our understanding of the evolution of close binary stars. Methods: To measure the fundamental parameters of the system, we collected photometric data in October 2009, June-September 2013, and June-December 2015. We analysed the light curves, O-C diagrams, and power spectra. Results: During our three observational seasons we detected four superoutburts and several normal outbursts. Based on the two consecutive superoutbursts detected in 2015, the supercycle length was derived as Psc = 74 ± 0.5 days, and it has been increasing with a rate of ˙P = 3.3 × 10-3 during the past twelve years. Based on the positive and negative superhumps, we calculated the period excess ɛ = 5.6% ± 0.1%, the period deficit ɛ- = 2.5% ± 0.6%, and as a result, the orbital period Porb = 0.0994(1) days (143.126 ± 0.144 min). We updated the basic light curve parameters of MN Draconis. Conclusions: MN Draconis is the first discovered SU UMa system in the period gap with an increasing supercycle length. Photometric data are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/603/A72

  12. A Long Term High-Cadence Nova Survey

    NASA Astrophysics Data System (ADS)

    Castelaz, Michael W.; Rottler, L.; Barker, T.; Coker, M.

    2014-01-01

    We have initiated a nova survey that uses a previously unstudied long term high cadence archive data set covering about 1/3 of the sky to 1) improve on the number and recurrence frequency of recurrent novae (RNe), and 2) permit an investigation of the puzzling and diverse set of features in classical novae (CNe) and RNe light curves. RNe are of great astrophysical interest because they have long been considered to be the prime candidates for progenitors of Type Ia supernovae. However, the recurrence time scale is not well known, but is an essential parameter determining whether any RNe become Type Ia supernovae. Novae exhibit a wide variety of light curves with features like pre-eruption rises and dips, flat-tops at peak, and flares superimposed on decline, for example. These features are poorly understood. The answers require more and better light curves. The data set our team is using to address RNe occurrence and light curves was taken in the 1950’s over a nearly 9 year period with two Baker Super-Schmidt telescopes 80 km apart in New Mexico, resulting in 42,000 photographic images. Each telescope had a 52 degree field of view. Images to a limiting stellar magnitude of 13 were taken at a rate of 2-3 per hour sampling a total of one-third of the entire sky. A similar data set does not exist anywhere else, nor is one planned with such high cadence and field of view. We are digitizing the films and through a data pipeline plan to identify candidate RNe and new CNe enhancing the number of known RNe and creating light curves leading up to and following novae eruptions. We will describe the digitizing process and data pipeline, and initial results from the first 1,600 films that we have surveyed.

  13. The Ghostly Novae of Spirits: Candidates, Confirmations, and Classifications

    NASA Astrophysics Data System (ADS)

    Corgan, David William

    2015-08-01

    The SPIRITS (SPitzer InfraRed Intensive Transients Survey) project has surveyed 242 galaxies across multiple epochs for over a year, searching for gap transient and variable star activity. To date, a wealth of candidate objects has been discovered in the warm Spitzer data being used, with the current total at 1426 individual detections. The discovery, confirmation, follow-up, and comparison to prediction rates of these candidates is presented. Employing subjective detection methods, discussed herein, individual discovery to group confirmation rates were found to be less than 3.6%. Photometric confirmation with correlated team instruments left 53 sources of interest remaining for further study. These targets ranged across 30 different galaxies including IC2163, Messier 101, and NGC3198. Follow-up ground observations in the 1.2, 1.6, and 2.2 µm wavelengths with the legacy 2MASS instrument at MLOF (Mount Lemmon Observing Facility) are highlighted. The data reduction process which has evolved to improve detections by ~.6mag is also detailed. These results are supplemented by SPIRITS team input from a variety of world-class infrared facilities to produce overall nova candidate characteristics, which are included. In some cases this extends to light curves from confirmed and observed novae to depths of ~20mag, while in others it is restricted to limiting magnitudes of ~18 at sight of occurrence (the true “ghosts” of SPIRITS). Candidate novae have been separated into classes where data allows, including the possible discovery of a new variable type coined SMIRTS (Super Massive InfraRed TransientS), and probable members of the elusive Luminous Red Novae category. Finally, comparison of numerical survey results to nova prediction rates is undertaken and results presented. Where deviations from luminosity curve fittings occur, such as in the overly active M81 and IC0342 galaxies, possible causes are proposed.

  14. Radiative shocks create environments for dust formation in classical novae

    NASA Astrophysics Data System (ADS)

    Derdzinski, Andrea M.; Metzger, Brian D.; Lazzati, Davide

    2017-08-01

    Classical novae commonly show evidence of rapid dust formation within months of the outburst. However, it is unclear how molecules and grains are able to condense within the ejecta, given the potentially harsh environment created by ionizing radiation from the white dwarf. Motivated by the evidence for powerful radiative shocks within nova outflows, we propose that dust formation occurs within the cool, dense shell behind these shocks. We incorporate a simple molecular chemistry network and classical nucleation theory with a model for the thermodynamic evolution of the post-shock gas, in order to demonstrate the formation of both carbon and forsterite (Mg2SiO4) grains. The high densities due to radiative shock compression (n ∼ 1014 cm-3) result in CO saturation and rapid dust nucleation. Grains grow efficiently to large sizes ≳ 0.1 μm, in agreement with IR observations of dust-producing novae, and with total dust masses sufficient to explain massive extinction events such as V705 Cas. As in dense stellar winds, dust formation is CO-regulated, with carbon-rich flows producing carbon-rich grains and oxygen-rich flows primarily forming silicates. CO is destroyed by non-thermal particles accelerated at the shock, allowing additional grain formation at late times, but the efficiency of this process appears to be low. Given observations showing that individual novae produce both carbonaceous and silicate grains, we concur with previous works attributing this bimodality to chemical heterogeneity of the ejecta. Nova outflows are diverse and inhomogeneous, and the observed variety of dust formation events can be reconciled by different abundances, the range of shock properties, and the observer viewing angle. The latter may govern the magnitude of extinction, with the deepest extinction events occurring for observers within the binary equatorial plane.

  15. The H-alpha light curves of novae in M31

    NASA Technical Reports Server (NTRS)

    Ciardullo, Robin; Shafter, Allen W.; Ford, Holland C.; Neill, James D.; Shara, Michael M.

    1990-01-01

    H-alpha and B light curves are presented for 11 M31 novae, four of which were well observed near maximum. These data, along with the H-alpha light curves of two Galactic novae, demonstrate that a nova's maximum H-alpha flux occurs days or weeks after its continuum maximum at a monochromatic intensity 1-2 magnitudes above its peak flux in B. Moreover, after this maximum is achieved, a typical nova will radiate a third as many photons in H-alpha as in the entire B bandpass. The most interesting part of a nova's H-alpha light curve, however, is its decline. It is found that, regardless of a nova's speed, its H-alpha decay rate after maximum is almost identical to its decay rate in B. This behavior suggests that most of a nova's optical luminosity during early decline is continuum emission from the nebula, rather than direct radiation from the central source.

  16. The Emission Line Spectrum of Nova Sagittarius 1993 IN the 35-DAY after Maximum

    NASA Astrophysics Data System (ADS)

    Lawson, W. A.; James, S. D.

    1994-07-01

    We report spectroscopic observations of Nova Sgr 1993, obtained between 20 and 35 d after maximum light following the outburst in 1993 September. We compile published spectra along with our observations to determine the spectroscopic evolution of the nova. On the Tololo classification system, the object appears to have evolved from a `Fe ii class' nova to an `He/N class' nova within 20 d after maximum. [Fe iii lines appeared within 34 d. The likely evolutionary sequence in the first 35 d is either Pfe,heN? or Pfe,nN?. The uncertainty in the classification is due to a lack of spectral coverage. Photometric observations indicate the nova to have faded on a time-scale t3 of 33 d, and a flux distribution increasingly dominated by Ha emission inthefirst40 d. Key words: stars: individual: Nova Sgr 1993 - novae, cataclysmic variables.

  17. Johannes Hevelius, nova CK Vulpeculae (1670) and the "hibernation" model of cataclysmic variables.

    NASA Astrophysics Data System (ADS)

    Smak, J.

    The author reviews the basic properties of cataclysmic variables and the thermonuclear runaway (TNR) theory of the outbursts of novae, including the "hibernation" model of cataclysmic variables. The TNR theory, while remarkably successful in explaining a number of observational properties of novae, met also with some difficulties related to (1) excessive mass-transfer rates in old novae, and (2) conflicting estimates of their space density. Both are estimated from absolute magnitudes of novae as observed within decades before, or after, their outbursts. Nova CK Vulpeculae (1670), the oldest recorded nova, was observed in 1670 - 1672 by Hevelius, whose observations - together with those by Anthelme and Cassini - were sufficiently numerous and accurate to permit a modern reconstruction of the light curve and its classification as a very slow nova.

  18. Spectral eclipse mapping of the accretion disk in the nova-like variable UX Ursae Majoris

    NASA Technical Reports Server (NTRS)

    Rutten, R. G. M.; Dhillon, V. S.; Horne, K.; Kuulkers, E.

    1994-01-01

    We analyze narrow-band eclipse light curves of the nova-like cataclysmic variable UX UMa, obtained from low-resolution spectra spanning lambda lambda 3600-9800 A . The light curves for narrow bands in the continuum as well as those for individual spectral lines are treated independently, and are used to construct images of the accretion disk's brightness distribution using the maximum-entropy eclipse-mapping technique. Particular attention is paid to the propagation of statistical uncertainties in the data and to how the analysis may introduce systematic errors in the final result. From the many narrrow band images we have reconstructed the spectra from isolated parts of the accretion disk. These spectra reveal that the inner disk radiates a continuum spectrum which peaks in the near UV and has the hydrogen Balmer lines in absorption (with the exception of H-alpha), whereas the outer disk is much fainter, has a much redder spectrum, and has Balmer emission lines. Our analysis reveals the presence of an uneclipsed component of the total light, whose spectrum is very red and has Balmer lines in emission. This unexpected feature of the eclipse mapping technique offers a new tool for an independent assessment of the secondary star's spectrum in eclipsing cataclysmic variables.

  19. Proper-motion age dating of the progeny of Nova Scorpii AD 1437.

    PubMed

    Shara, M M; Iłkiewicz, K; Mikołajewska, J; Pagnotta, A; Bode, M F; Crause, L A; Drozd, K; Faherty, J; Fuentes-Morales, I; Grindlay, J E; Moffat, A F J; Pretorius, M L; Schmidtobreick, L; Stephenson, F R; Tappert, C; Zurek, D

    2017-08-30

    'Cataclysmic variables' are binary star systems in which one star of the pair is a white dwarf, and which often generate bright and energetic stellar outbursts. Classical novae are one type of outburst: when the white dwarf accretes enough matter from its companion, the resulting hydrogen-rich atmospheric envelope can host a runaway thermonuclear reaction that generates a rapid brightening. Achieving peak luminosities of up to one million times that of the Sun, all classical novae are recurrent, on timescales of months to millennia. During the century before and after an eruption, the 'novalike' binary systems that give rise to classical novae exhibit high rates of mass transfer to their white dwarfs. Another type of outburst is the dwarf nova: these occur in binaries that have stellar masses and periods indistinguishable from those of novalikes but much lower mass-transfer rates, when accretion-disk instabilities drop matter onto the white dwarfs. The co-existence at the same orbital period of novalike binaries and dwarf novae-which are identical but for their widely varying accretion rates-has been a longstanding puzzle. Here we report the recovery of the binary star underlying the classical nova eruption of 11 March AD 1437 (refs 12, 13), and independently confirm its age by proper-motion dating. We show that, almost 500 years after a classical-nova event, the system exhibited dwarf-nova eruptions. The three other oldest recovered classical novae display nova shells, but lack firm post-eruption ages, and are also dwarf novae at present. We conclude that many old novae become dwarf novae for part of the millennia between successive nova eruptions.

  20. A Hubble Space Telescope Survey for Novae in M87. II. Snuffing out the Maximum Magnitude-Rate of Decline Relation for Novae as a Non-standard Candle, and a Prediction of the Existence of Ultrafast Novae

    NASA Astrophysics Data System (ADS)

    Shara, Michael M.; Doyle, Trisha; Lauer, Tod R.; Zurek, David; Baltz, Edward A.; Kovetz, Attay; Madrid, Juan P.; Mikołajewska, Joanna; Neill, J. D.; Prialnik, Dina; Welch, D. L.; Yaron, Ofer

    2017-04-01

    The extensive grid of numerical simulations of nova eruptions from the work of Yaron et al. first predicted that some classical novae might significantly deviate from the Maximum Magnitude-Rate of Decline (MMRD) relation, which purports to characterize novae as standard candles. Kasliwal et al. have announced the observational detection of a new class of faint, fast classical novae in the Andromeda galaxy. These objects deviate strongly from the MMRD relationship, as predicted by Yaron et al. Recently, Shara et al. reported the first detections of faint, fast novae in M87. These previously overlooked objects are as common in the giant elliptical galaxy M87 as they are in the giant spiral M31; they comprise about 40% of all classical nova eruptions and greatly increase the observational scatter in the MMRD relation. We use the extensive grid of the nova simulations of Yaron et al. to identify the underlying causes of the existence of faint, fast novae. These are systems that have accreted, and can thus eject, only very low-mass envelopes, of the order of 10-7-10-8 M ⊙, on massive white dwarfs. Such binaries include, but are not limited to, the recurrent novae. These same models predict the existence of ultrafast novae that display decline times, t 2, to be as short as five hours. We outline a strategy for their future detection. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under the NASA contract NAS 5-26555.

  1. Condições físicas do disco de acréscimo da nova-anã V4140 SGR

    NASA Astrophysics Data System (ADS)

    Borges, B.; Baptista, R.

    2003-08-01

    Discos de acréscimo são aparatos cósmicos que permitem que matéria seja eficientemente acrescida sobre uma fonte compacta pela remoção de momento angular via tensões viscosas enquanto transforma a energia potencial gravitacional em calor e, posteriormente, em radiação. Sistemas binários semi-ligados, como Variáveis Cataclísmicas (VCs) não-magnéticas, são talvez os melhores ambientes encontrados para o estudo da física desses discos de acréscimo. O desenvolvimento de técnicas de imageamento indireto, como o mapeamento por eclipses (MME) e a tomografia Doppler, permitiu avanços importantes na compreensão da física dos processos de acréscimo desses sistemas. V4140 Sagitarii é uma VC eclipsante de curto período orbital (~ 90 min) que não havia sido classificada como nova-anã ou polar. Neste trabalho apresentamos a análise do mapeamento por eclipse feito com dados de fotometria CCD nas bandas B, V e R de V4140 Sgr realizada no LNA. O objeto foi observado no declínio de erupção em julho de 1992 e em erupção em julho de 2001, isso indicou a classificação do sistema como uma nova-anã. A análise, feita sobre os mapas já apresentados em trabalho anterior, apresenta (i) diagrama cor-cor, que indica uma emissão opticamente espessa nas partes internas do disco em quiescência (R < RL1); (ii) diagrama cor-magnitude, usado para inferir uma distância de 600 +/- 10 pc ao sistema; (iii) a distribuição radial de temperatura observada que concorda com a lei de disco espesso em estado estacionário TµR-3/4, com temperaturas em torno de 10000 K e 3000 K ns partes internas e externas do disco em quiescência, respectivamente; (iv) a evolução da distribuição de temperatura no declínio de erupção; (v) estimativa da transferência de massa de 109.9+/-0.1 M¤/ano em quiescência, similar àquelas observadas em novas-like. O sistema é comparado à outras novas-anãs (e.g. OY Car e Z Cha) em quiescência e erupção, mostrando-se tratar um

  2. [Cerebral ischemia and histamine].

    PubMed

    Adachi, Naoto

    2002-10-01

    Cerebral ischemia induces excess release of glutamate and an increase in the intracellular Ca2+ concentration, which provoke catastrophic enzymatic processes leading to irreversible neuronal injury. Histamine plays the role of neurotransmitter in the central nervous system, and histaminergic fibers are widely distributed in the brain. In cerebral ischemia, release of histamine from nerve endings has been shown to be enhanced by facilitation of its activity. An inhibition of the histaminergic activity in ischemia aggravates the histologic outcome. In contrast, intracerebroventricular administration of histamine improves the aggravation, whereas blockade of histamine H2 receptors aggravates ischemic injury. Furthermore, H2 blockade enhances ischemic release of glutamate and dopamine. These findings suggest that central histamine provides beneficial effects against ischemic neuronal damage by suppressing release of excitatory neurotransmitters. However, histaminergic H2 action facilitates the permeability of the blood-brain barrier and shows deleterious effects on cerebral edema.

  3. Hypernatraemia in cerebral disorders

    PubMed Central

    Taylor, W. H.

    1962-01-01

    Six patients are described in whom cerebral damage was associated with raised plasma sodium and chloride concentrations and with extremely low urinary outputs of sodium and chloride. The patients were not clinically dehydrated and direct determinations showed that the blood and plasma volumes, the endogenous creatinine clearance, and the urinary output of antidiuretic hormone were normal. For these and other reasons it is concluded that the metabolic picture results not from diminished circulatory volume, water deficiency, sodium deficiency, undetected diabetes insipidus or osmotic diuresis, but from the cerebral damage itself. In these and other cited cases, the cerebral damage was localized chiefly in the frontal lobes, hypothalamus or lower brain-stem, thus suggesting a descending pathway, the relationship of which to the pineal area controlling aldosterone secretion requires clarification. Images PMID:13920001

  4. Duplicated middle cerebral artery.

    PubMed

    Perez, Jesus; Machado, Calixto; Scherle, Claudio; Hierro, Daniel

    2009-01-01

    Duplicated middle cerebral artery (DMCA) is an anomalous vessel arising from the internal carotid artery. The incidence DMCA is relatively law, and an association between this anomaly and cerebral aneurysms has been documented. There is a controversy whether DMCA may have perforating arteries. This is an important fact to consider in aneurysm surgery. We report the case of a 34-year-old black woman who suffered a subarachnoid hemorrhage and the angiography a left DMCA, and an aneurysm in an inferior branch of the main MCA. The DMCA and the MCA had perforating arteries. The aneurysm was clipped without complications. The observation of perforating arteries in our patient confirms that the DMCA may have perforating arteries. This is very important to be considered in cerebral aneurysms surgery. Moreover, the DMCA may potentially serve as a collateral blood supply to the MCA territory in cases of MCA occlusion.

  5. Cerebral venous sinus thrombosis with cerebral hemorrhage during early pregnancy

    PubMed Central

    Nie, Quanmin; Guo, Pin; Ge, Jianwei; Qiu, Yongming

    2015-01-01

    Cerebral venous sinus thrombosis (CVST) rarely induces cerebral hemorrhage, and CVST with cerebral hemorrhage during early pregnancy is extremely rare. Upon literature review, we are able to find only one case of CVST with cerebral hemorrhage in early pregnancy. In this paper, we report another case of a 27-year-old patient who developed CVST with cerebral hemorrhage in her fifth week of pregnancy. Although the optimal treatment for this infrequent condition remains controversial, we adopted anticoagulation as the first choice of treatment and obtained favorable results. PMID:25630781

  6. Hubble Space Telescope Eclipse Observations of the Nova Like Cataclysmic Variable UX Ursae Majoris

    NASA Technical Reports Server (NTRS)

    Knigge, Christian; Long, Knox S.; Wade, Richard A.; Baptista, Raymundo; Horne, Keith; Hubeny, Ivan; Rutten, Rene G. M.

    1998-01-01

    We present and analyze Hubble Space Telescope observations of the eclipsing nova-like cataclysmic variable UX UMa obtained with the Faint Object Spectrograph. Two eclipses each were observed with the G160L grating (covering the ultraviolet waveband) in 1994 August and with the PRISM (covering the near-ultraviolet to near-infrared) in November of the same year. The system was about 50% brighter in November than in August, which, if due to a change in the accretion rate, indicates a fairly substantial increase in Mass accretion by about 50%. The eclipse light curves are qualitatively consistent with the gradual occultation of an accretion disk with a radially decreasing temperature distribution. The light curves also exhibit asymmetries about mideclipse that are likely due to a bright spot at the disk edge. Bright-spot spectra have been constructed by differencing the mean spectra observed at pre- and posteclipse orbital phases. These difference spectra contain ultraviolet absorption lines and show the Balmer jump in emission. This suggests that part of the bright spot may be optically thin in the continuum and vertically extended enough to veil the inner disk and/or the outflow from UX UMa in some spectral lines. Model disk spectra constructed as ensembles of stellar atmospheres provide poor descriptions of the observed posteclipse spectra, despite the fact that UX UMa's light should be dominated by the disk at this time. Suitably scaled single temperature model stellar atmospheres with T(sub eff) approximately equals 12,500-14,500 K actually provide a better match to both the ultraviolet and optical posteclipse spectra. Evidently, great care must be taken in attempts to derive accretion rates from comparisons of disk models to observations. One way to reconcile disk models with the observed posteclipse spectra is to postulate the presence of a significant amount of optically thin material in the system. Such an optically thin component might be associated with the

  7. NON-EQUIPARTITION OF ENERGY, MASSES OF NOVA EJECTA, AND TYPE Ia SUPERNOVAE

    SciTech Connect

    Shara, Michael M.; Yaron, Ofer; Prialnik, Dina; Kovetz, Attay

    2010-04-01

    The total masses ejected during classical nova (CN) eruptions are needed to answer two questions with broad astrophysical implications: can accreting white dwarfs be 'pushed over' the Chandrasekhar mass limit to yield type Ia supernovae? Are ultra-luminous red variables a new kind of astrophysical phenomenon, or merely extreme classical novae? We review the methods used to determine nova ejecta masses. Except for the unique case of BT Mon (nova 1939), all nova ejecta mass determinations depend on untested assumptions and multi-parameter modeling. The remarkably simple assumption of equipartition between kinetic and radiated energy (E {sub kin} and E {sub rad}, respectively) in nova ejecta has been invoked as a way around this conundrum for the ultra-luminous red variable in M31. The deduced mass is far larger than that produced by any CN model. Our nova eruption simulations show that radiation and kinetic energy in nova ejecta are very far from being in energy equipartition, with variations of 4 orders of magnitude in the ratio E {sub kin}/E {sub rad} being commonplace. The assumption of equipartition must not be used to deduce nova ejecta masses; any such 'determinations' can be overestimates by a factor of up to 10,000. We data-mined our extensive series of nova simulations to search for correlations that could yield nova ejecta masses. Remarkably, the mass ejected during a nova eruption is dependent only on (and is directly proportional to) E {sub rad}. If we measure the distance to an erupting nova and its bolometric light curve, then E {sub rad} and hence the mass ejected can be directly measured.

  8. Proper-motion age dating of the progeny of Nova Scorpii AD 1437

    NASA Astrophysics Data System (ADS)

    Shara, M. M.; Iłkiewicz, K.; Mikołajewska, J.; Pagnotta, A.; Bode, M. F.; Crause, L. A.; Drozd, K.; Faherty, J.; Fuentes-Morales, I.; Grindlay, J. E.; Moffat, A. F. J.; Pretorius, M. L.; Schmidtobreick, L.; Stephenson, F. R.; Tappert, C.; Zurek, D.

    2017-08-01

    ‘Cataclysmic variables’ are binary star systems in which one star of the pair is a white dwarf, and which often generate bright and energetic stellar outbursts. Classical novae are one type of outburst: when the white dwarf accretes enough matter from its companion, the resulting hydrogen-rich atmospheric envelope can host a runaway thermonuclear reaction that generates a rapid brightening. Achieving peak luminosities of up to one million times that of the Sun, all classical novae are recurrent, on timescales of months to millennia. During the century before and after an eruption, the ‘novalike’ binary systems that give rise to classical novae exhibit high rates of mass transfer to their white dwarfs. Another type of outburst is the dwarf nova: these occur in binaries that have stellar masses and periods indistinguishable from those of novalikes but much lower mass-transfer rates, when accretion-disk instabilities drop matter onto the white dwarfs. The co-existence at the same orbital period of novalike binaries and dwarf novae—which are identical but for their widely varying accretion rates—has been a longstanding puzzle. Here we report the recovery of the binary star underlying the classical nova eruption of 11 March AD 1437 (refs 12, 13), and independently confirm its age by proper-motion dating. We show that, almost 500 years after a classical-nova event, the system exhibited dwarf-nova eruptions. The three other oldest recovered classical novae display nova shells, but lack firm post-eruption ages, and are also dwarf novae at present. We conclude that many old novae become dwarf novae for part of the millennia between successive nova eruptions.

  9. Nova Centauri 2013 = PNV J13544700-5909080

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2013-12-01

    Announces the discovery of V1369 Cen = Nova Cen 2013 = PNV J13544700-5909080 by John Seach (Chatsworth Island, NSW, Australia) at unfiltered magnitude 5.5 on 2013 December 02.692 UT. Low-resolution spectra obtained by Locke on Dec. 03.3776 UT and by Kaufman on Dec. 03.621 UT show strong Ha and Hb emission lines, indicating the object is a nova. Announced on IAU CBAT Central Bureau Electronic Telegram 3732 (Daniel W. E. Green, ed.). Finder charts with sequences may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details and observations.

  10. A transient radio jet in an erupting dwarf nova.

    PubMed

    Körding, Elmar; Rupen, Michael; Knigge, Christian; Fender, Rob; Dhawan, Vivek; Templeton, Matthew; Muxlow, Tom

    2008-06-06

    Astrophysical jets seem to occur in nearly all types of accreting objects, from supermassive black holes to young stellar objects. On the basis of x-ray binaries, a unified scenario describing the disc/jet coupling has evolved and been extended to many accreting objects. The only major exceptions are thought to be cataclysmic variables: Dwarf novae, weakly accreting white dwarfs, show similar outburst behavior to x-ray binaries, but no jet has yet been detected. Here we present radio observations of a dwarf nova in outburst showing variable flat-spectrum radio emission that is best explained as synchrotron emission originating in a transient jet. Both the inferred jet power and the relation to the outburst cycle are analogous to those seen in x-ray binaries, suggesting that the disc/jet coupling mechanism is ubiquitous.

  11. Pre-nova Mixing at the Surface of White Dwarfs

    NASA Astrophysics Data System (ADS)

    Rosner, R.; Young, Y. N.; Alexakis, A.; Dursi, L. J.; Truran, J.; Calder, A. C.; Fryxell, B.; Olson, K.; Ricker, P. M.; Timmes, F. X.; Zingale, M.; Tufo, H. M.; MacNeice, P.

    2000-12-01

    We report on studies of shear-driven mixing at the interface between a hydrogen-helium envelope and the carbon-oxygen surface of a pre-nova outburst white dwarf. Linear theory shows distinct regimes of unstable gravity surface waves and Kelvin-Helmholtz modes, which we follow into the weakly nonlinear regime by analytical techniques; we then follow the fully nonlinear evolution to the point of wave breaking, using the Chicago Flash Code. We also report on estimates of the mixing efficiency resulting from the combination of weakly driven convection and wave breaking; and discuss their implications for nova outbursts. This work was supported by the DOE ASCI/Alliances program at the University of Chicago, under grant No. B341495.

  12. A multiwavelength study of Nova QU Vulpeculae 1984

    NASA Technical Reports Server (NTRS)

    Saizar, Pedro; Starrfield, Sumner; Ferland, Gary J.; Wagner, R. M.; Truran, James W.; Kenyon, Scott J.; Sparks, Warren M.; Williams, Robert E.; Stryker, L. L.

    1992-01-01

    We have combined ground-based optical and satellite ultraviolet spectrophotometric data to study the ejected shell of Nova Vulpecula 1984 No. 2 (QU Vul). Substantial uncertainties concerning the nature of the ionizing continuum, and the role played by density inhomogeneities, now exist. Because of these uncertainties, the chemical composition is deduced from emission-line pairs chosen to minimize the effects of variations in temperature, density, and ionization. We find that the chemical composition of the ejected shell show enhancements of several elements relative to hydrogen, namely, He, N, O, Ne, Mg, Al, and Si, as is expected for an outburst occurring on an ONeMg white dwarf. It is also shown that QU Vul ejected a large amount of aluminum into the interstellar medium, and it is estimated that only a small fraction of slow novae of this type can account for the observed abundance of aluminum in the Galaxy.

  13. The Thermonuclear Runaway and the Classical Nova Outburst

    NASA Astrophysics Data System (ADS)

    Starrfield, S.; Iliadis, C.; Hix, W. R.

    2016-05-01

    Nova explosions occur on the white dwarf component of a cataclysmic variable binary stellar system that is accreting matter lost by its companion. When sufficient material has been accreted by the white dwarf, a thermonuclear runaway occurs and ejects material in what is observed as a classical nova explosion. We describe both the recent advances in our understanding of the progress of the outburst and outline some of the puzzles that are still outstanding. We report on the effects of improving both the nuclear reaction rate library and including a modern nuclear reaction network in our one-dimensional, fully implicit, hydrodynamic computer code. In addition, there has been progress in observational studies of supernovae Ia with implications about the progenitors, and we discuss that in this review.

  14. Recovering from the Classical-Nova Disaster (Abstract)

    NASA Astrophysics Data System (ADS)

    Patterson, J.

    2014-12-01

    (Abstract only) Classical novae rise from obscurity to shine among the brightest stars in the Galaxy. The story of how they return to quiescence is still only dimly known. Vast amounts of energy are loosed upon the white dwarf and its companion, and the light curves of post-novae suggest that they take not a few years, but a few thousand years, to return to quiescence. In the meantime, the secondary may experience a lot of heating from the white dwarf’s rediation—enough to overwhelm its intrinsic nuclear luminosity. I’ll discuss the stellar physics behind this suggestion, and propose how it might be tested by time-series photometry in the months and years (and if possible, centuries) after outburst.

  15. From RoboNova to HUBO: Platforms for Robot Dance

    NASA Astrophysics Data System (ADS)

    Grunberg, David; Ellenberg, Robert; Kim, Youngmoo E.; Oh, Paul Y.

    A robot with the ability to dance in response to music could lead to novel and interesting interactions with humans. For example, such a robot could be used to augment live performances alongside human dancers. This paper describes a system enabling humanoid robots to move in synchrony with music. A small robot, the Hitec RoboNova, was initially used to develop smooth sequences of complex gestures used in human dance. The system uses a real-time beat prediction algorithm so that the robot’s movements are synchronized with the audio. Finally, we implemented the overall system on a much larger robot, HUBO, to establish the validity of the smaller RoboNova as a useful prototyping platform.

  16. Nova Sagittarii 2012 No. 3 = PNV J17522579-2126215

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2012-07-01

    Nova Sagittarii 2012 No. 3 = PNV J17522579-212621 was discovered independently by: Koichi Itagaki (Yamagata, Japan, reported by Hitoshi Yamaoka, Kyushu University), Yukio Sakurai (Mito, Ibaraki-ken, Japan). Discovery Magnitude: Itagaki (magnitude 10.3 on an unfiltered CCD image taken with a 0.21-m reflector), Sakurai (magnitude 9.9 on four 20-s frames taken with a Fuji FinePix S2 Digital Camera + Nikon 180-mm f/2.8 lens). Discovery date: Itagaki (2012 June 26.5494 UT), Sakurai (2012 June 26.540 UT). Coordinates (2000.0) from Itagaki (R.A. 17 52 25.79 Dec. -21 26 21.5), from Sakurai (R.A. 17 52 25.59 Dec. -21 26 22.9). Spectra confirm the object as a He/N type nova. All details and image URLs are in IAU CBET 3156. Report observations to the AAVSO International Database.

  17. Black Hole X-ray Nova in M31

    NASA Astrophysics Data System (ADS)

    Murray, Steven

    2005-09-01

    During A02-6 we found more than a dozen Black Hole X-ray Novae (BHXN) in M31 using Chandra, and with HST (WF/PC2 and ACS) found >6 potential optical counterparts. We propose to continue this program, with the goals of understanding the behavior of BH and neutron star (NS) X-ray nova in our nearest neighbor galaxy. With sufficient numbers of optical counterparts we will be able to determine the orbital period distribution of BHXN in M31. Uninterrupted monitoring of M31 is necessary to investigate the duty cycles and long-term lightcurves of BHXN (and other variables) in M31, and only Chandra can provide this. By continuing the program though AO10 we will amass nearly 500ks on the bulge of M31, giving the most detailed view of a nearby galaxy possible until Gen-X.

  18. VERITAS OBSERVATIONS OF THE NOVA IN V407 CYGNI

    SciTech Connect

    Aliu, E.; Archambault, S.; Arlen, T.; Aune, T.; Bouvier, A.; Beilicke, M.; Buckley, J. H.; Bugaev, V.; Dickherber, R.; Benbow, W.; Bradbury, S. M.; Byrum, K.; Cannon, A.; Collins-Hughes, E.; Cesarini, A.; Connolly, M. P.; Ciupik, L.; Cui, W.; Decerprit, G.; Duke, C. E-mail: kazuma-tsurusaki@uiowa.edu; and others

    2012-07-20

    We report on very high energy (E > 100 GeV) gamma-ray observations of V407 Cygni, a symbiotic binary that underwent a nova outburst producing 0.1-10 GeV gamma rays during 2010 March 10-26. Observations were made with the Very Energetic Radiation Imaging Telescope Array System during 2010 March 19-26 at relatively large zenith angles due to the position of V407 Cyg. An improved reconstruction technique for large zenith angle observations is presented and used to analyze the data. We do not detect V407 Cygni and place a differential upper limit on the flux at 1.6 TeV of 2.3 Multiplication-Sign 10{sup -12} erg cm{sup -2} s{sup -1} (at the 95% confidence level). When considered jointly with data from Fermi-LAT, this result places limits on the acceleration of very high energy particles in the nova.

  19. Milli-Arcsecond Infrared Observations of the Nova RS Ophiuchi

    NASA Technical Reports Server (NTRS)

    Barry, Richard K.; Danchi, W. C.; Koresko, C.; Kuchner, M.; Traub, W. A.; Monnier, J. D.; Serabyn, E.; Mennesson, B.; Greenhouse, M. A.; Colavita, M. M.; hide

    2007-01-01

    We report on infrared interferometric measurements of the 2006 outburst of Nova RS Oph in H, K, and N bands. These measurements, conducted using the Infrared and Optical Telescope Array, the Palomar Testbed Interferometer, and the Keck Interferometer, show a small variation in the 3 mas size if this resolved source during the first 65 days of the outburst. Additionally, using interferometric closure phases, these observations show an unambiguous departure from point symmetry of the object. We also describe simultaneous N-band observations of the nova in two separate milli-arcsecond spatial regimes on day four in which we detect line emission indicating onset of the optically thin phase. These data represent the first science from the Keck Interferometer's nulling mode.

  20. VERITAS Observations of the Nova in V407 Cygni

    NASA Technical Reports Server (NTRS)

    Aliu, E.; Archambault, S.; Arlen, T.; Aune, T.; Beilicke, M.; Benbow, W.; Bouvier, A.; Bradbury, S. M.; Buckley, J. H.; Bugaev, V.; hide

    2012-01-01

    We report on very high energy (E > 100 GeV) gamma-ray observations of V407 Cygni, a symbiotic binary that underwent a nova outburst producing 0.1- 10 GeV gamma rays during 2010 March 10-26. Observations were made with the Very Energetic Radiation Imaging Telescope Array System during 2010 March 19-26 at relatively large zenith angles, due to the position of V407 Cyg. An improved reconstruction technique for large zenith angle observations is presented and used to analyze the data. We do not detect V407 Cygni and place a differential upper limit on the flux at 1.6 TeV of 2.3 10(exp -12) erg/sq cm/s (at the 95% confidence level). When considered jointly with data from Fermi-LAT, this result places limits on the acceleration of very high energy particles in the nova.

  1. PW Vul: A classical nova with nearly solar abundances

    SciTech Connect

    Saizar, P.; Ferland, G.J.; Wagner, R.M. . Dept. of Astronomy); Austin, S. . Dept. of Physics); Starrfield, S. . Dept. of Physics Los Alamos National Lab., NM Colorado Univ., Boulder, CO . IUE Regional Data Analysis Facility); Truran, J.W. . Dept.

    1990-01-01

    Ultraviolet and optical spectrophotometric data were combined in order to determine the physical parameters in the expanding shell of Nova PW Vul 1984 No. 1. Ultraviolet data were obtained with the IUE satellite from August 2, 1984 (a few days after discovery) until it became too faint to study with the satellite. The last IUE exposure was obtained in June 1988 but we have continued to follow it with ground-based optical telescopes. We will present a plot that shows the variation of electron density and temperature as a function of time. Analysis of the emission line intensities show that the abundances of this very slow nova are solar for helium, carbon, and oxygen while nitrogen is 50 times solar. We have also used the CLOUDY code of Ferland to model the emission line intensities and find very good agreement with the observations. We shall display plots of representative IUE and optical spectra. 10 refs., 5 figs.

  2. A multiwavelength study of Nova QU Vulpeculae 1984

    NASA Technical Reports Server (NTRS)

    Saizar, Pedro; Starrfield, Sumner; Ferland, Gary J.; Wagner, R. M.; Truran, James W.; Kenyon, Scott J.; Sparks, Warren M.; Williams, Robert E.; Stryker, L. L.

    1992-01-01

    We have combined ground-based optical and satellite ultraviolet spectrophotometric data to study the ejected shell of Nova Vulpecula 1984 No. 2 (QU Vul). Substantial uncertainties concerning the nature of the ionizing continuum, and the role played by density inhomogeneities, now exist. Because of these uncertainties, the chemical composition is deduced from emission-line pairs chosen to minimize the effects of variations in temperature, density, and ionization. We find that the chemical composition of the ejected shell show enhancements of several elements relative to hydrogen, namely, He, N, O, Ne, Mg, Al, and Si, as is expected for an outburst occurring on an ONeMg white dwarf. It is also shown that QU Vul ejected a large amount of aluminum into the interstellar medium, and it is estimated that only a small fraction of slow novae of this type can account for the observed abundance of aluminum in the Galaxy.

  3. Observational and theoretical studies of the nova outburst

    SciTech Connect

    Starrfield, S.; Vanlandingham, K.; Schwarz, G.

    1998-04-01

    A nova outburst is one consequence of the accretion of hydrogen rich material onto a white dwarf in a close binary system. The strong electron degeneracy of a massive white dwarf drives the temperatures in the nuclear burning region to values exceeding 108K under all circumstances. As a result, a major fraction of the CNO nuclei in the envelope are transformed into e{sup +}-decay nuclei, which constrains the nuclear energy generation and yields non-solar CNO isotopic abundance ratios. In addition, the observations demonstrate that white dwarf core material is dredged up into the accreted layers and these nuclei are the catalysts for producing peak rates of energy generation that can exceed 10{sup 16} erg gm{sup -1}s{sup -1}. Observations show that there are two compositional classes of novae, one that occurs on a carbon-oxygen white dwarf and the other that occurs on an oxygen-neon-magnesium white dwarf.

  4. Nocardia nova mycetoma over forehead in a lepromatous leprosy patient.

    PubMed

    Dhingra, M; Kaistha, N; Bansal, N; Solanki, L S; Chander, J; Thami, G P; van de Sande, W W

    2012-07-15

    We present a case of a 31-year-old male, a known patient with lepromatous leprosy with a type 2 lepra reaction, who presented with a slowly growing asymptomatic swelling with multiple discharging sinuses over the forehead that developed over 6 months. Smears of the serosanguinous discharge on Gram staining showed Gram-positive branching filamentous bacilli, which on culture on blood agar showed chalky-white colonies. Histology of the lesion showed suppurative granulomas with polymorphs surrounding characteristic grains. The isolate was identified as Nocardia nova by gene sequencing and the patient was started on combined antibiotic therapy that resulted in complete resolution of the infection in six months. To the best of our knowledge, this is the first report of mycetoma related to Nocardia nova in association with leprosy.

  5. Seroepidemiology of Q fever among domestic animals in Nova Scotia.

    PubMed Central

    Marrie, T J; Van Buren, J; Fraser, J; Haldane, E V; Faulkner, R S; Williams, J C; Kwan, C

    1985-01-01

    We used the indirect microimmunofluorescence test to determine the presence of antibodies in sheep, cattle, goat, cat, and dog sera to phase I and II Coxiella burnetii antigens in Nova Scotia. Only 6.7 per cent of the 329 sheep tested had antibodies to phase II antigen and none had antibodies to phase I. Of 29 goats tested, 7 per cent and 3.5 per cent had antibodies to phase II and phase I antigens, respectively. In contrast, 23.8 per cent of the 214 cattle tested had antibodies to phase II antigen, and 24.2 per cent had antibodies to phase I antigen; 24.1 per cent of 216 cats tested had antibodies to phase II antigen and 6 per cent had antibodies to phase I antigen. None of the 447 dogs tested had antibodies detected. We conclude that cattle and cats may be reservoirs for human Q fever in Nova Scotia. PMID:3890569

  6. Nova laser system at ultra high fluence levels

    SciTech Connect

    Hunt, J.T.

    1985-01-01

    The Nova experimental facility consists of a ten arm laser system and five experimental stations and was completed in December 1984. Two of these stations are used for inertial confinement fusion (ICF) experiments and the other three are dedicated to doing large aperture (30 to 74 cm) laser experiments. The laser system is deployed in a master oscillator-power amplifier architecture and uses Nd: phosphate glass for the active medium. The fundamental wavelength of the system is 1.05 microns. Frequency converters constructed from potassium dihydrogen phosphate (KDP) crystals are located at the end of each of the ten arms and are used to produce high power frequency doubled (0.53 microns) and tripled (0.35 microns) beams for either ICF or laser experiments. Thus, the Nova laser system can produce high power beams with wavelengths ranging from the infrared to the ultraviolet.

  7. A Dynamical Study of the Eclipsing Nova OY ARA

    NASA Astrophysics Data System (ADS)

    Zhao, P.; McClintock, J. E.

    1996-12-01

    We present the results of a dynamical study of the classical nova OY Ara. Photometric and spectroscopic observations of the object were carried out at CTIO. OY Ara is an eclipsing system with an orbital period of 0.155466 +/- 0.000003 days. The radial velocity semiamplitude of the H_alpha emission line is 118 +/- 9 km s(-1) . A dynamical analysis shows that the primary and the secondary have masses of M_1 ~ 0.85 Msun and M_2 ~ 0.34 Msun, respectively, assuming that the secondary is a main sequence star. We also find that the accretion disk of OY Ara is 4-7 magnitudes more luminous than the disk of X-ray novae, presumably due to the much higher rate of mass transfer occurring in OY Ara.

  8. Three-dimensional simulations of Nova capsule implosion experiments

    SciTech Connect

    Marinak, M.M.; Tipton, R.E.; Landen, O.L.

    1995-11-01

    Capsule implosion experiments carried out on the Nova laser are simulated with the three-dimensional HYDRA radiation hydrodynamics code. Simulations of ordered near single mode perturbations indicate that structures which evolve into round spikes can penetrate farthest into the hot spot. Bubble-shaped perturbations can burn through the capsule shell fastest, however, causing even more damage. Simulations of a capsule with multimode perturbations shows spike amplitudes evolving in good agreement with a saturation model during the deceleration phase. The presence of sizable low mode asymmetry, caused either by drive asymmetry or perturbations in the capsule shell, can dramatically affect the manner in which spikes approach the center of the hot spot. Three-dimensional coupling between the low mode shell perturbations intrinsic to Nova capsules and the drive asymmetry brings the simulated yields into closer agreement with the experimental values.

  9. Life after eruption - IV. Spectroscopy of 13 old novae

    NASA Astrophysics Data System (ADS)

    Tappert, C.; Vogt, N.; Della Valle, M.; Schmidtobreick, L.; Ederoclite, A.

    2014-07-01

    We present data on 13 post-nova systems. This includes the recovery via UBVR photometry of the five post-novae X Cir, V2104 Oph, V363 Sgr, V928 Sgr and V1274 Sgr and their spectroscopic confirmation. We provide accurate coordinates and finding charts for those objects. Additional first-time or improved spectroscopic data are presented for V356 Aql, V500 Aql, V604 Aql, V1370 Aql, MT Cen, V693 CrA, V697 Sco and MU Ser. Investigating the behaviour of a few easily accessible parameters yields (limited) information on the accretion state and the system inclination. We predict that X Cir and V697 Sco are likely to reveal their orbital period via time series photometry and that long-term photometric monitoring of V356 Aql, V500 Aql, V1370 Aql and X Cir has a good chance of discovering outburst-like behaviour in these systems.

  10. A theoretical study of problems in classical nova evolution

    SciTech Connect

    Shankar, A.

    1990-01-01

    Three distinct issues in classical nova evolution are addressed with the aid of one- and two-dimensional numerical hydrodynamics. The effects of convection on nova outbursts are examined within the confines of the mixing length theory. It is found that increasing the efficiency of convection enhances the violence of the thermonuclear runaway (TNR). This also relates to the question of the feasibility of obtaining nova outbursts on magnetic white dwarfs among the AM Her systems. The effects of a strong magnetic field on the TNR are explored. The field interferes with the development of convection during the TNR, which results in lower ejection velocities. However, for field strengths typical of cataclysmic variables, the violence of strong outbursts is affected only moderately. The conditions necessary for the production of strong TNR's in the hibernation model of cataclysmic binary evolution are also examined. The feasibility of obtaining strong nova outbursts is investigated when the accretion rate during hibernation is decreased. It is found that a reduction (by a factor of 100) for periods of longer than a couple thousand years, is sufficient to ensure violent outbursts, even in the presence of large pre-outburst accretion rates. The effects of a common envelope phase (CEP) on the outburst are discussed. The motion of the secondary through an expanding common envelope is resisted by frictional drag. This dissipates both energy and angular momentum from the orbit inducing hydrodynamic motion. Significant departures are found to occur in the manner in which mass is lost when the effects of drag are taken into account. Specifically, a CEP is found to accelerate and enhance mass loss. Ejection is found to be concentrated in the orbital plane, with velocities of a few thousand km/sec.

  11. Optical observations of the fast nova V2491 Cyg

    NASA Astrophysics Data System (ADS)

    Tomov, T.; Mikolajewski, M.; Ragan, E.; Swierczynski, E.; Wychudzki, P.

    2008-04-01

    We report on optical spectral observations and UBVRI brightness estimations obtained with 60/90 cm Schmidt and 60 cm Cassegrain telescopes of the Nicolaus Copernicus University Observatory (Torun, Poland). The nova V2491 Cyg was discovered on Apr. 10.728 UT with about 7.7 mag on unfiltered CCD frames (IAUC#8934). Additionally, the X-ray emission was detected for the prenova several months ago (ATel#1473).

  12. Reconnection-driven oscillations in dwarf nova disks

    NASA Technical Reports Server (NTRS)

    Tajima, T.; Gilden, D.

    1987-01-01

    A class of oscillations observed during eruption of dwarf novae has been interpreted as oscillations of the accretion disks in these systems.These oscillations are quasi-periodic with coherence times typically between three and 15 cycles. It is shown that magnetic field reconnection at high magnetic Reynolds number can drive disk oscillations. The expected stochastic geometry of disk magnetic fields could naturally produce the observed phase incoherency.

  13. Discovery of a possible nova in M81

    NASA Astrophysics Data System (ADS)

    Williams, S. C.; Darnley, M. J.

    2016-10-01

    We report the discovery of a new nova candidate in M81 on 3 & times; 300s H & alpha; images taken using IO:O on the 2m Liverpool Telescope (Steele et al. 2004) on 2016 Oct 8.25 UT. The position of the new transient is RA = 9h55m17.035s, Dec. = +69 & deg;06'31.69" (J2000).

  14. Multi-dimensional Modeling of Nova with Realistic Nuclear Physics

    SciTech Connect

    Krueger, B.; Zingale, M.; Hoffman, R.

    2011-10-10

    Over the past year, we continued our exploration of novae explosions through multidimensional simulations with the MAESTRO code. The basic physics needed for these simulations was already in place, but a lot of optimization and refining was needed to produce plausible models. Work focused both on the initial model and the reaction network, and simulations were performed using an NSF TeraGrid allocation on the Kraken machine.

  15. A theoretical study of problems in classical nova evolution

    NASA Astrophysics Data System (ADS)

    Shankar, Anurag

    Three distinct issues in classical nova evolution are addressed with the aid of one- and two-dimensional numerical hydrodynamics. The effects of convection on nova outbursts are examined within the confines of the mixing length theory. It is found that increasing the efficiency of convection enhances the violence of the thermonuclear runaway (TNR). This also relates to the question of the feasibility of obtaining nova outbursts on magnetic white dwarfs among the AM Her systems. The effects of a strong magnetic field on the TNR are explored. The field interferes with the development of convection during the TNR, which results in lower ejection velocities. However, for field strengths typical of cataclysmic variables, the violence of strong outbursts is affected only moderately. The conditions necessary for the production of strong TNR's in the hibernation model of cataclysmic binary evolution are also examined. The feasibility of obtaining strong nova outbursts is investigated when the accretion rate during hibernation is decreased. It is found that a reduction (by a factor of 100) for periods of longer than a couple thousand years, is sufficient to ensure violent outbursts, even in the presence of large pre-outburst accretion rates. The effects of a common envelope phase (CEP) on the outburst are discussed. The motion of the secondary through an expanding common envelope is resisted by frictional drag. This dissipates both energy and angular momentum from the orbit inducing hydrodynamic motion. Significant departures are found to occur in the manner in which mass is lost when the effects of drag are taken into account. Specifically, a CEP is found to accelerate and enhance mass loss. Ejection is found to be concentrated in the orbital plane, with velocities of a few thousand km/sec.

  16. {beta}-decay of {sup 23}Al and nova nucleosynthesis

    SciTech Connect

    Saastamoinen, A.; Jokinen, A.; Aeystoe, J.; Trache, L.; Hardy, J. C.; Iacob, V. E.; McCleskey, M.; Roeder, B.; Simmons, E.; Tabacaru, G.; Tribble, R. E.; Banu, A.; Bentley, M. A.; Jenkins, D. G.; Davinson, T.; Woods, P. J.

    2010-11-24

    We have studied the {beta}-decay of {sup 23}Al with a novel detector setup at the focal plane of the MARS separator at the Texas A and M University to resolve existing controversies about the proton intensities of the IAS in {sup 23}Mg and to determine the absolute proton branching ratios by combining our results to the latest {gamma}-decay data. Experimental technique, results and the relevance for nova nucleosynthesis are discussed.

  17. Shocks in nova outflows - II. Synchrotron radio emission

    NASA Astrophysics Data System (ADS)

    Vlasov, Andrey; Vurm, Indrek; Metzger, Brian D.

    2016-11-01

    The discovery of GeV gamma-rays from classical novae indicates that shocks and relativistic particle acceleration are energetically key in these events. Further evidence for shocks comes from thermal keV X-ray emission and an early peak in the radio light curve on a time-scale of months with a brightness temperature which is too high to result from freely expanding photoionized gas. Paper I developed a one-dimensional model for the thermal emission from nova shocks. This work concluded that the shock-powered radio peak cannot be thermal if line cooling operates in the post-shock gas at the rate determined by collisional ionization equilibrium. Here we extend this calculation to include non-thermal synchrotron emission. Applying our model to three classical novae, we constrain the amplification of the magnetic field ɛB and the efficiency ɛe of accelerating relativistic electrons of characteristic Lorentz factor γ ˜ 100. If the shocks are radiative (low velocity vsh ≲ 1000 km s-1) and cover a large solid angle of the nova outflow, as likely characterize those producing gamma-rays, then values of ɛe ˜ 0.01-0.1 are required to achieve the peak radio brightness for ɛB = 10-2. Such high efficiencies exclude secondary pairs from pion decay as the source of the radio-emitting particles, instead favouring the direct acceleration of electrons at the shock. If the radio-emitting shocks are instead adiabatic (high velocity), as likely characterize those responsible for the thermal X-rays, then much higher brightness temperatures are possible, allowing the radio-emitting shocks to cover a smaller outflow solid angle.

  18. Optical and ultraviolet observations of Nova Vul 1987

    SciTech Connect

    Starrfield, S.; Stryker, L.L.; Sonneborn, G.; Sparks, W.M.; Wagner, R.M.; Ferland, G.; Gallagher, J.S.; Wade, R.; Williams, R.E.; Gehrz, R.D.

    1988-01-01

    We present a brief summary of the outburst for a nova that was discovered in November 1987 and has been followed since that time. Although we were able to observe it with the IUE at maximum, its ultraviolet energy faded rapidly and after the first two weeks we were no longer able to observe it at IUE wavelengths. It was observed to form a thick dust shell and currently is in the nebular stage. 6 figs.

  19. Compton Observatory OSSE Studies of Supernovae and Novae

    DTIC Science & Technology

    1995-01-01

    Washington DC 20024 ABSTRACT A primary objective of the Compton Observatory is the direct study of explo- sive nucleosynthesis in supernovae and classical...our best chance to detect -rays from 22Na, a unique nucleosynthesis byproduct of the explosive hydrogen burning thought to power classical novae. The...radio, x-ray), or might go into PdV work. As for the last two e ects in the list, we doubt, based on straightforward nucleosynthesis arguments,9 that

  20. CATALOG OF 93 NOVA LIGHT CURVES: CLASSIFICATION AND PROPERTIES

    SciTech Connect

    Strope, Richard J.; Schaefer, Bradley E.; Henden, Arne A.

    2010-07-15

    We present a catalog of 93 very-well-observed nova light curves. The light curves were constructed from 229,796 individual measured magnitudes, with the median coverage extending to 8.0 mag below peak and 26% of the light curves following the eruption all the way to quiescence. Our time-binned light curves are presented in figures and as complete tabulations. We also calculate and tabulate many properties about the light curves, including peak magnitudes and dates, times to decline by 2, 3, 6, and 9 mag from maximum, the time until the brightness returns to quiescence, the quiescent magnitude, power-law indices of the decline rates throughout the eruption, the break times in this decline, plus many more properties specific to each nova class. We present a classification system for nova light curves based on the shape and the time to decline by 3 mag from the peak (t{sub 3}). The designations are 'S' for smooth light curves (38% of the novae), 'P' for plateaus (21%), 'D' for dust dips (18%), 'C' for cusp-shaped secondary maxima (1%), 'O' for quasi-sinusoidal oscillations superposed on an otherwise smooth decline (4%), 'F' for flat-topped light curves (2%), and 'J' for jitters or flares superposed on the decline (16%). Our classification consists of this single letter followed by the t{sub 3} value in parentheses; so, for example, V1500 Cyg is S(4), GK Per is O(13), DQ Her is D(100), and U Sco is P(3).