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Sample records for solar system binaries

  1. Ultra-Wide Trans-Neptunian Binaries: Tracers of the Outer Solar System's History

    NASA Astrophysics Data System (ADS)

    Parker, Alex Harrison

    Ultra-wide Trans-Neptunian Binaries (TNBs) are extremely sensitive to perturbation, and therefore make excellent probes of the past and present dynamical environment of the outer Solar System. Using data gathered from a host of facilities we have determined the mutual orbits for a sample of seven wide TNBs whose periods exceed one year. This characterized sample provides us with new information about the probable formation scenarios of TNBs, and has significant implications for the early dynamical and collisional history of the Kuiper Belt. We show that these wide binaries have short collisional lifetimes, and use them to produce a new estimate of the number of small (˜1 km) objects in the Kuiper Belt. Additionally, these systems are susceptible to tidal disruption, and we show that it is unlikely that they were ever subjected to a period of close encounters with the giant planets. We find that the current properties of these ultra-wide Trans-Neptunian Binaries suggest that planetesimal growth in the Cold Classical Kuiper Belt did not occur through slow hierarchical accretion, but rather through rapid gravitational collapse.

  2. New binary systems: beaming binaries

    NASA Astrophysics Data System (ADS)

    Morales, J. C.; Weingrill, J.; Mazeh, T.; Ribas, I.

    2011-11-01

    Exoplanet missions such as COROT and Kepler are providing precise photometric follow-up data of new kinds of variable stars undetected till now. Beaming binaries are among these objects. On these binary systems, the orbital motion of their components is fast enough to produce a detectable modulation on the received flux due to relativistic effects (Zucker et al. 2007). The great advantage of these systems is that it is possible to reconstruct the radial velocity curve of the system from this photometric modulation and thus, orbital parameters such as the mass ratio and the semi-major axis can be estimated from photometry without the necessity of spectroscopic follow-up. In this poster, we briefly introduce the analysis of this kind of binary systems and in particular, the eclipsing cases.

  3. Thermal phase diagram of acetamide-benzoic acid and benzoic acid-phthalimide binary systems for solar thermal applications

    NASA Astrophysics Data System (ADS)

    Kumar, Rohitash; Kumar, Ravindra; Dixit, Ambesh

    2016-05-01

    Thermal properties of Acetamide (AM) - Benzoic acid (BA) and Benzoic acid (BA) - Phthalimide (PM) binary eutectic systems are theoretically calculated using thermodynamic principles. We found that the binary systems of AM-BA at 67.6 : 32.4 molar ratio, BA-PM at 89.7 : 10.3 molar ratio form eutectic mixtures with melting temperatures ~ 54.5 °C and 114.3 °C respectively. Calculated latent heat of fusion for these eutectic mixtures are 191 kJ/kg and 146.5 kJ/kg respectively. These melting temperatures and heat of fusions of these eutectic mixtures make them suitable for thermal energy storage applications in solar water heating and solar cooking systems.

  4. A Solar-type Stellar Companion to a Deep Contact Binary in a Quadruple System

    NASA Astrophysics Data System (ADS)

    Zhou, X.; Qian, S.-B.; Zhang, J.; Jiang, L.-Q.; Zhang, B.; Kreiner, J.

    2016-02-01

    The four-color (B, V, Rc, Ic) light curves of V776 Cas are presented and analyzed using the Wilson-Devinney method. It is discovered that V776 Cas is an early F-type (F2V) overcontact binary with a very high contact degree (f = 64.6%) and an extremely low-mass ratio (q = 0.130), which indicate that it is at the final evolutionary stage of cool short-period binaries. The mass of the primary and secondary stars are calculated to be M1 = 1.55(±0.04) M⊙, M2 = 0.20(±0.01) M⊙. V776 Cas is supposed to be formed from an initially detached binary system via the loss of angular momentum due to the magnetic wind. The initial masses of the present primary and secondary components are calculated to be M1i = 0.86(±0.10) M⊙ and M2i = 2.13(±0.04) M⊙. The observed-calculated curve exhibits a cyclic period variation, which is due to the light-travel time effect caused by the presence of a third component with a period of 23.7 years. The mass of the third component is estimated to be M3 = 1.04(±0.03) M⊙ and the orbital inclination of the third component is calculated to be i‧ = 33.°1. The distance of the binary system to the mass center of the triple system is calculated to be {a}12\\prime = 3.45 AU. The presence of the close-in tertiary component may play an important role in the formation and evolution of this binary system by drawing angular momentum from the central system.

  5. A Mechanistic Understanding of a Binary Additive System to Synergistically Boost Efficiency in All-Polymer Solar Cells

    PubMed Central

    Kim, Yu Jin; Ahn, Sunyong; Wang, Dong Hwan; Park, Chan Eon

    2015-01-01

    All-polymer solar cells are herein presented utilizing the PBDTTT-CT donor and the P(NDI2OD-T2) acceptor with 1,8-diiodooctane (DIO) and 1-chloronaphthalene (CN) binary solvent additives. A systematic study of the polymer/polymer bulk heterojunction photovoltaic cells processed from the binary additives revealed that the microstructures and photophysics were quite different from those of a pristine system. The combination of DIO and CN with a DIO/CN ratio of 3:1 (3 vol% DIO, 1 vol% CN and 96 vol% o-DCB) led to suitable penetrating polymer networks, efficient charge generation and balanced charge transport, which were all beneficial to improving the efficiency. This improvement is attributed to increase in power conversion efficiency from 2.81% for a device without additives to 4.39% for a device with the binary processing additives. A detailed investigation indicates that the changes in the polymer:polymer interactions resulted in the formation of a percolating nasnoscale morphology upon processing with the binary additives. Depth profile measurements with a two-dimensional grazing incidence wide-angle X-ray scattering confirm this optimum phase feature. Furthermore impedance spectroscopy also finds evidence for synergistically boosting the device performance. PMID:26658472

  6. RR-Lyrae-type pulsations from a 0.26-solar-mass star in a binary system.

    PubMed

    Pietrzyński, G; Thompson, I B; Gieren, W; Graczyk, D; Stępień, K; Bono, G; Moroni, P G Prada; Pilecki, B; Udalski, A; Soszyński, I; Preston, G W; Nardetto, N; McWilliam, A; Roederer, I U; Górski, M; Konorski, P; Storm, J

    2012-04-01

    RR Lyrae pulsating stars have been extensively used as tracers of old stellar populations for the purpose of determining the ages of galaxies, and as tools to measure distances to nearby galaxies. There was accordingly considerable interest when the RR Lyrae star OGLE-BLG-RRLYR-02792 (referred to here as RRLYR-02792) was found to be a member of an eclipsing binary system, because the mass of the pulsator (hitherto constrained only by models) could be unambiguously determined. Here we report that RRLYR-02792 has a mass of 0.26 solar masses M[symbol see text] and therefore cannot be a classical RR Lyrae star. Using models, we find that its properties are best explained by the evolution of a close binary system that started with M[symbol see text] and 0.8M[symbol see text]stars orbiting each other with an initial period of 2.9 days. Mass exchange over 5.4 billion years produced the observed system, which is now in a very short-lived phase where the physical properties of the pulsator happen to place it in the same instability strip of the Hertzsprung-Russell diagram as that occupied by RR Lyrae stars. We estimate that only 0.2 per cent of RR Lyrae stars may be contaminated by systems similar to this one, which implies that distances measured with RR Lyrae stars should not be significantly affected by these binary interlopers. PMID:22481359

  7. Design of a condenser-boiler for a binary mercury-organic Rankine cycle solar dynamic space power system

    NASA Astrophysics Data System (ADS)

    Cotton, Randy M.

    1987-05-01

    A theoretical design was performed for the condenser/boiler of a space-based solar dynamic power system. The base system is a binary Rankine cycle with mercury and toluene as the working fluids. System output is 75 KWe with a combined efficiency of 41.1%. Design goals were to develop the most reliable, mass efficient unit possible for delivery to a space station. The design sized the unit based on toluene properties and used a computer generated heat balance to thermodynamically match the two fluids. Molybdenum was chosen as the material due to mass effectiveness in heat transfer, strength, and resistance to mercury corrosion. The unit transferred 137.46 kilowatts of thermal power and can operate at varying mass flow rates. Effectiveness in heat transfer is 0.96 and mass performance is 0.016 kg/KWth transferred. The design depends on using only existing technologies and the results call for no new developments.

  8. Double Degenerate Binary Systems

    SciTech Connect

    Yakut, K.

    2011-09-21

    In this study, angular momentum loss via gravitational radiation in double degenerate binary (DDB)systems (NS + NS, NS + WD, WD + WD, and AM CVn) is studied. Energy loss by gravitational waves has been estimated for each type of systems.

  9. The Spot Variability and Related Brightness variations of the Solar Type PreContact W UMa Binary System V1001 Cas

    NASA Astrophysics Data System (ADS)

    Samec, Ronald George; Koenke, Sam S.; Faulkner, Danny R.

    2015-08-01

    A new classification of eclipsing binary has emerged, Pre Contact WUMa Binaries (PCWB’s, Samec et al. 2012). These solar-type systems are usually detached or semidetached with one or both components under filling their critical Roche lobes. They usually have EA or EB-type light curves (unequal eclipse depths, indicating components with substantially different temperatures). The accepted scenario for these W UMa binaries is that they are undergoing steady but slow angular momentum losses due to magnetic braking as stellar winds blow radially away on stiff bipolar field lines. These binaries are believed to come into stable contact and eventually coalesce into blue straggler type, single, fast rotating A-type stars (Guinan and Bradstreet,1988). High precision 2012 and 2009 light curves are compared for the very short period (~0.43d) Precontact W UMa Binary (PCWB), V1001 Cassiopeia. This is the shortest period PCWB found so far. Its short period, similar to the majority of W UMa’s, in contrast to its distinct Algol-type light curve, make it a very rare and interesting system. Our solutions of light curves separated by some three years give approximately the same physical parameters. However the spots radically change, in temperature, area and position causing a distinctive variation in the shape of the light curves. We conclude that spots are very active on this solar type dwarf system and that it may mimic its larger cousins, the RS CVn binaries.

  10. Liquidus of Silicon Binary Systems

    NASA Astrophysics Data System (ADS)

    Safarian, Jafar; Kolbeinsen, Leiv; Tangstad, Merete

    2011-08-01

    Thermodynamic knowledge about liquid silicon is crucial for the production of solar-grade silicon feedstock from molten silicon. In the current study, liquidus for silicon binary alloys is formulated using a previously developed method in which the liquidus curve is calculated using two constants. The liquidus measurements for the silicon portion of the silicon alloys with Al, Ca, Mg, Fe, Ti, Zn, Cu, Ag, Au, Pt, Sn, Pb, Bi, Sb, Ga, In, Ni, Pd, Mn, and Rh are reviewed, and the consistent data were used to determine the liquidus constants. The liquidus curves for silicon binary systems are calculated and plotted. It is indicated that the calculated liquidus curves fit well with the experimental data. A correlation between the determined liquidus constants is also observed, which can be used to gain a better understanding of the thermodynamics of the silicon binary melts.

  11. DISCOVERY OF A RED GIANT WITH SOLAR-LIKE OSCILLATIONS IN AN ECLIPSING BINARY SYSTEM FROM KEPLER SPACE-BASED PHOTOMETRY

    SciTech Connect

    Hekker, S.; Debosscher, J.; De Ridder, J.; Aerts, C.; Van Winckel, H.; Beck, P. G.; Blomme, J.; Huber, D.; Hidas, M. G.; Stello, D.; Bedding, T. R.; Gilliland, R. L.; Christensen-Dalsgaard, J.; Kjeldsen, H.; Brown, T. M.; Borucki, W. J.; Koch, D.; Jenkins, J. M.; Pigulski, A.

    2010-04-20

    Oscillating stars in binary systems are among the most interesting stellar laboratories, as these can provide information on the stellar parameters and stellar internal structures. Here we present a red giant with solar-like oscillations in an eclipsing binary observed with the NASA Kepler satellite. We compute stellar parameters of the red giant from spectra and the asteroseismic mass and radius from the oscillations. Although only one eclipse has been observed so far, we can already determine that the secondary is a main-sequence F star in an eccentric orbit with a semi-major axis larger than 0.5 AU and orbital period longer than 75 days.

  12. Binary concatenated coding system

    NASA Technical Reports Server (NTRS)

    Monford, L. G., Jr.

    1973-01-01

    Coding, using 3-bit binary words, is applicable to any measurement having integer scale up to 100. System using 6-bit data words can be expanded to read from 1 to 10,000, and 9-bit data words can increase range to 1,000,000. Code may be ''read'' directly by observation after memorizing simple listing of 9's and 10's.

  13. Asteroseismic estimate of helium abundance of a solar analog binary system

    SciTech Connect

    Verma, Kuldeep; Antia, H. M.; Faria, João P.; Monteiro, Mário J. P. F. G.; Basu, Sarbani; Mazumdar, Anwesh; Appourchaux, Thierry; Chaplin, William J.; García, Rafael A.

    2014-08-01

    16 Cyg A and B are among the brightest stars observed by Kepler. What makes these stars more interesting is that they are solar analogs. 16 Cyg A and B exhibit solar-like oscillations. In this work we use oscillation frequencies obtained using 2.5 yr of Kepler data to determine the current helium abundance of these stars. For this we use the fact that the helium ionization zone leaves a signature on the oscillation frequencies and that this signature can be calibrated to determine the helium abundance of that layer. By calibrating the signature of the helium ionization zone against models of known helium abundance, the helium abundance in the envelope of 16 Cyg A is found to lie in the range of 0.231 to 0.251 and that of 16 Cyg B lies in the range of 0.218 to 0.266.

  14. Terrestrial Planet Formation in Binary Star Systems

    NASA Technical Reports Server (NTRS)

    Lissauer, J. J.; Quintana, E. V.; Adams, F. C.; Chambers, J. E.

    2006-01-01

    Most stars reside in binary/multiple star systems; however, previous models of planet formation have studied growth of bodies orbiting an isolated single star. Disk material has been observed around one or both components of various young close binary star systems. If planets form at the right places within such disks, they can remain dynamically stable for very long times. We have simulated the late stages of growth of terrestrial planets in both circumbinary disks around 'close' binary star systems with stellar separations ($a_B$) in the range 0.05 AU $\\le a_B \\le$ 0.4 AU and binary eccentricities in the range $0 \\le e \\le 0.8$ and circumstellar disks around individual stars with binary separations of tens of AU. The initial disk of planetary embryos is the same as that used for simulating the late stages of terrestrial planet growth within our Solar System and around individual stars in the Alpha Centauri system (Quintana et al. 2002, A.J., 576, 982); giant planets analogous to Jupiter and Saturn are included if their orbits are stable. The planetary systems formed around close binaries with stellar apastron distances less than or equal to 0.2 AU with small stellar eccentricities are very similar to those formed in the Sun-Jupiter-Saturn, whereas planetary systems formed around binaries with larger maximum separations tend to be sparser, with fewer planets, especially interior to 1 AU. Likewise, when the binary periastron exceeds 10 AU, terrestrial planets can form over essentially the entire range of orbits allowed for single stars with Jupiter-like planets, although fewer terrestrial planets tend to form within high eccentricity binary systems. As the binary periastron decreases, the radial extent of the terrestrial planet systems is reduced accordingly. When the periastron is 5 AU, the formation of Earth-like planets near 1 AU is compromised.

  15. Evolution of Close Binary Systems

    SciTech Connect

    Yakut, K; Eggleton, P

    2005-01-24

    We collected data on the masses, radii, etc. of three classes of close binary stars: low-temperature contact binaries (LTCBs), near-contact binaries (NCBs), and detached close binaries (DCBs). They restrict themselves to systems where (1) both components are, at least arguably, near the Main Sequence, (2) the periods are less than a day, and (3) there is both spectroscopic and photometric analysis leading to reasonably reliable data. They discuss the possible evolutionary connections between these three classes, emphasizing the roles played by mass loss and angular momentum loss in rapidly-rotating cool stars.

  16. Ultraviolet spectroscopy of binary systems

    NASA Technical Reports Server (NTRS)

    Dupree, A. K.; Hartmann, L.; Raymond, J. C.

    1980-01-01

    Four typical binary systems that illustrate some of the major problems in the study of binary stars are discussed. Consideration is given to (1) high-luminosity X-ray sources typified by Cyg X-1 (HDE 226868) and Vela XR-1 (HD 77581), (2) low-luminosity X-ray sources (HZ Her), (3) late-type systems of W UMa and RS CVn type, and (4) cool supergiants with a hot companion (VV Cephei).

  17. Planets in Evolved Binary Systems

    NASA Astrophysics Data System (ADS)

    Perets, Hagai B.

    2011-03-01

    Exo-planets are typically thought to form in protoplanetary disks left over from protostellar disk of their newly formed host star. However, additional planetary formation and evolution routes may exist in old evolved binary systems. Here we discuss the implications of binary stellar evolution on planetary systems in such environments. In these binary systems stellar evolution could lead to the formation of symbiotic stars, where mass is lost from one star and could be transferred to its binary companion, and may form an accretion disk around it. This raises the possibility that such a disk could provide the necessary environment for the formation of a new, second generation of planets in both circumstellar or circumbinary configurations. Pre-existing first generation planets surviving the post-MS evolution of such systems would be dynamically effected by the mass loss in the systems and may also interact with the newly formed disk. Such planets and/or planetesimals may also serve as seeds for the formation of the second generation planets, and/or interact with them, possibly forming atypical planetary systems. Second generation planetary systems should be typically found in white dwarf binary systems, and may show various observational signatures. Most notably, second generation planets could form in environment which are inaccessible, or less favorable, for first generation planets. The orbital phase space available for the second generation planets could be forbidden (in terms of the system stability) to first generation planets in the pre-evolved progenitor binaries. In addition planets could form in metal poor environments such as globular clusters and/or in double compact object binaries. Observations of exo-planets in such forbidden or unfavorable regions could possibly serve to uniquely identify their second generation character. Finally, we point out a few observed candidate second generation planetary systems, including Gl 86, HD 27442 and all of the

  18. Modular Solar Electric Power (MSEP) Systems (Presentation)

    SciTech Connect

    Hassani, V.

    2000-06-18

    This presentation discusses the development and deployment of Modular Solar Electric Power (MSEP) systems, the feasibility of application of existing binary power cycles to solar trough technology, and identification of next action items.

  19. Discs in misaligned binary systems

    NASA Astrophysics Data System (ADS)

    Rawiraswattana, Krisada; Hubber, David A.; Goodwin, Simon P.

    2016-08-01

    We perform SPH simulations to study precession and changes in alignment between the circumprimary disc and the binary orbit in misaligned binary systems. We find that the precession process can be described by the rigid-disc approximation, where the disc is considered as a rigid body interacting with the binary companion only gravitationally. Precession also causes change in alignment between the rotational axis of the disc and the spin axis of the primary star. This type of alignment is of great important for explaining the origin of spin-orbit misaligned planetary systems. However, we find that the rigid-disc approximation fails to describe changes in alignment between the disc and the binary orbit. This is because the alignment process is a consequence of interactions that involve the fluidity of the disc, such as the tidal interaction and the encounter interaction. Furthermore, simulation results show that there are not only alignment processes, which bring the components towards alignment, but also anti-alignment processes, which tend to misalign the components. The alignment process dominates in systems with misalignment angle near 90°, while the anti-alignment process dominates in systems with the misalignment angle near 0° or 180°. This means that highly misaligned systems will become more aligned but slightly misaligned systems will become more misaligned.

  20. Surprisingly Rapid Orbital Evolution: A Compendium of Solar Type Binaries

    NASA Astrophysics Data System (ADS)

    Samec, Ronald George

    2015-08-01

    Solar type binaries are believed to be undergoing steady but slow angular momentum losses due to magnetic braking (Réville et al. 2015, Jiang et al. 2014) as stellar winds leave radially away on semi-rigid (out to the Alfvén radius) bipolar field lines: There is an outward radial flow of ions along the rotating magnetic fields. This is happening simultaneously as the gravitationally locked binary rotates about its center of mass. The stream of ions spiral outward resulting in a resistant torque, causing a decay in the orbital radius along with a period decrease due to Kepler’s laws. My past studies have included more than 25 binaries that appear to be undergoing magnetic braking. I have extended the number of systems to 75+ in this group by perusing the literature of modern precision synthetic light curve studies. Several interesting facts arise including their surprisingly rapid orbital evolution, much faster than would be suggested by the theory. Further results are presented in this study.

  1. Trojan Binary Asteroid Systems as Future Mission Targets

    NASA Astrophysics Data System (ADS)

    Bellerose, Julie; Yano, Hajime

    To date, the Jupiter-Sun Lagrangian points are populated with almost 4500 asteroids, for which their formation and history are still debated. In the current work, we look at rationales for a mission to Jovian Trojan asteroids, and discuss the scientific benefits to investigate binary systems and contact binary systems. We summarized the dynamics for a solar sail mission, which is currently thought to go along the Europa Jupiter System Mission (EJSM), and we show a case study of the contact binary Hektor, and its moon S/2006, which offer the most suitable conditions for spacecraft operations. Trojans asteroids offer many opportunities, and we list some of the targets in time.

  2. Planetary Formation and Dynamics in Binary Systems

    NASA Astrophysics Data System (ADS)

    Xie, J. W.

    2013-01-01

    As of today, over 500 exoplanets have been detected since the first exoplanet was discovered around a solar-like star in 1995. The planets in binaries could be common as stars are usually born in binary or multiple star systems. Although current observations show that the planet host rate in multiple star systems is around 17%, this fraction should be considered as a lower limit because of noticeable selection effects against binaries in planet searches. Most of the current known planet-bearing binary systems are S-types, meaning the companion star acts as a distant satellite, typically orbiting the inner star-planet system over 100 AU away. Nevertheless, there are four systems with a smaller separation of 20 AU, including the Gamma Cephei, GJ 86, HD 41004, and HD 196885. In addition to the planets in circumprimary (S-type) orbits discussed above, planets in circumbinary (P-type) orbits have been found in only two systems. In this thesis, we mainly study the planet formation in the S-type binary systems. In chapter 1, we first summarize current observational facts of exoplanets both in single-star and binary systems, then review the theoretical models of planet formation, with special attention to the application in binary systems. Perturbative effects from stellar companions render the planet formation process in binary systems even more complex than that in single-star systems. The perturbations from a binary companion can excite planetesimal orbits, and increase their mutual impact velocities to the values that might exceed their escape velocity or even the critical velocity for the onset of eroding collisions. The intermediate stage of the formation process---from planetesimals to planetary embryos---is thus the most problematic. In the following chapters, we investigate whether and how the planet formation goes through such a problematic stage. In chapter 2, we study the effects of gas dissipation on the planetesimals' mutual accretion. We find that in a

  3. STAR HOPPERS: PLANET INSTABILITY AND CAPTURE IN EVOLVING BINARY SYSTEMS

    SciTech Connect

    Kratter, Kaitlin M.; Perets, Hagai B.

    2012-07-01

    Many planets are observed in stellar binary systems, and their frequency may be comparable to that of planetary systems around single stars. Binary stellar evolution in such systems influences the dynamical evolution of the resident planets. Here, we study the evolution of a single planet orbiting one star in an evolving binary system. We find that stellar evolution can trigger dynamical instabilities that drive planets into chaotic orbits. This instability leads to planet-star collisions, exchange of the planet between the binary stars ('star hoppers'), and ejection of the planet from the system. The means by which planets can be recaptured is similar to the pull-down capture mechanism for irregular solar system satellites. Because planets often suffer close encounters with the primary on the asymptotic giant branch, captures during a collision with the stellar envelope are also possible for more massive planets. Such capture could populate the habitable zone around white dwarfs.

  4. A general catalogue of close binary systems

    NASA Technical Reports Server (NTRS)

    Webbink, Ronald F.

    1994-01-01

    A comprehensive catalog of close binary stars to be used for the study of the fundamental properties of stars and for the exploration and elucidation of evolutionary processes in those systems, is presented. Spectroscopic binaries, variable stars, suspected variable stars, and interacting binaries are included in the scope of the catalog.

  5. Habitability of Planets Orbiting Binaries Consisting of Solar Mass Twins

    NASA Astrophysics Data System (ADS)

    Mason, Paul A.; Zuluaga, Jorge I.; Zhilkin, Andrey G.; Bisikalo, Dmitry V.

    2015-01-01

    An important problem in astrobiology is the study of the potential habitability of planets orbiting binary stars. Theoretical and observational studies of circumbinary planets indicate that it is not uncommon for circumbinary planets to be located in the habitable zones surrounding main sequence binaries. However, it is also clear that the time evolution of stellar activity of the individual stars in close binaries is of primary concern for the habitability of planets. For example, planets orbiting active stars may lose the entirety of their water budget due to atmospheric mass loss; despite being in the standard radiative habitable zone. Alternatively, stars in some binaries may undergo a reduction in stellar activity due to tidal effects that cause the rotation of the stars to slow faster than single stars. Thereby, magneto-coronal activity is reduced to less aggressive levels, allowing circumbinary planets to maintain surface water. We summarize these effects, which we call the Binary Habitability Mechanism (BHM). We performed orbital integrations of circumbinary, Earth-like, planets and find that resonances play a particularly important role in the stability of habitable zone planets orbiting solar twin binaries in the 20-60 day period range, allowing for the possibility of several habitable planets orbiting some binaries. We present numerical simulations of the effects of colliding winds in binaries containing solar mass twins. We used stellar wind parameters based on solar like conditions for our 3D hydrodynamic simulations. We find devastating effects for close in planets, yet relatively mild stellar wind conditions exist within the circumbinary habitable zone.

  6. Nonergodicity of microfine binary systems

    NASA Astrophysics Data System (ADS)

    Son, L. D.; Sidorov, V. E.; Popel', P. S.; Shul'gin, D. B.

    2016-02-01

    The correction to the equation of state that is related to the nonergodicity of diffusion dynamics is discussed for a binary solid solution with a limited solubility. It is asserted that, apart from standard thermodynamic variables (temperature, volume, concentration), this correction should be taken into account in the form of the average local chemical potential fluctuations associated with microheterogeneity in order to plot a phase diagram. It is shown that a low value of this correction lowers the miscibility gap and that this gap splits when this correction increases. This situation is discussed for eutectic systems and Ga-Pb, Fe-Cu, and Cu-Zr alloys.

  7. Formation and Evolution of Binary Systems Containing Collapsed Stars

    NASA Technical Reports Server (NTRS)

    Rappaport, Saul; West, Donald (Technical Monitor)

    2003-01-01

    This research includes theoretical studies of the formation and evolution of five types of interacting binary systems. Our main focus has been on developing a number of comprehensive population synthesis codes to study the following types of binary systems: (i) cataclysmic variables (#3, #8, #12, #15), (ii) low- and intermediate-mass X-ray binaries (#13, #20, #21), (iii) high-mass X-ray binaries (#14, #17, #22), (iv) recycled binary millisecond pulsars in globular clusters (#5, #10, #ll), and (v) planetary nebulae which form in interacting binaries (#6, #9). The numbers in parentheses refer to papers published or in preparation that are listed in this paper. These codes take a new unified approach to population synthesis studies. The first step involves a Monte Carlo selection of the primordial binaries, including the constituent masses, and orbital separations and eccentricities. Next, a variety of analytic methods are used to evolve the primary star to the point where either a dynamical episode of mass transfer to the secondary occurs (the common envelope phase), or the system evolves down an alternate path. If the residual core of the primary is greater than 2.5 solar mass, it will evolve to Fe core collapse and the production of a neutron star and a supernova explosion. In the case of systems involving neutron stars, a kick velocity is chosen randomly from an appropriate distribution and added to the orbital dynamics which determine the state of the binary system after the supernova explosion. In the third step, all binaries which commence stable mass transfer from the donor star (the original secondary in the binary system) to the compact object, are followed with a detailed binary evolution code. Finally, we include all the relevant dynamics of the binary system. For example, in the case of LMXBs, the binary system, with its recoil velocity from the supernova explosion, is followed in time through its path in the Galactic potential. For our globular cluster

  8. NONLINEAR TIDES IN CLOSE BINARY SYSTEMS

    SciTech Connect

    Weinberg, Nevin N.; Arras, Phil; Quataert, Eliot; Burkart, Josh

    2012-06-01

    We study the excitation and damping of tides in close binary systems, accounting for the leading-order nonlinear corrections to linear tidal theory. These nonlinear corrections include two distinct physical effects: three-mode nonlinear interactions, i.e., the redistribution of energy among stellar modes of oscillation, and nonlinear excitation of stellar normal modes by the time-varying gravitational potential of the companion. This paper, the first in a series, presents the formalism for studying nonlinear tides and studies the nonlinear stability of the linear tidal flow. Although the formalism we present is applicable to binaries containing stars, planets, and/or compact objects, we focus on non-rotating solar-type stars with stellar or planetary companions. Our primary results include the following: (1) The linear tidal solution almost universally used in studies of binary evolution is unstable over much of the parameter space in which it is employed. More specifically, resonantly excited internal gravity waves in solar-type stars are nonlinearly unstable to parametric resonance for companion masses M' {approx}> 10-100 M{sub Circled-Plus} at orbital periods P Almost-Equal-To 1-10 days. The nearly static 'equilibrium' tidal distortion is, however, stable to parametric resonance except for solar binaries with P {approx}< 2-5 days. (2) For companion masses larger than a few Jupiter masses, the dynamical tide causes short length scale waves to grow so rapidly that they must be treated as traveling waves, rather than standing waves. (3) We show that the global three-wave treatment of parametric instability typically used in the astrophysics literature does not yield the fastest-growing daughter modes or instability threshold in many cases. We find a form of parametric instability in which a single parent wave excites a very large number of daughter waves (N Almost-Equal-To 10{sup 3}[P/10 days] for a solar-type star) and drives them as a single coherent unit with

  9. Nonlinear Tides in Close Binary Systems

    NASA Astrophysics Data System (ADS)

    Weinberg, Nevin N.; Arras, Phil; Quataert, Eliot; Burkart, Josh

    2012-06-01

    We study the excitation and damping of tides in close binary systems, accounting for the leading-order nonlinear corrections to linear tidal theory. These nonlinear corrections include two distinct physical effects: three-mode nonlinear interactions, i.e., the redistribution of energy among stellar modes of oscillation, and nonlinear excitation of stellar normal modes by the time-varying gravitational potential of the companion. This paper, the first in a series, presents the formalism for studying nonlinear tides and studies the nonlinear stability of the linear tidal flow. Although the formalism we present is applicable to binaries containing stars, planets, and/or compact objects, we focus on non-rotating solar-type stars with stellar or planetary companions. Our primary results include the following: (1) The linear tidal solution almost universally used in studies of binary evolution is unstable over much of the parameter space in which it is employed. More specifically, resonantly excited internal gravity waves in solar-type stars are nonlinearly unstable to parametric resonance for companion masses M' >~ 10-100 M ⊕ at orbital periods P ≈ 1-10 days. The nearly static "equilibrium" tidal distortion is, however, stable to parametric resonance except for solar binaries with P <~ 2-5 days. (2) For companion masses larger than a few Jupiter masses, the dynamical tide causes short length scale waves to grow so rapidly that they must be treated as traveling waves, rather than standing waves. (3) We show that the global three-wave treatment of parametric instability typically used in the astrophysics literature does not yield the fastest-growing daughter modes or instability threshold in many cases. We find a form of parametric instability in which a single parent wave excites a very large number of daughter waves (N ≈ 103[P/10 days] for a solar-type star) and drives them as a single coherent unit with growth rates that are a factor of ≈N faster than the

  10. Solar Energy: Solar System Economics.

    ERIC Educational Resources Information Center

    Knapp, Henry H., III

    This module on solar system economics is one of six in a series intended for use as supplements to currently available materials on solar energy and energy conservation. Together with the recommended texts and references (sources are identified), these modules provide an effective introduction to energy conservation and solar energy technologies.…

  11. New RR Lyrae variables in binary systems

    NASA Astrophysics Data System (ADS)

    Hajdu, G.; Catelan, M.; Jurcsik, J.; Dékány, I.; Drake, A. J.; Marquette, J.-B.

    2015-04-01

    Despite their importance, very few RR Lyrae (RRL) stars have been known to reside in binary systems. We report on a search for binary RRL in the OGLE-III Galactic bulge data. Our approach consists in the search for evidence of the light-travel time effect in so-called observed minus calculated (O-C) diagrams. Analysis of 1952 well-observed fundamental-mode RRL in the OGLE-III data revealed an initial sample of 29 candidates. We used the recently released OGLE-IV data to extend the baselines up to 17 yr, leading to a final sample of 12 firm binary candidates. We provide O-C diagrams and binary parameters for this final sample, and also discuss the properties of eight additional candidate binaries whose parameters cannot be firmly determined at present. We also estimate that ≳ 4 per cent of the RRL reside in binary systems.

  12. Efficiency enhancement in dye sensitized solar cells using gel polymer electrolytes based on a tetrahexylammonium iodide and MgI2 binary iodide system.

    PubMed

    Bandara, T M W J; Dissanayake, M A K L; Jayasundara, W J M J S R; Albinsson, I; Mellander, B-E

    2012-06-28

    Quasi-solid-state dye-sensitized solar cells have drawn the attention of scientists and technologists as a potential candidate to supplement future energy needs. The conduction of iodide ions in quasi-solid-state polymer electrolytes and the performance of dye sensitized solar cells containing such electrolytes can be enhanced by incorporating iodides having appropriate cations. Gel-type electrolytes, based on PAN host polymers and mixture of salts tetrahexylammonium iodide (Hex4N(+)I(-)) and MgI2, were prepared by incorporating ethylene carbonate and propylene carbonate as plasticizers. The salt composition in the binary mixture was varied in order to optimize the performance of solar cells. The electrolyte containing 120% Hex4N(+)I(-) with respect to weight of PAN and without MgI2 showed the highest conductivity out of the compositions studied, 2.5 × 10(-3) S cm(-1) at 25 °C, and a glass transition at -102.4 °C. However, the electrolyte containing 100% Hex4N(+)I(-) and 20% MgI2 showed the best solar cell performance highlighting the influence of the cation on the performance of the cell. The predominantly ionic behaviour of the electrolytes was established from the dc polarization data and all the electrolytes exhibit iodide ion transport. Seven different solar cells were fabricated employing different electrolyte compositions. The best cell using the electrolyte with 100% Hex4N(+)I(-) and 20% MgI2 with respect to PAN weight showed 3.5% energy conversion efficiency and 8.6 mA cm(-2) short circuit current density. PMID:22618351

  13. Dynamical fate of wide binaries in the solar neighborhood

    SciTech Connect

    Weinberg, M.D.; Shapiro, S.L.; Wasserman, I.

    1987-01-01

    An analytical model is presented for the evolution of wide binaries in the Galaxy. The study is pertinent to the postulated solar companion, Nemesis, which may disturb the Oort cloud and cause catastrophic comet showers to strike the earth every 26 Myr. Distant gravitational encounters are modeled by Fokker-Planck coefficients for advection and diffusion of the orbital binding energy. It is shown that encounters with passing stars cause a diffusive evolution of the binding energy and semimajor axis. Encounters with subclumps in giant molecular clouds disrupt orbits to a degree dependent on the cumulative number of stellar encounters. The time scales of the vents and the limitations of scaling laws used are discussed. Results are provided from calculations of galactic distribution of wide binaries and the evolution of wide binary orbits. 38 references.

  14. Orbital Architectures of Planet-Hosting Binary Systems

    NASA Astrophysics Data System (ADS)

    Dupuy, Trent J.; Kratter, Kaitlin M.

    2016-01-01

    We present the first results from our Keck AO astrometric monitoring of Kepler Prime Mission planet-hosting binary systems. Observational biases in exoplanet discovery have long left the frequency, properties, and provenance of planets in most binary systems largely unconstrained. Recent results from our ongoing survey of a volume-limited sample of Kepler planet hosts indicate that binary companions at solar-system scales of 20-100 AU suppress the occurrence of planetary systems at a rate of 30-100%. However, some planetary systems do survive in binaries, and determining these systems' orbital architectures is key to understanding why. As a demonstration of this new approach to testing ideas of planet formation, we present a detailed analysis of the triple star system Kepler-444 (HIP 94931) that hosts five Ganymede- to Mars-sized planets. By combining our high-precision astrometry with radial velocities from HIRES we discover a highly eccentric stellar orbit that would have made this a seemingly hostile site for planet formation. This either points to an extremely robust and efficient planet formation mechanism or a rare case of favorable initial conditions. Such broader implications will be addressed by determining orbital architectures for our larger statistical sample of Kepler planet-hosting systems that have stellar companions on solar system scales.

  15. Eclipse Binary System BB Pegasus

    NASA Astrophysics Data System (ADS)

    Snyder, Leroy F.

    2008-05-01

    CCD ground-based photometry of the contact binary system BB Pegasus is presented along with analyses of the light curve. Recent radial velocity data with these obtained light curves were used to compute parameters. These results are compared with published values computed using spectroscopic values. The light curve displays total annular eclipses in the primary. The period is very short, equal to 0.3615015 days. A recent spectroscopic study indicates the existence of a third body. Three times of minimums were gathered for this poster paper and when added to those found in the literature a plotted quadratic ephemeris displays a sine-like variation of the O -- C curve indicating a tertiary component to the system. The light curve of this system shows an asymmetry in which the maximum after primary eclipse is higher than the other maximum, O'Connell effect. Two small cool stellar spots on star number 1 were used to make the parameter model fit the light curve data.

  16. Orbital Architectures of Planet-Hosting Binary Systems

    NASA Astrophysics Data System (ADS)

    Dupuy, Trent; Kratter, Kaitlin M.; Kraus, Adam; Isaacson, Howard T.; Mann, Andrew; Ireland, Michael; Howard, Andrew; Huber, Daniel

    2015-12-01

    We present the first results from our Keck AO astrometric monitoring of Kepler planet-hosting binary systems. Observational biases in exoplanet discovery have long left the frequency, properties, and provenance of planets in most binary systems largely unconstrained. Recent results from our ongoing survey of a volume-limited sample of Kepler planet hosts indicate that binary companions at solar-system scales of 20-100 AU suppress the occurrence of planetary systems at a rate of 30-100%. However, some planetary systems do survive in binaries, and determining these systems' orbital architectures is key to understanding why. As a demonstration of this new approach to testing ideas of planet formation, we present a detailed analysis of the triple star system Kepler-444 (HIP 94931) that hosts five Ganymede- to Mars-sized planets. By combining our high-precision astrometry with radial velocities from HIRES and computational dynamical modeling, we discover an unexpected orbital architecture for this multi-planet, triple-star system. Finally, we preview results from our full statistical sample, such as tests of coplanarity between binary and planet orbits in single versus multi-planet systems.

  17. KIC 7177553: A Quadruple System of Two Close Binaries

    NASA Astrophysics Data System (ADS)

    Lehmann, H.; Borkovits, T.; Rappaport, S. A.; Ngo, H.; Mawet, D.; Csizmadia, Sz.; Forgács-Dajka, E.

    2016-03-01

    KIC 7177553 was observed by the Kepler satellite to be an eclipsing eccentric binary star system with an 18-day orbital period. Recently, an eclipse timing study of the Kepler binaries has revealed eclipse timing variations (ETVs) in this object with an amplitude of ˜100 s and an outer period of 529 days. The implied mass of the third body is that of a super-Jupiter, but below the mass of a brown dwarf. We therefore embarked on a radial velocity (RV) study of this binary to determine its system configuration and to check the hypothesis that it hosts a giant planet. From the RV measurements, it became immediately obvious that the same Kepler target contains another eccentric binary, this one with a 16.5-day orbital period. Direct imaging using adaptive optics reveals that the two binaries are separated by 0.″4 (˜167 AU) and have nearly the same magnitude (to within 2%). The close angular proximity of the two binaries and very similar γ velocities strongly suggest that KIC 7177553 is one of the rare SB4 systems consisting of two eccentric binaries where at least one system is eclipsing. Both systems consist of slowly rotating, nonevolved, solar-like stars of comparable masses. From the orbital separation and the small difference in γ velocity, we infer that the period of the outer orbit most likely lies in the range of 1000-3000 yr. New images taken over the next few years, as well as the high-precision astrometry of the Gaia satellite mission, will allow us to set much narrower constraints on the system geometry. Finally, we note that the observed ETVs in the Kepler data cannot be produced by the second binary. Further spectroscopic observations on a longer timescale will be required to prove the existence of the massive planet.

  18. Terrestrial Planet Formation in Binary Star Systems

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.; Quintana, Elisa V.; Chambers, John; Duncan, Martin J.; Adams, Fred

    2003-01-01

    Most stars reside in multiple star systems; however, virtually all models of planetary growth have assumed an isolated single star. Numerical simulations of the collapse of molecular cloud cores to form binary stars suggest that disks will form within such systems. Observations indirectly suggest disk material around one or both components within young binary star systems. If planets form at the right places within such circumstellar disks, they can remain in stable orbits within the binary star systems for eons. We are simulating the late stages of growth of terrestrial planets within binary star systems, using a new, ultrafast, symplectic integrator that we have developed for this purpose. We show that the late stages of terrestrial planet formation can indeed take place in a wide variety of binary systems and we have begun to delineate the range of parameter space for which this statement is true. Results of our initial simulations of planetary growth around each star in the alpha Centauri system and other 'wide' binary systems, as well as around both stars in very close binary systems, will be presented.

  19. Misaligned protoplanetary disks in a young binary star system.

    PubMed

    Jensen, Eric L N; Akeson, Rachel

    2014-07-31

    Many extrasolar planets follow orbits that differ from the nearly coplanar and circular orbits found in our Solar System; their orbits may be eccentric or inclined with respect to the host star's equator, and the population of giant planets orbiting close to their host stars suggests appreciable orbital migration. There is at present no consensus on what produces such orbits. Theoretical explanations often invoke interactions with a binary companion star in an orbit that is inclined relative to the planet's orbital plane. Such mechanisms require significant mutual inclinations between the planetary and binary star orbital planes. The protoplanetary disks in a few young binaries are misaligned, but often the measurements of these misalignments are sensitive only to a small portion of the inner disk, and the three-dimensional misalignment of the bulk of the planet-forming disk mass has hitherto not been determined. Here we report that the protoplanetary disks in the young binary system HK Tauri are misaligned by 60 to 68 degrees, such that one or both of the disks are significantly inclined to the binary orbital plane. Our results demonstrate that the necessary conditions exist for misalignment-driven mechanisms to modify planetary orbits, and that these conditions are present at the time of planet formation, apparently because of the binary formation process. PMID:25079553

  20. Solar System Sleuth

    NASA Astrophysics Data System (ADS)

    Ryden, Barbara

    2005-11-01

    One of the great astronomers of the last century, Gerhard Peter Kuiper, was born 100 years ago this year. He is considered the father of modern planetary science and an expert on binary and white dwarf stars. Kuiper was recruited by Otto Struve to the Yerkes Observatory and used the 82-inch Telescope at McDonald Observatory for groundbreaking studies of Mars and the giant moons in the outer solar system. Later, he became the founding director of the Lunar and Planetary Laboratory at the University of Arizona. Kuiper predicted that a vast number of asteroid-like objects lie beyond the orbit of Pluto; this was later substantiated and called the Kuiper Belt. Late in life, Kuiper pioneered the use of infrared telescopes and instruments aboard aircraft and the NASA's original flying observatory was named the Kuiper Airborne Observatory in his honor.

  1. Solar electric systems

    SciTech Connect

    Warfield, G.

    1984-01-01

    Electricity from solar sources is the subject. The state-of-the-art of photovoltaics, wind energy and solar thermal electric systems is presented and also a broad range of solar energy activities throughout the Arab world is covered. Contents, abridged: Solar radiation fundamentals. Basic theory solar cells. Solar thermal power plants. Solar energy activities at the scientific research council in Iraq. Solar energy program at Kuwait Institute for Scientific Research. Prospects of solar energy for Egypt. Non-conventional energy in Syria. Wind and solar energies in Sudan. Index.

  2. Gamma-ray binaries and related systems

    NASA Astrophysics Data System (ADS)

    Dubus, Guillaume

    2013-08-01

    After initial claims and a long hiatus, it is now established that several binary stars emit high- (0.1-100 GeV) and very high-energy (>100 GeV) gamma rays. A new class has emerged called "gamma-ray binaries", since most of their radiated power is emitted beyond 1 MeV. Accreting X-ray binaries, novae and a colliding wind binary ( η Car) have also been detected—"related systems" that confirm the ubiquity of particle acceleration in astrophysical sources. Do these systems have anything in common? What drives their high-energy emission? How do the processes involved compare to those in other sources of gamma rays: pulsars, active galactic nuclei, supernova remnants? I review the wealth of observational and theoretical work that have followed these detections, with an emphasis on gamma-ray binaries. I present the current evidence that gamma-ray binaries are driven by rotation-powered pulsars. Binaries are laboratories giving access to different vantage points or physical conditions on a regular timescale as the components revolve on their orbit. I explain the basic ingredients that models of gamma-ray binaries use, the challenges that they currently face, and how they can bring insights into the physics of pulsars. I discuss how gamma-ray emission from microquasars provides a window into the connection between accretion-ejection and acceleration, while η Car and novae raise new questions on the physics of these objects—or on the theory of diffusive shock acceleration. Indeed, explaining the gamma-ray emission from binaries strains our theories of high-energy astrophysical processes, by testing them on scales and in environments that were generally not foreseen, and this is how these detections are most valuable.

  3. Planetary nebula progenitors that swallow binary systems

    NASA Astrophysics Data System (ADS)

    Soker, Noam

    2016-01-01

    I propose that some irregular messy planetary nebulae (PNe) owe their morphologies to triple-stellar evolution where tight binary systems evolve inside and/or on the outskirts of the envelope of asymptotic giant branch (AGB) stars. In some cases, the tight binary system can survive, in others, it is destroyed. The tight binary system might break up with one star leaving the system. In an alternative evolution, one of the stars of the broken-up tight binary system falls towards the AGB envelope with low specific angular momentum, and drowns in the envelope. In a different type of destruction process, the drag inside the AGB envelope causes the tight binary system to merge. This releases gravitational energy within the AGB envelope, leading to a very asymmetrical envelope ejection, with an irregular and messy PN as a descendant. The evolution of the triple-stellar system can be in a full common envelope evolution or in a grazing envelope evolution. Both before and after destruction (if destruction takes place), the system might launch pairs of opposite jets. One pronounced signature of triple-stellar evolution might be a large departure from axisymmetrical morphology of the descendant PN. I estimate that about one in eight non-spherical PNe is shaped by one of these triple-stellar evolutionary routes.

  4. A candidate sub-parsec supermassive binary black hole system.

    PubMed

    Boroson, Todd A; Lauer, Tod R

    2009-03-01

    The role of mergers in producing galaxies, together with the finding that most large galaxies harbour black holes in their nuclei, implies that binary supermassive black hole systems should be common. Here we report that the quasar SDSS J153636.22+044127.0 is a plausible example of such a system. This quasar shows two broad-line emission systems, separated in velocity by 3,500 km s(-1). A third system of unresolved absorption lines has an intermediate velocity. These characteristics are unique among known quasars. We interpret this object as a binary system of two black holes, having masses of 10(7.3) and 10(8.9) solar masses separated by approximately 0.1 parsec with an orbital period of approximately 100 years. PMID:19262667

  5. Tidal evolution in close binary systems.

    NASA Technical Reports Server (NTRS)

    Kopal, Z.

    1972-01-01

    Mathematical outline of the theory of tidal evolution in close binary systems of secularly constant total momentum. Following a general outline of the problem the basic expressions for the energy and momenta of close binaries consisting of components of arbitrary internal structure are established, and the maximum and minimum values of the energy (kinetic and potential) which such systems can attain for a given amount of total momentum are investigated. These results are compared with the actual facts encountered in binaries with components whose internal structure (and, therefore, rotational momenta) are known from evidence furnished by the observed rates of apsidal advance. The results show that all such systems whether of detached or semidetached type - disclose that more than 99% of their total momenta are stored in the orbital momentum. The sum of the rotational momenta of the constituent components amounts to less than 1% of the total -a situation characteristic of a state close to the minimum energy for given total momentum.

  6. The Impact of Stellar Multiplicity on Planetary Systems. I. The Ruinous Influence of Close Binary Companions

    NASA Astrophysics Data System (ADS)

    Kraus, Adam L.; Ireland, Michael J.; Huber, Daniel; Mann, Andrew W.; Dupuy, Trent J.

    2016-07-01

    The dynamical influence of binary companions is expected to profoundly influence planetary systems. However, the difficulty of identifying planets in binary systems has left the magnitude of this effect uncertain; despite numerous theoretical hurdles to their formation and survival, at least some binary systems clearly host planets. We present high-resolution imaging of 382 Kepler Objects of Interest (KOIs) obtained using adaptive-optics imaging and nonredundant aperture-mask interferometry on the Keck II telescope. Among the full sample of 506 candidate binary companions to KOIs, we super-resolve some binary systems to projected separations of <5 au, showing that planets might form in these dynamically active environments. However, the full distribution of projected separations for our planet-host sample more broadly reveals a deep paucity of binary companions at solar-system scales. For a field binary population, we should have found 58 binary companions with projected separation ρ < 50 au and mass ratio q > 0.4 we instead only found 23 companions (a 4.6σ deficit), many of which must be wider pairs that are only close in projection. When the binary population is parametrized with a semimajor axis cutoff a cut and a suppression factor inside that cutoff S bin, we find with correlated uncertainties that inside {a}{cut}={47}-23+59 au, the planet occurrence rate in binary systems is only {S}{bin}={0.34}-0.15+0.14 times that of wider binaries or single stars. Our results demonstrate that a fifth of all solar-type stars in the Milky Way are disallowed from hosting planetary systems due to the influence of a binary companion.

  7. Solar Energy Systems

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Calibrated in kilowatt hours per square meter, the solar counter produced by Dodge Products, Inc. provides a numerical count of the solar energy that has accumulated on a surface. Solar energy sensing, measuring and recording devices in corporate solar cell technology developed by Lewis Research Center. Customers for their various devices include architects, engineers and others engaged in construction and operation of solar energy facilities; manufacturers of solar systems or solar related products, such as glare reducing windows; and solar energy planners in federal and state government agencies.

  8. Solar array drive system

    NASA Technical Reports Server (NTRS)

    Berkopec, F. D.; Sturman, J. C.; Stanhouse, R. W.

    1976-01-01

    A solar array drive system consisting of a solar array drive mechanism and the corresponding solar array drive electronics is being developed. The principal feature of the solar array drive mechanism is its bidirectional capability which enables its use in mechanical redundancy. The solar array drive system is of a widely applicable design. This configuration will be tested to determine its acceptability for generic mission sets. Foremost of the testing to be performed is the testing for extended duration.

  9. Gravitational wave background from binary systems

    SciTech Connect

    Rosado, Pablo A.

    2011-10-15

    Basic aspects of the background of gravitational waves and its mathematical characterization are reviewed. The spectral energy density parameter {Omega}(f), commonly used as a quantifier of the background, is derived for an ensemble of many identical sources emitting at different times and locations. For such an ensemble, {Omega}(f) is generalized to account for the duration of the signals and of the observation, so that one can distinguish the resolvable and unresolvable parts of the background. The unresolvable part, often called confusion noise or stochastic background, is made by signals that cannot be either individually identified or subtracted out of the data. To account for the resolvability of the background, the overlap function is introduced. This function is a generalization of the duty cycle, which has been commonly used in the literature, in some cases leading to incorrect results. The spectra produced by binary systems (stellar binaries and massive black hole binaries) are presented over the frequencies of all existing and planned detectors. A semi-analytical formula for {Omega}(f) is derived in the case of stellar binaries (containing white dwarfs, neutron stars or stellar-mass black holes). Besides a realistic expectation of the level of background, upper and lower limits are given, to account for the uncertainties in some astrophysical parameters such as binary coalescence rates. One interesting result concerns all current and planned ground-based detectors (including the Einstein Telescope). In their frequency range, the background of binaries is resolvable and only sporadically present. In other words, there is no stochastic background of binaries for ground-based detectors.

  10. Solar tracking system

    DOEpatents

    Okandan, Murat; Nielson, Gregory N.

    2016-07-12

    Solar tracking systems, as well as methods of using such solar tracking systems, are disclosed. More particularly, embodiments of the solar tracking systems include lateral supports horizontally positioned between uprights to support photovoltaic modules. The lateral supports may be raised and lowered along the uprights or translated to cause the photovoltaic modules to track the moving sun.

  11. Solar dynamic systems

    NASA Technical Reports Server (NTRS)

    Dustin, M. O.

    1985-01-01

    The development of the solar dynamic system is discussed. The benefits of the solar dynamic system over pv systems are enumerated. The history of the solar dynamic development is recounted. The purpose and approach of the advanced development are outlined. Critical concentrator technology and critical heat recover technology are examined.

  12. Binary optics at Hughes Danbury Optical Systems

    NASA Technical Reports Server (NTRS)

    Logue, James; Power, Michael

    1993-01-01

    An overview of binary optics development at Hughes Danbury Optical Systems is presented. Design software used for mask design is presented. A brief discussion of fabrication follows. Two examples of actual projects are used to highlight the discussion: (1) a large aspheric lens; and (2) a set of grating and lenslet arrays.

  13. Brown Dwarf Binaries from Disintegrating Triple Systems

    NASA Astrophysics Data System (ADS)

    Reipurth, Bo; Mikkola, Seppo

    2015-04-01

    Binaries in which both components are brown dwarfs (BDs) are being discovered at an increasing rate, and their properties may hold clues to their origin. We have carried out 200,000 N-body simulations of three identical stellar embryos with masses drawn from a Chabrier IMF and embedded in a molecular core. The bodies are initially non-hierarchical and undergo chaotic motions within the cloud core, while accreting using Bondi-Hoyle accretion. The coupling of dynamics and accretion often leads to one or two dominant bodies controlling the center of the cloud core, while banishing the other(s) to the lower-density outskirts, leading to stunted growth. Eventually each system transforms either to a bound hierarchical configuration or breaks apart into separate single and binary components. The orbital motion is followed for 100 Myr. In order to illustrate 200,000 end-states of such dynamical evolution with accretion, we introduce the “triple diagnostic diagram,” which plots two dimensionless numbers against each other, representing the binary mass ratio and the mass ratio of the third body to the total system mass. Numerous freefloating BD binaries are formed in these simulations, and statistical properties are derived. The separation distribution function is in good correspondence with observations, showing a steep rise at close separations, peaking around 13 AU and declining more gently, reaching zero at separations greater than 200 AU. Unresolved BD triple systems may appear as wider BD binaries. Mass ratios are strongly peaked toward unity, as observed, but this is partially due to the initial assumptions. Eccentricities gradually increase toward higher values, due to the lack of viscous interactions in the simulations, which would both shrink the orbits and decrease their eccentricities. Most newborn triple systems are unstable and while there are 9209 ejected BD binaries at 1 Myr, corresponding to about 4% of the 200,000 simulations, this number has grown to

  14. White dwarfs in Be star binary systems

    NASA Technical Reports Server (NTRS)

    Apparao, K. M. V.

    1991-01-01

    An evaluation is made of possible reasons for the persistent inability to identify white dwarf stars in the Be binary systems. It is noted that many Be stars exhibiting large optical enhancements may be Be + WD and Be + He systems, and that observations of pulsations in the H-alpha emission, as well as observation of time delays between enhancements of optical line and continuum, can identify such systems.

  15. THE COEVALITY OF YOUNG BINARY SYSTEMS

    SciTech Connect

    Kraus, Adam L.; Hillenbrand, Lynne A.

    2009-10-10

    Multiple star systems are commonly assumed to form coevally; they thus provide the anchor for most calibrations of stellar evolutionary models. In this paper, we study the binary population of the Taurus-Auriga association, using the component positions in an HR diagram in order to quantify the frequency and degree of coevality in young binary systems. After identifying and rejecting the systems that are known to be affected by systematic errors (due to further multiplicity or obscuration by circumstellar material), we find that the relative binary ages, |DELTAlog tau|, have an overall dispersion sigma{sub |D}ELTA{sub logt}au{sub |}approx 0.40 dex. Random pairs of Taurus members are coeval only to within sigma{sub |D}ELTA{sub logt}au{sub |}approx 0.58 dex, indicating that Taurus binaries are indeed more coeval than the association as a whole. However, the distribution of |DELTAlog tau| suggests two populations, with approx2/3 of the sample appearing coeval to within the errors (sigma{sub |D}ELTA{sub logt}au{sub |}approx 0.16 dex) and the other approx1/3 distributed in an extended tail reaching |DELTAlog tau|approx 0.4-0.9 dex. To explain the finding of a multipeaked distribution, we suggest that the tail of the differential age distribution includes unrecognized hierarchical multiples, stars seen in scattered light, or stars with disk contamination; additional follow-up is required to rule out or correct for these explanations. The relative coevality of binary systems does not depend significantly on the system mass, mass ratio, or separation. Indeed, any pair of Taurus members wider than approx10' (approx0.7 pc) shows the full age spread of the association.

  16. Acceleration by pulsar winds in binary systems

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.; Gaisser, T. K.

    1990-01-01

    In the absence of accretion torques, a pulsar in a binary system will spin down due to electromagnetic dipole radiation and the spin-down power will drive a wind of relativistic electron-positron pairs. Winds from pulsars with short periods will prevent any subsequent accretion but may be confined by the companion star atmosphere, wind, or magnetosphere to form a standing shock. The authors investigate the possibility of particle acceleration at such a pulsar wind shock and the production of very high energy (VHE) and ultra high energy (UHE) gamma rays from interactions of accelerated protons in the companion star's wind or atmosphere. They find that in close binaries containing active pulsars, protons will be shock accelerated to a maximum energy dependent on the pulsar spin-down luminosity. If a significant fraction of the spin-down power goes into particle acceleration, these systems should be sources of VHE and possibly UHE gamma rays. The authors discuss the application of the pulsar wind model to binary sources such as Cygnus X-3, as well as the possibility of observing VHE gamma-rays from known binary radio pulsar systems.

  17. Acceleration by pulsar winds in binary systems

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.; Gaisser, T. K.

    1990-01-01

    In the absence of accretion torques, a pulsar in a binary system will spin down due to electromagnetic dipole radiation, and the spin-down power will drive a wind of relativistic electron-position pairs. Winds from pulsars with short periods will prevent any subsequent accretion but may be confined by the companion star atmosphere, wind, or magnetosphere to form a standing shock. This paper investigates the possibility of particle acceleration at such a pulsar wind shock and the production of VHE and UHE gamma-rays from interactions of accelerated protons in the companion star's wind or atmosphere. It is found that, in close binaries containing active pulsars, protons will be shock accelerated to a maximum energy dependent on the pulsar spin-down luminosity. If a significant fraction of the spin-down power goes into particle acceleration, these systems should be sources of VHE and possibly UHE gamma-rays. The application of the pulsar wind model to binary sources such as Cygnus X-3 is discussed, as well as the possibility of observing VHE gamma-rays from known binary radio pulsar systems.

  18. Mass loss from interacting close binary systems

    NASA Technical Reports Server (NTRS)

    Plavec, M. J.

    1981-01-01

    The three well-defined classes of evolved binary systems that show evidence of present and/or past mass loss are the cataclysmic variables, the Algols, and Wolf-Rayet stars. It is thought that the transformation of supergiant binary systems into the very short-period cataclysmic variables must have been a complex process. The new evidence that has recently been obtained from the far ultraviolet spectra that a certain subclass of the Algols (the Serpentids) are undergoing fairly rapid evolution is discussed. It is thought probable that the remarkable mass outflow observed in them is connected with a strong wind powered by accretion. The origin of the circumbinary clouds or flat disks that probably surround many strongly interacting binaries is not clear. Attention is also given to binary systems with hot white dwarf or subdwarf components, such as the symbiotic objects and the BQ stars; it is noted that in them both components may be prone to an enhanced stellar wind.

  19. Solar system positioning system

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin I.; Chui, Talso

    2006-01-01

    Power-rich spacecraft envisioned in Prometheus initiative open up possibilities for long-range high-rate communication. A constellation of spacecraft on orbits several A.U. from the Sun, equipped with laser transponders and precise clocks can be configured to measure their mutual distances to within few cm. High on-board power can create substantial non-inertial contribution to the spacecraft trajectory. We propose to alleviate this contribution by employing secondary ranging to a passive daughter spacecraft. Such constellation can form the basis of it navigation system capable of providing position information anywhere in the soIar system with similar accuracy. Apart from obvious Solar System exploration implications, this system can provide robust reference for GPS and its successors.

  20. Transit Timing Variations In Binary Star Systems

    NASA Astrophysics Data System (ADS)

    Sansone, Eric; Haghighipour, N.

    2012-01-01

    We present the results of a study of the effect of a stellar companion on the transit timing variations (TTV) of a planetary system. The purpose of our study is to determine the ranges of the orbital elements of a secondary star for which the amplitude of a currently existing TTV is enhanced. We chose the system of Kepler 9 as this system represents the first planetary system detected by the transit timing variation method, and studied its TTVs by considering a hypothetical secondary star in this system. By varying the mass, semi-major axis, and eccentricity of the fictitious binary companion, we tested the stability of the known planets Kepler-9c and Kepler-9b and identified the region of the parameter-space for which the binary planetary system would be stable. We calculated TTVs for the two planets of the system for different values of the orbital elements of the secondary star and calculated its difference with the system's already existing TTVs. Results of our study indicate that the effect of the binary companion is significant only when the secondary star is in a highly eccentric orbit and/or the planets of the system are within the range of Super-Earth or terrestrial sizes. This work was funded by the National Science Foundation in the form of a Research Experience for Undergraduates program at the University of Hawaii at Manoa.

  1. Solar ADEPT: Efficient Solar Energy Systems

    SciTech Connect

    2011-01-01

    Solar ADEPT Project: The 7 projects that make up ARPA-E's Solar ADEPT program, short for 'Solar Agile Delivery of Electrical Power Technology,' aim to improve the performance of photovoltaic (PV) solar energy systems, which convert the sun's rays into electricity. Solar ADEPT projects are integrating advanced electrical components into PV systems to make the process of converting solar energy to electricity more efficient.

  2. THE AGE AND STELLAR PARAMETERS OF THE PROCYON BINARY SYSTEM

    SciTech Connect

    Liebert, James; Arnett, David; Fontaine, Gilles; Young, Patrick A.; Williams, Kurtis A. E-mail: darnett@as.arizona.edu E-mail: pyoung.3@asu.edu

    2013-05-20

    The Procyon AB binary system (orbital period 40.838 yr, a newly refined determination) is near and bright enough that the component radii, effective temperatures, and luminosities are very well determined, although more than one possible solution to the masses has limited the claimed accuracy. Preliminary mass determinations for each component are available from Hubble Space Telescope imaging, supported by ground-based astrometry and an excellent Hipparcos parallax; we use these for our preferred solution for the binary system. Other values for the masses are also considered. We have employed the TYCHO stellar evolution code to match the radius and luminosity of the F5 IV-V primary star to determine the system's most likely age as 1.87 {+-} 0.13 Gyr. Since prior studies of Procyon A found its abundance indistinguishable from solar, the solar composition of Asplund, Grevesse, and Sauval (Z = 0.014) is assumed for the Hertzsprung-Russell diagram fitting. An unsuccessful attempt to fit using the older solar abundance scale of Grevesse and Sauval (Z = 0.019) is also reported. For Procyon B, 11 new sequences for the cooling of non-DA white dwarfs have been calculated to investigate the dependences of the cooling age on (1) the mass, (2) core composition, (3) helium layer mass, and (4) heavy-element opacities in the helium envelope. Our calculations indicate a cooling age of 1.19 {+-} 0.11 Gyr, which implies that the progenitor mass of Procyon B was 2.59{sub -0.26}{sup +0.44} M{sub Sun }. In a plot of initial versus final mass of white dwarfs in astrometric binaries or star clusters (all with age determinations), the Procyon B final mass lies several {sigma} below a straight line fit.

  3. Dynamics and Habitability in Binary Star Systems

    NASA Astrophysics Data System (ADS)

    Eggl, Siegfried; Georgakarakos, Nikolaos; Pilat-Lohinger, Elke

    2014-07-01

    Determining planetary habitability is a complex matter, as the interplay between a planet's physical and atmospheric properties with stellar insolation has to be studied in a self consistent manner. Standardized atmospheric models for Earth-like planets exist and are commonly accepted as a reference for estimates of Habitable Zones. In order to define Habitable Zone boundaries, circular orbital configurations around main sequence stars are generally assumed. In gravitationally interacting multibody systems, such as double stars, however, planetary orbits are forcibly becoming non circular with time. Especially in binary star systems even relatively small changes in a planet's orbit can have a large impact on habitability. Hence, we argue that a minimum model for calculating Habitable Zones in binary star systems has to include dynamical interactions.

  4. Determination of stellar parameters using binary system models

    NASA Astrophysics Data System (ADS)

    Blay, Georgina; Lovekin, Catherine

    2015-12-01

    Stellar parameters can be constrained more tightly with binary systems than can typically be done with single stars. We used a freely available binary fitting code to determine the best fitting parameters of a collection of potential eclipsing binary systems observed with the Kepler satellite. These model fits constrain the mass ratio, radii ratio, surface brightness ratio, and the orbital inclination of both stars in the binary system. The frequencies of these pulsations can then be determined and used to constrain asteroseismic models.

  5. Detailed Chemical Abundances of Planet-Hosting Wide Binary Systems

    NASA Astrophysics Data System (ADS)

    Mack, Claude Ernest; Schuler, Simon; Stassun, Keivan

    2015-08-01

    We present a detailed chemical abundance analysis of planet-hosting wide binary systems. Each of these binary systems consists of two stars with similar spectral types (ranging from G2V - K2V), and in each system, at least one star hosts a giant planet with an orbital pericenter ~< 0.5 AU. We examine the photospheric abundances of the host stars to determine if they have ingested rocky planetary material as a result of the close-in giant planets scattering inner rocky planets into the star as they migrated to their present-day locations. Using high-resolution, high signal-to-noise echelle spectra, for both stars in each system we derive the chemical abundances ([X/H]) of 15 elements covering a range of condensation temperatures (Tc). For stars in our sample with approximately solar metallicity, the refractory elements (Tc > 900 K) show a positive correlation between [X/H] and Tc. However, for stars with super-solar metallicities, the refractory elements show a negative correlation between [X/H] and Tc. We interpret these results in the context of numerical simulations of giant planet migration that predict the accretion of hydrogen-depleted rocky material by the host star. We demonstrate that a simple model for a solar-metallicity star accreting material with Earth-like composition predicts a positive correlation between [X/H] and Tc, while for a supersolar-metallicity star the model predicts a negative correlation. The stark contrast between the predicted correlations for solar-metallicity and supersolar-metallicity stars may indicate that extracting any chemical signature of rocky planetary accretion is particularly challenging for very metal-rich stars.

  6. The effective tidal viscosity in close solar-type binaries

    NASA Astrophysics Data System (ADS)

    Goldman, I.

    2008-09-01

    A major problem confronting the understanding of tidal evolution of close solar-type binaries is the inefficiency of the turbulent convection. The value of the effective viscosity estimated, in the framework of the mixing length theory (MLT), implies circularization timescales which are almost two orders of magnitude longer than observed. Moreover, the reduction of the effective viscosity due to the fast time-variation of the tidal shear in short period binaries, increases the discrepancy to about three orders of magnitude. This state of affairs has motivated suggestions that tidal orbital evolution, notably circularization occurs mainly during the pre-main-sequence phase. However, observational data accumulated over the recent decades imply that circularization does occur during the the main-sequence phase (Mazeh 2008). In this work, we examine the possibility that the apparent inefficiency of turbulent convection is merely a shortcoming of MLT approach. Indeed, a recent 3D numerical simulation (Penev et al. 2007), suggests that the true convective viscosity is probably larger than the MLT value and that the reduction due to the time-variation of the shear is not drastic. We employ a model for stellar turbulent convection (Canuto, Goldman & Mazzitelli 1996) to evaluate the effective viscosity both for a steady for and time dependent tidal shear. The model is physically based, self-consistent, and accounts for the full spectrum of the turbulent eddies. It has been found advantageous, compared to the MLT, in many applications. We use an analytic approximation to the turbulent spectrum to obtain the reduction of the efficiency due to the time-variation of the tide. The results are: (i) an enhanced effective viscosity (by a factor of ˜ 4.5), and more importantly (ii) only a mild reduction due to the time-variation of the tidal shear. Overall, for binaries with orbital period of 15 days the discrepancy is ``only" a factor of ˜ 30 down from a factor of ˜ 1000. These

  7. CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. II. P-TYPE BINARIES

    SciTech Connect

    Haghighipour, Nader; Kaltenegger, Lisa

    2013-11-10

    We have developed a comprehensive methodology for calculating the circumbinary habitable zone (HZ) in planet-hosting P-type binary star systems. We present a general formalism for determining the contribution of each star of the binary to the total flux received at the top of the atmosphere of an Earth-like planet and use the Sun's HZ to calculate the inner and outer boundaries of the HZ around a binary star system. We apply our calculations to the Kepler's currently known circumbinary planetary systems and show the combined stellar flux that determines the boundaries of their HZs. We also show that the HZ in P-type systems is dynamic and, depending on the luminosity of the binary stars, their spectral types, and the binary eccentricity, its boundaries vary as the stars of the binary undergo their orbital motion. We present the details of our calculations and discuss the implications of the results.

  8. Binary systems, their evolution and environments

    NASA Astrophysics Data System (ADS)

    de Grijs, Richard

    2014-09-01

    More than half of all stars form part of binary or higher-order multiple systems at least temporarily during their lifetimes. Yet, the highly successful field of stellar population synthesis all but ignores the presence of large fractions of stellar multiplicity. During this conference, we aim at bringing together observers, theorists and modellers to explore the synergies among the closely related fields focusing on stellar evolution and stellar dynamics, with particular emphasis on the contributions and properties of binary and higher-order mulitple systems. Although we aim at addressing the key issues in these rapidly evolving areas from a population synthesis perspective, we will pay special attention to those individual stellar species that contribute most significantly to the stellar population properties that are most uniquely related to stellar multiplicity.

  9. Coalescence of Magnetized Binary Neutron Star Systems

    NASA Astrophysics Data System (ADS)

    Motl, Patrick M.; Anderson, Matthew; Lehner, Luis; Liebling, Steven L.; Neilsen, David; Palenzuela, Carlos; Ponce, Marcelo

    2015-01-01

    We present simulations of the merger of binary neutron star systems calculated with full general relativity and incorporating the global magnetic field structure for the stars evolved with resistive magnetohydrodynamics. Our simulation tools have recently been improved to incorporate the effects of neutrino cooling and have been generalized to allow for tabular equations of state to describe the degenerate matter. Of particular interest are possible electromagnetic counterparts to the gravitational radiation that emerges from these systems. We focus on magnetospheric interactions that ultimately tap into the gravitational potential energy of the binary to power a Poynting flux and deposition of energy through Joule heating and magnetic reconnection. We gratefully acknowledge the support of NASA through the Astrophysics Theory Program grant NNX13AH01G.

  10. Detailed Chemical Abundances of Planet-Hosting Wide Binary Systems

    NASA Astrophysics Data System (ADS)

    Mack, Claude E.; Schuler, Simon C.; Stassun, Keivan; Pepper, Joshua

    2015-01-01

    We present a detailed chemical abundance analysis of planet-hosting wide binary systems. Each of these binary systems consists of two stars with similar spectral types (ranging from G2V - K2V), and in each system, at least one star hosts a giant planet with an orbital pericenter ~< 0.5 AU. We investigate if giant planets on such orbits could have scattered inner rocky planets into the atmospheres of their host stars, and thereby imprint a detectable chemical signature in the stellar photospheric abundances. Using high-resolution, high signal-to-noise echelle spectra, we derive the chemical abundances ([X/H]) of 15 elements covering a range of condensation temperatures (Tc). For stars in our sample with approximately solar metallicity, the refractory elements (Tc > 900 K) show a positive correlation between [X/H] and Tc. However, for stars with super-solar metallicities, the refractory elements show a negative correlation between [X/H] and Tc. We interpret these results in the context of numerical simulations of giant planet migration that predict the accretion of hydrogen-depleted rocky material by the host star. We demonstrate that a simple model for a solar-metallicity star accreting material with Earth-like composition predicts a positive correlation between [X/H] and Tc, while for a supersolar-metallicity star the model predicts a negative correlation. The stark contrast between the predicted correlations for solar-metallicity and supersolar-metallicity stars may indicate that extracting any chemical signature of rocky planetary accretion is particularly challenging for very metal-rich stars.

  11. Pulsars in binary systems: probing binary stellar evolution and general relativity.

    PubMed

    Stairs, Ingrid H

    2004-04-23

    Radio pulsars in binary orbits often have short millisecond spin periods as a result of mass transfer from their companion stars. They therefore act as very precise, stable, moving clocks that allow us to investigate a large set of otherwise inaccessible astrophysical problems. The orbital parameters derived from high-precision binary pulsar timing provide constraints on binary evolution, characteristics of the binary pulsar population, and the masses of neutron stars with different mass-transfer histories. These binary systems also test gravitational theories, setting strong limits on deviations from general relativity. Surveys for new pulsars yield new binary systems that increase our understanding of all these fields and may open up whole new areas of physics, as most spectacularly evidenced by the recent discovery of an extremely relativistic double-pulsar system. PMID:15105492

  12. Coordinate System Issues in Binary Star Computations

    NASA Astrophysics Data System (ADS)

    Kaplan, George H.

    2015-08-01

    It has been estimated that half of all stars are components of binary or multiple systems. Yet the number of known orbits for astrometric and spectroscopic binary systems together is less than 7,000 (including redundancies), almost all of them for bright stars. A new generation of deep all-sky surveys such as Pan-STARRS, Gaia, and LSST are expected to lead to the discovery of millions of new systems. Although for many of these systems, the orbits may be undersampled initially, it is to be expected that combinations of new and old data sources will eventually lead to many more orbits being known. As a result, a revolution in the scientific understanding of these systems may be upon us.The current database of visual (astrometric) binary orbits represents them relative to the “plane of the sky”, that is, the plane orthogonal to the line of sight. Although the line of sight to stars constantly changes due to proper motion, aberration, and other effects, there is no agreed upon standard for what line of sight defines the orbital reference plane. Furthermore, the computation of differential coordinates (component B relative to A) for a given date must be based on the binary system’s direction at that date. Thus, a different “plane of the sky” is appropriate for each such date, i.e., each observation. However, projection effects between the reference planes, differential aberration, and the curvature of the sky are generally neglected in such computations. Usually the only correction applied is for the change in the north direction (position angle zero) due to precession (and sometimes also proper motion). This paper will present an algorithm for a more complete model of the geometry involved, and will show that such a model is necessary to avoid errors in the computed observables that are significant at modern astrometric accuracy. The paper will also suggest where conventions need to be established to avoid ambiguities in how quantities related to binary star

  13. The Solar-Type Contact Binary BX Pegasi Revisited

    NASA Astrophysics Data System (ADS)

    Lee, Jae Woo; Kim, Seung-Lee; Lee, Chung-Uk; Youn, Jae-Hyuck

    2009-12-01

    We present the results of new CCD photometry for the contact binary BX Peg, made during three successive months beginning on 2008 September. As do historical light curves, our observations display an O'Connell effect and the November data by themselves indicate clear evidence for very short-term brightness disturbance. For these variations, model spots are applied separately to the two data sets, Group I (Sep.-Oct.) and Group II (Nov.). The former is described by a single cool spot on the secondary photosphere and the latter by a two-spot model with a cool spot on the cool star and a hot one on either star. These are generalized manifestations of the magnetic activity of the binary system. Twenty light-curve timings calculated from Wilson-Devinney code were used for a period study, together with all other minimum epochs. The complex period changes of BX Peg can be sorted into a secular period decrease caused dominantly by angular momentum loss due to magnetic stellar wind braking, a light-travel time (LTT) effect due to the orbit of a low-mass third companion, and a previously unknown short-term oscillation. This last period modulation could be produced either by a second LTT orbit with a period of about 16 yr due to the existence of a fourth body, or by the effect of magnetic activity with a cycle length of about 12 yr.

  14. Homemade Solar Systems

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Through the use of NASA Tech Briefs, Peter Kask, was able to build a solarized domestic hot water system. Also by applying NASA's solar energy design information, he was able to build a swimming pool heating system with minimal outlay for materials.

  15. OO Aquilae: a solar-type contact binary with intrinsic light curve changes

    NASA Astrophysics Data System (ADS)

    Li, Hua-Li; Wei, Jian-Yan; Yang, Yuan-Gui; Dai, Hai-Feng

    2016-01-01

    New multi-color photometry of the solar-type contact binary OO Aql was obtained in 2012 and 2013, using the 60 cm telescope at Xinglong Station of the National Astronomical Observatories, Chinese Academy of Sciences. From two sets of light curves LC1 and LC2, photometric models were performed by using the 2003 version of the Wilson-Devinney code. The overcontact factor of the binary system was determined to be f = 37.0(±0.5)%. The intrinsic variability of this binary occurs in light maxima and minima, which could result from a possible third component and magnetic activity of the late type components. Based on all available light minimum times, the orbital period may change in a complicated mode, i.e., sudden period jumps or continuous period variations. The period of OO Aql may possibly undergo a secular period decrease with a rate of dP/dt = -3.63(±0.30) × 10-8 d yr-1, superimposed by two possible cyclic variations in the O - C curve. The long-term period decrease may be interpreted as conserved mass transfer from the more massive component to the less massive one. The 21.5-yr oscillation may be attributed to cyclic magnetic activity, and the 69.3-yr one may result from the light-time effect of an unseen tertiary body.

  16. Subsystems in Nearby Solar-type Wide Binaries

    NASA Astrophysics Data System (ADS)

    Tokovinin, Andrei; Hartung, Markus; Hayward, Thomas L.

    2010-08-01

    We conducted a deep survey of resolved subsystems among wide binaries with solar-type components within 67 pc of the Sun. Images of 61 stars in the K and H bands were obtained with the Near-Infrared Coronagraphic Imager adaptive-optics instrument on the 8 m Gemini-South telescope. Our maximum detectable magnitude difference is about 5 mag and 7.8 mag at 0farcs15 and 0farcs9 separations, respectively. This enables a complete census of subsystems with stellar companions in the projected separation range from 5 to 100 AU. Out of seven such companions found in our sample, only one was previously known. We determine that the fraction of subsystems with projected separations above 5 AU is 0.12 ± 0.04 and that the distribution of their mass ratio is flat, with a power-law index of 0.2 ± 0.5. Comparing this with the properties of closer spectroscopic subsystems (separations below 1 AU), it appears that the mass-ratio distribution does not depend on the separation. The frequency of subsystems in the separation ranges below 1 AU and between 5 and 100 AU is similar, about 0.15. Unbiased statistics of multiplicity higher than 2, advanced by this work, provide constraints on star formation theory. Based on observations obtained at the Gemini Observatory (Program ID GS-2009B-Q-49), which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the National Science Foundation on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência e Tecnologia (Brazil), and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).

  17. RS CV sub n binary systems

    NASA Technical Reports Server (NTRS)

    Linsky, J. L.

    1984-01-01

    An attempt is made to place in context the vast amount of data obtained as a result of X-ray, ultraviolet, optical, and microwave observations of RS CVn and similar spectroscopic binary systems. Emphasis is on the RS CVn systems and their long period analogs. The following questions are considered: (1) are the original defining characteristics still valid and still adequate? (2) what is the evidence for discrete active regions? (3) have any meaningful physical properties for the atmospheres of RS CVn systems been derived? (4) what do the flare observations tell about magnetic fields in RS CVn systems? (5) is there evidence for systematic trends in RS CVn systems with spectral type?

  18. Synchronization of magnetic stars in binary systems

    NASA Technical Reports Server (NTRS)

    Lamb, F. K.; Aly, J.-J.; Cook, M. C.; Lamb, D. Q.

    1983-01-01

    Asynchronous rotation of magnetic stars in close binary systems drives substantial field-aligned electrical currents between the magnetic star and its companion. The resulting magnetohydrodynamic torque is able to account for the heretofore unexplained synchronous rotation of the strongly magnetic degenerate dwarf component in systems like AM Her, VV Pup, AN UMa, and EF Eri as well as the magnetic A type component in systems like HD 98088 and 41 Tauri. The electric fields produced by even a small asynchronism are large and may accelerate some electrons to high energies, producing radio emission. The total energy dissipation rate in systems with degenerate dwarf spin periods as short as 1 minute may reach 10 to the 33rd ergs/s. Total luminosities of this order may be a characteristic feature of such systems.

  19. Long-Term Stability of Planets in Binary Systems

    NASA Technical Reports Server (NTRS)

    Holman, Matthew J.; Wiegert, Paul A.

    1999-01-01

    A simple question of celestial mechanics is investigated: in what regions of phase space near a binary system can planets persist for long times? The planets are taken to be test particles moving in the field of an eccentric binary system. A range of values of the binary eccentricity and mass ratio is studied, and both the case of planets orbiting close to one of the stars, and that of planets outside the binary orbiting the systems center of mass, are examined. From the results, empirical expressions are developed for both (1) the largest orbit around each of the stars and (2) the smallest orbit around the binary system as a whole, in which test particles survive the length of the integration (10A4 binary periods). The empirical expressions developed, which are roughly linear in both the mass ratio mu and the binary eccentricity e, are determined for the range 0.0=e=0.7-0.8 and 0.1=mu=0.9 in both regions and can be used to guide searches for planets in binary systems. After considering the case of a single low-mass planet in binary systems, the stability of a mutually interacting system of planets orbiting one star of a binary system is examined, though in less detail.

  20. Solar Electric System

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Heat Pipe Technology, Inc. undertook the development of a PV system that could bring solar electricity to the individual home at reasonable cost. His system employs high efficiency PV modules plus a set of polished reflectors that concentrate the solar energy and enhance the output of the modules. Dinh incorporated a sun tracking system derived from space tracking technology. It automatically follows the sun throughout the day and turns the modules so that they get maximum exposure to the solar radiation, further enhancing the system efficiency.

  1. SARA South Observations and Analysis of the Solar Type, Totally Eclipsing, Shallow Contact Binary, CW Sculptoris

    NASA Astrophysics Data System (ADS)

    Samec, Ronald G.; Norris, Cody; Van Hamme, Walter V.; Faulkner, Danny R.; Hill, Robert L.

    2016-01-01

    CW Scl is a Solar Type (T1 ~ 6000K) solar type eclipsing binary. It was observed in October and November, 2014 at Cerro Tololo in remote mode with the 0.6-m SARA South reflector. Three times of minimum light were calculated from our present observations, two primary and one secondary eclipses:HJD Min I = 2456939.60799±0.0002, 2456976.62450±0.0002,HJD Min II = 2456940.57227±0.0006.In addition, six observations at minima were determined from archived All Sky Automated Survey Data:HJD Min I = 2452177.603, 2452466.793, 2454404.752,HJD Min II = 2453647.652, 2454669.843, 2455101.701.The following quadratic ephemerides was determined from all available times of minimum light:JD Hel Min I=2452940.67733±0.0003d + 0.3855865917±0.00031 X E+0.000000000114±0.000000000002 X E2A BVRcIc simultaneous Wilson-Devinney Program (W-D) solution reveals that the system has a mass ratio of ~0.39, and a component temperature difference of ~200 K. A Binary Maker fitted cool spot was eliminatedby WD Synthetic Light Curve Computations. The Roche Lobe fill-out is only 7/%. The inclination is ~86°. An eclipse duration of 19.5 minutes was determined for the primary eclipse. Additional and more detailedinformation is given in this report.

  2. First Photometric Investigation of the Solar-type Contact Binary GSC 1537-1557

    NASA Astrophysics Data System (ADS)

    Xiang, F.-Y.; Xiao, T.-Y.; Zhang, B.; Shi, X.-D.

    2015-07-01

    By analyzing Rc and Ic light curves of the short-period solar-type eclipsing binary GSC 1537-1557 we discovered that it is a shallow contact binary with a degree of contact factor of f=(8.10+/- 1.79)%. Photometric solutions reveal that GSC 1537-1557 is a W-type system with a mass ratio of q={M}2/{M}1=2.645 where the less massive component (the primary star) is about 110 K hotter than the more massive one (the secondary star). The asymmetry and variation of the light curves were explained as the activity of spots on the solar-type component stars. By investigating all of the available times of light minima, we found that the observed-calculated (O-C) curve shows a cyclic variation with a small amplitude of 0.00335 days and a period of 8.1 years. The small-amplitude cyclic change in the O-C curve was analyzed for the light-travel time effect via the presence of an extremely cool stellar companion. The mass of the third body was determined to be {M}3{sin}{i}\\prime =(0.19+/- 0.01) {M}⊙ when {M}1+{M}2=1.31 {M}⊙ is adopted for GSC 1537-1557. The semimajor axis of the outer obit is {a}\\prime {sin}{i}\\prime =(4.58+/- 0.33) AU.

  3. Evolution of close binary systems: Observational aspects

    NASA Technical Reports Server (NTRS)

    Plavec, M. J.

    1981-01-01

    Detached close binary systems define the main sequence band satisfactorily, but very little is known about the masses of giants and supergiants. High dispersion international ultraviolet explorer satellite observations promise an improvement, since blue companions are now frequently found to late type supergiants. Mu Sagittaril and in particular Xi Aurigae are discussed in more detail. The barium star abundance anomaly appears to be due to mass transfer in interacting systems. The symbiotic stars are another type of binary systems containing late type giants; several possible models for the hotter star and for the type of interaction are discussed. The W Serpentis stars appear to be Algols in the rapid phase of mass transfer, but a possible link relating them to the symbiotics is also indicated. Evidence of hot circumstellar plasmas has now been found in several ordinary Algols; there may exist a smooth transition between very quiescent Algols and the W Serpentis stars. Beta Lyrae is discussed in the light of new spectrophotometric results.

  4. OJ287 binary black hole system.

    NASA Astrophysics Data System (ADS)

    Valtonen, M.; Ciprini, S.

    The light curve of the quasar OJ287 extends from 1891 up today without major gaps. This is partly due to extensive studies of historical plate archives by Rene Hudec and associates, partly due to several observing campaigns in recent times. Here we summarize the results of the 2005 - 2010 observing campaign in which several hundred scientists and amateur astronomers took part. The main results are the following: (1) The 2005 October optical outburst came at the expected time, thus confirming the general relativistic precession in the binary black hole system. This result disproved the model of a single black hole system with accretion disk oscillations, as well as several toy models of binaries without relativistic precession. In the latter models the main outburst would have been a year later. (2) The nature of the radiation of the 2005 October outburst was expected to be bremsstrahlung from hot gas at the temperature of 3× 105 oK. This was confirmed by combined ground based and ultraviolet observations using the XMM-Newton X-ray telescope. (3) A secondary outburst of the same nature was expected at 2007 September 13. Within the accuracy of observations (about 6 hours), it started at the correct time. Thus the prediction was accurate at the same level as the prediction of the return of Halley's comet in 1986. (4) Further synchrotron outbursts were expected following the two bremsstrahlung outbursts. They came as scheduled between 2007 October and 2009 December. (5) Due to the effect of the secondary on the overall direction of the jet, the parsec scale jet was expected to rotate in the sky by a large angle around 2009. This rotation may have been seen at high frequency radio observations. OJ287 binary black hole system is currently our best laboratory for testing theories of gravitation. Using OJ287, the correctness of General Relativity has now been demonstrated up to the third Post-Newtonian order, at higher order than has been possible using the binary pulsars.

  5. Solar power system

    SciTech Connect

    Hasford, G.S.

    1990-01-30

    This patent describes a solar power system. It comprises: solar concentrator means; power conversion means for converting solar energy from the solar concentrator means to electrical energy, through the medium of a working fluid, to power appropriate loads; integrated combustor/heat exchanger means coupled to the power conversion means for heating the working fluid during periods of solar eclipse and giving off a water combustion product; electrolyzer means for receiving the water combustion product from the integrated combustor/heat exchanger mean and regenerating the water combustion product to gaseous hydrogen and oxygen. The electrolyzer means being coupled to the power conversion means as to be powered thereby during periods of excess electrical energy; and means for supplying the hydrogen and oxygen for combustion in the integrated combustor/heat exchanger during the periods of solar eclipse.

  6. Residential Solar Systems.

    ERIC Educational Resources Information Center

    Fulkerson, Dan

    This publication contains student and teacher instructional materials for a course in residential solar systems. The text is designed either as a basic solar course or as a supplement to extend student skills in areas such as architectural drafting, air conditioning and refrigeration, and plumbing. The materials are presented in four units…

  7. Solar energy collection system

    NASA Technical Reports Server (NTRS)

    Selcuk, M. K. (Inventor)

    1977-01-01

    An improved solar energy collection system, having enhanced energy collection and conversion capabilities, is delineated. The system is characterized by a plurality of receivers suspended above a heliostat field comprising a multiplicity of reflector surfaces, each being adapted to direct a concentrated beam of solar energy to illuminate a target surface for a given receiver. A magnitude of efficiency, suitable for effectively competing with systems employed in collecting and converting energy extracted from fossil fuels, is indicated.

  8. Utilizing Energy Transfer in Binary and Ternary Bulk Heterojunction Organic Solar Cells.

    PubMed

    Feron, Krishna; Cave, James M; Thameel, Mahir N; O'Sullivan, Connor; Kroon, Renee; Andersson, Mats R; Zhou, Xiaojing; Fell, Christopher J; Belcher, Warwick J; Walker, Alison B; Dastoor, Paul C

    2016-08-17

    Energy transfer has been identified as an important process in ternary organic solar cells. Here, we develop kinetic Monte Carlo (KMC) models to assess the impact of energy transfer in ternary and binary bulk heterojunction systems. We used fluorescence and absorption spectroscopy to determine the energy disorder and Förster radii for poly(3-hexylthiophene-2,5-diyl), [6,6]-phenyl-C61-butyric acid methyl ester, 4-bis[4-(N,N-diisobutylamino)-2,6-dihydroxyphenyl]squaraine (DIBSq), and poly(2,5-thiophene-alt-4,9-bis(2-hexyldecyl)-4,9-dihydrodithieno[3,2-c:3',2'-h][1,5]naphthyridine-5,10-dione). Heterogeneous energy transfer is found to be crucial in the exciton dissociation process of both binary and ternary organic semiconductor systems. Circumstances favoring energy transfer across interfaces allow relaxation of the electronic energy level requirements, meaning that a cascade structure is not required for efficient ternary organic solar cells. We explain how energy transfer can be exploited to eliminate additional energy losses in ternary bulk heterojunction solar cells, thus increasing their open-circuit voltage without loss in short-circuit current. In particular, we show that it is important that the DIBSq is located at the electron donor-acceptor interface; otherwise charge carriers will be trapped in the DIBSq domain or excitons in the DIBSq domains will not be able to dissociate efficiently at an interface. KMC modeling shows that only small amounts of DIBSq (<5% by weight) are needed to achieve substantial performance improvements due to long-range energy transfer. PMID:27456294

  9. Solar Energy: Solar System Design Fundamentals.

    ERIC Educational Resources Information Center

    Knapp, Henry H., III

    This module on solar system design fundamentals is one of six in a series intended for use as supplements to currently available materials on solar energy and energy conservation. Together with the recommended texts and references (sources are identified), these modules provide an effective introduction to energy conservation and solar energy…

  10. Solar system fault detection

    DOEpatents

    Farrington, R.B.; Pruett, J.C. Jr.

    1984-05-14

    A fault detecting apparatus and method are provided for use with an active solar system. The apparatus provides an indication as to whether one or more predetermined faults have occurred in the solar system. The apparatus includes a plurality of sensors, each sensor being used in determining whether a predetermined condition is present. The outputs of the sensors are combined in a pre-established manner in accordance with the kind of predetermined faults to be detected. Indicators communicate with the outputs generated by combining the sensor outputs to give the user of the solar system and the apparatus an indication as to whether a predetermined fault has occurred. Upon detection and indication of any predetermined fault, the user can take appropriate corrective action so that the overall reliability and efficiency of the active solar system are increased.

  11. Solar system fault detection

    DOEpatents

    Farrington, Robert B.; Pruett, Jr., James C.

    1986-01-01

    A fault detecting apparatus and method are provided for use with an active solar system. The apparatus provides an indication as to whether one or more predetermined faults have occurred in the solar system. The apparatus includes a plurality of sensors, each sensor being used in determining whether a predetermined condition is present. The outputs of the sensors are combined in a pre-established manner in accordance with the kind of predetermined faults to be detected. Indicators communicate with the outputs generated by combining the sensor outputs to give the user of the solar system and the apparatus an indication as to whether a predetermined fault has occurred. Upon detection and indication of any predetermined fault, the user can take appropriate corrective action so that the overall reliability and efficiency of the active solar system are increased.

  12. Merging compact binaries in hierarchical triple systems: Resonant excitation of binary eccentricity

    NASA Astrophysics Data System (ADS)

    Liu, Bin; Lai, Dong; Yuan, Ye-Fei

    2015-12-01

    We study the secular dynamics of compact binaries (consisting of white dwarfs, neutron stars or black holes) with tertiary companions in hierarchical triple systems. As the inner binary (with initially negligible eccentricity) undergoes orbital decay due to gravitational radiation, its eccentricity can be excited by gravitational forcing from the tertiary. This excitation occurs when the triple system passes through an "apsidal precession resonance," when the precession rate of the inner binary, driven by the gravitational perturbation of the external companion and general relativity, matches the precession rate of the outer binary. The eccentricity excitation requires the outer companion to be on an eccentric orbit, with the mutual inclination between the inner and outer orbits less than ˜40 ° . Gravitational wave (GW) signals from the inner binary can be significantly modified as the system evolves through the apsidal precession resonance. For some system parameters (e.g., a white dwarf binary with a brown dwarf tertiary), the resonance can happen when the binary emits GWs in the 10-4-10-1 Hz range (the sensitivity band of LISA).

  13. Conjugating binary systems for spacecraft thermal control

    NASA Technical Reports Server (NTRS)

    Grodzka, Philomena G.; Dean, William G.; Sisk, Lori A.; Karu, Zain S.

    1989-01-01

    The materials search was directed to liquid pairs which can form hydrogen bonds of just the right strength, i.e., strong enough to give a high heat of mixing, but weak enough to enable phase change to occur. The cursory studies performed in the area of additive effects indicate that Conjugating Binary (CB) performance can probably be fine-tuned by this means. The Fluid Loop Test Systems (FLTS) tests of candidate CBs indicate that the systems Triethylamine (TEA)/water and propionaldehyde/water show close to the ideal, reversible behavior, at least initially. The Quick Screening Tests QSTs and FLTS tests, however, both suffer from rather severe static due either to inadequate stirring or temperature control. Thus it is not possible to adequately evaluate less than ideal CB performers. Less than ideal performers, it should be noted, may have features that make them better practical CBs than ideal performers. Improvement of the evaluation instrumentation is thus indicated.

  14. Orbit of an Astrometric Binary System

    NASA Astrophysics Data System (ADS)

    Descamps, Pascal

    2005-08-01

    We present a new method to solve the problem of initial orbit determination of any binary system. This method is mainly based on the material available for an observer, for example relative positions at a given time of the couple in the “plane of sky”, namely the tangent plane to the celestial sphere at the position of the primary component. The problem of orbit determination is solved by splitting in successive stages in order to decorrelate the parameters of each other as much as possible. On one hand, the geometric problem is solved using the first Kepler’s law from a single observing run and, on the other hand, dynamical parameters are then inferred from the fit of the Kepler’s equation. At last, the final stage consists in determining the main physical parameters involved in the secular evolution of the system, that is the spin axis and the J2 parameter of the primary if we assume that it is a quasi-spherical body. As a matter of fact there is no need to make too restrictive initial assumptions (such as circular orbit or zero eccentricity) and initial guesses of parameters required by a non-linear least-squares Levenberg Marquardt algorithm are finally obtained after each stage. Such a protocol is very useful to study systems like binary asteroids for which all of the parameters should be considered a priori as unknowns. As an example of application, we used our method to estimate the set of the Pluto Charon system parameters from observations collected in the literature since 1980.

  15. Fragmentary Solar System History

    NASA Technical Reports Server (NTRS)

    Marti, Kurt

    1997-01-01

    The objective of this research is an improved understanding of the early solar system environment and of the processes involved in the nebula and in the evolution of solid bodies. We present results of our studies on the isotopic signatures in selected primitive solar system objects and on the evaluation of the cosmic ray records and of inferred collisional events. Furthermore, we report data of trapped martian atmospheric gases in meteorites and the inferred early evolution of Mars' atmosphere.

  16. The new solar system

    SciTech Connect

    Beatty, J.K.; Oleary, B.; Chaikin, A.

    1981-01-01

    Current knowledge about the solar system is reviewed, with particular emphasis on the results of recent space exploration. Among the many topics discussed are the sun, magnetospheres and the interplanetary medium, the surfaces of the terrestrial bodies, the moon, Mars, asteroids, Jupiter and Saturn, planetary rings, the Galilean satellites, Titan, the outer solar system, comets, and meteorites. Particular attention is given to the Voyager 1 and 2 flybys of Jupiter and Saturn. The work includes many illustrative photographs of the celestial bodies discussed.

  17. Binary stars.

    PubMed

    Paczynacuteski, B

    1984-07-20

    Most stars in the solar neighborhood are either double or multiple systems. They provide a unique opportunity to measure stellar masses and radii and to study many interesting and important phenomena. The best candidates for black holes are compact massive components of two x-ray binaries: Cygnus X-1 and LMC X-3. The binary radio pulsar PSR 1913 + 16 provides the best available evidence for gravitational radiation. Accretion disks and jets observed in close binaries offer a very good testing ground for models of active galactic nuclei and quasars. PMID:17749544

  18. Planetary system disruption by Galactic perturbations to wide binary stars.

    PubMed

    Kaib, Nathan A; Raymond, Sean N; Duncan, Martin

    2013-01-17

    Nearly half the exoplanets found within binary star systems reside in very wide binaries with average stellar separations greater than 1,000 astronomical units (one astronomical unit (AU) being the Earth-Sun distance), yet the influence of such distant binary companions on planetary evolution remains largely unstudied. Unlike their tighter counterparts, the stellar orbits of wide binaries continually change under the influence of the Milky Way's tidal field and impulses from other passing stars. Here we report numerical simulations demonstrating that the variable nature of wide binary star orbits dramatically reshapes the planetary systems they host, typically billions of years after formation. Contrary to previous understanding, wide binary companions may often strongly perturb planetary systems, triggering planetary ejections and increasing the orbital eccentricities of surviving planets. Although hitherto not recognized, orbits of giant exoplanets within wide binaries are statistically more eccentric than those around isolated stars. Both eccentricity distributions are well reproduced when we assume that isolated stars and wide binaries host similar planetary systems whose outermost giant planets are scattered beyond about 10 AU from their parent stars by early internal instabilities. Consequently, our results suggest that although wide binaries eventually remove the most distant planets from many planetary systems, most isolated giant exoplanet systems harbour additional distant, still undetected planets. PMID:23292514

  19. The New Solar System

    NASA Astrophysics Data System (ADS)

    Beatty, J. Kelly; Collins Petersen, Carolyn; Chaikin, Andrew

    1999-01-01

    As the definitive guide for the armchair astronomer, The New Solar System has established itself as the leading book on planetary science and solar system studies. Incorporating the latest knowledge of the solar system, a distinguished team of researchers, many of them Principal Investigators on NASA missions, explain the solar system with expert ease. The completely-revised text includes the most recent findings on asteroids, comets, the Sun, and our neighboring planets. The book examines the latest research and thinking about the solar system; looks at how the Sun and planets formed; and discusses our search for other planetary systems and the search for life in the solar system. In full-color and heavily-illustrated, the book contains more than 500 photographs, portrayals, and diagrams. An extensive set of tables with the latest characteristics of the planets, their moon and ring systems, comets, asteroids, meteorites, and interplanetary space missions complete the text. New to this edition are descriptions of collisions in the solar system, full scientific results from Galileo's mission to Jupiter and its moons, and the Mars Pathfinder mission. For the curious observer as well as the student of planetary science, this book will be an important library acquisition. J. Kelly Beatty is the senior editor of Sky & Telescope, where for more than twenty years he has reported the latest in planetary science. A renowned science writer, he was among the first journalists to gain access to the Soviet space program. Asteroid 2925 Beatty was named on the occasion of his marriage in 1983. Carolyn Collins Petersen is an award-winning science writer and co-author of Hubble Vision (Cambridge 1995). She has also written planetarium programs seen at hundreds of facilities around the world. Andrew L. Chaikin is a Boston-based science writer. He served as a research geologist at the Smithsonian Institution's Center for Earth and Planetary Studies. He is a contributing editor to

  20. The reflection effect in eclipsing binary systems

    NASA Astrophysics Data System (ADS)

    Vaz, L. P. R.

    1985-07-01

    The weakest point in the modern models of eclipsing binary systems (EBS) is the treatment given to the effects of mutual irradiation. In this review, which does not have a similar one in the literature, an attempt is made to collect all the work done on the irradiation problem until the middle of 1984, in order to make possible an evaluation of the present status of this problem. Special emphasis is given to the applicability of the results to the analysis of EBS. The treatment given to the effect by the early studies, as well as by practically all the modern models of EBS, is described, and special attention is given to works analysing the problem using stellar model atmospheres. It turns out that the effect is more complex than suspected earlier, but that significant progress has been made recently.

  1. CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. I. S-TYPE BINARIES

    SciTech Connect

    Kaltenegger, Lisa; Haghighipour, Nader

    2013-11-10

    We have developed a comprehensive methodology for calculating the boundaries of the habitable zone (HZ) of planet-hosting S-type binary star systems. Our approach is general and takes into account the contribution of both stars to the location and extent of the binary HZ with different stellar spectral types. We have studied how the binary eccentricity and stellar energy distribution affect the extent of the HZ. Results indicate that in binaries where the combination of mass-ratio and orbital eccentricity allows planet formation around a star of the system to proceed successfully, the effect of a less luminous secondary on the location of the primary's HZ is generally negligible. However, when the secondary is more luminous, it can influence the extent of the HZ. We present the details of the derivations of our methodology and discuss its application to the binary HZ around the primary and secondary main-sequence stars of an FF, MM, and FM binary, as well as two known planet-hosting binaries α Cen AB and HD 196886.

  2. Analytical modeling and experimental investigation on optical properties of new class of nanofluids (Al2O3-CuO binary nanofluids) for direct absorption solar thermal energy

    NASA Astrophysics Data System (ADS)

    Menbari, Amir; Alemrajabi, Ali Akbar

    2016-02-01

    Nanofluids play a major role in many modern engineering processes. Binary nanofluids are a new class of nanofluids that are prepared by dispersing simultaneously two dissimilar nanoparticles in a base fluid. They offer a good potential for use in direct absorption solar systems. The present study investigates both experimentally and analytically the optical properties of binary nanofluids for direct absorption in solar applications. For this purpose, two dissimilar nanoparticles, i.e. CuO and γ-Al2O3, are dispersed in water, ethylene glycol, and the ethylene glycol-water mixture to form binary nanofluids. In addition, a new method is developed for calculating the extinction coefficient of the binary nanofluids based on the classical electromagnetic theory. It will be shown that the extinction coefficients obtained from both analytical and experimental studies are in good agreement. Moreover, the extinction coefficient of the binary nanofluids is found to be approximately equal to the sum of the extinction coefficients of the constituent components, determined both analytically and experimentally. By increasing the nanoparticle volume fraction, improvements are observed in the extinction coefficient of the binary nanofluids prepared. Also, the analytical and experimental results of the study show that the extinction coefficient of the binary nanoparticles dispersed in water as the "base fluid" is greater than those of the binary nanoparticles dispersed in ethylene glycol or the mixture of ethylene glycol-water.

  3. Discovering the Solar System

    NASA Astrophysics Data System (ADS)

    Jones, Barrie W.

    1999-04-01

    Discovering the Solar System Barrie W. Jones The Open University, Milton Keynes, UK Discovering the Solar System is a comprehensive, up-to-date account of the Solar System and of the ways in which the various bodies have been investigated and modelled. The approach is thematic, with sequences of chapters on the interiors of planetary bodies, on their surfaces, and on their atmospheres. Within each sequence there is a chapter on general principles and processes followed by one or two chapters on specific bodies. There is also an introductory chapter, a chapter on the origin of the Solar System, and a chapter on asteroids, comets and meteorites. Liberally illustrated with diagrams, black and white photographs and colour plates, Discovering the Solar System also features: * tables of essential data * question and answers within the text * end of section review questions with answers and comments Discovering the Solar System is essential reading for all undergraduate students for whom astronomy or planetary science are components of their degrees, and for those at a more advanced level approaching the subject for the first time. It will also be of great interest to non-specialists with a keen interest in astronomy. A small amount of scientific knowledge is assumed plus familiarity with basic algebra and graphs. There is no calculus. Praise for this book includes: ".certainly qualifies as an authoritative text. The author clearly has an encyclopedic knowledge of the subject." Meteorics and Planetary Science ".liberally doused with relevant graphs, tables, and black and white figures of good quality." EOS, Transactions of the American Geophysical Union ".one of the best books on the Solar System I have seen. The general accuracy and quality of the content is excellent." Journal of the British Astronomical Association

  4. GLAST Solar System Science

    SciTech Connect

    Share, Gerald H.; Murphy, Ronald J.

    2007-07-12

    We briefly discuss GLAST's capabilities for observing high-energy radiation from various energetic phenomena in our solar system. These emissions include: bremsstrahlung, nuclear-line and pion-decay gamma-radiation, and neutrons from solar flares; bremsstrahlung and pion-decay gamma radiation from cosmic-ray interactions with the Sun, the Moon, and the Earth's atmosphere; and inverse Compton radiation from cosmic-ray electron interactions with sunlight.

  5. Solar System Educators Program

    NASA Astrophysics Data System (ADS)

    Knudsen, R.

    2004-11-01

    The Solar System Educators Program is a nationwide network of highly motivated teachers who lead workshops that show other teachers in their local communities how to successfully incorporate NASA materials and research into their classes. Currently there are 57 Solar System Educators in 37 states whose workshops are designed to assist their fellow teachers in understanding and including standards-based NASA materials into their classroom activities. Solar System Educators attend a training institute during their first year in the program and have the option of attending subsequent annual institutes. The volunteers in this program receive additional web-based mission-specific telecon trainings in conjunction with the Solar System Ambassadors. Resource and handout materials in the form of DVDs, posters, pamphlets, fact sheets, postcards and bookmarks are also provided. Scientists can get involved with this program by partnering with the Solar System Educators in their regions, presenting at their workshops and mentoring these outstanding volunteers. This formal education program helps optimize project funding set aside for education through the efforts of these volunteer master teachers. At the same time, teachers become familiar with NASA's educational materials with which to inspire students into pursuing careers in science, technology, engineering and math.

  6. Dynamics of Satellites in Binary Near-Earth Asteroid Systems: A Study Based on Radar Observations

    NASA Astrophysics Data System (ADS)

    Naidu, Shantanu

    In the past 15 years, three previously unrecognized sub-populations of near-Earth asteroids (NEAs) have been discovered. About 15% of NEAs are binaries, at least 10% of NEAs are contact binaries, and dozens of asteroid pairs have been identified. Numerous science questions have arisen about the formation and evolution processes of these systems and about the inter-relationships between these groups. Addressing these questions informs us about a wide range of important solar system processes that shape small bodies and planetesimals. Here I have chosen to focus on providing one of the most complete characterizations of a binary system among all known asteroid binaries, and on studying the spin-orbit interactions in this and 8 additional binary systems. One hypothesis that has not been fully explored is the possibility of chaotic rotation of asteroid satellites and the impact that such a state has on the evolution of the binary systems. I examine this problem as well as the possibility of detecting librational motions in synchronous satellites. Because the Arecibo and Goldstone radar systems enable superb characterizations of binaries and NEAs in general, this dissertation makes abundant use of radar data. Radar observations provide images of asteroids at decameter resolution, and these images can be inverted to determine the 3D shapes of the components, which are essential to properly model the system dynamics. Radar data also enable precise determination of the mutual orbit, which is another crucial ingredient. In the first two chapters of the dissertation, I describe the observations and physical characterizations of asteroid 2000~ET70 and binary asteroid 2000 DP107. The characterization of 2000 DP107 includes size, shape, spin, mass, and density of each component, making this binary one of the best-characterized asteroid binary to date. In the last chapter of the dissertation, I describe a computationally efficient fourth-order numerical integrator that I used to

  7. Evolution of the symbiotic binary system AG Dranconis

    NASA Technical Reports Server (NTRS)

    Mikolajewska, Joanna; Kenyon, Scott J; Mikolajewski, Maciej; Garcia, Michael R.; Polidan, Ronald S.

    1995-01-01

    We present an analysis of new and archival photometric and spectroscopic observations of the symbiotic star AG Draconis. This binary has undergone several 1 - 3 mag optical and ultraviolet eruptions during the past 15 years. Our combination of optical and ultraviolet spectroscopic data allow a more complete analysis of this system than in previous papers. AG Dra is composed of a K-type bright giant M(sub g) approximately 1.5 solar mass) and a hot, compact star M(sub h approximatelly 0.4 - 0.6 solar mass) embedded in a dense, low metallicity nebula. The hot component undergoes occasional thermonuclear runaways that produce 2 - 3 mag optical/ultraviolet eruptions. During these eruptions, the hot component develops a low velocity wind that quenches x-ray emission from the underlying hot white dwarf. The photoionized nebula changes its volume by a factor of 5 throughout an eruptin cycle. The K bright giant occults low ionization emission lines during superior conjunctions at all outburst phases but does not occult high ionization lines in outburst (and perhaps quiescence). This geometry and the component masses suggest a system inclination of i approximately 30 deg - 45 deg.

  8. SAGE III L2 Solar Event Species Profiles (Binary)

    Atmospheric Science Data Center

    2016-06-14

    ... and Order:  Reverb   Reverb Tutorial FTP Access:  Data Pool V3  |  Data Pool V4 Parameters:  Aerosol ... Order Data Additional Info:  Data Format: Big Endian/IEEE Binary; Avg Size in MB: 0.044 SCAR-B Block:  ...

  9. Solar energy collection system

    NASA Technical Reports Server (NTRS)

    Miller, C. G.; Stephens, J. B. (Inventor)

    1979-01-01

    A fixed, linear, ground-based primary reflector having an extended curved sawtooth-contoured surface covered with a metalized polymeric reflecting material, reflects solar energy to a movably supported collector that is kept at the concentrated line focus reflector primary. The primary reflector may be constructed by a process utilizing well known freeway paving machinery. The solar energy absorber is preferably a fluid transporting pipe. Efficient utilization leading to high temperatures from the reflected solar energy is obtained by cylindrical shaped secondary reflectors that direct off-angle energy to the absorber pipe. A seriatim arrangement of cylindrical secondary reflector stages and spot-forming reflector stages produces a high temperature solar energy collection system of greater efficiency.

  10. Solar system sputtering

    NASA Technical Reports Server (NTRS)

    Tombrello, T. A.

    1982-01-01

    The sites and materials involved in solar system sputtering of planetary surfaces are reviewed, together with existing models for the processes of sputtering. Attention is given to the interaction of the solar wind with planetary atmospheres in terms of the role played by the solar wind in affecting the He-4 budget in the Venus atmosphere, and the erosion and differentiation of the Mars atmosphere by solar wind sputtering. The study is extended to the production of isotopic fractionation and anomalies in interplanetary grains by irradiation, and to erosion effects on planetary satellites with frozen volatile surfaces, such as with Io, Europa, and Ganymede. Further measurements are recommended of the molecular form of the ejected material, the yields and energy spectra of the sputtered products, the iosotopic fractionation sputtering causes, and the possibility of electronic sputtering enhancement with materials such as silicates.

  11. Quasistatic Evolution of Binary Neutron Star Systems Before Merging

    NASA Astrophysics Data System (ADS)

    Eriguchi, Y.; Usui, F.

    Binary neutron star systems evolve due to the back reaction of gravitational wave emission. Although this evolution is essentially a time dependent phenomenon, most stages of the evolution can be regarded as if the system were in a stationary state. Consequently we can follow the evolution of binary neutron star systems quasistatically by connecting quasiequilibrium states of binary neutron stars. On the equilibrium sequences of congruent binary neutron star systems there are two important states of equilibrium configurations: 1) the minimum angular momentum state where some unstable phenomenon sets in and 2) the contact state from which a single body sequence will continue. Recent numerical results of quasiequilibrium approaches for the binary neutron star evolution are briefly reviewed and some problems in general relativistic treatments are discussed.

  12. XZ And a semidetached asynchronous binary system

    NASA Astrophysics Data System (ADS)

    Manzoori, Davood

    2016-05-01

    In this work the light curves (LCs) solutions along with the radial velocity curve of the semidetached binary systemXZ And are presented using the PHOEBE program(ver 0.31a). Absolute parameters of the stellar components were then determined, enabling us to discuss structure and evolutionary status of the system. The analysis indicates that the primary is a non-synchronous (i.e., F1 = 3.50 ± 0.01) Main Sequence (MS) star and the secondary is a bit more evolved, and fills its Roche critical surface. In addition, times of minima data (" O - C curve") were analyzed. Apart from an almost parabolic variation in the general trend of O - C data, which was attributed to a mass transfer from the secondary with the rate ˙2 = (9.52 ± 0.41) × 10-10 M ⊙ yr-1; two cyclic variations with mean periods of 34.8 ± 2.4 and 23.3 ± 3.0 yr, modulating the orbital period, were found, which were attributed to a third body orbiting around the system, and magnetic activity cycle effect, respectively.

  13. Baby Solar System

    NASA Technical Reports Server (NTRS)

    Currie, Thayne; Grady, Carol

    2012-01-01

    What did our solar system look like in its infancy,...... when the planets were forming? We cannot travel back in time to take an image of the early solar system, but in principle we can have the next best thing: images of infant planetary systems around Sun-like stars with ages of 1 to 5 million years, the time we think it took for the giant planets to form. Infant exoplanetary systems are critically important because they can help us understand how our solar system fits within the context of planet formation in general. More than 80% of stars are born with gas- and dust-rich disks, and thus have the potential to form planets. Through many methods we have identified more than 760 planetary systems around middle-aged stars like the Sun, but many of these have architectures that look nothing like our solar system. Young planetary systems are important missing links between various endpoints and may help us understand how and when these differences emerge. Well-known star-forming regions in Taurus, Scorpius. and Orion contain stars that could have infant planetary systems. But these stars are much more distant than our nearest neighbors such as Alpha Centauri or Sirius, making it extremely challenging to produce clear images of systems that can reveal signs of recent planet formation, let alone reveal the planets themselves. Recently, a star with the unassuming name LkCa 15 may have given us our first detailed "baby picture" of a young planetary system similar to our solar system. Located about 450 light-years away in the Taurus starforming region. LkCa 15 has a mass comparable to the Sun (0.97 solar mass) and an age of l to 5 million years, comparable to the time at which Saturn and perhaps Jupiter formed. The star is surrounded by a gas-rich disk similar in structure to the one in our solar system from which the planets formed. With new technologies and observing strategies, we have confirmed suspicions that LkCa 15's disk harbors a young planetary system.

  14. Milankovitch Cycles of Terrestrial Planets in Binary Star Systems

    NASA Astrophysics Data System (ADS)

    Forgan, Duncan

    2016-08-01

    The habitability of planets in binary star systems depends not only on the radiation environment created by the two stars, but also on the perturbations to planetary orbits and rotation produced by the gravitational field of the binary and neighbouring planets. Habitable planets in binaries may therefore experience significant perturbations in orbit and spin. The direct effects of orbital resonances and secular evolution on the climate of binary planets remain largely unconsidered. We present latitudinal energy balance modelling of exoplanet climates with direct coupling to an N Body integrator and an obliquity evolution model. This allows us to simultaneously investigate the thermal and dynamical evolution of planets orbiting binary stars, and discover gravito-climatic oscillations on dynamical and secular timescales. We investigate the Kepler-47 and Alpha Centauri systems as archetypes of P and S type binary systems respectively. In the first case, Earthlike planets would experience rapid Milankovitch cycles (of order 1000 years) in eccentricity, obliquity and precession, inducing temperature oscillations of similar periods (modulated by other planets in the system). These secular temperature variations have amplitudes similar to those induced on the much shorter timescale of the binary period. In the Alpha Centauri system, the influence of the secondary produces eccentricity variations on 15,000 year timescales. This produces climate oscillations of similar strength to the variation on the orbital timescale of the binary. Phase drifts between eccentricity and obliquity oscillations creates further cycles that are of order 100,000 years in duration, which are further modulated by neighbouring planets.

  15. SARA South Observations and Analysis of the Solar Type, Totally Eclipsing, Contact Binary, DD Indus

    NASA Astrophysics Data System (ADS)

    Samec, Ronald G.; Norris, Cody; Van Hamme, Walter V.; Faulkner, Danny R.

    2016-06-01

    DD Ind (NSVS5066754) is a Solar Type (T ~ 5850K) solar type eclipsing binary. It was observed in June to September, 2013 at Cerro Tololo in remote mode with the 0.6-m SARA South reflector. Five times of minimum light were calculated from our present observations, for three primary and two secondary eclipses: HJD Min I = 2456505.8085±0.0002, 2456533.73933±0.00003, 2456536.6378±0.0012HJD Min II = 2456503.8132±00.0014, 2456533.5583±0.0004In addition, two observations at minima were determined from archived All Sky Automated Survey Data:HJD Min II = 2452872.9104, 2452883.6097.The following quadratic ephemerides was determined from all available times of minimum light:JD Hel Min I=2456533.7394±0.0002d + 0.3627463±0.0000002 X E +0.00000000006 ± 0.00000000002 X E2A BVRcIc filtered simultaneous Wilson-Devinney Program (W-D) solution reveals that the system has a mass ratio of ~0.46, and a component temperature difference of ~200 K. Two weak (Tfact ~ 0.95, ~20 degree radius) cool spots were iterated on the secondary component in the WD Synthetic Light Curve Computations. They appeared in the Northern Hemisphere (colatitude 45 degrees) and near the equator (colatitude ~95 degrees), respectively.The Roche Lobe fill-out of the binary is ~13%. The inclination is ~84.8o. An eclipse duration of ~16 minutes was determined for the primary eclipse. Additional and more detailed information is given in the meeting report.

  16. Solar cell activation system

    SciTech Connect

    Apelian, L.

    1983-07-05

    A system for activating solar cells involves the use of phosphorescent paint, the light from which is amplified by a thin magnifying lens and used to activate solar cells. In a typical system, a member painted with phosphorescent paint is mounted adjacent a thin magnifying lens which focuses the light on a predetermined array of sensitive cells such as selenium, cadmium or silicon, mounted on a plastic board. A one-sided mirror is mounted adjacent the cells to reflect the light back onto said cells for purposes of further intensification. The cells may be coupled to rechargeable batteries or used to directly power a small radio or watch.

  17. Close binary systems before and after mass transfer. III - Spectroscopic binaries

    NASA Astrophysics Data System (ADS)

    Vansina, F.; De Greve, J. P.

    1982-10-01

    A method is presented, for the computation of absolute dimensions from spectroscopic data on binary systems, which has been adapted for use with the 7th Catalogue of Batten et al. (1978) and takes into account several results of close binary evolution, with emphasis on the phase of slow mass transfer during a case B mass transfer. Among the unevolved systems, the mass transfer case B is found to be the most abundant type of interaction. In the set of evolving systems, a subset of 18 interacting systems was found with mass ratio near unity, the first star being the mass loser as well as the brightest.

  18. Solar System Dynamics

    NASA Technical Reports Server (NTRS)

    Wisdom, Jack

    2002-01-01

    In these 18 years, the research has touched every major dynamical problem in the solar system, including: the effect of chaotic zones on the distribution of asteroids, the delivery of meteorites along chaotic pathways, the chaotic motion of Pluto, the chaotic motion of the outer planets and that of the whole solar system, the delivery of short period comets from the Kuiper belt, the tidal evolution of the Uranian arid Galilean satellites, the chaotic tumbling of Hyperion and other irregular satellites, the large chaotic variations of the obliquity of Mars, the evolution of the Earth-Moon system, and the resonant core- mantle dynamics of Earth and Venus. It has introduced new analytical and numerical tools that are in widespread use. Today, nearly every long-term integration of our solar system, its subsystems, and other solar systems uses algorithms that was invented. This research has all been primarily Supported by this sequence of PGG NASA grants. During this period published major investigations of tidal evolution of the Earth-Moon system and of the passage of the Earth and Venus through non-linear core-mantle resonances were completed. It has published a major innovation in symplectic algorithms: the symplectic corrector. A paper was completed on non-perturbative hydrostatic equilibrium.

  19. Effect of Blend Composition on Binary Organic Solar Cells Using a Low Band Gap Polymer.

    PubMed

    Wright, Matthew; Lin, Rui; Tayebjee, Murad J Y; Yang, Xiaohan; Veettil, Binesh Puthen; Wen, Xiaoming; Uddin, Ashraf

    2015-03-01

    This report investigates the influence of the solution blend composition of binary bulk heterojunction organic solar cells composed of poly(2,1,3-benzothiadiazole-4,7-diyl[4,4-bis(2-ethylhexyl)-4H- cyclopenta[2,1-b:3,4-b'dithiophene-2,6-diy

  20. ANALYSIS OF THE MOTION OF AN EXTRASOLAR PLANET IN A BINARY SYSTEM

    SciTech Connect

    Plávalová, Eva; Solovaya, Nina A. E-mail: solov@sai.msu.ru

    2013-11-01

    More than 10% of extra-solar planets (EPs) orbit in a binary or multiple stellar system. We investigated the motion of planets revolving in binary systems in the case of the three-body problem. We carried out an analysis of the motion of an EP revolving in a binary system with the following conditions: (1) a planet in a binary system revolves around one of the components (parent star); (2) the distance between the star's components is greater than that between the parent star and the orbiting planet (ratio of the semi-major axes is a small parameter); and (3) the mass of the planet is smaller than the mass of the stars, but is not negligible. The Hamiltonian of the system without short periodic terms was used. We expanded the Hamiltonian in terms of the Legendre polynomial and truncated after the second-order term, depending on only one angular variable. In this case, the solution of the system was obtained and the qualitative analysis of the motion was produced. We have applied this theory to real EPs and compared to the numerical integration. Analyses of the possible regions of motion are presented. It is shown that stable and unstable motions of EPs are possible. We applied our calculations to two binary systems hosting an EP and calculated the possible values for their unknown orbital elements.

  1. Three long-period contact or semi-detached binary systems

    NASA Astrophysics Data System (ADS)

    Li, Zong-Yun; Ding, Yue-Rong; Leung, Kam-Ching

    1988-06-01

    The photometric data of three long-period binaries are analyzed, noting that 5 Ceti and CoD-30 5135 are contact systems with respective periods of 96.41 and 158.0 days, and that HD 104901 B is a semidetached system of period 106.6 days. Combining all the available spectroscopic observations, the absolute dimensions of 5 Ceti are derived, showing a mass of 94 solar masses and a radius of 246 solar radii. Containing a supergiant or giant component may be a common characteristic of long-period, contact, or semidetached systems.

  2. Metallicity dependence of Type Ib/c and IIb supernova progenitors in binary systems

    NASA Astrophysics Data System (ADS)

    Yoon, Sung-CHul

    2015-08-01

    Type Ib/c supernovae (SNe Ib/c) are characterized by the lack of prominent hydrogen lines in the spectra, implying that their progenitors have lost most of their hydrogen envelopes by the time of the iron core collapse. Binary interactions provide an important evolutionary chanel for SNe Ib/c, and recent observations indicate that the inferred ejecta masses of SNe Ibc are more consistent with the prediction of the binary scenario than that of the single star scenario that invokes mass loss as the key evolutionary factor for SNe Ib/c progenitors. So far, theoretical predictions on the detailed properties of SNe Ib/c progenitors in binary systems have been made mostly with models using solar metallicity. However, unlike the single star scenario, where SNe Ib/c are expected only for sufficiently high metallicity, hydrogen-deficent SN progenitors can be produced via binary interactions at any metallicity. In this talk, I will discuss theoretical predictions on the metallicity dependence of the SNe Ib/c progenitor structure, based on evolutionary models of massive binary stars. Sepefically, I will address how the ejecta masses of SNe Ib and Ic and the ratio of SN Ib/c to SN IIb as well as SN Ib to SN Ic would systematically change as a function of metallicity, and which new types of SNe are expected in binary systems at low metallicity.

  3. The New Solar System

    ERIC Educational Resources Information Center

    Wilkinson, John

    2009-01-01

    Since 2006, the details of bodies making up our solar system have been revised. This was largely as a result of new discoveries of a number of planet-like objects beyond the orbit of Pluto. The International Astronomical Union redefined what constituted a planet and established two new classifications--dwarf planets and plutoids. As a result, the…

  4. Probing the Solar System

    ERIC Educational Resources Information Center

    Wilkinson, John

    2013-01-01

    Humans have always had the vision to one day live on other planets. This vision existed even before the first person was put into orbit. Since the early space missions of putting humans into orbit around Earth, many advances have been made in space technology. We have now sent many space probes deep into the Solar system to explore the planets and…

  5. Solar System Remote Sensing

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This volume contains abstracts that have been accepted for presentation at the symposium on Solar System Remote Sensing, September 20-21, 2002, in Pittsburgh, Pennsylvania. Administration and publications support for this meeting were provided by the staff of the Publications and Program Services Departments at the Lunar and Planetary Institute.

  6. The organic Solar System

    NASA Astrophysics Data System (ADS)

    Gibb, Bruce C.

    2015-05-01

    In the second of two essays looking at organic chemistry that can be found in the Solar System, Bruce C. Gibb focuses on the gas and ice giants as well as their satellites -- concluding the tour on Saturn's fascinating moon Titan.

  7. Detection of X-ray emission from the PSR 1259-63/SS 2883 binary system

    NASA Technical Reports Server (NTRS)

    Cominsky, Lynn; Roberts, Mallory; Johnston, Simon

    1994-01-01

    Nonpulsed but variable X-ray emission has been detected from the binary system containing the radio pulsar PSR 1259-63 during two pointed ROSAT observations, taken 5 months apart. This 47.7 ms radio pulsar is in a highly eccentric (epsilon approximately 0.85) binary system with the 10-15 solar mass Be star SS 2883. It is the first radio pulsar found to be in a binary system with a massive main-sequence companion; it is also the most highly eccentric binary system known to contain a neutron star. The level of X-ray flux detected in the ROSAT observations has increased with orbital phase by a factor of at least 10 between 1992 February and 1993 February. The X-ray flux is significantly greater than expected from the Be star's corona and seems likely to originate either from low-level stellar wind accretion onto the neutron star or from the shock between the stellar wind and the relativistic pulsar wind. The system may be the progenitor of the more slowly rotating Be X-ray binary pulsar systems.

  8. Photometric Analysis of the Very Short Period Solar Type Binary, FY Bootis

    NASA Astrophysics Data System (ADS)

    Samec, Ronald G.; Oliver, B.; Jaso, A.; Faulkner, D. R.; Hamme, W. V.

    2010-05-01

    We present a BVRcIc photometric analyses of the very short period eclipsing binary, FY Bootis. Our observations were taken with the 0.81-m Lowell Reflector on March 10-14 2009. A period study and a light curve solution is presented. The light curves were premodeled with Binary 3.0, then solved with the 2004 version Wilson code with intermediate integrations performed with PHOEBE. Our modeled light curves included 107 B, 109 V, 95 R and 98 I individual CCD observations taken with the 2K X 2K NASACAM. A hotter star modeling temperature of 4750 K was chosen after considering 2MASS J-H and H-K values and the Rucinski (1994) period color relation. These gave spectral types in the K0-K5V range. Six mean times of minimum light were determined, including HJDMin I= 2454901.9711 (±0.0022)d, 2454902.9350 (±0.0024)d, 2454904.8587 (±0.0002)d, 2454905.8304 (±0.0002)d and HJDMin II=2454904.9774 (±0.0007)d, 2454905.9491 (±0.0002)d. Some 30 minima from the literature were included with ours to reveal a sinusoidal ephemeris: HJD Min I =2454904.8646 (±0.0018)d + 0. 24116(±0.00158)*E +(0.0016±0.00004)sin [(0.00051±0.00006)*E-(0.4±0.6)]. The period of oscillation is 8±1 years with an amplitude of 0.2 AU in light travel time, assuming the orbital inclination of a third component is identical to the main binary orbit. The third body has 0.05 solar masses. Our Wilson Code analysis of FY Boo revealed it to be a W-type contact binary (the less massive component is the hotter) and a mass ratio of 2.5. The system parameters included a fill-out of 0.11, a component temperature difference of 200 K and an inclination of 82o. One large 68o magnetic region was modeled on the hotter companion with an average temperature of 0.96 times that of the photosphere. We wish to thank the American Astronomical Society for supporting this research through its small research grant program.

  9. Equilibrium, stability, and orbital evolution of close binary systems

    NASA Technical Reports Server (NTRS)

    Lai, Dong; Rasio, Frederic A.; Shapiro, Stuart L.

    1994-01-01

    We present a new analytic study of the equilibrium and stability properties of close binary systems containing polytropic components. Our method is based on the use of ellipsoidal trial functions in an energy variational principle. We consider both synchronized and nonsynchronized systems, constructing the compressible generalizations of the classical Darwin and Darwin-Riemann configurations. Our method can be applied to a wide variety of binary models where the stellar masses, radii, spins, entropies, and polytropic indices are all allowed to vary over wide ranges and independently for each component. We find that both secular and dynamical instabilities can develop before a Roche limit or contact is reached along a sequence of models with decreasing binary separation. High incompressibility always makes a given binary system more susceptible to these instabilities, but the dependence on the mass ratio is more complicated. As simple applications, we construct models of double degenerate systems and of low-mass main-sequence star binaries. We also discuss the orbital evoltuion of close binary systems under the combined influence of fluid viscosity and secular angular momentum losses from processes like gravitational radiation. We show that the existence of global fluid instabilities can have a profound effect on the terminal evolution of coalescing binaries. The validity of our analytic solutions is examined by means of detailed comparisons with the results of recent numerical fluid calculations in three dimensions.

  10. Close encounters of the third-body kind. [intruding bodies in binary star systems

    NASA Technical Reports Server (NTRS)

    Davies, M. B.; Benz, W.; Hills, J. G.

    1994-01-01

    We simulated encounters involving binaries of two eccentricities: e = 0 (i.e., circular binaries) and e = 0.5. In both cases the binary contained a point mass of 1.4 solar masses (i.e., a neutron star) and a 0.8 solar masses main-sequence star modeled as a polytrope. The semimajor axes of both binaries were set to 60 solar radii (0.28 AU). We considered intruders of three masses: 1.4 solar masses (a neutron star), 0.8 solar masses (a main-sequence star or a higher mass white dwarf), and 0.64 solar masses (a more typical mass white dwarf). Our strategy was to perform a large number (40,000) of encounters using a three-body code, then to rerun a small number of cases with a three-dimensional smoothed particle hydrodynamics (SPH) code to determine the importance of hydrodynamical effects. Using the results of the three-body runs, we computed the exchange across sections, sigma(sub ex). From the results of the SPH runs, we computed the cross sections for clean exchange, denoted by sigma(sub cx); the formation of a triple system, denoted by sigma(sub trp); and the formation of a merged binary with an object formed from the merger of two of the stars left in orbit around the third star, denoted by sigma(sub mb). For encounters between either binary and a 1.4 solar masses neutron star, sigma(sub cx) approx. 0.7 sigma(sub ex) and sigma(sub mb) + sigma(sub trp) approx. 0.3 sigma(sub ex). For encounters between either binary and the 0.8 solar masses main-sequence star, sigma(sub cx) approx. 0.50 sigma(sub ex) and sigma(sub mb) + sigma(sub trp) approx. 1.0 sigma(sub ex). If the main sequence star is replaced by a main-sequence star of the same mass, we have sigma(sub cx) approx. 0.5 sigma(sub ex) and sigma(sub mb) + sigma(sub trp) approx. 1.6 sigma(sub ex). Although the exchange cross section is a sensitive function of intruder mass, we see that the cross section to produce merged binaries is roughly independent of intruder mass. The merged binaries produced have semi

  11. Photometric Study on an Eclipsing Close Binary System NSVS 14256825

    NASA Astrophysics Data System (ADS)

    Yilmaz, Semra; Kalomeni, Belinda

    2016-07-01

    Photometric Study on an Eclipsing Close Binary System NSVS 14256825 We present multi colour light variations of a close binary system NSVS14256825 obtained at the TÜBİTAK National Observatory with T100 telescope. Orbital and physical parameters of the system NSVS14256825 are obtained by simultaneous solution of the newly obtained data with the photometric and spectroscopic data that exist in the literature .

  12. NASA's Solar System Exploration Program

    NASA Technical Reports Server (NTRS)

    Robinson, James

    2005-01-01

    A viewgraph presentation describing NASA's Solar System Exploration Program is shown. The topics include: 1) Solar System Exploration with Highlights and Status of Programs; 2) Technology Drivers and Plans; and 3) Summary

  13. Are the orbital poles of binary stars in the solar neighbourhood anisotropically distributed?

    NASA Astrophysics Data System (ADS)

    Agati, J.-L.; Bonneau, D.; Jorissen, A.; Soulié, E.; Udry, S.; Verhas, P.; Dommanget, J.

    2015-02-01

    We test whether or not the orbital poles of the systems in the solar neighbourhood are isotropically distributed on the celestial sphere. The problem is plagued by the ambiguity on the position of the ascending node. Of the 95 systems closer than 18 pc from the Sun with an orbit in the 6th Catalogue of Orbits of Visual Binaries, the pole ambiguity could be resolved for 51 systems using radial velocity collected in the literature and CORAVEL database or acquired with the HERMES/Mercator spectrograph. For several systems, we can correct the erroneous nodes in the 6th Catalogue of Orbits and obtain new combined spectroscopic/astrometric orbits for seven systems [WDS 01083+5455Aa,Ab; 01418+4237AB; 02278+0426AB (SB2); 09006+4147AB (SB2); 16413+3136AB; 17121+4540AB; 18070+3034AB]. We used of spherical statistics to test for possible anisotropy. After ordering the binary systems by increasing distance from the Sun, we computed the false-alarm probability for subsamples of increasing sizes, from N = 1 up to the full sample of 51 systems. Rayleigh-Watson and Beran tests deliver a false-alarm probability of 0.5% for the 20 systems closer than 8.1 pc. To evaluate the robustness of this conclusion, we used a jackknife approach, for which we repeated this procedure after removing one system at a time from the full sample. The false-alarm probability was then found to vary between 1.5% and 0.1%, depending on which system is removed. The reality of the deviation from isotropy can thus not be assessed with certainty at this stage, because only so few systems are available, despite our efforts to increase the sample. However, when considering the full sample of 51 systems, the concentration of poles toward the Galactic position l = 46.0°, b = 37°, as observed in the 8.1 pc sphere, totally vanishes (the Rayleigh-Watson false-alarm probability then rises to 18%). Tables 1-3 and Appendices are available in electronic form at http://www.aanda.org† Deceased October 1, 2014.

  14. Binary Asteroids

    NASA Astrophysics Data System (ADS)

    Harris, Alan W.; Pravec, P.

    2006-06-01

    There are now nearly 100 binary asteroids known. In the last year alone, 30 binary asteroids have been discovered, half of them by lightcurves showing eclipse events. Similar to eclipsing binary stars, such observations allow determination of orbit period and sizes and shapes of the primary and secondary relative to the orbital dimension. From these parameters one can estimate the mean density of the system, and a number of dynamical properties such as total specific angular momentum, tidal evolution time scales of spins and orbit, and precession frequencies of the orbit about the primary and of the solar induced "general precession" of the system. We have extracted parameters for all systems with enough observations to allow meaningful determinations. Some preliminary results include: (1) Binaries are roughly as prevalent among small main-belt asteroids as among Near-Earth Asteroids. (2) Most binaries are partially asynchronous, with the secondary synchronized to the orbit period, but the primary still spinning much faster. This is consistent with estimated tidal damping time scales. (3) Most systems have near the critical maximum angular momentum for a single "rubble pile" body, but not much more, and some less. Thus fission appears not to be a viable formation mechanism for all binaries, although near-critical spin rate seems to play a role. (4) Orbits of the secondaries are essentially in the equatorial plane of the primary. Since most primary spins are still fast, the satellites must have been formed into low inclination orbits. (5) Precession frequencies are in the range of the shorter resonance frequencies in the solar system (tens of thousands of years), thus resonance interactions can be expected to have altered spin orientations as systems evolved slowly by tidal friction or other processes. (6) Primaries are unusually spheroidal, which is probably necessary for stability of the binary once formed.

  15. KOI-3278: A Self-Lensing Binary Star System

    NASA Astrophysics Data System (ADS)

    Kruse, Ethan; Agol, Eric

    2014-04-01

    Over 40% of Sun-like stars are bound in binary or multistar systems. Stellar remnants in edge-on binary systems can gravitationally magnify their companions, as predicted 40 years ago. By using data from the Kepler spacecraft, we report the detection of such a “self-lensing” system, in which a 5-hour pulse of 0.1% amplitude occurs every orbital period. The white dwarf stellar remnant and its Sun-like companion orbit one another every 88.18 days, a long period for a white dwarf-eclipsing binary. By modeling the pulse as gravitational magnification (microlensing) along with Kepler’s laws and stellar models, we constrain the mass of the white dwarf to be ~63% of the mass of our Sun. Further study of this system, and any others discovered like it, will help to constrain the physics of white dwarfs and binary star evolution.

  16. KOI-3278: a self-lensing binary star system.

    PubMed

    Kruse, Ethan; Agol, Eric

    2014-04-18

    Over 40% of Sun-like stars are bound in binary or multistar systems. Stellar remnants in edge-on binary systems can gravitationally magnify their companions, as predicted 40 years ago. By using data from the Kepler spacecraft, we report the detection of such a "self-lensing" system, in which a 5-hour pulse of 0.1% amplitude occurs every orbital period. The white dwarf stellar remnant and its Sun-like companion orbit one another every 88.18 days, a long period for a white dwarf-eclipsing binary. By modeling the pulse as gravitational magnification (microlensing) along with Kepler's laws and stellar models, we constrain the mass of the white dwarf to be ~63% of the mass of our Sun. Further study of this system, and any others discovered like it, will help to constrain the physics of white dwarfs and binary star evolution. PMID:24744369

  17. High Efficiency Pb-In Binary Metal Perovskite Solar Cells.

    PubMed

    Wang, Zhao-Kui; Li, Meng; Yang, Ying-Guo; Hu, Yun; Ma, Heng; Gao, Xing-Yu; Liao, Liang-Sheng

    2016-08-01

    Mixed Pb-In perovskite solar cells are fabricated by using lead(II) chloride and indium(III) chloride with methylammonium iodide. A maximum power conversion efficiency as high as 17.55% is achieved owing to the high quality of perovskites with multiple ordered crystal orientations. PMID:27184107

  18. Performance of binary FSK data transmission systems

    NASA Technical Reports Server (NTRS)

    Batson, B. H.

    1973-01-01

    Matched-filter detection of binary signals is discussed in terms of the probability of bit error. The equations for the probability of error are derived for coherent phase shift keying, and coherent frequency shift keying (FSK). Suboptimum detection of FSK signals is also discussed for discriminators.

  19. BVRI Photometric Study of the Totally Eclipsing Short Period Solar Type, Near-Contact W UMA Binary, NSVS 5066754

    NASA Astrophysics Data System (ADS)

    Caton, Daniel B.; Samec, Ronald G.; Nyaude, Ropafadzo; Faulkner, Danny R.

    2016-06-01

    High precision BVRcIc light curves of NSVS 5066754 were observed on May 17-20, 2014 at Dark Sky Observatory in North Carolina with the 0.81-m reflector of Appalachian State University. It is a solar type eclipsing binary (T1~5750 K) with a period of only 0.375132 (1) d. In fact, it appeared as one of the shortest period in Shaw’s list of near contact binaries. Therefore, we initially believed this to be a pre-contact WUMa Binary (PCWB’s). However, the Binary Maker fits and our Wilson-Devinney solutions show that the binary could have either a semi-detached or a contact binary configuration.Five times of minimum light were calculated, for 3 primary and 2 secondary eclipses from our present observations: In addition, observations at minima were introduced from archived All Sky Automated Survey Data along with the discovery ephemeris. The following decreasing quadratic ephemeris was determined from all available times of minimum light:JDHelMinI=2456797.63848±0.00047d + 0.3747796± 0. 0000068 X E --0.0000000241± 0.0000000005X E2Our contact solution, with a sum of square residuals = 0.49, gave a mass ratio of 0.50, and a component temperature difference of ~360 K, somewhat large for a contact binary. Two substantial cool spots were determined in this solution of 37 deg and 28 deg radius with a t-factor or 0.92 and 0.78 respectively. The fill-out is very shallow, ~6%.The semi-detached solution (mode 4: V1010 Oph configuration, meaning the system is approaching first contact) is of poorer quality with a sum of square residuals = 0.87. It has a mass ratio of 0.63, and a component temperature of ~460 K. The fill-outs are 100% and 97% for the primary and secondary components, respectively. Two spots were determined, one hot (t-factor of 1.16, 14 deg radius, colatitude 101 deg) and one cool spot (t-factor of 0.94, 48 deg radius, colatitude 90 deg). The models in both cases are total eclipsing with high inclinations in the 86-89 deg range, and a time of constant light is

  20. The evolution of highly compact binary stellar systems in globular clusters

    NASA Technical Reports Server (NTRS)

    Krolik, J. H.; Meiksin, A.; Joss, P. C.

    1984-01-01

    A highly compact binary represents a system which is composed of a collapsed object (degenerate dwarf, neutron star, or black hole) in orbit with a low-mass (equal to or less than 0.5 solar mass) secondary star. Matter may be transferred from the secondary to the collapsed star due to the decay of the orbit resulting from the emission of gravitational radiation. The present investigation has the objective to study quantitatively the evolution of highly compact binaries in globular cluster cores, subject to the interplay of gravitational radiation and collisions with field stars. The investigation is exploratory in nature. The numerical methods employed are based on the techniques developed by Rappaport et al. (1982). It is found that occasional close encounters with field stars strongly dominate the evolution of highly compact binaries in dense globular cluster cores. Attention is given to the applicability of the findings to observations of X-ray sources and cataclysmic variables.

  1. Deep, Low Mass Ratio Overcontact Binary Systems. V. The Lowest Mass Ratio Binary V857 Herculis

    NASA Astrophysics Data System (ADS)

    Qian, S.-B.; Zhu, L.-Y.; Soonthornthum, B.; Yuan, J.-Z.; Yang, Y.-G.; He, J.-J.

    2005-09-01

    Charge-coupled device (CCD) photometric light curves in the B, V, and R bands of the complete eclipsing binary star V857 Her are presented. It is shown that the light curves of the W UMa-type binary are symmetric and of A type according to Binnendijk's classification. Our four epochs of light minimum along with others compiled from the literature were used to revise the period and study the period change. Weak evidence indicates that the orbital period of V857 Her may show a continuous increase at a rate of dP/dt=+2.90×10-7 days yr-1. The photometric parameters of the system were determined with the 2003 version of the Wilson-Devinney code. It is shown that V857 Her is a deep overcontact binary system with f=83.8%+/-5.1%. The derived mass ratio of q=0.06532+/-0.0002 suggests that it has the lowest mass ratio among overcontact binary systems. As the orbital period increases, the decrease of the mass ratio will cause it to evolve into a single rapidly rotating star when it meets the more familiar criterion that the orbital angular momentum be less than 3 times the total spin angular momentum. To understand the evolutionary state of the system, long-term photometric monitoring and spectroscopic observations will be required.

  2. The missing Wolf-Rayet X-ray binary systems

    NASA Astrophysics Data System (ADS)

    Munoz, M.; Moffat, A. F. J.; Hill, G. M.; Richardson, N. D.; Pablo, H.

    We investigate the rarity of the Wolf-Rayet X-ray binaries (WRXRBs) in contrast to their predecessors, the high mass X-ray binaries (HMXRBs). Recent studies suggest that common envelope (CE) mergers during the evolution of a HMXRBs may be responsible (Linden et al. 2012). We conduct a binary population synthesis to generate a population of HMXRBs mimicking the Galactic sample and vary the efficiency parameter during the CE phase to match the current WRXRB to HMXRB ratio. We find that ˜50% of systems must merge to match observational constraints.

  3. Digital solar system geology

    NASA Technical Reports Server (NTRS)

    Batson, R. M.; Kozak, R. C.; Isbell, Nancy K.

    1991-01-01

    All available synoptic maps of the solid-surface bodies of the Solar System were digitized for presentation in the planned Atlas of the Solar System by Greeley and Batson. Since the last report (Batson et al., 1990), preliminary Uranian satellite maps were replaced with improved versions, Galilean satellite geology was simplified and digitized, structure was added to many maps, and the maps were converted to a standard format, with corresponding standing colors for the mapped units. Following these changes, the maps were re-reviewed by their authors and are now undergoing final editing before preparation for publication. In some cases (for Mercury, Venus, and Mars), more detailed maps were digitized and then simplified for the Atlas. Other detailed maps are planned to be digitized in the coming year for the Moon and the Galilean satellites. For most of the remaining bodies such as the Uranian satellites, the current digitized versions contain virtually all the detail that can be mapped given the available data; those versions will be unchanged for the Atlas. These digital geologic maps are archived at the digital scale of 1/16 degree/ pixel, in sinusoidal format. The availability of geology of the Solar System in a digital database will facilitate comparisons and integration with other data: digitized lunar geologic maps have already been used in a comparison with Galileo SSI observations of the Moon.

  4. Solar trough systems

    SciTech Connect

    1998-04-01

    Trough systems predominate among today`s commercial solar power plants. All together, nine trough power plants, also called Solar Energy Generating Systems (SEGS), were built in the 1980s in the Mojave Desert near Barstow, California. These plants have a combined capacity of 354 megawatts (MW) and today generate enough electricity to meet the needs of approximately 500,000 people. Trough systems convert the heat from the sun into electricity. Because of their parabolical shape, troughs can focus the sun at 30--60 times its normal intensity on a receiver pipe located along the focal line of the trough. Synthetic oil captures this heat as the oil circulates through the pipe, reaching temperatures as high as 390 C (735 F). The hot oil is pumped to a generating station and routed through a heat exchanger to produce steam. Finally, electricity is produced in a conventional steam turbine. In addition to operating on solar energy the SEGS plants are configured as hybrids to operate on natural gas on cloudy days or after dark. Natural gas provides 25% of the output of the SEGS plants.

  5. Solar Powered Refrigeration System

    NASA Technical Reports Server (NTRS)

    Ewert, Michael K. (Inventor); Bergeron, David J., III (Inventor)

    2002-01-01

    A solar powered vapor compression refrigeration system is made practicable with thermal storage and novel control techniques. In one embodiment, the refrigeration system includes a photovoltaic panel, a variable speed compressor, an insulated enclosure, and a thermal reservoir. The photovoltaic (PV) panel converts sunlight into DC (direct current) electrical power. The DC electrical power drives a compressor that circulates refrigerant through a vapor compression refrigeration loop to extract heat from the insulated enclosure. The thermal reservoir is situated inside the insulated enclosure and includes a phase change material. As heat is extracted from the insulated enclosure, the phase change material is frozen, and thereafter is able to act as a heat sink to maintain the temperature of the insulated enclosure in the absence of sunlight. The conversion of solar power into stored thermal energy is optimized by a compressor control method that effectively maximizes the compressor's usage of available energy. A capacitor is provided to smooth the power voltage and to provide additional current during compressor start-up. A controller monitors the rate of change of the smoothed power voltage to determine if the compressor is operating below or above the available power maximum, and adjusts the compressor speed accordingly. In this manner, the compressor operation is adjusted to convert substantially all available solar power into stored thermal energy.

  6. Solar system plasma waves

    NASA Technical Reports Server (NTRS)

    Gurnett, Donald A.

    1995-01-01

    An overview is given of spacecraft observations of plasma waves in the solar system. In situ measurements of plasma phenomena have now been obtained at all of the planets except Mercury and Pluto, and in the interplanetary medium at heliocentric radial distances ranging from 0.29 to 58 AU. To illustrate the range of phenomena involved, we discuss plasma waves in three regions of physical interest: (1) planetary radiation belts, (2) planetary auroral acceleration regions and (3) the solar wind. In each region we describe examples of plasma waves that are of some importance, either due to the role they play in determining the physical properties of the plasma, or to the unique mechanism involved in their generation.

  7. Advanced Solar Power Systems

    NASA Technical Reports Server (NTRS)

    Atkinson, J. H.; Hobgood, J. M.

    1984-01-01

    The Advanced Solar Power System (ASPS) concentrator uses a technically sophisticated design and extensive tooling to produce very efficient (80 to 90%) and versatile energy supply equipment which is inexpensive to manufacture and requires little maintenance. The advanced optical design has two 10th order, generalized aspheric surfaces in a Cassegrainian configuration which gives outstanding performance and is relatively insensitive to temperature changes and wind loading. Manufacturing tolerances also have been achieved. The key to the ASPS is the direct absorption of concentrated sunlight in the working fluid by radiative transfers in a black body cavity. The basic ASPS design concepts, efficiency, optical system, and tracking and focusing controls are described.

  8. Solar system exploration

    NASA Technical Reports Server (NTRS)

    Chapman, Clark R.; Ramlose, Terri (Editor)

    1989-01-01

    The goal of planetary exploration is to understand the nature and development of the planets, as illustrated by pictures from the first two decades of spacecraft missions and by the imaginations of space artists. Planets, comets, asteroids, and moons are studied to discover the reasons for their similarities and differences and to find clues that contain information about the primordial process of planet origins. The scientific goals established by the National Academy of Sciences as the foundation of NASA's Solar System Exploration Program are covered: to determine the nature of the planetary system, to understand its origin and evolution, the development of life on Earth, and the principles that shape present day Earth.

  9. Mergers of Binary Neutron Star Systems

    NASA Astrophysics Data System (ADS)

    Motl, Patrick M.; Anderson, Matthew; Lehner, Luis; Liebling, Steven; Neilsen, David; Palenzuela, Carlos

    2016-04-01

    We present results from fully relativistic simulations of binary neutron star mergers varying the tabular equation of state used to approximate the degenerate material and the mass ratio. The simulations incorporate both magnetic fields and the effects of neutrino cooling. In particular, we examine the amount and properties of material ejected from the merger. We gratefully acknowledge the support of NASA through the Astrophysics Theory Program grant NNX13AH01G.

  10. Solar-System Ephemeris Toolbox

    NASA Technical Reports Server (NTRS)

    Walker, Charles F.

    2005-01-01

    NASA s Jet Propulsion Laboratory (JPL) generates planetary and lunar ephemeris data and FORTRAN routines that allow users to obtain state data for the Sun, the moon, and the planets. The JPL Solar System Ephemeris Toolbox, developed at Kennedy Space Center, is a set of functions that provides the same functionality in the MATLAB computing environment along with some additional capabilities. The toolbox can be used interactively via a graphical user interface (GUI), or individual functions can be called from the MATLAB command prompt or other MATLAB scripts and functions. The toolbox also includes utility functions to define and perform coordinate transformation (e.g., mean-of-date, true-of-date, J2000) that are common in the use of these ephemerides. An attached README file guides the user through the process of constructing binary ephemeris files, verifying correct installation, and using functions to extract state data. This process also can be performed using the GUI. Help from each toolbox function is available through MATLAB s "help" function. Many of the functions in the toolbox are MATLAB equivalents of the JPL-written FORTRAN programs and subroutines used for the same purposes. A novice can use the GUI to extract state data, while a more experienced user can use the functions directly, as needed, in his/her applications. The toolbox has been tested using MATLAB Releases 13 an

  11. Speckle interferometry applied to asteroids and other solar system objects

    NASA Technical Reports Server (NTRS)

    Drummond, J. D.; Hege, E. K.

    1985-01-01

    The application of speckle interferometry to asteroids and other solar system objects is discussed. The assumption of a triaxial ellipsoid rotating about its shortest axis is the standard model. Binary asteroids, 433 Eros, 532 Herculina, 511 Davida, and Pallas are discussed.

  12. THE SPECTROSCOPIC ORBITS OF FIVE SOLAR-TYPE, SINGLE-LINED BINARIES

    SciTech Connect

    Fekel, Francis C.; Rajabi, Samira; Muterspaugh, Matthew W.; Williamson, Michael H. E-mail: samira@coe.tsuniv.edu E-mail: michael.h.williamson@gmail.com

    2013-04-15

    We have determined spectroscopic orbits for five single-lined spectroscopic binaries, HD 100167, HD 135991, HD 140667, HD 158222, HD 217924. Their periods range from 60.6 to 2403 days and the eccentricities from 0.20 to 0.84. Our spectral classes for the stars confirm that they are of solar type, F9-G5, and all are dwarfs. Their [Fe/H] abundances, determined spectroscopically, are close to the solar value and on average are 0.12 greater than abundances from a photometric calibration. Four of the five stars are rotating faster than their predicted pseudosynchronous rotational velocities.

  13. Magnetised winds in single and binary star systems

    NASA Astrophysics Data System (ADS)

    Johnstone, Colin

    2016-07-01

    Stellar winds are fundamentally important for the stellar magnetic activity evolution and for the immediate environment surrounding their host stars. Ionised winds travel at hundreds of km/s, impacting planets and clearing out large regions around the stars called astropheres. Winds influence planets in many ways: for example, by compressing the magnetosphere and picking up atmospheric particles, they can cause significant erosion of a planetary atmosphere. By removing angular momentum, winds cause the rotation rates of stars to decrease as they age. This causes the star's magnetic dynamo to decay, leading to a significant decay in the star's levels of X-ray and extreme ultraviolet emission. Despite their importance, little is currently known about the winds of other Sun-like stars. Their small mass fluxes have meant that no direct detections have so far been possible. What is currently known has either been learned indirectly or through analogies with the solar wind. In this talk, I will review what is known about the properties and evolution of the winds of other Sun-like stars. I will also review wind dynamics in binary star systems, where the winds from both stars impact each other, leading to shocks and compression regions.

  14. Terrestrial solar thermionic energy conversion systems concept

    NASA Technical Reports Server (NTRS)

    Shimada, K.; Swerdling, M.

    1975-01-01

    Results obtained from studies of a (1) solar concentrator, (2) solar energy receiver - thermionic converter system, and (3) solar thermionic topping system are described. Peripheral subsystems, which are required for any solar energy conversion system, are also discussed.

  15. Solar thermal power system

    DOEpatents

    Bennett, Charles L.

    2010-06-15

    A solar thermal power generator includes an inclined elongated boiler tube positioned in the focus of a solar concentrator for generating steam from water. The boiler tube is connected at one end to receive water from a pressure vessel as well as connected at an opposite end to return steam back to the vessel in a fluidic circuit arrangement that stores energy in the form of heated water in the pressure vessel. An expander, condenser, and reservoir are also connected in series to respectively produce work using the steam passed either directly (above a water line in the vessel) or indirectly (below a water line in the vessel) through the pressure vessel, condense the expanded steam, and collect the condensed water. The reservoir also supplies the collected water back to the pressure vessel at the end of a diurnal cycle when the vessel is sufficiently depressurized, so that the system is reset to repeat the cycle the following day. The circuital arrangement of the boiler tube and the pressure vessel operates to dampen flow instabilities in the boiler tube, damp out the effects of solar transients, and provide thermal energy storage which enables time shifting of power generation to better align with the higher demand for energy during peak energy usage periods.

  16. Models for supernova progenitors in massive binary systems

    NASA Astrophysics Data System (ADS)

    Yoon, Sung Chul

    2014-09-01

    The diversity of core-collapse supernovae is closely related to binary interactions. For example, the majority of Type Ib/c and Type IIb supernovae may occur in massive binary systems as a result of mass transfer at various evolutionary stages. I will present some evolutionary models of massive binary stars including several important physical ingredients, like tidal interactions and mass and angular momentum exchange, and discuss their implications for supernova progenitors and their populations. I will particularly emphasize that Type Ib/c supernova progenitors at their pre-supernova stage should have very different properties compared to the observed Wolf-Rayet stars, which are widely believed to represent SN Ibc progenitors, and that many observed properties of SNe Ib/c and IIb can be explained well with the binary scenario.

  17. Near-Contact Binaries (NCB): Close Binary Systems in a Key Evolutionary Stage

    NASA Astrophysics Data System (ADS)

    Zhu, L. Y.; Qian, S. B.

    2007-08-01

    Short-period eclipsing binary systems with EB-type light variations are interesting objects for understanding the evolutionary changes undergone by close binaries. As investigated by many authors (Kalużny, J., Yamasaki, A., Zhai, D. S, Zhang, X. B Hilditch, R. W., McFarlane, T. M, King, D. J, Shaw, J. S., Samec, R. G., Niarchos, P. G., Oh, Kyu-Dong. etc ), a majority of them belong to an important subclass of close binaries called near-contact binaries (NCBs). According to the geometric definition of this subclass, NCBs actually comprise semi-detached, marginal-contact, and marginal-detached systems. They can be in the intermediate stage between detached or semi-detached state and contact state. Therefore, NCBs are the important observational targets which may be lying in key evolutionary states. In this paper, we observed and investigated several NCBs (BL And, GW Tau, RU UMi, GSC3658-0076, UU Lyn, AS Ser, IR Cas, EP Aur). Our results show that the orbital periods of BL And, GW Tau, RU UMi and UU Lyn are decreasing while that of IR Cas is decreasing and oscillating. The mechanisms that could explain the period variations are discussed. Combining the photometric solutions with period variations of these systems, we divide them into four types: BL And is a semi-detached system with the lobe filling primary, RU UMi and EP Aur are the semi-detached system with the lobe filling secondary, GW Tau, UU Lyn and AS Ser are the marginal contact system while GSC3658-0076 is the marginal detached system. Finally, the evolutionary stage of each system is discussed and some statistical relations of NCBs are presented.

  18. Improved solar heating systems

    DOEpatents

    Schreyer, J.M.; Dorsey, G.F.

    1980-05-16

    An improved solar heating system is described in which the incident radiation of the sun is absorbed on collector panels, transferred to a storage unit and then distributed as heat for a building and the like. The improvement is obtained by utilizing a storage unit comprising separate compartments containing an array of materials having different melting points ranging from 75 to 180/sup 0/F. The materials in the storage system are melted in accordance with the amount of heat absorbed from the sun and then transferred to the storage system. An efficient low volume storage system is provided by utilizing the latent heat of fusion of the materials as they change states in storing ad releasing heat for distribution.

  19. Solar heating system

    DOEpatents

    Schreyer, James M.; Dorsey, George F.

    1982-01-01

    An improved solar heating system in which the incident radiation of the sun is absorbed on collector panels, transferred to a storage unit and then distributed as heat for a building and the like. The improvement is obtained by utilizing a storage unit comprising separate compartments containing an array of materials having different melting points ranging from 75.degree. to 180.degree. F. The materials in the storage system are melted in accordance with the amount of heat absorbed from the sun and then transferred to the storage system. An efficient low volume storage system is provided by utilizing the latent heat of fusion of the materials as they change states in storing and releasing heat for distribution.

  20. Searching for Binary Y Dwarfs with the Gemini Multi-conjugate Adaptive Optics System (GeMS)

    NASA Astrophysics Data System (ADS)

    Opitz, Daniela; Tinney, C. G.; Faherty, Jacqueline K.; Sweet, Sarah; Gelino, Christopher R.; Kirkpatrick, J. Davy

    2016-03-01

    The NASA Wide-field Infrared Survey Explorer (WISE) has discovered almost all the known members of the new class of Y-type brown dwarfs. Most of these Y dwarfs have been identified as isolated objects in the field. It is known that binaries with L- and T-type brown dwarf primaries are less prevalent than either M-dwarf or solar-type primaries, they tend to have smaller separations and are more frequently detected in near-equal mass configurations. The binary statistics for Y-type brown dwarfs, however, are sparse, and so it is unclear if the same trends that hold for L- and T-type brown dwarfs also hold for Y-type ones. In addition, the detection of binary companions to very cool Y dwarfs may well be the best means available for discovering even colder objects. We present results for binary properties of a sample of five WISE Y dwarfs with the Gemini Multi-Conjugate Adaptive Optics System. We find no evidence for binary companions in these data, which suggests these systems are not equal-luminosity (or equal-mass) binaries with separations larger than ˜0.5-1.9 AU. For equal-mass binaries at an age of 5 Gyr, we find that the binary binding energies ruled out by our observations (i.e., 1042 erg) are consistent with those observed in previous studies of hotter ultra-cool dwarfs.

  1. Planetary Dynamics and Evolution in Evolved Binary Systems

    NASA Astrophysics Data System (ADS)

    Perets, Hagai; Kratter, K.; Kenyon, S.

    2011-09-01

    Exo-planets typically form in protoplanetary disks left over from the formation of their host star. We discuss additional evolutionary routes which may may exist in old evolved binary systems. Stellar evolution in binaries could lead to the formation of symbiotic stars, where mass is lost from one star and (partially) transferred to its binary companion, forming an accretion disk. Planetary orbits around the mass losing star can expand and destabilize, and may result in chaotic evolution. Possible outcomes include exchange of the planet to the companion star, ejection, collision, or tidal capture by one of the binary components. We show that the conditions in the newly formed accretion disk could be very similar to protoplanetary disks. Planets around the accreting companion may interact with the disk, leading to (re)growth and (re)migration of the planets. The disk may also provide the necessary environment for the formation of a new, second generation of planets in both circumstellar or circumbinary configurations. Pre-existing planets and/or planetesimals may serve as seeds for the formation of the second generation planets. Such systems should be found in white dwarf binary systems, and may show various unique observational signatures. Most notably, second generation planets could form in environments which are unfavorable for first generation planets. The phase space available for these planets could be forbidden (unstable) to first generation planets in the pre-evolved progenitor binaries. Planets may also form in double compact object binaries and in metal poor environments. Observations of exo-planets in such unfavorable regions could possibly serve to uniquely identify their second generation character. Finally, we point out a few observed candidate second generation planetary systems (Gl 86, HD 27442 and observed circumbinary planet candidates). A second generation origin for these systems could explain their unique configurations.

  2. Outer Solar System Nomenclature

    NASA Technical Reports Server (NTRS)

    Owen, Tobias C.

    1998-01-01

    The Principal Investigator's responsibilities on this grant fell into two categories according to his participation. In the nomenclature work of the International Astronomical Union (IAU). Owen is chair of the Task Group for the Outer Solar System. He is also a member of the IAU's Working Group on Planetary and Satellite Nomenclature (WGPSN) which is composed of the chairs of the several Task Groups plus the presidents of two IAU Commissions and several outside consultants. The WGPSN is presided over by its President, Professor Kaare Aksnes from the Rosseland Institute for Theoretical Astrophysics in Oslo, Norway.

  3. Solar System Visualizations

    NASA Technical Reports Server (NTRS)

    Brown, Alison M.

    2005-01-01

    Solar System Visualization products enable scientists to compare models and measurements in new ways that enhance the scientific discovery process, enhance the information content and understanding of the science results for both science colleagues and the public, and create.visually appealing and intellectually stimulating visualization products. Missions supported include MER, MRO, and Cassini. Image products produced include pan and zoom animations of large mosaics to reveal the details of surface features and topography, animations into registered multi-resolution mosaics to provide context for microscopic images, 3D anaglyphs from left and right stereo pairs, and screen captures from video footage. Specific products include a three-part context animation of the Cassini Enceladus encounter highlighting images from 350 to 4 meter per pixel resolution; Mars Reconnaissance Orbiter screen captures illustrating various instruments during assembly and testing at the Payload Hazardous Servicing Facility at Kennedy Space Center; and an animation of Mars Exploration Rover Opportunity's 'Rub al Khali' panorama where the rover was stuck in the deep fine sand for more than a month. This task creates new visualization products that enable new science results and enhance the public's understanding of the Solar System and NASA's missions of exploration.

  4. Exploration of the solar system

    NASA Technical Reports Server (NTRS)

    Henderson, A., Jr. (Editor); Grey, J.

    1974-01-01

    The potential achievements of solar system exploration are outlined, and a course of action is suggested which will maximize the rewards. Also provided is a sourcebook of information on the solar system and the technology being brought to bear for its exploration. The document explores the degree to which three practical questions can be answered: why it is necessary to explore the solar system, why understanding of the solar system is important to us, and why we cannot wait until all terrestrial problems are solved before an attempt is made to solve problems in space.

  5. On the Possibility of Habitable Trojan Planets in Binary Star Systems.

    PubMed

    Schwarz, Richard; Funk, Barbara; Bazsó, Ákos

    2015-12-01

    Approximately 60% of all stars in the solar neighbourhood (up to 80% in our Milky Way) are members of binary or multiple star systems. This fact led to the speculations that many more planets may exist in binary systems than are currently known. To estimate the habitability of exoplanetary systems, we have to define the so-called habitable zone (HZ). The HZ is defined as a region around a star where a planet would receive enough radiation to maintain liquid water on its surface and to be able to build a stable atmosphere. We search for new dynamical configurations-where planets may stay in stable orbits-to increase the probability to find a planet like the Earth. PMID:26113154

  6. How frequent are substellar companions in T Tauri binary systems?

    NASA Astrophysics Data System (ADS)

    Woitas, J.; Leinert, Ch.

    Using speckle interferometry we have determined the J-band magnitudes for the components of 27 close T Tauri multiples (separations <= 1 arcsec) in Taurus-Auriga detected by Leinert et al. (A&A 278, 129, 1993). The J-band is least affected by emission of circumstellar material, so it can be used as an estimator for a star's luminosity. Taking the spectral type of the system as that of the main component and assuming that both stars are coeval, we can place them into the HRD. A comparison with theoretical PMS evolution tracks by D'Antona & Mazzitelli (ApJS, 90, 467, 1994) yields the masses of the components. Since almost all T Tauri stars in Taurus-Auriga form in multiple systems (Leinert et al. ,1993, see above), the resultant mass function should be an estimation of the initial mass function (IMF) in this star forming region. The result is that the IMF has a turnover at M ~0.3M_{\\odot} and that there are not many brown dwarf candidates. Only three out of 57 stars, namely the companions of CZ Tau, FS Tau and Haro 6-28 seem to have masses close to or below the substellar limit. Multiplicity surveys of e. g. Koehler & Leinert (A&A 331, 977, 1998) have revealed that the binary frequency among T Tauri stars in Taurus-Auriga is about twice as high as that observed in the solar neighbourhood (Duquennoy & Mayor, A&A 248, 485, 1991). One proposed explanation for this overabundance is that there are many substellar companions that are relatively bright during their PMS evolution, but are not detectable on the main sequence stage. Our results suggest that this is in fact not the case.

  7. Orbital evolution of eccentric interacting binary star systems

    NASA Astrophysics Data System (ADS)

    Sepinsky, Jeremy Francis

    2009-06-01

    We provide a comprehensive description of the long-term (secular) orbital evolution of eccentric interacting binary systems. The evolution of circular interacting binary systems is a well studied phenomenon, but observations have shown the existence of a small but significant number of eccentric interacting binary systems. We begin by extending the commonly accepted Roche formalism for binary interacting to include eccentric orbits and asynchronously rotating stars. Using this, we calculate orbital trajectories for particles ejected from a Roche lobe-filling donor star at the periastron of the eccentric orbit. These particles admit of three possible trajectories: direct impact onto the secondary star, self accretion back onto the donor star, and the formation of a disk about the accretor. We provide a proscription for determining a priorithe trajectory of the particle given the initial system parameters, as well as describe the secular evolution of the system for each of the three cases described above. We find that these orbital evolution timescales are comparable to the mass transfer timescale which can be significantly longer than expected from the literature. Furthermore, while it is commonly assumed that any mass transfer interactions will act to circularize the orbit, we find that there are regimes of parameter space where mass transfer can cause an increase in eccentricity, and can do so at a timescale comparable to the circularization timescale created by tidal interactions. The formalism presented here can be incorporated into binary evolution and population synthesis models to create a self-consistent treatment of mass transfer in eccentric binaries.

  8. Solar system to scale

    NASA Astrophysics Data System (ADS)

    Gerwig López, Susanne

    2016-04-01

    One of the most important successes in astronomical observations has been to determine the limit of the Solar System. It is said that the first man able to measure the distance Earth-Sun with only a very slight mistake, in the second century BC, was the wise Greek man Aristarco de Samos. Thanks to Newtońs law of universal gravitation, it was possible to measure, with a little margin of error, the distances between the Sun and the planets. Twelve-year old students are very interested in everything related to the universe. However, it seems too difficult to imagine and understand the real distances among the different celestial bodies. To learn the differences among the inner and outer planets and how far away the outer ones are, I have considered to make my pupils work on the sizes and the distances in our solar system constructing it to scale. The purpose is to reproduce our solar system to scale on a cardboard. The procedure is very easy and simple. Students of first year of ESO (12 year-old) receive the instructions in a sheet of paper (things they need: a black cardboard, a pair of scissors, colored pencils, a ruler, adhesive tape, glue, the photocopies of the planets and satellites, the measurements they have to use). In another photocopy they get the pictures of the edge of the sun, the planets, dwarf planets and some satellites, which they have to color, cut and stick on the cardboard. This activity is planned for both Spanish and bilingual learning students as a science project. Depending on the group, they will receive these instructions in Spanish or in English. When the time is over, the students bring their works on their cardboard to the class. They obtain a final mark: passing, good or excellent, depending on the accuracy of the measurements, the position of all the celestial bodies, the asteroids belts, personal contributions, etc. If any of the students has not followed the instructions they get the chance to remake it again properly, in order not

  9. Hydrodynamic Simulations of Close and Contact Binary Systems using Bipolytropes

    NASA Astrophysics Data System (ADS)

    Kadam, Kundan

    2016-01-01

    I will present the results of hydrodynamic simulations of close and contact bipolytropic binary systems. This project is motivated by the peculiar case of the red nova, V1309 Sco, which is indeed a merger of a contact binary. Both the stars are believed to have evolved off the main sequence by the time of the merger and possess a small helium core. In order to represent the binary accurately, I need a core-envelope structure for both the stars. I have achieved this using bipolytropes or composite polytropes. For the simulations, I use an explicit 3D Eulerian hydrodynamics code in cylindrical coordinates. I will discuss the evolution and merger scenarios of systems with different mass ratios and core mass fractions as well as the effects due to the treatment of the adiabatic exponent.

  10. Towards A Complete Census of the Solar-Type Binaries in the Young Open Cluster M37

    NASA Astrophysics Data System (ADS)

    Geller, Aaron M.; Meibom, Soren; Barnes, Sydney A.; Mathieu, Robert D.

    2012-08-01

    Binary stars govern the dynamical evolution of star clusters and determine the formation rates and mechanisms for exotic stars like blue stragglers and X-ray sources. Understanding the near-primordial (after removal of the natal gas) binary population of star clusters is of primary importance for dynamical models of star clusters, which have the potential to revolutionize our understanding of star cluster evolution. Yet the binary frequencies and distributions of binary orbital parameters (period, eccentricity, etc.) for young coeval stellar populations are poorly known, due to a lack of necessary observations. Time-series radial-velocity surveys are essential for identifying and characterizing binary populations. Using WIYN/Hydra data, we have already identified a nearly complete sample of 329 solar-type (1.5 <=M [M_⊙] <=1.0) candidate members in the young (~540 Myr) open cluster M37. Of these stars, 82 show significant radial-velocity variability, indicative of a binary companion. Kinematic orbital solutions are crucial to define the initial binary conditions critical for dynamical star cluster models, and to understand how binaries affects stellar rotational evolution. As we have already identified the binaries in M37, we have a unique opportunity to add significantly to our knowledge of young binaries with minimal additional telescope time. We propose to initiate a WIYN/Hydra multi-epoch radial-velocity survey of the 82 velocity variables in M37.

  11. Confronting Numerical Relativity With Nature: A model-independent characterization of binary black-hole systems in LIGO

    NASA Astrophysics Data System (ADS)

    Jani, Karan; Clark, James; Shoemaker, Deirdre; LIGO Scientific Collaboration; Virgo Collaboration

    2016-03-01

    Stellar and Intermediate mass binary black hole systems (10-1000 solar masses) are likely to be among the strongest sources of gravitational wave detection in Advanced LIGO. In this talk we discuss the prospects for the detection and characterization of these extreme astrophysical system using robust, morphology-independent analysis techniques. In particular, we demonstrate how numerical relativity simulations of black hole collisions may be combined with waveform reconstructions to constrain properties of a binary black-hole system using only exact solutions from general relativity and any potential gravitational wave signal in the data.

  12. Binary-binary interactions and the formation of the PSR B1620-26 triple system in M4

    NASA Technical Reports Server (NTRS)

    Rasio, Frederic A.; Mcmillan, Steve; Hut, Piet

    1995-01-01

    The hierarchical triple system containing the millisecond pulsar PSR B1620-26 in M4 is the first star system ever detected in a globular cluster. Such systems should form in globular clusters as a result of dynamical interactions between binaries. We propose that the triple system containing PSR B1620-26 formed through an exchange interaction between a wide primordial binary and a pre-existing binary millisecond pulsar. This scenario would have the advantage of reconciling the approximately 10(exp 9) yr timing age of the pulsar with the much shorter lifetime of the triple system in the core of M4.

  13. Solar Systems at Last

    NASA Astrophysics Data System (ADS)

    Villaver, Eva

    2015-12-01

    Planet host stars, the Sun among them, will eventually evolve into giants, through the Planetary Nebula phase to finally end their lives as white dwarfs. Planets will be engulfed along the giant phases, evaporated during the Planetary Nebula phase, and possibly destabilized when the star enters the white dwarf cooling track. A large number of planets will eventually be destroyed and there is a lot to be learned from that. The conditions on the planet surface of those that survive are expected to be modified as well as the result of the evolution of the star. I will discuss the new limits that the theoretical studies allow us to set on the survival and habitability of planets as the star runs out of its hydrogen fuel and the possibilities for the formation of second generation planets. Finally, I will present new results on the real consequences that the presence and destruction of these Extreme Solar systems have in the evolution of stars.

  14. A ROSAT Survey of Near-Contact Binary Systems

    NASA Astrophysics Data System (ADS)

    Shaw, J. S.; Caillault, J.-P.; Schmitt, J. H. M. M.

    1994-12-01

    We have conducted a survey of near-contact binary systems observed during the ROSAT All-Sky Survey (RASS). The near-contact binaries (NCBs) have an A- or F-type primary, with a companion which is one to two spectral types cooler. The systems have periods less than one day and display strong tidal interaction, but are not in contact like the W UMa systems. There are more than 150 such systems known to exist. We have analyzed the RASS data for all of those (58) within 400 pc. We report the detection of 14 systems with X-ray count rates > 0.01 cts s(-1) . The X-ray luminosity function for the NCBs is very similar to that for A-type W UMa systems (derived, admittedly, from only a handful of EINSTEIN observations), but appears to be significantly different from those of W-type W UMa systems and RS CVn binaries. This is consistent with the proposed scenario that the NCBs are evolutionary precursors to the A-type W UMa binaries. The mean X-ray luminosity of the NCBs is log L_x = 29.3+/-0.1 ergs s(-1) , less than that of the RS CVns, but greater than that of normal late-type main sequence star s. The detection of these systems may help to explain why many presumably single A-type stars were detected in the RASS; i.e., the ``single" A-stars may, in fact, be binaries, like the NCBs, with late-type companions. This research was supported in part by NASA Grants NAG 5-1610 and NAG 5-2095 to the University of Georgia.

  15. Radiation reaction in binary systems in general relativity

    NASA Astrophysics Data System (ADS)

    Kennefick, Daniel John

    1997-09-01

    This thesis is concerned with current problems in, and historical aspects of, the problem of radiation reaction in stellar binary systems in general relativity. Part I addresses current issues in the orbital evolution due to gravitational radiation damping of compact binaries. A particular focus is on the inspiral of small bodies orbiting large black holes, employing a perturbation formalism. In addition, the merger, at the end of the insprial, of comparable mass compact binaries, such as neutron star binaries is also discussed. The emphasis of Part I is on providing detailed descriptions of sources and signals with a view to optimising signal analysis in gravitational wave detectors, whether ground- or space- based interferometers, or resonant mass detectors. Part II of the thesis examines the historical controversies surrounding the problem of gravitational waves, and gravitational radiation damping in stellar binaries. In particular, it focuses on debates in the mid 20th-century on whether binary star systems would really exhibit this type of damping and emit gravitational waves, and on the 'quadrupole formula controversy' of the 1970s and 1980s, on the question whether the standard formular describing energy loss due to emission of gravitational waves was correctly derived for such systems. The study shed light on the role of analogy in science, especially where its use is controversial, on the importance of style in physics and on the problem of identity in science, as the use of history as a rhetorical device in controversial debate is examined. The concept of the Theoretician's Regress is introduced to explain the difficulty encountered by relativists in closing debate in this controversy, which persisted in one forms or another for several decades.

  16. ABSOLUTE PROPERTIES OF THE HIGHLY ECCENTRIC, SOLAR-TYPE ECLIPSING BINARY HD 74057

    SciTech Connect

    Sowell, James R.; Henry, Gregory W.; Fekel, Francis C. E-mail: gregory.w.henry@gmail.com

    2012-01-15

    We have obtained Stroemgren b and y differential photometric observations of the solar-type eclipsing binary HD 74057 plus follow-up high-resolution, red wavelength spectroscopic observations. The system has an orbital period of 31.2198 days, a high eccentricity of 0.47, and is seen almost exactly edge on with an inclination of 89.{sup 0}8. The two main-sequence G0 stars are nearly identical in all physical characteristics. We used the Wilson-Devinney program to obtain a simultaneous solution of our photometric and spectroscopic observations. The resulting masses of the components are M{sub 1} = 1.138 {+-} 0.003 M{sub Sun} and M{sub 2} = 1.131 {+-} 0.003 M{sub Sun }, and the radii are R{sub 1} = 1.064 {+-} 0.002 R{sub Sun} and R{sub 2} = 1.049 {+-} 0.002 R{sub Sun }. The effective temperatures are 5900 K (fixed) and 5843 K, and the iron abundance, [Fe/H], is estimated to be +0.07. A comparison with evolutionary tracks suggests that the system may be even more metal rich. The components rotate with periods of 8.4 days, significantly faster than the predicted pseudosynchronous period of 12.7 days. We see evidence that one or both components have cool spots. Both stars are close to the zero-age main sequence and are about 1.0 Gyr old.

  17. Wind in the Solar System

    ERIC Educational Resources Information Center

    McIntosh, Gordon

    2010-01-01

    As an astronomy instructor I am always looking for commonly experienced Earthly phenomena to help my students and me understand and appreciate similar occurrences elsewhere in the solar system. Recently I wrote short "TPT" articles on frost and precipitation. The present article is on winds in the solar system. A windy day or storm might motivate…

  18. Solar Heating Systems: Instructor's Guide.

    ERIC Educational Resources Information Center

    Green, Joanne; And Others

    This Instructor's Guide for a Solar Heating System Curriculum is designed to accompany the Student Manual and the Progress Checks and Test Manual for the course (see note), in order to facilitate the instruction of classes on solar heating systems. The Instructor's Guide contains a variety of materials used in teaching the courses, including…

  19. Solar Heating Systems: Student Manual.

    ERIC Educational Resources Information Center

    Green, Joanne; And Others

    This Student Manual for a Solar Heating System curriculum contains 22 units of instructional materials for students to use in a course or courses on solar heating systems (see note). For each unit (task), objectives, assignment sheets, laboratory assignments, information sheets, checkpoints (tests), and job sheets are provided. Materials are set…

  20. Exploration of the solar system

    NASA Technical Reports Server (NTRS)

    Henderson, A., Jr.; Grey, J.

    1974-01-01

    A sourcebook of information on the solar system and the technology used for its exploration is presented. An outline of the potential achievements of solar system exploration is given along with a course of action which maximizes the rewards to mankind.

  1. Binary systems, star clusters and the Galactic-field population. Applied stellar dynamics

    NASA Astrophysics Data System (ADS)

    Kroupa, Pavel

    2002-01-01

    This book contains the results of recent theoretical work on the evolution of primordial binary systems in young star clusters, their effect on the evolution of their host clusters, implications for the distribution of young stars in the Milky Way, and the formation of bound star clusters. This work shows that if the Galactic-field binary population is a dynamically evolved version of the Taurus-Auriga pre-main sequence population, then most stars form in clusters with typically a few hundred binaries within a radius of about 0.5-1 pc. The results also suggest that the population I primordial binary-star orbital-parameter distribution functions may be universal, much like the initial mass function. Most solar-like planetary systems can survive in such clusters. The work presented here also establishes that most observed triple and quadruple systems must be primordial, but that α Cen A/B-Proxima Cen-like systems can form in clusters through dynamical capture. Precise N-body calculations using Aarseth's N-body codes of clusters containing up to 104 stars are used to create an extensive young-cluster library. These data demonstrate that the primordial binary systems are disrupted on a crossing-time scale, and that the truncation of the surviving period distribution measures the maximum concentration the cluster ever experienced. The N-body calculations demonstrate that Galactic star clusters form readily as nuclei of expanding OB associations despite a star-formation efficiency of typically 30 per cent and gas-expulsion over a time-span shorter than the cluster crossing time.

  2. Supernovae in Binary Systems: An Application of Classical Mechanics.

    ERIC Educational Resources Information Center

    Mitalas, R.

    1980-01-01

    Presents the supernova explosion in a binary system as an application of classical mechanics. This presentation is intended to illustrate the power of the equivalent one-body problem and provide undergraduate students with a variety of insights into elementary classical mechanics. (HM)

  3. Solar dish/engine systems

    SciTech Connect

    Not Available

    1998-04-01

    Solar dish/engine systems convert the energy from the sun into electricity at a very high efficiency. Using a mirror array formed into the shape of a dish, the solar dish focuses the sun`s rays onto a receiver. The receiver transmits the energy to an engine that generates electric power. Because of the high concentration ratios achievable with parabolic dishes and the small size of the receiver, solar dishes are efficient at collecting solar energy at very high temperatures. Tests of prototype systems and components at locations throughout the US have demonstrated net solar to electric conversion efficiencies as high as 30%. This is significantly higher than any other solar technology.

  4. Eclipsing Binaries with Classical Cepheid Component in the Magellanic System

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    We present a census of eclipsing binary systems with classical Cepheid as a component. All such systems known were found in the OGLE collection of classical Cepheids in the Magellanic System. We extend the list of potential candidates adding four new objects found in the OGLE-IV photometric data. One of the new Cepheids in the eclipsing system, OGLE-SMC-CEP-3235, revealed only one eclipse during 15 years of the OGLE photometric monitoring. However, it additionally shows very well pronounced light-time effect indicating that the binarity is real and the system is physically bound. We also search for the light-time effect in other known eclipsing Cepheids and we clearly detect it in OGLE-LMC-CEP-1812. We discuss application of this tool for the search for Cepheids in non-eclipsing binary systems.

  5. Binary system parameters and the hibernation model of cataclysmic variables

    SciTech Connect

    Livio, M.; Shara, M.M.

    1987-08-01

    The hibernation model, in which nova systems spend most of the time between eruptions in a state of low mass transfer rate, is examined. The binary systems more likely to undergo hibernation are determined. The predictions of the hibernation scenario are shown to be consistent with available observational data. It is shown how the hibernation scenario provides links between classical novae, dwarf novae, and novalike variables, all of which represent different stages in the cyclic evolution of the same systems. 72 references.

  6. VX Her: Eclipsing Binary System or Single Variable Star

    NASA Astrophysics Data System (ADS)

    Perry, Kathleen; Castelaz, Michael; Henson, Gary; Boghozian, Andrew

    2015-01-01

    VX Her is a pulsating variable star with a period of .4556504 days. It is believed to be part of an eclipsing binary system (Fitch et al. 1966). This hypothesis originated from Fitch seeing VX Her's minimum point on its light curve reaching a 0.7 magnitude fainter than normal and remaining that way for nearly two hours. If VX Her were indeed a binary system, I would expect to see similar results with a fainter minimum and a broader, more horizontal dip. Having reduced and analyzed images from the Southeastern Association for Research in Astronomy Observatory in Chile and Kitt Peak, as well as images from a 0.15m reflector at East Tennessee State University, I found that VX Her has the standard light curve of the prototype variable star, RR Lyrae. Using photometry, I found no differing features in its light curve to suggest that it is indeed a binary system. However, more observations are needed in case VX Her is a wide binary.

  7. Solar Energy Systems

    NASA Technical Reports Server (NTRS)

    1981-01-01

    A waste water treatment plant in Wilton, Maine, where sludge is converted to methane gas, and Monsanto Company's Environmental Health Laboratory in St. Louis Missouri, where more than 200 solar collectors provide preheating of boiler feed water for laboratory use are representative of Grumman's Sunstream line of solar energy equipment. This equipment was developed with technology from NASA's Apollo lunar module program.

  8. Solar Power System Design for the Solar Probe+ Mission

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Schmitz, Paul C.; Kinnison, James; Fraeman, Martin; Roufberg, Lew; Vernon, Steve; Wirzburger, Melissa

    2008-01-01

    Solar Probe+ is an ambitious mission proposed to the solar corona, designed to make a perihelion approach of 9 solar radii from the surface of the sun. The high temperature, high solar flux environment makes this mission a significant challenge for power system design. This paper summarizes the power system conceptual design for the solar probe mission. Power supplies considered included nuclear, solar thermoelectric generation, solar dynamic generation using Stirling engines, and solar photovoltaic generation. The solar probe mission ranges from a starting distance from the sun of 1 AU, to a minimum distance of about 9.5 solar radii, or 0.044 AU, from the center of the sun. During the mission, the solar intensity ranges from one to about 510 times AM0. This requires power systems that can operate over nearly three orders of magnitude of incident intensity.

  9. Understanding the Evolution of Close Binary Systems with Radio Pulsars

    NASA Astrophysics Data System (ADS)

    Benvenuto, O. G.; De Vito, M. A.; Horvath, J. E.

    2014-05-01

    We calculate the evolution of close binary systems (CBSs) formed by a neutron star (behaving as a radio pulsar) and a normal donor star, which evolve either to a helium white dwarf (HeWD) or to ultra-short orbital period systems. We consider X-ray irradiation feedback and evaporation due to radio pulsar irradiation. We show that irradiation feedback leads to cyclic mass transfer episodes, allowing CBSs to be observed in between episodes as binary radio pulsars under conditions in which standard, non-irradiated models predict the occurrence of a low-mass X-ray binary. This behavior accounts for the existence of a family of eclipsing binary systems known as redbacks. We predict that redback companions should almost fill their Roche lobe, as observed in PSR J1723-2837. This state is also possible for systems evolving with larger orbital periods. Therefore, binary radio pulsars with companion star masses usually interpreted as larger than expected to produce HeWDs may also result in such quasi-Roche lobe overflow states, rather than hosting a carbon-oxygen WD. We found that CBSs with initial orbital periods of Pi < 1 day evolve into redbacks. Some of them produce low-mass HeWDs, and a subgroup with shorter Pi becomes black widows (BWs). Thus, BWs descend from redbacks, although not all redbacks evolve into BWs. There is mounting observational evidence favoring BW pulsars to be very massive (gsim 2 M ⊙). As they should be redback descendants, redback pulsars should also be very massive, since most of the mass is transferred before this stage.

  10. UNDERSTANDING THE EVOLUTION OF CLOSE BINARY SYSTEMS WITH RADIO PULSARS

    SciTech Connect

    Benvenuto, O. G.; De Vito, M. A.

    2014-05-01

    We calculate the evolution of close binary systems (CBSs) formed by a neutron star (behaving as a radio pulsar) and a normal donor star, which evolve either to a helium white dwarf (HeWD) or to ultra-short orbital period systems. We consider X-ray irradiation feedback and evaporation due to radio pulsar irradiation. We show that irradiation feedback leads to cyclic mass transfer episodes, allowing CBSs to be observed in between episodes as binary radio pulsars under conditions in which standard, non-irradiated models predict the occurrence of a low-mass X-ray binary. This behavior accounts for the existence of a family of eclipsing binary systems known as redbacks. We predict that redback companions should almost fill their Roche lobe, as observed in PSR J1723-2837. This state is also possible for systems evolving with larger orbital periods. Therefore, binary radio pulsars with companion star masses usually interpreted as larger than expected to produce HeWDs may also result in such quasi-Roche lobe overflow states, rather than hosting a carbon-oxygen WD. We found that CBSs with initial orbital periods of P{sub i} < 1 day evolve into redbacks. Some of them produce low-mass HeWDs, and a subgroup with shorter P{sub i} becomes black widows (BWs). Thus, BWs descend from redbacks, although not all redbacks evolve into BWs. There is mounting observational evidence favoring BW pulsars to be very massive (≳ 2 M {sub ☉}). As they should be redback descendants, redback pulsars should also be very massive, since most of the mass is transferred before this stage.

  11. The synchronous rotations of Eris/Dysnomia and Orcus/Vanth binary systems

    NASA Astrophysics Data System (ADS)

    Rabinowitz, David L.; Owainati, Yasi

    2014-11-01

    We have measured the rotation periods of the Eris/Dysnomia and Orcus/Vanth binary systems using long-term observations obtained with the SMARTS 1.3m telescope at Cerro Tololo, combined with incidental observations obtained by the La Silla - QUEST survey on the ESO 1.0-m Schmidt at La Silla, and using historical observations of Eris published by others. We find that both binary systems are synchronous, with the dominant periodicity in their light curves matching their mutual orbit periods (9.54 and 15.774 days, respectively). For Orcus/Vanth, the reflected light from both bodies contributes to the signal. The measured periodicity could be due to the rotation of Orcus or Vanth separately, but it is most likely the system is doubly synchronous. For Eris/Dysnomia, only Eris is bright enough to contribute significantly to the observations. The conclusion is therefore unambiguous that Eris is synchronously rotating with the orbit of Dysnomia. This is surprising given that Eris is 500 times brighter than Dysnomia, and likely to be 100 to 10000 times more massive (assuming an albedo > 5% for Dysnomia). If Dysnomia has migrated outward from Eris owing to long-term tidal interactions, the time for Eris to slow from an initially fast rotation (period < 1 day) to a synchronous one is longer than the age of the solar system. We discuss the constraints these observations place on the relative albedos, masses, and internal composition of the two binary systems.

  12. High-energy signatures of binary systems of supermassive black holes

    NASA Astrophysics Data System (ADS)

    Romero, G. E.; Vila, G. S.; Pérez, D.

    2016-04-01

    Context. Binary systems of supermassive black holes are expected to be strong sources of long gravitational waves prior to merging. These systems are good candidates to be observed with forthcoming space-borne detectors. Only a few of these systems, however, have been firmly identified to date. Aims: We aim at providing a criterion for the identification of some supermassive black hole binaries based on the characteristics of the high-energy emission of a putative relativistic jet launched from the most massive of the two black holes. Methods: We study supermassive black hole binaries where the less massive black hole has carved an annular gap in the circumbinary disk, but nevertheless there is a steady mass flow across its orbit. Such a perturbed disk is hotter and more luminous than a standard thin disk in some regions. Assuming that the jet contains relativistic electrons, we calculate its broadband spectral energy distribution focusing on the inverse Compton up-scattering of the disk photons. We also compute the opacity to the gamma rays produced in the jet by photon annihilation with the disk radiation and take into account the effects of the anisotropy of the target photon field as seen from the jet. Results: We find that the excess of low-energy photons radiated by the perturbed disk causes an increment in the external Compton emission from the jet in the X-ray band, and a deep absorption feature at energies of tens of TeVs for some sets of parameters. According to our results, observations with Cherenkov telescopes might help in the identification of supermassive black hole binaries, especially those black hole binaries that host primaries from tens to hundreds of million of solar masses.

  13. What Makes Red Giants Tick? Linking Tidal Forces, Activity, and Solar-Like Oscillations via Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Rawls, Meredith L.; Gaulme, Patrick; McKeever, Jean; Jackiewicz, Jason

    2016-01-01

    Thanks to advances in asteroseismology, red giants have become astrophysical laboratories for studying stellar evolution and probing the Milky Way. However, not all red giants show solar-like oscillations. It has been proposed that stronger tidal interactions from short-period binaries and increased magnetic activity on spotty giants are linked to absent or damped solar-like oscillations, yet each star tells a nuanced story. In this work, we characterize a subset of red giants in eclipsing binaries observed by Kepler. The binaries exhibit a range of orbital periods, solar-like oscillation behavior, and stellar activity. We use orbital solutions together with a suite of modeling tools to combine photometry and spectroscopy in a detailed analysis of tidal synchronization timescales, star spot activity, and stellar evolution histories. These red giants offer an unprecedented opportunity to test stellar physics and are important benchmarks for ensemble asteroseismology.

  14. Outer Solar System Nomenclature

    NASA Technical Reports Server (NTRS)

    Owen, Tobias C.; Grant, John (Technical Monitor)

    2003-01-01

    This grant has supported work by T. Owen and B. A. Smith on planetary and satellite nomenclature, carried out under the general auspices of the International Astronomical Union (IAU). The IAU maintains a Working Group on Planetary and Satellite Nomenclature (WGPSN) whose current chair is Prof.Kaare Aksnes of the Rosseland Institute for Theoretical Astrophysics in Oslo, Norway. Both Owen and Smith are members of the WGPSN; Owen as chair of the Outer Solar System Task Group, and Smith as chair of the Mars Task Group. The major activity during the last grant period (2002) was the approval of several new names for features on Mars by Smith's group and features on Jovian satellites plus new names for satellites of Jupiter, Saturn and Uranus by Owen's group. Much of this work was accomplished by e-mail exchanges, but the new nomenclature was formally discussed and approved at a meeting of the WGPSN held in conjunction with the Division for Planetary Sciences meeting in Birmingham, Alabama in October 2002.

  15. Astrometric solar system anomalies

    SciTech Connect

    Nieto, Michael Martin; Anderson, John D

    2009-01-01

    There are at least four unexplained anomalies connected with astrometric data. perhaps the most disturbing is the fact that when a spacecraft on a flyby trajectory approaches the Earth within 2000 km or less, it often experiences a change in total orbital energy per unit mass. next, a secular change in the astronomical unit AU is definitely a concern. It is increasing by about 15 cm yr{sup -1}. The other two anomalies are perhaps less disturbing because of known sources of nongravitational acceleration. The first is an apparent slowing of the two Pioneer spacecraft as they exit the solar system in opposite directions. Some astronomers and physicists are convinced this effect is of concern, but many others are convinced it is produced by a nearly identical thermal emission from both spacecraft, in a direction away from the Sun, thereby producing acceleration toward the Sun. The fourth anomaly is a measured increase in the eccentricity of the Moon's orbit. Here again, an increase is expected from tidal friction in both the Earth and Moon. However, there is a reported unexplained increase that is significant at the three-sigma level. It is produent to suspect that all four anomalies have mundane explanations, or that one or more anomalies are a result of systematic error. Yet they might eventually be explained by new physics. For example, a slightly modified theory of gravitation is not ruled out, perhaps analogous to Einstein's 1916 explanation for the excess precession of Mercury's perihelion.

  16. Space solar power systems

    NASA Technical Reports Server (NTRS)

    Toliver, C.

    1977-01-01

    Studies were done on the feasibility of placing a solar power station called POwersat, in space. A general description of the engineering features are given as well as a brief discussion of the economic considerations.

  17. Orbital Motions in Binary Protostellar Systems

    NASA Astrophysics Data System (ADS)

    Rodríguez, L. F.

    2004-08-01

    Using high-resolution ( ˜ 0to z @. hss ''1), multi-epoch Very Large Array observations, we have detected orbital motions in several low-luminosity protobinary systems in the Taurus and ρ Ophiuchus molecular complexes. The masses obtained from Kepler's third law are of the order of 0.5 to 2 M⊙, as expected for such low-mass protostars. The relatively large bolometric luminosities of these young systems corroborates the notion that protostars obtain most of their luminosity from accretion and not from nuclear reactions. In addition, in one of the sources studied (a multiple system in Taurus), a low-mass young star has shown a drastic change in its orbit after a close approach with another component of the system, presumed to be a double star. The large proper motion achieved by this low mass protostar (20 km s-1), suggests an ejection from the system.

  18. Galaxy and the solar system

    SciTech Connect

    Smoluchowski, R.; Bahcall, J.M.; Matthews, M.S.

    1986-01-01

    The solar-Galactic neighborhood, massive interstellar clouds and other Galactic features, the Oort cloud, perturbations of the solar system, and the existence and stability of a solar companion star are examined in chapters based on contributions to a conference held in Tucson, AZ during January 1985. The individual topics addressed include: the Galactic environment of the solar system; stars within 25 pc of the sun; the path of the sun in 100 million years; the local velocity field in the last billion years; interstellar clouds near the sun; and evidence for a local recent supernova. Also considered are: dynamic influence of Galactic tides and molecular clouds on the Oort cloud; cometary evidence for a solar companion; dynamical interactions between the Oort cloud and the Galaxy; geological periodicities and the Galaxy; giant comets and the Galaxy; dynamical evidence for Planet X; evolution of the solar system in the presence of a solar companion star; mass extinctions, crater ages, and comet showers; evidence for Nemesis, a solar companion star.

  19. Evolution of Noncoplanar Disks and Planets in Binary Systems

    NASA Astrophysics Data System (ADS)

    Lubow, Stephen H.; Martin, Rebecca G.

    2016-06-01

    We have been analyzing the evolution of a gaseous disk and planet that orbit a member of a binary star system. The disk and planet lie in orbital planes that are initially tilted with respect to the binary orbital plane. Some of our main results are as follows.1) A disk without a planet that is tilted by more than about 40 degrees can undergo coherent Kozai-Lidov tilt oscillations that cause oscillations in disk eccentricity and enhanced dissipation.2) A disk and planet that are initially mutually coplanar, but tilted by a small angle with respect to the binary orbital plane, do not remain mutually coplanar. They undergo mutual tilt oscillations that are amplified by a secular resonance.3) A disk and planet that are initially mutually coplanar, but somewhat tilted with respect to the binary orbital plane, each undergo Kozai-Lidov oscillations, in addition to the mutual tilt oscillations discussed in item 2. The latter oscillations can boost a relatively small initial tilt into the Kozai-Lidov regime.4) Kozai-Lidov disk oscillations of a disk with some self-gravity expedite disk fragmentation. The fragmentation may in turn result in planet formation.

  20. Segregation of Fluidized Binary Hard-Sphere Systems Under Gravity

    NASA Astrophysics Data System (ADS)

    Kim, Soon-Chul

    We have derived an analytic expression for the contact value of the local density of binary hard-sphere systems under gravity. We have obtained the crossover conditions for the Brazil-nut type segregation of binary hard-sphere mixtures and binary hard-sphere chain mixtures from the segregation criterion, where the segregation occurs when the density (or the pressure) of the small spheres at the bottom is higher than that of the large spheres, or vice versa. For the binary hard-sphere chain mixtures, the crossover condition for the segregation depends on the number of monomers composed of hard-sphere chains as well as the mass and the diameter of each species. The fundamental-measure theories (FMTs) and local density approximation (LDA) are employed to examine the crossover condition for the segregation of the gravity-induced hard-sphere mixtures. The calculated results show that the LDA does not explain the density oscillation near the bottom, whereas the modified fundamental-measure theory (MFMT) compares with molecular dynamics simulations.

  1. The evolution of highly compact binary stellar systems

    NASA Technical Reports Server (NTRS)

    Rappaport, S.; Joss, P. C.; Webbink, R. F.

    1982-01-01

    A new theoretical treatment of the evolution of highly compact binary systems is presented. The evolution is calculated until almost the entire mass of the secondary has been transferred to the primary or lost from the system. It is assumed that gravitational radiation from the system is the cause of mass transfer. It is found that the structure of the mass-losing star can be approximated by an n = 3/2 polytrope, and as a result a relatively large number of different cases can be explored and some general conclusions drawn. An explanation is found for the existence of a cutoff in the orbital period distribution among the cataclysmic variables and light is shed upon the possible generic relationships among cataclysmic variables, the low-mass X-ray binaries, and the spectrally soft transient X-ray sources.

  2. On dynamic stability boundaries for binary systems

    NASA Technical Reports Server (NTRS)

    Young, M. I.

    1990-01-01

    Dynamic stability boundaries are developed for linear two-degree-of-freedom systems with damping and elastic couplings. Special emphasis is placed on the influence of natural frequency proximity and those instabilities which stem from skew-symmetric stiffness properties. These arise in aeroelasticity and flight dynamics systems. Insight is provided into the destabilizing effects of the 'dreaded modal resonance' which results when the two natural frequencies in the modal natural frequency ratio match or nearly match.

  3. Solar Thermal Electricity Generating System

    NASA Astrophysics Data System (ADS)

    Mishra, Sambeet; Tripathy, Pratyasha

    2012-08-01

    A Solar Thermal Electricity generating system also known as Solar Thermal Power plant is an emerging renewable energy technology, where we generate the thermal energy by concentrating and converting the direct solar radiationat medium/high temperature (300∫C ñ 800∫C). The resulting thermal energy is then used in a thermodynamic cycleto produce electricity, by running a heat engine, which turns a generator to make electricity. Solar thermal power is currently paving the way for the most cost-effective solar technology on a large scale and is heading to establish a cleaner, pollution free and secured future. Photovoltaic (PV) and solar thermal technologies are two main ways of generating energy from the sun, which is considered the inexhaustible source of energy. PV converts sunlight directly into electricity whereas in Solar thermal technology, heat from the sun's rays is concentrated to heat a fluid, whose steam powers a generator that produces electricity. It is similar to the way fossil fuel-burning power plants work except that the steam is produced by the collected heat rather than from the combustion of fossil fuels. In order to generate electricity, five major varieties of solar thermal technologies used are:* Parabolic Trough Solar Electric Generating System (SEGS).* Central Receiver Power Plant.* Solar Chimney Power Plant.* Dish Sterling System.* Solar Pond Power Plant.Most parts of India,Asia experiences a clear sunny weather for about 250 to 300 days a year, because of its location in the equatorial sun belt of the earth, receiving fairly large amount of radiation as compared to many parts of the world especially Japan, Europe and the US where development and deployment of solar technologies is maximum.Whether accompanied with this benefit or not, usually we have to concentrate the solar radiation in order to compensate for the attenuation of solar radiation in its way to earthís surface, which results in from 63,2 GW/m2 at the Sun to 1 kW/m2 at

  4. THE ELM SURVEY. II. TWELVE BINARY WHITE DWARF MERGER SYSTEMS

    SciTech Connect

    Kilic, Mukremin; Brown, Warren R.; Kenyon, S. J.; Prieto, Carlos Allende; Agueeros, M. A.; Heinke, Craig

    2011-01-20

    We describe new radial velocity and X-ray observations of extremely low-mass white dwarfs (ELM WDs, {approx}0.2 M{sub sun}) in the Sloan Digital Sky Survey Data Release 4 and the MMT Hypervelocity Star survey. We identify four new short period binaries, including two merger systems. These observations bring the total number of short period binary systems identified in our survey to 20. No main-sequence or neutron star companions are visible in the available optical photometry, radio, and X-ray data. Thus, the companions are most likely WDs. Twelve of these systems will merge within a Hubble time due to gravitational wave radiation. We have now tripled the number of known merging WD systems. We discuss the characteristics of this merger sample and potential links to underluminous supernovae, extreme helium stars, AM CVn systems, and other merger products. We provide new observational tests of the WD mass-period distribution and cooling models for ELM WDs. We also find evidence for a new formation channel for single low-mass WDs through binary mergers of two lower mass objects.

  5. Evolution of the Solar System

    NASA Technical Reports Server (NTRS)

    Alfven, H.; Arrhenius, G.

    1976-01-01

    The origin and evolution of the solar system are analyzed. Physical processes are first discussed, followed by experimental studies of plasma-solid reactions and chemical and mineralogical analyses of meteorites and lunar and terrestrial samples.

  6. Views of the solar system

    SciTech Connect

    Hamilton, C.

    1995-02-01

    Views of the Solar System has been created as an educational tour of the solar system. It contains images and information about the Sun, planets, moons, asteroids and comets found within the solar system. The image processing for many of the images was done by the author. This tour uses hypertext to allow space travel by simply clicking on a desired planet. This causes information and images about the planet to appear on screen. While on a planet page, hyperlinks travel to pages about the moons and other relevant available resources. Unusual terms are linked to and defined in the Glossary page. Statistical information of the planets and satellites can be browsed through lists sorted by name, radius and distance. History of Space Exploration contains information about rocket history, early astronauts, space missions, spacecraft and detailed chronology tables of space exploration. The Table of Contents page has links to all of the various pages within Views Of the Solar System.

  7. Exobiology in Solar System Exploration

    NASA Technical Reports Server (NTRS)

    Carle, Glenn C. (Editor); Schwartz, Deborah E. (Editor); Huntington, Judith L. (Editor)

    1992-01-01

    A symposium, 'Exobiology in Solar System Exploration,' was held on 24-26 Aug. 1988. The symposium provided an in-depth investigation of the role of Exobiology in solar system exploration. It is expected that the symposium will provide direction for future participation of the Exobiology community in solar system exploration and alert the Planetary community to the continued importance of an Exobiology Flight Program. Although the focus of the symposium was primarily on Exobiology in solar system exploration missions, several ground based and Earth-orbital projects such as the Search for Extraterrestrial Intelligence, Gas Grain Facility, and Cosmic Dust Collection Facility represent upcoming research opportunities planned to accommodate the goals and objectives of the Exobiology community as well. This report contains papers for all but one of the presentations given at the symposium.

  8. Solar System Observations with JWST

    NASA Technical Reports Server (NTRS)

    Norwood, James; Hammel, Heidi; Milam, Stefanie; Stansberry, John; Lunine, Jonathan; Chanover, Nancy; Hines, Dean; Sonneborn, George; Tiscareno, Matthew; Brown, Michael; Ferruit, Pierre

    2014-01-01

    The James Webb Space Telescope will enable a wealth of new scientific investigations in the near- and mid- infrared, with sensitivity and spatial-spectral resolution greatly surpassing its predecessors. In this paper, we focus upon Solar System science facilitated by JWST, discussing the most current information available concerning JWST instrument properties and observing techniques relevant to planetary science. We also present numerous example observing scenarios for a wide variety of Solar System targets to illustrate the potential of JWST science to the Solar System community. This paper updates and supersedes the Solar System white paper published by the JWST Project in 2010 (Lunine et al., 2010). It is based both on that paper and on a workshop held at the annual meeting of the Division for Planetary Sciences in Reno, NV in 2012.

  9. GRAVITATIONAL CONUNDRUM? DYNAMICAL MASS SEGREGATION VERSUS DISRUPTION OF BINARY STARS IN DENSE STELLAR SYSTEMS

    SciTech Connect

    De Grijs, Richard; Li, Chengyuan; Zheng, Yong; Kouwenhoven, M. B. N.; Deng, Licai; Hu, Yi; Wicker, James E.

    2013-03-01

    Upon their formation, dynamically cool (collapsing) star clusters will, within only a few million years, achieve stellar mass segregation for stars down to a few solar masses, simply because of gravitational two-body encounters. Since binary systems are, on average, more massive than single stars, one would expect them to also rapidly mass segregate dynamically. Contrary to these expectations and based on high-resolution Hubble Space Telescope observations, we show that the compact, 15-30 Myr old Large Magellanic Cloud cluster NGC 1818 exhibits tantalizing hints at the {approx}> 2{sigma} level of significance (>3{sigma} if we assume a power-law secondary-to-primary mass-ratio distribution) of an increasing fraction of F-star binary systems (with combined masses of 1.3-1.6 M {sub Sun }) with increasing distance from the cluster center, specifically between the inner 10''-20'' (approximately equivalent to the cluster's core and half-mass radii) and the outer 60''-80''. If confirmed, then this will offer support for the theoretically predicted but thus far unobserved dynamical disruption processes of the significant population of 'soft' binary systems-with relatively low binding energies compared to the kinetic energy of their stellar members-in star clusters, which we have access to here by virtue of the cluster's unique combination of youth and high stellar density.

  10. Comets. [and solar system evolution

    NASA Technical Reports Server (NTRS)

    Neugebauer, M.

    1986-01-01

    The nature, history, and evolution of comets are considered. Cometary ions, formed by photoionization and other processes, are forced into a highly structured ion tail by the interaction with the solar wind. The importance of comets to solar-system studies lies in the possibilities that they are well-preserved samples of either the interstellar cloud which collapsed to form the solar system or the planetesimals from which the outer planets accumulated, and that they provided either the prebiotic complex molecules from which life evolved or some volatiles necessary for the evolution of these molecules.

  11. DETECTABILITY OF EARTH-LIKE PLANETS IN CIRCUMSTELLAR HABITABLE ZONES OF BINARY STAR SYSTEMS WITH SUN-LIKE COMPONENTS

    SciTech Connect

    Eggl, Siegfried; Pilat-Lohinger, Elke; Haghighipour, Nader

    2013-02-20

    Given the considerable percentage of stars that are members of binaries or stellar multiples in the solar neighborhood, it is expected that many of these binaries host planets, possibly even habitable ones. The discovery of a terrestrial planet in the {alpha} Centauri system supports this notion. Due to the potentially strong gravitational interaction that an Earth-like planet may experience in such systems, classical approaches to determining habitable zones (HZ), especially in close S-type binary systems, can be rather inaccurate. Recent progress in this field, however, allows us to identify regions around the star permitting permanent habitability. While the discovery of {alpha} Cen Bb has shown that terrestrial planets can be detected in solar-type binary stars using current observational facilities, it remains to be shown whether this is also the case for Earth analogs in HZs. We provide analytical expressions for the maximum and rms values of radial velocity and astrometric signals, as well as transit probabilities of terrestrial planets in such systems, showing that the dynamical interaction of the second star with the planet may indeed facilitate the planets' detection. As an example, we discuss the detectability of additional Earth-like planets in the averaged, extended, and permanent HZs around both stars of the {alpha} Centauri system.

  12. Planetary Systems Around Spectroscopic Binary Stars: The Very Dusty, Old, Sun-like BD+20 307

    NASA Astrophysics Data System (ADS)

    Zuckerman, Ben M.; Fekel, F. C.; Williamson, M. H.; Henry, G. W.; Muno, M. P.; Melis, C.; Marois, C.

    2009-01-01

    Field star BD+20 307 is the dustiest known main sequence star, based on the fraction of its bolometric luminosity, 4%, emitted at infrared wavelengths (Song et al. 2005; Rhee et al. 2008). The temperature of the particles that carry this large IR luminosity is comparable to that of the Sun's zodiacal dust, and their existence is likely a consequence of a fairly recent collision of large objects such as planets or planetary embryos. BD+20 307 is now known to be a 3.4 day spectroscopic binary composed of two nearly equal solar-mass stars (Weinberger 2008; Zuckerman et al. 2008). Consideration of various age indicators implies that that star is likely to be at least one Gyr old, perhaps many Gyr old. Probably the dust around this close binary star has nothing to do with planet formation and everything to do with some major catastrophic event that recently took place near 1 AU in a mature planetary system. Destabilizing planetary orbits in an old system with a single star at its center appears to be possible, e.g., Mercury (Batygin & Laughlin 2008 and references therein). Destabilization may be easier to achieve in a close binary star system and easier yet in a triple star system. Tokovinin et al. (2006) conclude that, for a spectroscopic binary star with an orbital period of 3.4 days, the probability is 70% that a third star is present. Thus, we have searched for such a tertiary star in the BD+20 307 system using accurate radial velocities measured at Fairborn and Lick observatories and with adaptive optics imaging at Keck observatory. As of the writing of this abstract, no third star is detected. Limits on mass and semimajor axis of any tertiary star will be discussed. This research was supported by a grant from the Chandra X-ray Observatory.

  13. Near Infrared Excess Energy in Binary System V367 Cygni

    NASA Astrophysics Data System (ADS)

    Gunasekera, Saraj

    Spectral energy distribution of the Serpentid type binary V367 Cyg was obtained using several previous photometric measurements made on this system in different spectral bands. We found Near IR excess starting from 3μm and this excess flux is attributed to the free-free emission from the mass accretion disk of the binary system. We adopted the temperature of primary component as 8,000°K. We added the free-free emission flux of the circumstellar disk to the black body energy of the primary component to find a best fit for the observed near infrared excess flux. In this fitting we left the electron density of the circumstellar disk ne of the free-free emission as a free parameter. We found that volume emission measure of the circumstellar disk is ˜ 9 × 1059 cm-3.

  14. Balance between the physical diffusion and the exchange reaction on binary ionic liquid electrolyte for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Hao, Feng; Lin, Hong; Zhang, Jing; Li, Jianbao

    A comprehensive characterizations of viscosities, conductivities, triiodide diffusion coefficients, charge-transfer resistances and photovoltaic performance of a potential dye-sensitized solar cell (DSC) electrolyte systems based on binary ionic liquid (IL) mixtures, namely, 1-ethyl-3-methylimidazolium dicyanamide (EMIDCA)/1-methyl-3-propylimidazolium iodide (PMII) with a fixed iodine concentration at varying EMIDCA volume fraction are investigated in the present study. Viscosity and conductivity values are accurately correlated with regard to temperature and EMIDCA volume fraction. The triiodide diffusion coefficients, the predominant electrolyte parameter for limitation of DSC efficiency, are determined by symmetrical cell methods. The physical diffusion and exchange reactions between the iodide and triiodide dominate the apparent triiodide diffusion coefficients at different range of EMIDCA volume fraction. A balance between the viscosity-dependent physical diffusion and the exchange reactions can get at an optimal volume percents of EMIDCA. Impedance spectroscopy and photovoltaic results both support the existence of an optimized binary IL electrolyte composition. Hence, for optimizing an IL-based electrolyte in regards to triiodide transport, a low viscosity is not the exclusive crucial factor since exchange reactions transport effects also play an important role to resolve the diffusion limitation of DSC efficiency.

  15. Kepler eclipsing binary stars. IV. Precise eclipse times for close binaries and identification of candidate three-body systems

    SciTech Connect

    Conroy, Kyle E.; Stassun, Keivan G.; Prša, Andrej; Orosz, Jerome A.; Welsh, William F.; Fabrycky, Daniel C.

    2014-02-01

    We present a catalog of precise eclipse times and analysis of third-body signals among 1279 close binaries in the latest Kepler Eclipsing Binary Catalog. For these short-period binaries, Kepler's 30 minute exposure time causes significant smearing of light curves. In addition, common astrophysical phenomena such as chromospheric activity, as well as imperfections in the light curve detrending process, can create systematic artifacts that may produce fictitious signals in the eclipse timings. We present a method to measure precise eclipse times in the presence of distorted light curves, such as in contact and near-contact binaries which exhibit continuously changing light levels in and out of eclipse. We identify 236 systems for which we find a timing variation signal compatible with the presence of a third body. These are modeled for the light travel time effect and the basic properties of the third body are derived. This study complements J. A. Orosz et al. (in preparation), which focuses on eclipse timing variations of longer period binaries with flat out-of-eclipse regions. Together, these two papers provide comprehensive eclipse timings for all binaries in the Kepler Eclipsing Binary Catalog, as an ongoing resource freely accessible online to the community.

  16. Stability of a planet in the HD 41004 binary system

    NASA Astrophysics Data System (ADS)

    Satyal, S.; Musielak, Z. E.

    2016-03-01

    The Hill stability criterion is applied to analyse the stability of a planet in the binary star system of HD 41004 AB, with the primary and secondary separated by 22 AU, and masses of 0.7 M_⊙ and 0.4 M_⊙, respectively. The primary hosts one planet in an S-type orbit, and the secondary hosts a brown dwarf (18.64 M_J) on a relatively close orbit, 0.0177 AU, thereby forming another binary pair within this binary system. This star-brown dwarf pair (HD 41004 B+Bb) is considered a single body during our numerical calculations, while the dynamics of the planet around the primary, HD 41004 Ab, is studied in different phase-spaces. HD 41004 Ab is a 2.6 M_J planet orbiting at the distance of 1.7 AU with orbital eccentricity 0.39. For the purpose of this study, the system is reduced to a three-body problem and is solved numerically as the elliptic restricted three-body problem (ERTBP). The {Hill stability} function is used as a chaos indicator to configure and analyse the orbital stability of the planet, HD 41004 Ab. The indicator has been effective in measuring the planet's orbital perturbation due to the secondary star during its periastron passage. The calculated Hill stability time series of the planet for the coplanar case shows the stable and quasi-periodic orbits for at least ten million years. For the reduced ERTBP the stability of the system is also studied for different values of planet's orbital inclination with the binary plane. Also, by recording the planet's {ejection time} from the system or {collision time} with a star during the integration period, stability of the system is analysed in a bigger phase-space of the planet's orbital inclination, ≤ 90o, and its semimajor axis, 1.65-1.75 AU. Based on our analysis it is found that the system can maintain a stable configuration for the planet's orbital inclination as high as 65o relative to the binary plane. The results from the Hill stability criterion and the planet's dynamical lifetime map are found to be

  17. The Solar-Type Hard-Binary Frequency and Distributions of Orbital Parameters in the Open Cluster M37

    NASA Astrophysics Data System (ADS)

    Geller, Aaron M.; Meibom, Soren; Barnes, Sydney A.; Mathieu, Robert D.

    2014-02-01

    Binary stars, and particularly the short-period ``hard'' binaries, govern the dynamical evolution of star clusters and determine the formation rates and mechanisms for exotic stars like blue stragglers and X-ray sources. Understanding the near-primordial hard-binary population of star clusters is of primary importance for dynamical models of star clusters, which have the potential to greatly advance our understanding of star cluster evolution. Yet the binary frequencies and distributions of binary orbital parameters (period, eccentricity, etc.) for young coeval stellar populations are poorly known, due to a lack of necessary observations. The young (~540 Myr) open cluster M37 hosts a rich binary population that can be used to empirically define these initial conditions. Importantly, this cluster has been the target of a comprehensive WIYN/Hydra radial-velocity (RV) survey, from which we have already identified a nearly complete sample of 329 solar-type (1.5 <=M [M_⊙] <=1.0) members in M37. Of these stars, 82 show significant RV variability, indicative of a binary companion. We propose to build upon these data with a multi-epoch RV survey using WIYN/Hydra to derive kinematic orbital solutions for these 82 binaries in M37. This project was granted time in 2013B and scheduled for later this year. We anticipate that about half of the detected binaries in M37 will acquire enough RV measurements (>=10) in 2013B to begin searching for orbital solutions. With this proposal and perhaps one additional semester we should achieve >=10 RV measurements for the remaining binaries.

  18. Space Missions to Small Solar System Bodies

    NASA Astrophysics Data System (ADS)

    Scheeres, Daniel

    2012-07-01

    The scientific study of small solar system bodies such as asteroids and comets is of great current interest to the scientific community and to society at large. The exploration of these bodies provides insights into the formational epoch of the solar system and its subsequent evolution. It also provides insights into humanity's future through the better characterization of the properties of these bodies, their potential uses, and how their impact with the Earth could be prevented. The in situ exploration of these bodies provides the best insight into their nature, but are also the most challenging type of exploration. Due to their small size, distended shapes, and wide range of potential spin states, developing systematic exploration methodologies of these bodies is challenging and has spurred the development of non-standard and novel approaches to the study of motion about these bodies. These same techniques that have been developed to better control and understand spacecraft motion about these bodies also provides novel insights into the study of the environment and evolution of these same bodies. These approaches have led to the development of specific predictions of how small bodies evolve in terms of their shape, how they can form binary systems, their spin dynamics, and even their heliocentric orbits. The current talk will summarize our understanding of spacecraft motion and control in the vicinity of small bodies and show how this theory can be translated into improved scientific analysis and understanding of these bodies. Specific case studies will be presented.

  19. Mixing behavior of colyophilized binary systems.

    PubMed

    Shamblin, S L; Taylor, L S; Zografi, G

    1998-06-01

    The purpose of this study was to investigate the factors which govern the mixing of amorphous sucrose with trehalose, poly(vinylpyrrolidone) (PVP), dextran, and poly(vinylpyrrolidone-co-vinyl acetate) (PVP/VA). These materials were chosen as model systems to represent multicomponent freeze-dried pharmaceutical preparations. Mixtures were prepared by colyophilization of the components from aqueous solutions. The glass transition temperatures (Tg) of these mixtures were measured using differential scanning calorimetry (DSC) and were compared to predictions based on simple mixing rules. FT-Raman spectroscopy was used to probe selected mixtures for evidence of molecular interactions between components. Colyophilized mixtures were confirmed to be amorphous by X-ray powder diffraction. The Tg values of the various mixtures generally were lower than values predicted from free volume and thermodynamic models, indicating that mixing is not ideal. The FT-Raman spectra of colyophilized sucrose-PVP and sucrose-PVP/VA mixtures provided evidence for interaction between the components through hydrogen bonding. Hydrogen bonds formed between components in colyophilized sucrose-additive mixtures are formed at the expense of hydrogen bonds within sucrose and in some cases within the additive. A thermodynamic analysis of these mixtures indicates that mixing is endothermic, which is consistent with a net loss in the degree of hydrogen bonding on mixing. There is also a positive excess entropy of mixing which accompanies the net loss in hydrogen bonds. Despite this gain in excess entropy, the excess free energy of mixing is positive, consistent with the observed deviations in Tg from values predicted using models which assume ideal mixing. PMID:9607945

  20. On the Nb-Ge Binary System

    NASA Astrophysics Data System (ADS)

    Papadimitriou, Ioannis; Utton, Claire; Tsakiropoulos, Panos

    2015-12-01

    First-principles calculations were used to study intermetallic compounds in the Nb-Ge system, to gain a better understanding of the phase diagram and resolve conflicts reported in the literature. The enthalpy of formation with regard to temperature was calculated for all the intermetallic compounds, to investigate phase stabilities and phase equilibria at low and elevated temperatures. These results, combined with the electronic DOS, suggest that the tI32 (W5Si3-type) Nb5Ge3 and NbGe2 compounds are stable over the whole temperature range. The stoichiometric cP8 Nb3Ge becomes stable close to its melting temperature. Regarding different compositions of the cP8 Nb3Ge, the calculations suggest the (Nb)0.75(Nb,Ge)0.25 model for the Nb3Ge phase instead of the proposed model, (Nb)0.75(Nb,Ge,Va)0.25, where Va represents vacancy. The calculations show that the tI32 (Cr5B3-type) Nb5Ge3, hP16 (Mn5Si3-type) Nb5Ge3 and Nb10Ge7 compounds should be considered metastable. The elastic constants, bulk, shear, and Young's modulus, Poisson's ratio, and Debye temperature of the Nb, Ge, cP8 Nb3Ge, tP32 Nb3Ge, tI32 (Cr5B3-type) Nb5Ge3, tI32 (W5Si3-type) Nb5Ge3, hP16 (Mn5Si3-type) Nb5Ge3, Nb10Ge7 and NbGe2 were calculated. These phases were found to be mechanically stable. Using the Cauchy pressure, Pugh's index of ductility, and the Poisson's ratio as criteria, the calculations suggest that the tI32 (Cr5B3-type) Nb5Ge3 and NbGe2 intermetallics should be brittle (with the latter being the most brittle) and the cP8 Nb3Ge, tP32 Nb3Ge, hP16 Nb5Si3 and Nb10Ge7 ductile (with cP8 Nb3Ge being the most ductile).

  1. Binary nanoparticle superlattices of soft-particle systems

    PubMed Central

    Travesset, Alex

    2015-01-01

    The solid-phase diagram of binary systems consisting of particles of diameter σA=σ and σB=γσ (γ≤1) interacting with an inverse p = 12 power law is investigated as a paradigm of a soft potential. In addition to the diameter ratio γ that characterizes hard-sphere models, the phase diagram is a function of an additional parameter that controls the relative interaction strength between the different particle types. Phase diagrams are determined from extremes of thermodynamic functions by considering 15 candidate lattices. In general, it is shown that the phase diagram of a soft repulsive potential leads to the morphological diversity observed in experiments with binary nanoparticles, thus providing a general framework to understand their phase diagrams. Particular emphasis is given to the two most successful crystallization strategies so far: evaporation of solvent from nanoparticles with grafted hydrocarbon ligands and DNA programmable self-assembly. PMID:26195799

  2. Phase equilibrium behavior of the carbon dioxide + benzophenone binary system

    SciTech Connect

    Tarantino, D.E.; Kohn, J.P.; Brennecke, J.F. . Dept. of Chemical Engineering)

    1994-01-01

    Phase equilibrium behavior of various binary CO[sub 2] + hydrocarbon mixtures has been studied by many researchers, providing data which are useful in the design of economically attractive separation processes using carbon dioxide as a solvent. Pressure, liquid-phase composition, and liquid-phase molar volumes are presented for the binary vapor-liquid system CO[sub 2] + benzophenone at 25, 35, and 50 C. Also, pressure, liquid-phase compositions, and liquid-phase molar volumes on the S[sub 1]-L[sub 1]-V curve and L[sub 1]-L[sub 2]-V curve are presented. The termination points of these loci are located and characterized.

  3. Close Stellar Binary Systems by Grazing Envelope Evolution

    NASA Astrophysics Data System (ADS)

    Soker, Noam

    2015-02-01

    I suggest a spiral-in process in which a stellar companion grazes the envelope of a giant star while both the orbital separation and the giant radius shrink simultaneously, forming a close binary system. The binary system might be viewed as evolving in a constant state of "just entering a common envelope (CE) phase." In cases where this process takes place, it can be an alternative to CE evolution where the secondary star is immersed in the giant's envelope. Grazing envelope evolution (GEE) is made possible only if the companion manages to accrete mass at a high rate and launches jets that remove the outskirts of the giant envelope, hence preventing the formation of a CE. The high accretion rate is made possible by the accretion disk launching jets which efficiently carry the excess angular momentum and energy from the accreted mass. The orbital decay itself is caused by the gravitational interaction of the secondary star with the envelope inward of its orbit, i.e., dynamical friction (gravitational tide). Mass loss through the second Lagrangian point can carry additional angular momentum and envelope mass. The GEE lasts for tens to hundreds of years. The high accretion rate, with peaks lasting from months to years, might lead to a bright object referred to as the intermediate luminosity optical transient (Red Novae; Red Transients). A bipolar nebula and/or equatorial ring are formed around the binary remnant.

  4. Searching Planets Around Some Selected Eclipsing Close Binary Stars Systems

    NASA Astrophysics Data System (ADS)

    Nasiroglu, Ilham; Slowikowska, Agnieszka; Krzeszowski, Krzysztof; Zejmo, M. Michal; Er, Hüseyin; Goździewski, Krzysztof; Zola, Stanislaw; Koziel-Wierzbowska, Dorota; Debski, Bartholomew; Ogloza, Waldemar; Drozdz, Marek

    2016-07-01

    We present updated O-C diagrams of selected short period eclipsing binaries observed since 2009 with the T100 Telescope at the TUBITAK National Observatory (Antalya, Turkey), the T60 Telescope at the Adiyaman University Observatory (Adiyaman, Turkey), the 60cm at the Mt. Suhora Observatory of the Pedagogical University (Poland) and the 50cm Cassegrain telescope at the Fort Skala Astronomical Observatory of the Jagiellonian University in Krakow, Poland. All four telescopes are equipped with sensitive, back-illuminated CCD cameras and sets of wide band filters. One of the targets in our sample is a post-common envelope eclipsing binary NSVS 14256825. We collected more than 50 new eclipses for this system that together with the literature data gives more than 120 eclipse timings over the time span of 8.5 years. The obtained O-C diagram shows quasi-periodic variations that can be well explained by the existence of the third body on Jupiter-like orbit. We also present new results indicating a possible light time travel effect inferred from the O-C diagrams of two other binary systems: HU Aqr and V470 Cam.

  5. Wobbling and Precessing Jets from Warped Disks in Binary Systems

    NASA Astrophysics Data System (ADS)

    Sheikhnezami, Somayeh; Fendt, Christian

    2015-12-01

    We present results of the first ever three-dimensional (3D) magnetohydrodynamic (MHD) simulations of the accretion-ejection structure. We investigate the 3D evolution of jets launched symmetrically from single stars but also jets from warped disks in binary systems. We have applied various model setups and tested them by simulating a stable and bipolar symmetric 3D structure from a single star-disk-jet system. Our reference simulation maintains a good axial symmetry and also a bipolar symmetry for more than 500 rotations of the inner disk, confirming the quality of our model setup. We have then implemented a 3D gravitational potential (Roche potential) due by a companion star and run a variety of simulations with different binary separations and mass ratios. These simulations show typical 3D deviations from axial symmetry, such as jet bending outside the Roche lobe or spiral arms forming in the accretion disk. In order to find indications of precession effects, we have also run an exemplary parameter setup, essentially governed by a small binary separation of only ≃200 inner disk radii. This simulation shows a strong indication that we observe the onset of a jet precession caused by the wobbling of the jet-launching disk. We estimate the opening angle of the precession cone defined by the lateral motion of the jet axis to be about 4° after about 5000 dynamical time steps.

  6. Solar tracking system

    SciTech Connect

    White, P.R.; Scott, D.R.

    1981-04-01

    A solar tracker for a solar collector is described in detail. The collector is angularly oriented by a motor wherein the outputs of two side-by-side photodetectors are discriminated as to three ranges: a first corresponding to a low light or darkness condition a second corresponding to light intensity lying in an intermediate range and a third corresponding to light above an intermediate range, direct sunlight. The first output drives the motor to a selected maximum easterly angular position the second enables the motor to be driven westerly at the Earth rotational rate and the third output, the separate outputs of the two photodetectors, differentially controls the direction of rotation of the motor to effect actual tracking of the Sun. Official Gazette of the U.S. Patent and Trademark Office

  7. Solar tracking system

    NASA Technical Reports Server (NTRS)

    White, P. R.; Scott, D. R. (Inventor)

    1981-01-01

    A solar tracker for a solar collector is described in detail. The collector is angularly oriented by a motor wherein the outputs of two side-by-side photodetectors are discriminated as to three ranges: a first corresponding to a low light or darkness condition; a second corresponding to light intensity lying in an intermediate range; and a third corresponding to light above an intermediate range, direct sunlight. The first output drives the motor to a selected maximum easterly angular position; the second enables the motor to be driven westerly at the Earth rotational rate; and the third output, the separate outputs of the two photodetectors, differentially controls the direction of rotation of the motor to effect actual tracking of the Sun.

  8. Chaos in the Solar System

    NASA Technical Reports Server (NTRS)

    Lecar, Myron; Franklin, Fred A.; Holman, Matthew J.; Murray, Norman J.

    2001-01-01

    The physical basis of chaos in the solar system is now better understood: In all cases investigated so far, chaotic orbits result from overlapping resonances. Perhaps the clearest examples are found in the asteroid belt. Overlapping resonances account for its kirkwood gaps and were used to predict and find evidence for very narrow gaps in the outer belt. Further afield, about one new "short-peroid" comet is discovered each year. They are believed to come from the "Kuiper Belt" (at 40 AU or more) via chaotic orbits produced by mean-motion and secular resonances with Neptune. Finally, the planetary system itself is not immune from chaos. In the inner solar system, overlapping secular resonances have been identified as the possible source of chaos. For example, Mercury in 1012 years, may suffer a close encounter with Venus or plunge into the Sun. In the outer solar system, three-body resonances have been identified as a source of chaos, but on an even longer time scale of 109 times the age of the solar system. On the human time scale, the planets do follow their orbits in a stately procession, and we can predict their trajectories for hundreds of thousands of years. That is because the mavericks, with shorter instability times, have long since been ejected. The solar system is not stable; it is just old!

  9. Hybrids of Solar Sail, Solar Electric, and Solar Thermal Propulsion for Solar-System Exploration

    NASA Technical Reports Server (NTRS)

    Wilcox, Brian H.

    2012-01-01

    Solar sails have long been known to be an attractive method of propulsion in the inner solar system if the areal density of the overall spacecraft (S/C) could be reduced to approx.10 g/sq m. It has also long been recognized that the figure (precise shape) of useful solar sails needs to be reasonably good, so that the reflected light goes mostly in the desired direction. If one could make large reflective surfaces with reasonable figure at an areal density of approx.10 g/sq m, then several other attractive options emerge. One is to use such sails as solar concentrators for solar-electric propulsion. Current flight solar arrays have a specific output of approx. 100W/kg at 1 Astronomical Unit (AU) from the sun, and near-term advances promise to significantly increase this figure. A S/C with an areal density of 10 g/sq m could accelerate up to 29 km/s per year as a solar sail at 1 AU. Using the same sail as a concentrator at 30 AU, the same spacecraft could have up to approx. 45 W of electric power per kg of total S/C mass available for electric propulsion (EP). With an EP system that is 50% power-efficient, exhausting 10% of the initial S/C mass per year as propellant, the exhaust velocity is approx. 119 km/s and the acceleration is approx. 12 km/s per year. This hybrid thus opens attractive options for missions to the outer solar system, including sample-return missions. If solar-thermal propulsion were perfected, it would offer an attractive intermediate between solar sailing in the inner solar system and solar electric propulsion for the outer solar system. In the example above, both the solar sail and solar electric systems don't have a specific impulse that is near-optimal for the mission. Solar thermal propulsion, with an exhaust velocity of the order of 10 km/s, is better matched to many solar system exploration missions. This paper derives the basic relationships between these three propulsion options and gives examples of missions that might be enabled by

  10. Counter electrodes from binary ruthenium selenide alloys for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Li, Pinjiang; Cai, Hongyuan; Tang, Qunwei; He, Benlin; Lin, Lin

    2014-12-01

    Dye-sensitized solar cell (DSSC) is a promising solution to global energy and environmental problems because of its merits on clean, cost-effectiveness, relatively high efficiency, and easy fabrication. However, the reduction of fabrication cost without sacrifice of power conversion efficiencies of the DSSCs is a golden rule for their commercialization. Here we design a new binary ruthenium selenide (Ru-Se) alloy counter electrodes (CEs) by a low-temperature hydrothermal reduction method. The electrochemical behaviors are evaluated by cyclic voltammogram, electrochemical impedance, and Tafel measurements, giving an optimized Ru/Se molar ratio of 1:1. The DSSC device with RuSe alloy CE achieves a power conversion efficiency of 7.15%, which is higher than 5.79% from Pt-only CE based DSSC. The new concept, easy process along with promising results provide a new approach for reducing cost but enhancing photovoltaic performances of DSSCs.

  11. Photometric Analysis of the Contact Binary System V829 Hercules

    NASA Astrophysics Data System (ADS)

    Özkardeş, B.; Erdem, A.

    2007-05-01

    New BVR light curves and photometric analysis of the contact binary star V829 Her are presented. The light curves were obtained at the çanakkale Onsekiz Mart University Observatory in 2005. All the times of minimum light were collected and combined with the new ones presented in this work. The variation of the orbital period of the system was then analysed. Sinusoidal and secular changes were found. These variations were examined in terms of two plausible mechanisms, namely (i) mass transfer, and (ii) a light-time effect due to an unseen component in the system. The instrumental differential magnitudes of the system were converted into standard magnitudes. So, we calculate BVR standard magnitudes of the system and obtain the mean color indices of B-V=0.59±0.01 for V829 Her, which indicates the spectral type of the system to be G0-1. The light curves are generally those of contact binaries, but there are large asymmetries between maxima. New BVR light curves and radial velocity curves available from the literature were analysed, simultaneously. Light curve asymmetries of the system were explained in terms of a large dark starspot on the more massive component. Absolute parameters of the system were also derived.

  12. Observation of asteroids with GRAVITY - Physical characterization of binary systems

    NASA Astrophysics Data System (ADS)

    Matter, A.; Delbo, M.; Carry, B.; Tanga, P.

    2014-12-01

    Density and internal structures are among the most important characteristics of asteroids, yet these properties are also some of the least known. For distant asteroids (in the Main Belt and beyond) these properties were up to now accessible only for the largest (>100 km in size) asteroids. Going to smaller and fainter asteroids can revolutionize our understanding because we will be sampling a new regime in physical properties. Here we discuss how ground-based optical interferometry with the GRAVITY instrument can be used to observe the motion of asteroid satellites to determine the mass of small binary systems. Following the expected sensitivity performances in K-band of GRAVITY, we present a sample of binary targets potentially observable in single-field mode. The feasibility of such observations will strongly be dependent on the ability of the control software of GRAVITY to track objects moving at high rate on the sky (differential motion ˜f 10 mas.s^{-1}). Although the dual-field mode could allow to increase the sample of small binary asteroids observable, it seems to be currently unfeasible given the high differential motion of asteroids.

  13. Non-coplanar planet-disc interactions in binary star systems

    NASA Astrophysics Data System (ADS)

    Martin, Rebecca G.; Lubow, Stephen H.; Nixon, Chris; Armitage, Philip J.

    2016-06-01

    About half of observed exoplanets are estimated to be in binary systems. Thus, understanding planet formation and evolution in binaries is essential for explaining observed exoplanet properties. We will show how planet-disc interactions in a mildly inclined disc around one component of a binary can lead to the formation of highly eccentric and highly inclined planets.

  14. Integrated solar energy system optimization

    NASA Astrophysics Data System (ADS)

    Young, S. K.

    1982-11-01

    The computer program SYSOPT, intended as a tool for optimizing the subsystem sizing, performance, and economics of integrated wind and solar energy systems, is presented. The modular structure of the methodology additionally allows simulations when the solar subsystems are combined with conventional technologies, e.g., a utility grid. Hourly energy/mass flow balances are computed for interconnection points, yielding optimized sizing and time-dependent operation of various subsystems. The program requires meteorological data, such as insolation, diurnal and seasonal variations, and wind speed at the hub height of a wind turbine, all of which can be taken from simulations like the TRNSYS program. Examples are provided for optimization of a solar-powered (wind turbine and parabolic trough-Rankine generator) desalinization plant, and a design analysis for a solar powered greenhouse.

  15. Solar liquid heating system

    SciTech Connect

    Finn, D.J.

    1990-05-08

    This patent describes a solar heater for heating liquids. It comprises: a heatable bag, a support means supporting the heatable bag, a heatable body of liquid in the heatable bag, the heatable bag being disposed in sunlight so as to become heated thereby, a topside gas bag above the heatable bag, the topside gas bag containing a gas for serving as insulation, a topside fluid bag disposed above the topside gas bag and containing a fluid for further insulation. The bags being substantially gasproof and waterproof and also being flexible whereby the gravity pull on the bags and the flexibility thereof causes the upper sides of the bags to seek horizontal levels.

  16. Masses of black holes in binary stellar systems

    NASA Astrophysics Data System (ADS)

    Cherepashchuk, Anatolii M.

    1996-08-01

    Mass determination methods and their results for ten black holes in X-ray binary systems are summarised. A unified interpretation of the radial velocity and optical light curves allows one to reliably justify the close binary system model and to prove the correctness of determination of the optical star mass function fv(m).The orbit plane inclination i can be estimated from an analysis of optical light curve of the system, which is due mainly to the ellipsoidal shape of the optical star (the so-called ellipticity effect). The component mass ratio q = mx/mv is obtained from information about the distance to the binary system as well as from data about rotational broadening of absorption lines in the spectrum of the optical star. These data allow one to obtain from the value of fv(m) a reliable value of the black hole mass mx or its low limit, as well as the optical star mass mv. An independent estimate of the optical star mass mv obtained from information about its spectral class and luminosity gives us test results. Additional test comes from information about the absence or presence of X-ray eclipses in the system. Effects of the non-zero dimension of the optical star, its pear-like shape, and X-ray heating on the absorption line profiles and the radial velocity curve are investigated. It is very significant that none of ten known massive (mx > 3M) X-ray sources considered as black hole candidates is an X-ray pulsar or an X-ray burster of the first kind.

  17. An Observational Study of Algol-Type Binary System

    NASA Astrophysics Data System (ADS)

    Zhang, J.

    2015-01-01

    The Algol-Type binary systems are a subtype of binary systems. Their unique semi-detached structure leads to have abundant physical phenomena, including the dramatically distorted donor star, strong magnetic activities, various ways of mass transfer, the evolution stage quite different from that of single stars, and specific formation tracks. In this paper, we introduce the fundamental physics of light curves, as well as the models or programs used in the past. We show the influence of different parameters on the light curves, including the inclination, temperature, abundance, surface gravity, the third light, radius, orbital eccentricity, and the argument of periastron. Based on the current catalog of Algols, we investigate their statistic characteristics. We observe three Algols and analyze the data in detail. The results are as follows: (1)Our statistical analyses of Algols support the previous suggestion that most of the detached component stars are main sequence stars. The distribution of the mass ratio agrees to our calculated critical value of the mass ratio for Algols. We suggest that there could be a lower limit of the radius ratio. We also show that there are good correlations among the temperature, luminosity, radius, and the mass of the component stars. (2) The binary FG Gem is observed, and the data are analyzed. Based on the solutions of large combinations of the temperature and luminosity, we use a new age-comparing method to show that the FG Gem is a semi-detached system, and a new temperature-searching method to get a better estimate of the temperature of the detached component star. We suggest that a combination of the intermittent mass flow and the continuous magnetic braking can explain its orbital period change. (3) Taking the VV Vir as an example, we discuss some properties of the mass flow in a semi-detached binary. Some of them can reflect the common characteristics of the mass flows in the Algol systems, e.g., the radius of the mass flow is

  18. Solar hot-water system

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Design data brochure describes domestic solar water system that uses direct-feed system designed to produce 80 gallons of 140 F hot water per day to meet needs of single family dwelling. Brochure also reviews annual movements of sun relative to earth and explains geographic considerations in collector orientation and sizing.

  19. Solar-powered cooling system

    DOEpatents

    Farmer, Joseph C

    2013-12-24

    A solar-powered adsorption-desorption refrigeration and air conditioning system uses nanostructural materials made of high specific surface area adsorption aerogel as the adsorptive media. Refrigerant molecules are adsorbed on the high surface area of the nanostructural material. A circulation system circulates refrigerant from the nanostructural material to a cooling unit.

  20. SELF-CONSISTENT MAGNETIC STELLAR EVOLUTION MODELS OF THE DETACHED, SOLAR-TYPE ECLIPSING BINARY EF AQUARII

    SciTech Connect

    Feiden, Gregory A.; Chaboyer, Brian E-mail: Brian.Chaboyer@Dartmouth.edu

    2012-12-10

    We introduce a new one-dimensional stellar evolution code, based on the existing Dartmouth code, that self-consistently accounts for the presence of a globally pervasive magnetic field. The methods involved in perturbing the equations of stellar structure, the equation of state, and the mixing-length theory of convection are presented and discussed. As a first test of the code's viability, stellar evolution models are computed for the components of a solar-type, detached eclipsing binary (DEB) system, EF Aquarii, shown to exhibit large disagreements with stellar models. The addition of the magnetic perturbation corrects the radius and effective temperature discrepancies observed in EF Aquarii. Furthermore, the required magnetic field strength at the model photosphere is within a factor of two of the magnetic field strengths estimated from the stellar X-ray luminosities measured by ROSAT and those predicted from Ca II K line core emission. These models provide firm evidence that the suppression of thermal convection arising from the presence of a magnetic field is sufficient to significantly alter the structure of solar-type stars, producing noticeably inflated radii and cooler effective temperatures. The inclusion of magnetic effects within a stellar evolution model has a wide range of applications, from DEBs and exoplanet host stars to the donor stars of cataclysmic variables.

  1. Experiences in solar cooling systems

    NASA Astrophysics Data System (ADS)

    Ward, D. S.

    The results of performance evaluations for nine solar cooling systems are presented, and reasons fow low or high net energy balances are discussed. Six of the nine systems are noted to have performed unfavorably compared to standard cooling systems due to thermal storage losses, excessive system electrical demands, inappropriate control strategies, poor system-to-load matching, and poor chiller performance. A reduction in heat losses in one residential unit increased the total system efficiency by 2.5%, while eliminating heat losses to the building interior increased the efficiency by 3.3%. The best system incorporated a lithium bromide absorption chiller and a Rankine cycle compression unit for a commercial application. Improvements in the cooling tower and fan configurations to increase the solar cooling system efficiency are indicated. Best performances are expected to occur in climates inducing high annual cooling loads.

  2. Solar System Science with JWST

    NASA Technical Reports Server (NTRS)

    Sonneborn, G.; Lunine, J.; Hammel, H.; Long, K.; Hutchings, J.; Rieke, G.

    2007-01-01

    JWST will enable breakthroughs in our understanding of the physical characteristics of cold bodies in the outer reaches of the Solar System. These objects include Pluto and other Kuiper Belt Objects (KBOs), the icy moons of the giant planets, and distant cometary nuclei. Recent discoveries of large objects in the Kuiper belt, along with many smaller members, make it clear that this region represents a major constituent of our Solar System, one that was hidden until recently because it is so remote and challenging to observe. The near-IR and mid-IR performance of JWST will be unique in its power to probe this region. This poster describes the science drivers for JWST observations of Solar System objects and plans for implementing this capability.

  3. Origin of Outer Solar System

    NASA Technical Reports Server (NTRS)

    Holman, Matthew J.; Lindstrom, David (Technical Monitor)

    2005-01-01

    Our ongoing research program combines extensive deep and wide-field observations using a variety of observational platforms with numerical studies of the dynamics of small bodies in the outer solar system in order to advance the main scientific goals of the community studying the Kuiper belt and the outer solar system. These include: (1) determining the relative populations of the known classes of KBOs as well as other possible classes; ( 2 ) determining the size distributions or luminosity function of the individual populations or the Kuiper belt as a whole; (3) determining the inclinations distributions of these populations; (4) establishing the radial extent of the Kuiper belt; ( 5 ) measuring and relating the physical properties of different types of KBOs to those of other solar system bodies; and, (6) completing our systematic inventory of the satellites of the outer planets.

  4. Solar thermophotovoltaic system using nanostructures.

    PubMed

    Ungaro, Craig; Gray, Stephen K; Gupta, Mool C

    2015-09-21

    This paper presents results on a highly efficient experimental solar thermophotovoltaic (STPV) system using simulated solar energy. An overall power conversion efficiency of 6.2% was recorded under solar simulation. This was matched with a thermodynamic model, and the losses within the system, as well as a path forward to mitigate these losses, have been investigated. The system consists of a planar, tungsten absorbing/emitting structure with an anti-reflection layer coated laser-microtextured absorbing surface and single-layer dielectric coated emitting surface. A GaSb PV cell was used to capture the emitted radiation and convert it into electrical energy. This simple structure is both easy to fabricate and temperature stable, and contains no moving parts or heat exchange fluids. PMID:26406745

  5. EVOLUTION OF THE BINARY FRACTION IN DENSE STELLAR SYSTEMS

    SciTech Connect

    Fregeau, John M.; Ivanova, Natalia; Rasio, Frederic A.

    2009-12-20

    Using our recently improved Monte Carlo evolution code, we study the evolution of the binary fraction in globular clusters. In agreement with previous N-body simulations, we find generally that the hard binary fraction in the core tends to increase with time over a range of initial cluster central densities for initial binary fractions approx<90%. The dominant processes driving the evolution of the core binary fraction are mass segregation of binaries into the cluster core and preferential destruction of binaries there. On a global scale, these effects and the preferential tidal stripping of single stars tend to roughly balance, leading to overall cluster binary fractions that are roughly constant with time. Our findings suggest that the current hard binary fraction near the half-mass radius is a good indicator of the hard primordial binary fraction. However, the relationship between the true binary fraction and the fraction of main-sequence stars in binaries (which is typically what observers measure) is nonlinear and rather complicated. We also consider the importance of soft binaries, which not only modify the evolution of the binary fraction, but can also drastically change the evolution of the cluster as a whole. Finally, we briefly describe the recent addition of single and binary stellar evolution to our cluster evolution code.

  6. Application of the Thermodynamic Solution Model of Dilute Binary Systems

    NASA Astrophysics Data System (ADS)

    Luáek, J.

    1997-12-01

    The thermodynamic solution model by Tanaka et al. for liquid binary systems was extended to solid binary systems. On the basis of this extension the activity coefficients of solute elements in the solid phase in infinite dilution for transition metals were calculated in Part I of this paper. The determination of the activity coefficients in both solid and liquid phases can enable one to predict the equilibrium segregation coefficient of the solute elements in transition metal base alloys without the knowledge of equilibrium binary phase diagrams. The model was applied on Ti, Zr and Hf-base dilute alloys at their melting points. The calculated values of equilibrium segregation coefficients are compared with values derived by other methods. The effect of the model parameters on the value of equilibrium segregation coefficients was discussed. Das thermodynamische Modell für flüssige binäre Systeme nach Tanaka wurde auf feste binäre Systeme ausgedehnt. Auf dieser Grundlage wurden die Aktivitätskoeffizienten der gelösten Elemente in der Solidusphase für die Übergangsmetalle in Teil I dieser Arbeit berechnet. Die Bestimmung der Aktivitätskoeffizienten in der Solidus- und Liquidusphase ermöglicht die Vorhersage des Gleichgewichtsverteilungskoeffizienten der gelösten Elemente in den Legierungen der Übergangsmetalle ohne Kenntnis ihrer Zustandsdiagramme. Das Modell wurde auf Ti, Zr und Hf-Legierungen im Bereich der Schmelztemperatur der Hauptkomponente angewandt. Die berechneten Werte der Gleichgewichtsverteilungskoeffizienten wurden mit den Werten anderer Methoden verglichen. Der Einfluss der Eingangsparameter in unserem Modell auf die Werte der Gleichgewichtsverteilungskoeffizienten wurde diskutiert.

  7. SELF-REGULATED SHOCKS IN MASSIVE STAR BINARY SYSTEMS

    SciTech Connect

    Parkin, E. R.; Sim, S. A. E-mail: s.sim@qub.ac.uk

    2013-04-20

    In an early-type, massive star binary system, X-ray bright shocks result from the powerful collision of stellar winds driven by radiation pressure on spectral line transitions. We examine the influence of the X-rays from the wind-wind collision shocks on the radiative driving of the stellar winds using steady-state models that include a parameterized line force with X-ray ionization dependence. Our primary result is that X-ray radiation from the shocks inhibits wind acceleration and can lead to a lower pre-shock velocity, and a correspondingly lower shocked plasma temperature, yet the intrinsic X-ray luminosity of the shocks, L{sub X}, remains largely unaltered, with the exception of a modest increase at small binary separations. Due to the feedback loop between the ionizing X-rays from the shocks and the wind driving, we term this scenario as self-regulated shocks. This effect is found to greatly increase the range of binary separations at which a wind-photosphere collision is likely to occur in systems where the momenta of the two winds are significantly different. Furthermore, the excessive levels of X-ray ionization close to the shocks completely suppress the line force, and we suggest that this may render radiative braking less effective. Comparisons of model results against observations reveal reasonable agreement in terms of log (L{sub X}/L{sub bol}). The inclusion of self-regulated shocks improves the match for kT values in roughly equal wind momenta systems, but there is a systematic offset for systems with unequal wind momenta (if considered to be a wind-photosphere collision).

  8. Decentalized solar photovoltaic energy systems

    SciTech Connect

    Krupka, M. C.

    1980-09-01

    Environmental data for decentralized solar photovoltaic systems have been generated in support of the Technology Assessment of Solar Energy Systems program (TASE). Emphasis has been placed upon the selection and use of a model residential photovoltaic system to develop and quantify the necessary data. The model consists of a reference home located in Phoenix, AZ, utilizing a unique solar cell array-roof shingle combination. Silicon solar cells, rated at 13.5% efficiency at 28/sup 0/C and 100 mW/cm/sup 2/ (AMI) insolation are used to generate approx. 10 kW (peak). An all-electric home is considered with lead-acid battery storage, dc-ac inversion and utility backup. The reference home is compared to others in regions of different insolation. Major material requirements, scaled to quad levels of end-use energy include significant quantities of silicon, copper, lead, antimony, sulfuric acid and plastics. Operating residuals generated are negligible with the exception of those from the storage battery due to a short (10-year) lifetime. A brief general discussion of other environmental, health, and safety and resource availability impacts is presented. It is suggested that solar cell materials production and fabrication may have the major environmental impact when comparing all facets of photovoltaic system usage. Fabrication of the various types of solar cell systems involves the need, handling, and transportation of many toxic and hazardous chemicals with attendant health and safety impacts. Increases in production of such materials as lead, antimony, sulfuric acid, copper, plastics, cadmium and gallium will be required should large scale usage of photovoltaic systems be implemented.

  9. Searching for Binary Y dwarfs with the Gemini Multi-Conjugate Adaptive Optics System (GeMS)

    NASA Astrophysics Data System (ADS)

    Opitz, Daniela; Tinney, Chris

    2015-08-01

    The NASA Wide-field Infrared Survey Explorer (WISE) has discovered almost all the known members of the new class of Y-type brown dwarfs. Most of these Y dwarfs have been identified as isolated objects in the field. It is known that binaries with L- and T-type brown dwarf primaries are less prevalent than either M-dwarf or solar-type primaries, they tend to be closely separated and are more frequently detected in near-equal mass configurations. The binary status of Y- type brown dwarfs is still unclear and therefore, determining if Y-type primaries hold the same trend, is of considerable interest. In addition, the detection of binary companions to very cool Y dwarfs may well be the best means available for discovering even colder objects. We present results from a diffraction-limited study of a sample of five WISE Y dwarfs observed with the Gemini Multi-Conjugate Adaptive Optics System (GeMS). We find no evidence for binary companions in these data, which suggests these systems are not equal luminosity (or equivalently equal mass) binaries at separations larger than ~ 0.3-1.9 AU.

  10. Our Solar System. Our Solar System Topic Set

    ERIC Educational Resources Information Center

    Phelan, Glen

    2006-01-01

    This book examines the planets and other objects in space that make up the solar system. It also shows how technology helps students learn about our neighbors in space. The suggested age range for this book is 3-8 with a guided reading level of Q-R. The Fry level is 3.2.