Identifying Exoplanets with Deep Learning: A Five-planet Resonant Chain around Kepler-80 and an Eighth Planet around Kepler-90

NASA Astrophysics Data System (ADS)

Shallue, Christopher J.; Vanderburg, Andrew

2018-02-01

NASA’s Kepler Space Telescope was designed to determine the frequency of Earth-sized planets orbiting Sun-like stars, but these planets are on the very edge of the mission’s detection sensitivity. Accurately determining the occurrence rate of these planets will require automatically and accurately assessing the likelihood that individual candidates are indeed planets, even at low signal-to-noise ratios. We present a method for classifying potential planet signals using deep learning, a class of machine learning algorithms that have recently become state-of-the-art in a wide variety of tasks. We train a deep convolutional neural network to predict whether a given signal is a transiting exoplanet or a false positive caused by astrophysical or instrumental phenomena. Our model is highly effective at ranking individual candidates by the likelihood that they are indeed planets: 98.8% of the time it ranks plausible planet signals higher than false-positive signals in our test set. We apply our model to a new set of candidate signals that we identified in a search of known Kepler multi-planet systems. We statistically validate two new planets that are identified with high confidence by our model. One of these planets is part of a five-planet resonant chain around Kepler-80, with an orbital period closely matching the prediction by three-body Laplace relations. The other planet orbits Kepler-90, a star that was previously known to host seven transiting planets. Our discovery of an eighth planet brings Kepler-90 into a tie with our Sun as the star known to host the most planets.

Kepler AutoRegressive Planet Search

NASA Astrophysics Data System (ADS)

Caceres, Gabriel Antonio; Feigelson, Eric

2016-01-01

The Kepler AutoRegressive Planet Search (KARPS) project uses statistical methodology associated with autoregressive (AR) processes to model Kepler lightcurves in order to improve exoplanet transit detection in systems with high stellar variability. We also introduce a planet-search algorithm to detect transits in time-series residuals after application of the AR models. One of the main obstacles in detecting faint planetary transits is the intrinsic stellar variability of the host star. The variability displayed by many stars may have autoregressive properties, wherein later flux values are correlated with previous ones in some manner. Our analysis procedure consisting of three steps: pre-processing of the data to remove discontinuities, gaps and outliers; AR-type model selection and fitting; and transit signal search of the residuals using a new Transit Comb Filter (TCF) that replaces traditional box-finding algorithms. The analysis procedures of the project are applied to a portion of the publicly available Kepler light curve data for the full 4-year mission duration. Tests of the methods have been made on a subset of Kepler Objects of Interest (KOI) systems, classified both as planetary `candidates' and `false positives' by the Kepler Team, as well as a random sample of unclassified systems. We find that the ARMA-type modeling successfully reduces the stellar variability, by a factor of 10 or more in active stars and by smaller factors in more quiescent stars. A typical quiescent Kepler star has an interquartile range (IQR) of ~10 e-/sec, which may improve slightly after modeling, while those with IQR ranging from 20 to 50 e-/sec, have improvements from 20% up to 70%. High activity stars (IQR exceeding 100) markedly improve. A periodogram based on the TCF is constructed to concentrate the signal of these periodic spikes. When a periodic transit is found, the model is displayed on a standard period-folded averaged light curve. Our findings to date on real

Kepler Planet Detection Mission: Introduction and First Results

NASA Technical Reports Server (NTRS)

Borucki, William; Koch, David; Basri, Gibor; Batalha, Natalie; Brown, Timothy; Lissauer, Jack J.; Morrison, David; Rowe, Jason; Bryson, Stephen T.; Dotson, Jessie;

The Scattering Outcomes of Kepler Circumbinary Planets: Planet Mass Ratio

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gong, Yan-Xiang; Ji, Jianghui, E-mail: yxgong@pmo.ac.cn, E-mail: jijh@pmo.ac.cn

Recent studies reveal that the free eccentricities of Kepler-34b and Kepler-413b are much larger than their forced eccentricities, implying that scattering events may take place in their formation. The observed orbital configuration of Kepler-34b cannot be well reproduced in disk-driven migration models, whereas a two-planet scattering scenario can play a significant role of shaping the planetary configuration. These studies indicate that circumbinary planets discovered by Kepler may have experienced scattering process. In this work, we extensively investigate the scattering outcomes of circumbinary planets focusing on the effects of planet mass ratio . We find that the planetary mass ratio andmore » the the initial relative locations of planets act as two important parameters that affect the eccentricity distribution of the surviving planets. As an application of our model, we discuss the observed orbital configurations of Kepler-34b and Kepler-413b. We first adopt the results from the disk-driven models as the initial conditions, then simulate the scattering process that occurs in the late evolution stage of circumbinary planets. We show that the present orbital configurations of Kepler-34b and Kepler-413b can be well reproduced when considering a two unequal-mass planet ejection model. Our work further suggests that some of the currently discovered circumbinary single-planet systems may be survivors of original multiple-planet systems. The disk-driven migration and scattering events occurring in the late stage both play an irreplaceable role in sculpting the final systems.« less

Kepler Planet Detection Metrics: Pixel-Level Transit Injection Tests of Pipeline Detection Efficiency for Data Release 25

NASA Technical Reports Server (NTRS)

Christiansen, Jessie L.

2017-01-01

This document describes the results of the fourth pixel-level transit injection experiment, which was designed to measure the detection efficiency of both the Kepler pipeline (Jenkins 2002, 2010; Jenkins et al. 2017) and the Robovetter (Coughlin 2017). Previous transit injection experiments are described in Christiansen et al. (2013, 2015a,b, 2016).In order to calculate planet occurrence rates using a given Kepler planet catalogue, produced with a given version of the Kepler pipeline, we need to know the detection efficiency of that pipeline. This can be empirically determined by injecting a suite of simulated transit signals into the Kepler data, processing the data through the pipeline, and examining the distribution of successfully recovered transits. This document describes the results for the pixel-level transit injection experiment performed to accompany the final Q1-Q17 Data Release 25 (DR25) catalogue (Thompson et al. 2017)of the Kepler Objects of Interest. The catalogue was generated using the SOC pipeline version 9.3 and the DR25 Robovetter acting on the uniformly processed Q1-Q17 DR25 light curves (Thompson et al. 2016a) and assuming the Q1-Q17 DR25 Kepler stellar properties (Mathur et al. 2017).

Transiting circumbinary planets Kepler-34 b and Kepler-35 b

DOE Office of Scientific and Technical Information (OSTI.GOV)

Welsh, William F.; Orosz, Jerome A.; Carter, Joshua A.

Most Sun-like stars in the Galaxy reside in gravitationally-bound pairs of stars called 'binary stars'. While long anticipated, the existence of a 'circumbinary planet' orbiting such a pair of normal stars was not definitively established until the discovery of Kepler-16. Incontrovertible evidence was provided by the miniature eclipses ('transits') of the stars by the planet. However, questions remain about the prevalence of circumbinary planets and their range of orbital and physical properties. Here we present two additional transiting circumbinary planets, Kepler-34 and Kepler-35. Each is a low-density gas giant planet on an orbit closely aligned with that of its parentmore » stars. Kepler-34 orbits two Sun-like stars every 289 days, while Kepler-35 orbits a pair of smaller stars (89% and 81% of the Sun's mass) every 131 days. Due to the orbital motion of the stars, the planets experience large multi-periodic variations in incident stellar radiation. The observed rate of circumbinary planets implies > ~1% of close binary stars have giant planets in nearly coplanar orbits, yielding a Galactic population of at least several million.« less

Kepler False Positive Rate & Occurrence of Earth-size and Larger Planets

NASA Astrophysics Data System (ADS)

Fressin, Francois; Torres, G.; Charbonneau, D.; Kepler Team

2013-01-01

We model the Kepler exoplanet survey targets and their background stars to estimate the occurrence of astrophysical configurations which could mimic an exoplanetary transit. Using real noise level estimates, we compute the number and the characteristics of detectable eclipsing pairs involving stars or planets. We select the fraction of those that would pass the Kepler candidate vetting procedure, including the modeling of the centroid shift of their position on the Kepler camera. By comparing their distribution with that of the Kepler Object Interests from the first 6 quarters of Kepler data, we quantify the false positive rate of Kepler, as a function of candidate planet size and period. Most importantly, this approach allows quantifying and characterizing the distribution of planets, with no assumption of any prior, as the remaining population of the Kepler candidate list minus the simulated population of alternate astrophysical causes. We study the actual detection recovery rate for Kepler that allows reproducing both the KOI size and period distribution as well as their SNR distribution. We estimate the occurrence of planets down to Earth-size, and study if their frequency is correlated with their host star spectral type. This work is supported by the Spitzer General Observer Proposal #80117 - Validating the First Habitable-Zone Planet Candidates Identified by the NASA Kepler Mission, and by the Kepler Participating Scientist Contract led by David Charbonneau, to confirm the planetary nature of candidates identified by the Kepler mission

Kepler Planet Detection Metrics: Window and One-Sigma Depth Functions for Data Release 25

NASA Technical Reports Server (NTRS)

Burke, Christopher J.; Catanzarite, Joseph

2017-01-01

This document describes the window and one-sigma depth functions relevant to the Transiting Planet Search (TPS) algorithm in the Kepler pipeline (Jenkins 2002; Jenkins et al. 2017). The window function specifies the fraction of unique orbital ephemeris epochs over which three transits are observable as a function of orbital period. In this context, the epoch and orbital period, together, comprise the ephemeris of an orbiting companion, and ephemerides with the same period are considered equivalent if their epochs differ by an integer multiple of the period. The one-sigma depth function specifies the depth of a signal (in ppm) for a given light curve that results in a one-sigma detection of a transit signature as a function of orbital period when averaged over all unique orbital ephemerides. These planet detection metrics quantify the ability of TPS to detect a transiting planet signature on a star-by-star basis. They are uniquely applicable to a specific Kepler data release, since they are dependent on the details of the light curves searched and the functionality of the TPS algorithm used to perform the search. This document describes the window and one-sigma depth functions relevant to Kepler Data Release 25 (DR25), where the data were processed (Thompson et al. 2016) and searched (Twicken et al. 2016) with the SOC 9.3 pipeline. In Section 4, we describe significant differences from those reported in Kepler Data Release 24 (Burke Seader 2016) and document our verification method.

Kepler Planet Formation

NASA Technical Reports Server (NTRS)

Lissauer, Jack J.

2015-01-01

Kepler has vastly increased our knowledge of planets and planetary systems located close to stars. The new data shows surprising results for planetary abundances, planetary spacings and the distribution of planets on a mass-radius diagram. The implications of these results for theories of planet formation will be discussed.

Kepler Planet Detection Metrics: Automatic Detection of Background Objects Using the Centroid Robovetter

NASA Technical Reports Server (NTRS)

Mullally, Fergal

2017-01-01

We present an automated method of identifying background eclipsing binaries masquerading as planet candidates in the Kepler planet candidate catalogs. We codify the manual vetting process for Kepler Objects of Interest (KOIs) described in Bryson et al. (2013) with a series of measurements and tests that can be performed algorithmically. We compare our automated results with a sample of manually vetted KOIs from the catalog of Burke et al. (2014) and find excellent agreement. We test the performance on a set of simulated transits and find our algorithm correctly identifies simulated false positives approximately 50 of the time, and correctly identifies 99 of simulated planet candidates.

CHANGING PHASES OF ALIEN WORLDS: PROBING ATMOSPHERES OF KEPLER PLANETS WITH HIGH-PRECISION PHOTOMETRY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Esteves, Lisa J.; Mooij, Ernst J. W. De; Jayawardhana, Ray, E-mail: esteves@astro.utoronto.ca, E-mail: demooij@astro.utoronto.ca, E-mail: rayjay@yorku.ca

We present a comprehensive analysis of planetary phase variations, including possible planetary light offsets, using eighteen quarters of data from the Kepler space telescope. Our analysis found fourteen systems with significant detections in each of the phase curve components: planet’s phase function, secondary eclipse, Doppler boosting, and ellipsoidal variations. We model the full phase curve simultaneously, including primary and secondary transits, and derive albedos, day- and night-side temperatures and planet masses. Most planets manifest low optical geometric albedos (< 0.25), with the exception of Kepler-10b, Kepler-91b, and KOI-13b. We find that KOI-13b, with a small eccentricity of 0.0006 ± 0.0001,more » is the only planet for which an eccentric orbit is favored. We detect a third harmonic for HAT-P-7b for the first time, and confirm the third harmonic for KOI-13b reported in Esteves et al.: both could be due to their spin–orbit misalignments. For six planets, we report a planetary brightness peak offset from the substellar point: of those, the hottest two (Kepler-76b and HAT-P-7b) exhibit pre-eclipse shifts or on the evening-side, while the cooler four (Kepler-7b, Kepler-8b, Kepler-12b, and Kepler-41b) peak post-eclipse or on the morning-side. Our findings dramatically increase the number of Kepler planets with detected planetary light offsets, and provide the first evidence in the Kepler data for a correlation between the peak offset direction and the planet’s temperature. Such a correlation could arise if thermal emission dominates light from hotter planets that harbor hot spots shifted toward the evening-side, as theoretically predicted, while reflected light dominates cooler planets with clouds on the planet’s morning-side.« less

Kepler Planet Detection Metrics: Robovetter Completeness and Effectiveness for Data Release 25

NASA Technical Reports Server (NTRS)

Coughlin, Jeffrey L.

2017-01-01

calculate accurate occurrence rates, the completeness and effectiveness of the Robovetter must be characterized. We define these terms as applied to the Robovetter, following Thompson et al. (2017), as:1. Completeness: The fraction of transiting planets detected by the pipeline that are classified as planet candidates by the Robovetter.2. Effectiveness: The fraction of false positives detected by the pipeline that are classified as false positives by the Robovetter.The remainder of this document describes products that can be used to quantitatively assess Robovetter completeness and effectiveness for an arbitrary set of Kepler stars.

KEPLER PLANETS: A TALE OF EVAPORATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Owen, James E.; Wu, Yanqin, E-mail: jowen@cita.utoronto.ca, E-mail: wu@astro.utoronto.ca

2013-10-01

Inspired by the Kepler mission's planet discoveries, we consider the thermal contraction of planets close to their parent star, under the influence of evaporation. The mass-loss rates are based on hydrodynamic models of evaporation that include both X-ray and EUV irradiation. We find that only low mass planets with hydrogen envelopes are significantly affected by evaporation, with evaporation being able to remove massive hydrogen envelopes inward of ∼0.1 AU for Neptune-mass objects, while evaporation is negligible for Jupiter-mass objects. Moreover, most of the evaporation occurs in the first 100 Myr of stars' lives when they are more chromospherically active. Wemore » construct a theoretical population of planets with varying core masses, envelope masses, orbital separations, and stellar spectral types, and compare this population with the sizes and densities measured for low-mass planets, both in the Kepler mission and from radial velocity surveys. This exercise leads us to conclude that evaporation is the driving force of evolution for close-in Kepler planets. In fact, some 50% of the Kepler planet candidates may have been significantly eroded. Evaporation explains two striking correlations observed in these objects: a lack of large radius/low density planets close to the stars and a possible bimodal distribution in planet sizes with a deficit of planets around 2 R{sub ⊕}. Planets that have experienced high X-ray exposures are generally smaller than this size, and those with lower X-ray exposures are typically larger. A bimodal planet size distribution is naturally predicted by the evaporation model, where, depending on their X-ray exposure, close-in planets can either hold on to hydrogen envelopes ∼0.5%-1% in mass or be stripped entirely. To quantitatively reproduce the observed features, we argue that not only do low-mass Kepler planets need to be made of rocky cores surrounded with hydrogen envelopes, but few of them should have initial masses above

Inferring Planet Occurrence Rates With a Q1-Q17 Kepler Planet Candidate Catalog Produced by a Machine Learning Classifier

NASA Astrophysics Data System (ADS)

Catanzarite, Joseph; Jenkins, Jon Michael; McCauliff, Sean D.; Burke, Christopher; Bryson, Steve; Batalha, Natalie; Coughlin, Jeffrey; Rowe, Jason; mullally, fergal; thompson, susan; Seader, Shawn; Twicken, Joseph; Li, Jie; morris, robert; smith, jeffrey; haas, michael; christiansen, jessie; Clarke, Bruce

2015-08-01

NASA’s Kepler Space Telescope monitored the photometric variations of over 170,000 stars, at half-hour cadence, over its four-year prime mission. The Kepler pipeline calibrates the pixels of the target apertures for each star, produces light curves with simple aperture photometry, corrects for systematic error, and detects threshold-crossing events (TCEs) that may be due to transiting planets. The pipeline estimates planet parameters for all TCEs and computes diagnostics used by the Threshold Crossing Event Review Team (TCERT) to produce a catalog of objects that are deemed either likely transiting planet candidates or false positives.We created a training set from the Q1-Q12 and Q1-Q16 TCERT catalogs and an ensemble of synthetic transiting planets that were injected at the pixel level into all 17 quarters of data, and used it to train a random forest classifier. The classifier uniformly and consistently applies diagnostics developed by the Transiting Planet Search and Data Validation pipeline components and by TCERT to produce a robust catalog of planet candidates.The characteristics of the planet candidates detected by Kepler (planet radius and period) do not reflect the intrinsic planet population. Detection efficiency is a function of SNR, so the set of detected planet candidates is incomplete. Transit detection preferentially finds close-in planets with nearly edge-on orbits and misses planets whose orbital geometry precludes transits. Reliability of the planet candidates must also be considered, as they may be false positives. Errors in detected planet radius and in assumed star properties can also bias inference of intrinsic planet population characteristics.In this work we infer the intrinsic planet population, starting with the catalog of detected planet candidates produced by our random forest classifier, and accounting for detection biases and reliabilities as well as for radius errors in the detected population.Kepler was selected as the 10th mission

Kepler-1647b: The Largest and Longest-period Kepler Transiting Circumbinary Planet

NASA Astrophysics Data System (ADS)

Kostov, Veselin B.; Orosz, Jerome A.; Welsh, William F.; Doyle, Laurance R.; Fabrycky, Daniel C.; Haghighipour, Nader; Quarles, Billy; Short, Donald R.; Cochran, William D.; Endl, Michael; Ford, Eric B.; Gregorio, Joao; Hinse, Tobias C.; Isaacson, Howard; Jenkins, Jon M.; Jensen, Eric L. N.; Kane, Stephen; Kull, Ilya; Latham, David W.; Lissauer, Jack J.; Marcy, Geoffrey W.; Mazeh, Tsevi; Müller, Tobias W. A.; Pepper, Joshua; Quinn, Samuel N.; Ragozzine, Darin; Shporer, Avi; Steffen, Jason H.; Torres, Guillermo; Windmiller, Gur; Borucki, William J.

2016-08-01

We report the discovery of a new Kepler transiting circumbinary planet (CBP). This latest addition to the still-small family of CBPs defies the current trend of known short-period planets orbiting near the stability limit of binary stars. Unlike the previous discoveries, the planet revolving around the eclipsing binary system Kepler-1647 has a very long orbital period (˜1100 days) and was at conjunction only twice during the Kepler mission lifetime. Due to the singular configuration of the system, Kepler-1647b is not only the longest-period transiting CBP at the time of writing, but also one of the longest-period transiting planets. With a radius of 1.06 ± 0.01 R Jup, it is also the largest CBP to date. The planet produced three transits in the light curve of Kepler-1647 (one of them during an eclipse, creating a syzygy) and measurably perturbed the times of the stellar eclipses, allowing us to measure its mass, 1.52 ± 0.65 M Jup. The planet revolves around an 11-day period eclipsing binary consisting of two solar-mass stars on a slightly inclined, mildly eccentric (e bin = 0.16), spin-synchronized orbit. Despite having an orbital period three times longer than Earth’s, Kepler-1647b is in the conservative habitable zone of the binary star throughout its orbit.

Kepler Mission: A Search for Terrestrial Planets

NASA Technical Reports Server (NTRS)

Koch, D.; Borucki, W.; Jenkens, J.; Dunham, E.; DeVincenzi, Donald (Technical Monitor)

2001-01-01

The Kepler Mission is a search for terrestrial planets by monitoring a large ensemble of stars for the periodic transits of planets. The mission consists of a 95-cm aperture photometer with 105 square deg field of view that monitors 100,000 dwarf stars for four years. The mission is unique in its ability to detect Earth-size planets in the habitable zone of other stars in the extended solar neighborhood. An Earth-size transit of a solar-like star causes a change in brightness of about 100 ppm. Laboratory testing has demonstrated that a total system noise level of 20 ppm is readily achievable on the timescale of transits. Earth-like transits have been created and reliably measured in an end-to-end system test that has all known sources of noise including, spacecraft jitter. To detect Earth-size planets, the photometer must be spaceborne; this also eliminates the day-night and seasonal cycle interruptions of ground-based observing. The photometer will stare at a single field of stars for four years, with an option to continue for two more years. This allows for detection of four transits of planets in Mars-like orbits and detection of planets even smaller than Earth especially for short period orbits, since the signal to noise improves as the square root of the number of transits observed. In addition to detection of planets, Kepler data are also useful for understanding the activity cycles and rotation rates of the stars observed. For the 3,000 stars brighter than mv= 11.4 p-mode oscillations are measured. The mission has been selected as one of three candidates for NASA's next Discovery mission.

Characterizing the Habitable Zone Planets of Kepler Stars

NASA Astrophysics Data System (ADS)

Fischer, Debra

Planet Hunters (PH) is a well-established and successful web interface that allows citizen scientists to search for transiting planets in the NASA Kepler public archive data. Over the past 3 years, our users have made more than 20 million light curve classifications. We now have more than 300,000 users around the world. However, more than half of the Kepler data has not yet been displayed to our volunteers. In June 2014 we are launching Planet Hunters v2.0. The backend of the site has been completely redesigned. The new website is more intuitive and faster; we have improved the real-time weighting algorithm that assigns transit scores for faster and more accurate extraction of the transit events from the database. With Planet Hunters v2.0, we expect that assessments will be ten times faster, so that we have the opportunity to complete the classifications for the backlog of Kepler light curve in the next three years. There are three goals for this project. First, we will data-mine the PH classifications to search for long period planets with fewer than 5 transit events. We have demonstrated that our volunteers are efficient at detecting planets with long periods and radii greater than a few REARTH. This region of parameter space is optimal for characterizing larger planets orbiting close to the habitable zone. To build upon the citizen science efforts, we will model the light curves, search for evidence of false positives, and contribute observations of stellar spectra to refine both the stellar and orbital parameters. Second, we will carry out a careful analysis of the fraction of transits that are missed (a function of planet radius and orbital period) to derive observational incompleteness factors. The incompleteness factors will be combined with geometrical detection factors to assess the planet occurrence rate for wide separations. This is a unique scientific contribution current studies of planet occurrence rate are either restricted to orbital periods shorter

Transiting Planet Search in the Kepler Pipeline

NASA Technical Reports Server (NTRS)

Jenkins, Jon M.; Chandrasekaran, Hema; McCauliff, Sean D.; Caldwell, Douglas A.; Tenebaum, Peter; Li, Jie; Klaus, Todd C.; Cote, Mile T.; Middour, Christopher

2010-01-01

The Kepler Mission simultaneously measures the brightness of more than 160,000 stars every 29.4 minutes over a 3.5-year mission to search for transiting planets. Detecting transits is a signal-detection problem where the signal of interest is a periodic pulse train and the predominant noise source is non-white, non-stationary (1/f) type process of stellar variability. Many stars also exhibit coherent or quasi-coherent oscillations. The detection algorithm first identifies and removes strong oscillations followed by an adaptive, wavelet-based matched filter. We discuss how we obtain super-resolution detection statistics and the effectiveness of the algorithm for Kepler flight data.

Kepler Confirms First Earth-Sized Planet Outside Our Solar System (Kepler-20) (Reporter Package)

NASA Image and Video Library

2011-12-19

NASA's Kepler mission has confirmed the discovery of the first Earth-size planets outside our solar system orbiting a sun-like star. Located about 1,000 light years from Earth, the Kepler-20 solar system has five planets orbiting a star similar to the Sun. Kepler-20f, the 4th planet in the system, is about 90 percent the size of Earth. Kepler-20f is slightly larger than Earth,with a radius that is 3 percent larger.

Characterization and Validation of Transiting Planets in the Kepler and TESS Pipelines

NASA Astrophysics Data System (ADS)

Twicken, Joseph; Brownston, Lee; Catanzarite, Joseph; Clarke, Bruce; Cote, Miles; Girouard, Forrest; Li, Jie; McCauliff, Sean; Seader, Shawn; Tenenbaum, Peter; Wohler, Bill; Jenkins, Jon Michael; Batalha, Natalie; Bryson, Steve; Burke, Christopher; Caldwell, Douglas

2015-08-01

Light curves for Kepler targets are searched for transiting planet signatures in the Transiting Planet Search (TPS) component of the Science Operations Center (SOC) Processing Pipeline. Targets for which the detection threshold is exceeded are subsequently processed in the Data Validation (DV) Pipeline component. The primary functions of DV are to (1) characterize planets identified in the transiting planet search, (2) search for additional transiting planet signatures in light curves after modeled transit signatures have been removed, and (3) perform a comprehensive suite of diagnostic tests to aid in discrimination between true transiting planets and false positive detections. DV output products include extensive reports by target, one-page report summaries by planet candidate, and tabulated planet model fit and diagnostic test results. The DV products are employed by humans and automated systems to vet planet candidates identified in the pipeline. The final revision of the Kepler SOC codebase (9.3) was released in March 2015. It will be utilized to reprocess the complete Q1-Q17 data set later this year. At the same time, the SOC Pipeline codebase is being ported to support the Transiting Exoplanet Survey Satellite (TESS) Mission. TESS is expected to launch in 2017 and survey the entire sky for transiting exoplanets over a period of two years. We describe the final revision of the Kepler Data Validation component with emphasis on the diagnostic tests and reports. This revision also serves as the DV baseline for TESS. The diagnostic tests exploit the flux (i.e., light curve), centroid and pixel time series associated with each target to facilitate the determination of the true origin of each purported transiting planet signature. Candidate planet detections and DV products for Kepler are delivered to the Exoplanet Archive at the NASA Exoplanet Science Institute (NExScI). The Exoplanet Archive is located at exoplanetarchive.ipac.caltech.edu. Funding for the Kepler

Prevalence and Properties of Planets from Kepler and K2

NASA Astrophysics Data System (ADS)

Petigura, Erik; Marcy, Geoffrey W.; Howard, Andrew; Crossfield, Ian; Beichman, Charles; Sinukoff, Evan

2015-12-01

Discoveries from the prime Kepler mission demonstrated that small planets (< 3 Earth-radii) are common outcomes of planet formation around G, K, and M stars. While Kepler detected many such planets, all but a handful orbit faint, distant stars, which are not amenable to precise follow up measurements. NASA's K2 mission has the potential to increase the number of known small, transiting planets around bright stars by an order of magnitude. I will present the latest results from my team's efforts to detect, confirm, and characterize planets using the K2 mission. I will highlight some of the progress and remaining challenges involved with generating denoised K2 photometry and with detecting planets in the presence of severe instrument systematics. Among our recent discoveries are the K2-3 and K2-21 planetary systems: M dwarfs hosting multiple transiting Earth-size planets with low equilibrium temperatures. These systems offer a convenient laboratory for studying the bulk composition and atmospheric properties of small planets receiving low levels of stellar irradiation, where processes such as mass loss by photo-evaporation could play a weaker role.

Kepler’s Earth-like Planets Should Not Be Confirmed without Independent Detection: The Case of Kepler-452b

NASA Astrophysics Data System (ADS)

Mullally, Fergal; Thompson, Susan E.; Coughlin, Jeffrey L.; Burke, Christopher J.; Rowe, Jason F.

2018-05-01

We show that the claimed confirmed planet Kepler-452b (a.k.a., K07016.01, KIC 8311864) cannot be confirmed using a purely statistical validation approach. Kepler detects many more periodic signals from instrumental effects than it does from transits, and it is likely impossible to confidently distinguish the two types of events at low signal-to-noise. As a result, the scenario that the observed signal is due to an instrumental artifact cannot be ruled out with 99% confidence, and the system must still be considered a candidate planet. We discuss the implications for other confirmed planets in or near the habitable zone.

Spacing of Kepler Planets: Sculpting by Dynamical Instability

NASA Astrophysics Data System (ADS)

Pu, Bonan; Wu, Yanqin

2015-07-01

We study the orbital architecture of multi-planet systems detected by the Kepler transit mission using N-body simulations, focusing on the orbital spacing between adjacent planets in systems showing four or more transiting planets. We find that the observed spacings are tightly clustered around 12 mutual Hill radii, when transit geometry and sensitivity limits are accounted for. In comparison, dynamical integrations reveal that the minimum spacing required for systems of similar masses to survive dynamical instability for as long as 1 billion yr is ∼10 if all orbits are circular and coplanar and ∼12 if planetary orbits have eccentricities of ∼0.02 (a value suggested by studies of planet transit-time variations). This apparent coincidence, between the observed spacing and the theoretical stability threshold, leads us to propose that typical planetary systems were formed with even tighter spacing, but most, except for the widest ones, have undergone dynamical instability, and are pared down to a more anemic version of their former selves, with fewer planets and larger spacings. So while the high-multiple systems (five or more transiting planets) are primordial systems that remain stable, the single or double planetary systems, abundantly discovered by the Kepler mission, may be the descendants of more closely packed high-multiple systems. If this hypothesis is correct, we infer that the formation environment of Kepler systems should be more dissipative than that of the terrestrial planets.

LGS-AO Imaging of Every Kepler Planet Candidate: the Robo-AO KOI Survey

NASA Astrophysics Data System (ADS)

Baranec, Christoph; Law, Nicholas; Morton, Timothy; Ziegler, Carl; Nofi, Larissa; Atkinson, Dani; Riddle, Reed

2015-12-01

The Robo-AO Kepler Planetary Candidate Survey is observing every Kepler planet candidate host star with laser adaptive optics imaging, to search for blended nearby stars which may be physically associated companions and/or responsible for transit false positives. We will present the results from searching for companions around over 3,000 Kepler planet hosts in 2012-2015. We will describe our first data release covering 715 planet candidate hosts, and give a preview of ongoing results including improved statistics on the likelihood of false positive planet detections in the Kepler dataset, many new planets in multiple star systems, and new exotic multiple star systems containing Kepler planets. We will also describe the automated Robo-AO survey data reduction methods, including a method of using the large ensemble of target observations as mutual point-spread-function references, along with a new automated companion-detection algorithm designed for extremely large adaptive optics surveys. Our first data release covered 715 objects, searching for companions from 0.15” to 2.5” separation with contrast up to 6 magnitudes. We measured the overall nearby-star-probability for Kepler planet candidates to be 7.4+/-1.0%, and we will detail the variations in this number with stellar host parameters. We will also discuss plans to extend the survey to other transiting planet missions such as K2 and TESS as Robo-AO is in the process of being re-deployed to the 2.1-m telescope at Kitt Peak for 3 years and a higher-contrast Robo-AO system is being developed for the 2.2-m UH telescope on Maunakea.

DISCOVERY AND ATMOSPHERIC CHARACTERIZATION OF GIANT PLANET KEPLER-12b: AN INFLATED RADIUS OUTLIER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fortney, Jonathan J.; Nutzman, Philip; Demory, Brice-Olivier

We report the discovery of planet Kepler-12b (KOI-20), which at 1.695 {+-} 0.030 R{sub J} is among the handful of planets with super-inflated radii above 1.65 R{sub J}. Orbiting its slightly evolved G0 host with a 4.438 day period, this 0.431 {+-} 0.041 M{sub J} planet is the least irradiated within this largest-planet-radius group, which has important implications for planetary physics. The planet's inflated radius and low mass lead to a very low density of 0.111 {+-} 0.010 g cm{sup -3}. We detect the occultation of the planet at a significance of 3.7{sigma} in the Kepler bandpass. This yields amore » geometric albedo of 0.14 {+-} 0.04; the planetary flux is due to a combination of scattered light and emitted thermal flux. We use multiple observations with Warm Spitzer to detect the occultation at 7{sigma} and 4{sigma} in the 3.6 and 4.5 {mu}m bandpasses, respectively. The occultation photometry timing is consistent with a circular orbit at e < 0.01 (1{sigma}) and e < 0.09 (3{sigma}). The occultation detections across the three bands favor an atmospheric model with no dayside temperature inversion. The Kepler occultation detection provides significant leverage, but conclusions regarding temperature structure are preliminary, given our ignorance of opacity sources at optical wavelengths in hot Jupiter atmospheres. If Kepler-12b and HD 209458b, which intercept similar incident stellar fluxes, have the same heavy-element masses, the interior energy source needed to explain the large radius of Kepler-12b is three times larger than that of HD 209458b. This may suggest that more than one radius-inflation mechanism is at work for Kepler-12b or that it is less heavy-element rich than other transiting planets.« less

Kepler-16: a transiting circumbinary planet.

PubMed

Doyle, Laurance R; Carter, Joshua A; Fabrycky, Daniel C; Slawson, Robert W; Howell, Steve B; Winn, Joshua N; Orosz, Jerome A; Prša, Andrej; Welsh, William F; Quinn, Samuel N; Latham, David; Torres, Guillermo; Buchhave, Lars A; Marcy, Geoffrey W; Fortney, Jonathan J; Shporer, Avi; Ford, Eric B; Lissauer, Jack J; Ragozzine, Darin; Rucker, Michael; Batalha, Natalie; Jenkins, Jon M; Borucki, William J; Koch, David; Middour, Christopher K; Hall, Jennifer R; McCauliff, Sean; Fanelli, Michael N; Quintana, Elisa V; Holman, Matthew J; Caldwell, Douglas A; Still, Martin; Stefanik, Robert P; Brown, Warren R; Esquerdo, Gilbert A; Tang, Sumin; Furesz, Gabor; Geary, John C; Berlind, Perry; Calkins, Michael L; Short, Donald R; Steffen, Jason H; Sasselov, Dimitar; Dunham, Edward W; Cochran, William D; Boss, Alan; Haas, Michael R; Buzasi, Derek; Fischer, Debra

2011-09-16

We report the detection of a planet whose orbit surrounds a pair of low-mass stars. Data from the Kepler spacecraft reveal transits of the planet across both stars, in addition to the mutual eclipses of the stars, giving precise constraints on the absolute dimensions of all three bodies. The planet is comparable to Saturn in mass and size and is on a nearly circular 229-day orbit around its two parent stars. The eclipsing stars are 20 and 69% as massive as the Sun and have an eccentric 41-day orbit. The motions of all three bodies are confined to within 0.5° of a single plane, suggesting that the planet formed within a circumbinary disk.

Kepler AutoRegressive Planet Search

NASA Astrophysics Data System (ADS)

Feigelson, Eric

NASA's Kepler mission is the source of more exoplanets than any other instrument, but the discovery depends on complex statistical analysis procedures embedded in the Kepler pipeline. A particular challenge is mitigating irregular stellar variability without loss of sensitivity to faint periodic planetary transits. This proposal presents a two-stage alternative analysis procedure. First, parametric autoregressive ARFIMA models, commonly used in econometrics, remove most of the stellar variations. Second, a novel matched filter is used to create a periodogram from which transit-like periodicities are identified. This analysis procedure, the Kepler AutoRegressive Planet Search (KARPS), is confirming most of the Kepler Objects of Interest and is expected to identify additional planetary candidates. The proposed research will complete application of the KARPS methodology to the prime Kepler mission light curves of 200,000: stars, and compare the results with Kepler Objects of Interest obtained with the Kepler pipeline. We will then conduct a variety of astronomical studies based on the KARPS results. Important subsamples will be extracted including Habitable Zone planets, hot super-Earths, grazing-transit hot Jupiters, and multi-planet systems. Groundbased spectroscopy of poorly studied candidates will be performed to better characterize the host stars. Studies of stellar variability will then be pursued based on KARPS analysis. The autocorrelation function and nonstationarity measures will be used to identify spotted stars at different stages of autoregressive modeling. Periodic variables with folded light curves inconsistent with planetary transits will be identified; they may be eclipsing or mutually-illuminating binary star systems. Classification of stellar variables with KARPS-derived statistical properties will be attempted. KARPS procedures will then be applied to archived K2 data to identify planetary transits and characterize stellar variability.

On the Nature of Small Planets around the Coolest Kepler Stars

NASA Astrophysics Data System (ADS)

Gaidos, Eric; Fischer, Debra A.; Mann, Andrew W.; Lépine, Sébastien

2012-02-01

We constrain the densities of Earth- to Neptune-size planets around very cool (Te = 3660-4660 K) Kepler stars by comparing 1202 Keck/HIRES radial velocity measurements of 150 nearby stars to a model based on Kepler candidate planet radii and a power-law mass-radius relation. Our analysis is based on the presumption that the planet populations around the two sets of stars are the same. The model can reproduce the observed distribution of radial velocity variation over a range of parameter values, but, for the expected level of Doppler systematic error, the highest Kolmogorov-Smirnov probabilities occur for a power-law index α ≈ 4, indicating that rocky-metal planets dominate the planet population in this size range. A single population of gas-rich, low-density planets with α = 2 is ruled out unless our Doppler errors are >=5 m s-1, i.e., much larger than expected based on observations and stellar chromospheric emission. If small planets are a mix of γ rocky planets (α = 3.85) and 1 - γ gas-rich planets (α = 2), then γ > 0.5 unless Doppler errors are >=4 m s-1. Our comparison also suggests that Kepler's detection efficiency relative to ideal calculations is less than unity. One possible source of incompleteness is target stars that are misclassified subgiants or giants, for which the transits of small planets would be impossible to detect. Our results are robust to systematic effects, and plausible errors in the estimated radii of Kepler stars have only moderate impact. Some data were obtained at the W. M. Keck Observatory, which is operated by the California Institute of Technology, the University of California, and NASA, and made possible by the financial support of the W. M. Keck Foundation.

Plans for Follow-Up Observations of Kepler Planet Candidates

NASA Astrophysics Data System (ADS)

Gautier, Thomas N., III

2009-05-01

Ground based follow-up observations of transiting planet candidates identified by Kepler are pursued to identify false positives and to search for non-transiting planets in the systems of true transiting planets. I will describe the observational protocols developed by the Kepler team and the web based infrastructure we are using to support the observations. The current state of the Kepler follow-up observations will be reported.

Spectroscopy of Kepler Exo-planet Transit Candidate Stars

NASA Astrophysics Data System (ADS)

Howell, Steve B.; Everett, Mark; Silva, David; Rowe, Jason; Szkody, Paula; Mighell, Ken; Ciardi, David

2012-02-01

We propose a long term spectroscopic follow-up program in support of the NASA Kepler exo-planet mission. The Kepler project is now focusing on exo-planet candidates which are smaller in radius (down to Earth- size), have longer period orbits and many of which orbit fainter stars. Our program will spend 85% of the time on our primary goal, spectroscopy of the host stars of exoplanet candidates, and 15% of the time on investigation of other astrophysically interesting stars discovered by Kepler. Our prime goal is to obtain reconnaissance spectra of newly discovered exo-planet stars yielding model fits to T_eff and log g. Secondary goals are to obtain velocity information on EBs with a third component aimed toward discovery of circumbinary planets (such as Kepler 16b) and identification spectra of U-band selected targets in order to find more white dwarfs for Kepler focal plane calibration purposes. All of these tasks can be accomplished using the Kitt Peak 4-m telescope and RCspec as shown by our previous time allocations.

Transiting Planets from Kepler, K2 & TESS

NASA Technical Reports Server (NTRS)

Lissauer, Jack

2018-01-01

NASA's Kepler spacecraft, launched in 2009, has been a resounding success. More than 4000 planet candidates have been identified using data from Kepler primary mission, which ended in 2013, and greater than 2000 of these candidates have been verified as bona fide exoplanets. After the loss of two reaction wheels ended the primary mission, the Kepler spacecraft was repurposed in 2014 to observe many fields on the sky for short periods. This new mission, dubbed K2, has led to the discovery of greater than 600 planet candidates, approximately 200 of which have been verified to date; most of these exoplanets are closer to us than the majority of exoplanets discovered by the primary Kepler mission. TESS, launching in 2018, will survey most of the sky for exoplanets, with emphasis on those orbiting nearby and/or bright host stars, making these planets especially well-suited for follow-up observations with other observatories to characterize atmospheric compositions and other properties. More than one-third of the planet candidates found by NASA's are associated with target stars that have more than one planet candidate, and such 'multis' account for the majority of candidates that have been verified as true planets. The large number of multis tells us that flat multiplanet systems like our Solar System are common. Virtually all of the candidate planetary systems are stable, as tested by numerical integrations that assume a physically motivated mass-radius relationship. Statistical studies performed on these candidate systems reveal a great deal about the architecture of planetary systems, including the typical spacing of orbits and flatness. The characteristics of several of the most interesting confirmed Kepler & K2 multi-planet systems will also be discussed.

Kepler-62: a five-planet system with planets of 1.4 and 1.6 Earth radii in the habitable zone.

PubMed

Borucki, William J; Agol, Eric; Fressin, Francois; Kaltenegger, Lisa; Rowe, Jason; Isaacson, Howard; Fischer, Debra; Batalha, Natalie; Lissauer, Jack J; Marcy, Geoffrey W; Fabrycky, Daniel; Désert, Jean-Michel; Bryson, Stephen T; Barclay, Thomas; Bastien, Fabienne; Boss, Alan; Brugamyer, Erik; Buchhave, Lars A; Burke, Chris; Caldwell, Douglas A; Carter, Josh; Charbonneau, David; Crepp, Justin R; Christensen-Dalsgaard, Jørgen; Christiansen, Jessie L; Ciardi, David; Cochran, William D; DeVore, Edna; Doyle, Laurance; Dupree, Andrea K; Endl, Michael; Everett, Mark E; Ford, Eric B; Fortney, Jonathan; Gautier, Thomas N; Geary, John C; Gould, Alan; Haas, Michael; Henze, Christopher; Howard, Andrew W; Howell, Steve B; Huber, Daniel; Jenkins, Jon M; Kjeldsen, Hans; Kolbl, Rea; Kolodziejczak, Jeffery; Latham, David W; Lee, Brian L; Lopez, Eric; Mullally, Fergal; Orosz, Jerome A; Prsa, Andrej; Quintana, Elisa V; Sanchis-Ojeda, Roberto; Sasselov, Dimitar; Seader, Shawn; Shporer, Avi; Steffen, Jason H; Still, Martin; Tenenbaum, Peter; Thompson, Susan E; Torres, Guillermo; Twicken, Joseph D; Welsh, William F; Winn, Joshua N

2013-05-03

We present the detection of five planets--Kepler-62b, c, d, e, and f--of size 1.31, 0.54, 1.95, 1.61 and 1.41 Earth radii (R⊕), orbiting a K2V star at periods of 5.7, 12.4, 18.2, 122.4, and 267.3 days, respectively. The outermost planets, Kepler-62e and -62f, are super-Earth-size (1.25 R⊕ < planet radius ≤ 2.0 R⊕) planets in the habitable zone of their host star, respectively receiving 1.2 ± 0.2 times and 0.41 ± 0.05 times the solar flux at Earth's orbit. Theoretical models of Kepler-62e and -62f for a stellar age of ~7 billion years suggest that both planets could be solid, either with a rocky composition or composed of mostly solid water in their bulk.

Revised Masses and Densities of the Planets around Kepler-10

NASA Astrophysics Data System (ADS)

Weiss, Lauren M.; Rogers, Leslie A.; Isaacson, Howard T.; Agol, Eric; Marcy, Geoffrey W.; Rowe, Jason F.; Kipping, David; Fulton, Benjamin J.; Lissauer, Jack J.; Howard, Andrew W.; Fabrycky, Daniel

2016-03-01

Determining which small exoplanets have stony-iron compositions is necessary for quantifying the occurrence of such planets and for understanding the physics of planet formation. Kepler-10 hosts the stony-iron world Kepler-10b, and also contains what has been reported to be the largest solid silicate-ice planet, Kepler-10c. Using 220 radial velocities (RVs), including 72 precise RVs from Keck-HIRES of which 20 are new from 2014 to 2015, and 17 quarters of Kepler photometry, we obtain the most complete picture of the Kepler-10 system to date. We find that Kepler-10b ({R}{{p}}=1.47 {R}\\oplus ) has mass 3.72\\quad +/- \\quad 0.42\\quad {M}\\oplus and density 6.46\\quad +/- \\quad 0.73\\quad {{g}} {{cm}}-3. Modeling the interior of Kepler-10b as an iron core overlaid with a silicate mantle, we find that the iron core constitutes 0.17 ± 0.11 of the planet mass. For Kepler-10c ({R}{{p}}=2.35 {R}\\oplus ) we measure mass 13.98\\quad +/- \\quad 1.79\\quad {M}\\oplus and density 5.94\\quad +/- \\quad 0.76\\quad {{g}} {{cm}}-3, significantly lower than the mass computed in Dumusque et al. (17.2+/- 1.9 {M}\\oplus ). Our mass measurement of Kepler-10c rules out a pure stony-iron composition. Internal compositional modeling reveals that at least 10% of the radius of Kepler-10c is a volatile envelope composed of hydrogen-helium (0.2% of the mass, 16% of the radius) or super-ionic water (28% of the mass, 29% of the radius). However, we note that analysis of only HIRES data yields a higher mass for planet b and a lower mass for planet c than does analysis of the HARPS-N data alone, with the mass estimates for Kepler-10 c being formally inconsistent at the 3σ level. Moreover, dividing the data for each instrument into two parts also leads to somewhat inconsistent measurements for the mass of planet c derived from each observatory. Together, this suggests that time-correlated noise is present and that the uncertainties in the masses of the planets (especially planet c) likely

Kepler Planet-Detection Mission: Introduction and First Results

DTIC Science & Technology

2010-02-19

those predicted for gas giant planets. Since the first discoveries of planetarycompanions around pulsars (1, 2) andnormal stars (3), more than 400...0.5 0 0.5 1 1.5 Orbital distance, AU lo g( P la ne t m as s (M J) ) 5b 6b,8b 7b 4b Fig. 2. Comparison of stars associated with the Kepler exoplanets...4 Kepler−6 −3 −2.5 −2 −1.5 −1 −0.5 0 0.5 1 1.5 −1.5 −1 −0.5 0 0.5 1 1.5 log(Planet mass (MJ)) lo g( P la ne t d en si ty ( cg s) ) E N U 4b S J 5b

Inferring Planet Occurrence Rates With a Q1-Q16 Kepler Planet Candidate Catalog Produced by a Machine Learning Classifier

NASA Astrophysics Data System (ADS)

Catanzarite, Joseph; Jenkins, Jon Michael; Burke, Christopher J.; McCauliff, Sean D.; Kepler Science Operations Center

2015-01-01

NASA's Kepler Space Telescope monitored the photometric variations of over 170,000 stars within a ~100 square degree field in the constellation Cygnus, at half-hour cadence, over its four year prime mission. The Kepler SOC (Science Operations Center) pipeline calibrates the pixels of the target apertures for each star, corrects light curves for systematic error, and detects TCEs (threshold-crossing events) that may be due to transiting planets. Finally the pipeline estimates planet parameters for all TCEs and computes quantitative diagnostics that are used by the TCERT (Threshold Crossing Event Review Team) to produce a catalog containing KOIs (Kepler Objects of Interest). KOIs are TCEs that are determined to be either likely transiting planets or astrophysical false positives such as background eclipsing binary stars. Using examples from the Q1-Q16 TCERT KOI catalog as a training set, we created a machine-learning classifier that dispositions the TCEs into categories of PC (planet candidate), AFP (astrophysical false positive) and NTP (non-transiting phenomenon). The classifier uniformly and consistently applies heuristics developed by TCERT as well as other diagnostics to the Q1-Q16 TCEs to produce a more robust and reliable catalog of planet candidates than is possible with only human classification. In this work, we estimate planet occurrence rates, based on the machine-learning-produced catalog of Kepler planet candidates. Kepler was selected as the 10th mission of the Discovery Program. Funding for this mission is provided by NASA, Science Mission Directorate.

Kepler Discovers First Confirmed Planet in the Habitable Zone (Kepler-22); Celebrates 1000 Days

NASA Image and Video Library

2011-12-07

At a press conference held at NASA Ames Research Center,the Kepler team announced the discovery of its first confirmed planet in the 'habitable zone' or the region around a star where liquid water could exist on a planet's surface. Named Kepler-22b, the planet is about 2.4 times the radius of the Earth and orbits a sun-like star about 600 light years away between the constellations of Cygnus and Lyra.

Revised Masses and Densities of the Planets around Kepler-10

NASA Astrophysics Data System (ADS)

Weiss, Lauren M.; Rogers, Leslie A.; Isaacson, Howard T.; Agol, Eric; Marcy, Geoffrey W.; Rowe, Jason F.; Kipping, David; Fulton, Benjamin; Lissauer, Jack; Howard, Andrew; Clark Fabrycky, Daniel

2015-12-01

Determining which small exoplanets have stony-iron compositions is necessary for quantifying the occurrence of such planets and for understanding the physics of planet formation. Kepler-10 hosts the stony-iron world Kepler-10b, and also contains what has been reported to be the largest solid silicate-ice planet, Kepler-10c. Using 220 radial velocities (RVs), including 72 new precise RVs from Keck-HIRES, and 17 quarters of Kepler photometry, we obtain the most complete picture of the Kepler-10 system to date. We find that Kepler-10b (Rp = 1.47 R⊕) has mass 3.70 ± 0.43 M⊕ and density 6.44 ± 0.73 g cm-3. Modeling the interior of Kepler-10b as an iron core overlaid with a silicate mantle, we find that the core constitutes 0.17 ± 0.11 of the planet mass. For Kepler-10c (Rp = 2.35 R⊕) we measure mass 13.32 ± 1.65 M⊕and density 5.67 ± 0.70 g cm-3, significantly lower than the mass in Dumusque et al. (2014, 17.2±1.9 M⊕). Kepler-10c is not sufficiently dense to have a pure stony-iron composition. Internal compositional modeling reveals that at least 10% of the radius of Kepler-10c is a volatile envelope composed of either hydrogen-helium (0.0027 ± 0.0015 of the mass, 0.172±0.037 of the radius) or super-ionic water (0.309±0.11 of the mass, 0.305±0.075 of the radius). Transit timing variations (TTVs) of Kepler-10c indicate the likely presence of a third planet in the system, KOI-72.X. The TTVs and RVs are consistent with KOI-72.X having an orbital period of 24, 71, 82, or 101 days, and a mass from 1-7 M⊕.

PREDICTING A THIRD PLANET IN THE KEPLER-47 CIRCUMBINARY SYSTEM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hinse, Tobias C.; Haghighipour, Nader; Kostov, Veselin B.

2015-01-20

We have studied the possibility that a third circumbinary planet in the Kepler-47 planetary system is the source of the single unexplained transiting event reported during the discovery of these planets. We applied the MEGNO technique to identify regions in the phase space where a third planet can maintain quasi-periodic orbits, and assessed the long-term stability of the three-planet system by integrating the entire five bodies (binary + planets) for 10 Myr. We identified several stable regions between the two known planets as well as a region beyond the orbit of Kepler-47c where the orbit of the third planet could bemore » stable. To constrain the orbit of this planet, we used the measured duration of the unexplained transit event (∼4.15 hr) and compared that with the transit duration of the third planet in an ensemble of stable orbits. To remove the degeneracy among the orbits with similar transit durations, we considered the planet to be in a circular orbit and calculated its period analytically. The latter places an upper limit of 424 days on the orbital period of the third planet. Our analysis suggests that if the unexplained transit event detected during the discovery of the Kepler-47 circumbinary system is due to a planetary object, this planet will be in a low eccentricity orbit with a semi-major axis smaller than 1.24 AU. Further constraining of the mass and orbital elements of this planet requires a re-analysis of the entire currently available data, including those obtained post-announcement of the discovery of this system. We present details of our methodology and discuss the implication of the results.« less

Kepler AutoRegressive Planet Search: Motivation & Methodology

NASA Astrophysics Data System (ADS)

Caceres, Gabriel; Feigelson, Eric; Jogesh Babu, G.; Bahamonde, Natalia; Bertin, Karine; Christen, Alejandra; Curé, Michel; Meza, Cristian

2015-08-01

The Kepler AutoRegressive Planet Search (KARPS) project uses statistical methodology associated with autoregressive (AR) processes to model Kepler lightcurves in order to improve exoplanet transit detection in systems with high stellar variability. We also introduce a planet-search algorithm to detect transits in time-series residuals after application of the AR models. One of the main obstacles in detecting faint planetary transits is the intrinsic stellar variability of the host star. The variability displayed by many stars may have autoregressive properties, wherein later flux values are correlated with previous ones in some manner. Auto-Regressive Moving-Average (ARMA) models, Generalized Auto-Regressive Conditional Heteroskedasticity (GARCH), and related models are flexible, phenomenological methods used with great success to model stochastic temporal behaviors in many fields of study, particularly econometrics. Powerful statistical methods are implemented in the public statistical software environment R and its many packages. Modeling involves maximum likelihood fitting, model selection, and residual analysis. These techniques provide a useful framework to model stellar variability and are used in KARPS with the objective of reducing stellar noise to enhance opportunities to find as-yet-undiscovered planets. Our analysis procedure consisting of three steps: pre-processing of the data to remove discontinuities, gaps and outliers; ARMA-type model selection and fitting; and transit signal search of the residuals using a new Transit Comb Filter (TCF) that replaces traditional box-finding algorithms. We apply the procedures to simulated Kepler-like time series with known stellar and planetary signals to evaluate the effectiveness of the KARPS procedures. The ARMA-type modeling is effective at reducing stellar noise, but also reduces and transforms the transit signal into ingress/egress spikes. A periodogram based on the TCF is constructed to concentrate the signal

Speckle Imaging and Spectroscopy of Kepler Exo-planet Transit Candidate Stars

NASA Astrophysics Data System (ADS)

Howell, Steve B.; Sherry, William; Horch, Elliott; Doyle, Laurance

2010-02-01

The NASA Kepler mission was successfully launched on 6 March 2009 and has begun science operations. Commissioning tests done early on in the mission have shown that for the bright sources, 10-15 ppm relative photometry can be achieved. This level assures we will detect Earth- like transits if they are present. ``Hot Jupiter" and similar large planet candidates have already been discovered and will be discussed at the Jan. AAS meeting as well as in a special issue of Science magazine to appear near years end. The plethora of variability observed is astounding and includes a number of eclipsing binaries which appear to have Jupiter and smaller size objects as an orbiting their body. Our proposal consists of three highly related objectives: 1) To continue our highly successful speckle imaging program which is a major component of defense to weed out false positive candidate transiting planets found by Kepler and move the rest to probable or certain exo-planet detections; 2) To obtain low resolution ``discovery" type spectra for planet candidate stars in order to provide spectral type and luminosity class indicators as well as a first look triage to eliminate binaries and rapid rotators; and 3) to obtain ~1Aresolution time ordered spectra of eclipsing binaries that are exo-planet candidates in order to obtain the velocity solution for the binary star, allowing its signal to be modeled and removed from the Keck or HET exo-planet velocity search. As of this writing, Kepler has produced a list of 227 exo-planet candidates which require false positive decision tree observations. Our proposed effort performs much of the first line of defense for the mission.

Forming Circumbinary Planets: N-body Simulations of Kepler-34

NASA Astrophysics Data System (ADS)

Lines, S.; Leinhardt, Z. M.; Paardekooper, S.; Baruteau, C.; Thebault, P.

2014-02-01

Observations of circumbinary planets orbiting very close to the central stars have shown that planet formation may occur in a very hostile environment, where the gravitational pull from the binary should be very strong on the primordial protoplanetary disk. Elevated impact velocities and orbit crossings from eccentricity oscillations are the primary contributors to high energy, potentially destructive collisions that inhibit the growth of aspiring planets. In this work, we conduct high-resolution, inter-particle gravity enabled N-body simulations to investigate the feasibility of planetesimal growth in the Kepler-34 system. We improve upon previous work by including planetesimal disk self-gravity and an extensive collision model to accurately handle inter-planetesimal interactions. We find that super-catastrophic erosion events are the dominant mechanism up to and including the orbital radius of Kepler-34(AB)b, making in situ growth unlikely. It is more plausible that Kepler-34(AB)b migrated from a region beyond 1.5 AU. Based on the conclusions that we have made for Kepler-34, it seems likely that all of the currently known circumbinary planets have also migrated significantly from their formation location with the possible exception of Kepler-47(AB)c.

Kepler Mission Discovers Trove of Extrasolar Planet Candidates

NASA Astrophysics Data System (ADS)

Showstack, Randy

2011-02-01

NASA's Kepler discovery mission is collecting more than just pennies from heaven. Results from the first 4 months of science operations of the Kepler space telescope, announced on 2 February, include the discovery of 1235 candidate planets orbiting 997 stars in a small portion of the Milky Way galaxy examined by the telescope. Follow-up observations likely could confirm about 80% of the candidates as actual planets rather than false positives, according to researchers. This new trove of possible exoplanets could greatly expand the number of known planets outside of our solar system.

Size of Kepler Planet Candidates

NASA Image and Video Library

2013-01-07

Kepler data has increased by 20 percent and now totals 2,740 potential planets orbiting 2,036 stars; dramatic increases are seen in the number of Earth-size and super Earth-size candidates discovered.

A Search for Lost Planets in the Kepler Multi-planet Systems and the Discovery of the Long-period, Neptune-sized Exoplanet Kepler-150 f

NASA Astrophysics Data System (ADS)

Schmitt, Joseph R.; Jenkins, Jon M.; Fischer, Debra A.

2017-04-01

The vast majority of the 4700 confirmed planets (CPs) and planet candidates discovered by the Kepler mission were first found by the Kepler pipeline. In the pipeline, after a transit signal is found, all data points associated with those transits are removed, creating a “Swiss cheese”-like light curve full of holes, which is then used for subsequent transit searches. These holes could render an additional planet undetectable (or “lost”). We examine a sample of 114 stars with 3+ CPs to evaluate the effect of this “Swiss cheesing.” A simulation determines that the probability that a transiting planet is lost due to the transit masking is low, but non-negligible, reaching a plateau at ˜3.3% lost in the period range of P = 400-500 days. We then model all planet transits and subtract out the transit signals for each star, restoring the in-transit data points, and use the Kepler pipeline to search the transit-subtracted (I.e., transit-cleaned) light curves. However, the pipeline did not discover any credible new transit signals. This demonstrates the validity and robustness of the Kepler pipeline’s choice to use transit masking over transit subtraction. However, a follow-up visual search through all the transit-subtracted data, which allows for easier visual identification of new transits, revealed the existence of a new, Neptune-sized exoplanet (Kepler-150 f) and a potential single transit of a likely false positive (FP) (Kepler-208). Kepler-150 f (P = 637.2 days, {R}{{P}}={3.64}-0.39+0.52 R⊕) is confirmed with >99.998% confidence using a combination of the planet multiplicity argument, an FP probability analysis, and a transit duration analysis.

The Kepler Dichotomy in Planetary Disks: Linking Kepler Observables to Simulations of Late-stage Planet Formation

NASA Astrophysics Data System (ADS)

Moriarty, John; Ballard, Sarah

2016-11-01

NASA’s Kepler Mission uncovered a wealth of planetary systems, many with planets on short-period orbits. These short-period systems reside around 50% of Sun-like stars and are similarly prevalent around M dwarfs. Their formation and subsequent evolution is the subject of active debate. In this paper, we simulate late-stage, in situ planet formation across a grid of planetesimal disks with varying surface density profiles and total mass. We compare simulation results with observable characteristics of the Kepler sample. We identify mixture models with different primordial planetesimal disk properties that self-consistently recover the multiplicity, radius, period and period ratio, and duration ratio distributions of the Kepler planets. We draw three main conclusions. (1) We favor a “frozen-in” narrative for systems of short-period planets, in which they are stable over long timescales, as opposed to metastable. (2) The “Kepler dichotomy,” an observed phenomenon of the Kepler sample wherein the architectures of planetary systems appear to either vary significantly or have multiple modes, can naturally be explained by formation within planetesimal disks with varying surface density profiles. Finally, (3) we quantify the nature of the “Kepler dichotomy” for both GK stars and M dwarfs, and find that it varies with stellar type. While the mode of planet formation that accounts for high multiplicity systems occurs in 24% ± 7% of planetary systems orbiting GK stars, it occurs in 63% ± 16% of planetary systems orbiting M dwarfs.

Kepler Data Validation I—Architecture, Diagnostic Tests, and Data Products for Vetting Transiting Planet Candidates

NASA Astrophysics Data System (ADS)

Twicken, Joseph D.; Catanzarite, Joseph H.; Clarke, Bruce D.; Girouard, Forrest; Jenkins, Jon M.; Klaus, Todd C.; Li, Jie; McCauliff, Sean D.; Seader, Shawn E.; Tenenbaum, Peter; Wohler, Bill; Bryson, Stephen T.; Burke, Christopher J.; Caldwell, Douglas A.; Haas, Michael R.; Henze, Christopher E.; Sanderfer, Dwight T.

2018-06-01

The Kepler Mission was designed to identify and characterize transiting planets in the Kepler Field of View and to determine their occurrence rates. Emphasis was placed on identification of Earth-size planets orbiting in the Habitable Zone of their host stars. Science data were acquired for a period of four years. Long-cadence data with 29.4 min sampling were obtained for ∼200,000 individual stellar targets in at least one observing quarter in the primary Kepler Mission. Light curves for target stars are extracted in the Kepler Science Data Processing Pipeline, and are searched for transiting planet signatures. A Threshold Crossing Event is generated in the transit search for targets where the transit detection threshold is exceeded and transit consistency checks are satisfied. These targets are subjected to further scrutiny in the Data Validation (DV) component of the Pipeline. Transiting planet candidates are characterized in DV, and light curves are searched for additional planets after transit signatures are modeled and removed. A suite of diagnostic tests is performed on all candidates to aid in discrimination between genuine transiting planets and instrumental or astrophysical false positives. Data products are generated per target and planet candidate to document and display transiting planet model fit and diagnostic test results. These products are exported to the Exoplanet Archive at the NASA Exoplanet Science Institute, and are available to the community. We describe the DV architecture and diagnostic tests, and provide a brief overview of the data products. Transiting planet modeling and the search for multiple planets on individual targets are described in a companion paper. The final revision of the Kepler Pipeline code base is available to the general public through GitHub. The Kepler Pipeline has also been modified to support the Transiting Exoplanet Survey Satellite (TESS) Mission which is expected to commence in 2018.

Kepler Data Validation I: Architecture, Diagnostic Tests, and Data Products for Vetting Transiting Planet Candidates

NASA Technical Reports Server (NTRS)

Twicken, Joseph D.; Catanzarite, Joseph H.; Clarke, Bruce D.; Giroud, Forrest; Jenkins, Jon M.; Klaus, Todd C.; Li, Jie; McCauliff, Sean D.; Seader, Shawn E.; Tennenbaum, Peter;

Comparing HARPS and Kepler surveys. The alignment of multiple-planet systems

NASA Astrophysics Data System (ADS)

Figueira, P.; Marmier, M.; Boué, G.; Lovis, C.; Santos, N. C.; Montalto, M.; Udry, S.; Pepe, F.; Mayor, M.

2012-05-01

Context. The recent results of the HARPS and Kepler surveys provided us with a bounty of extrasolar systems. While the two teams extensively analyzed each of their data-sets, little work has been done comparing the two. Aims: We study a subset of the planetary population whose characterization is simultaneously within reach of both instruments. We compare the statistical properties of planets in systems with msini > 5-10 M⊕ and R > 2 R⊕, as inferred from the HARPS and Kepler surveys, respectively. If we assume that the underlying population has the same characteristics, the different detection sensitivity to the orbital inclination relative to the line of sight allows us to probe the planets' mutual inclination. Methods: We considered the frequency of systems with one, two, and three planets as dictated by HARPS data. We used Kepler's planetary period and host mass and radius distributions (corrected from detection bias) to model planetary systems in a simple, yet physically plausible way. We then varied the mutual inclination between planets in a system according to different prescriptions (completely aligned, Rayleigh distributions, and isotropic) and compared the transit frequencies with one, two, or three planets with those measured by Kepler. Results: The results show that the two datasets are compatible, a remarkable result especially because there are no tunable knobs other than the assumed inclination distribution. For msini cutoffs of 7-10 M⊕, which are those expected to correspond to the radius cutoff of 2 R⊕, we conclude that the results are better described by a Rayleigh distribution with a mode of 1° or smaller. We show that the best-fit scenario only becomes a Rayleigh distribution with a mode of 5° if we assume a quite extreme mass-radius relationship for the planetary population. Conclusions: These results have important consequences for our understanding of the role of several proposed formation and evolution mechanisms. They confirm that

The Evaporation Valley in the Kepler Planets

NASA Astrophysics Data System (ADS)

Owen, James E.; Wu, Yanqin

2017-09-01

A new piece of evidence supporting the photoevaporation-driven evolution model for low-mass, close-in exoplanets was recently presented by the California-Kepler Survey. The radius distribution of the Kepler planets is shown to be bimodal, with a “valley” separating two peaks at 1.3 and 2.6 R ⊕. Such an “evaporation valley” had been predicted by numerical models previously. Here, we develop a minimal model to demonstrate that this valley results from the following fact: the timescale for envelope erosion is the longest for those planets with hydrogen/helium-rich envelopes that, while only a few percent in weight, double its radius. The timescale falls for envelopes lighter than this because the planet’s radius remains largely constant for tenuous envelopes. The timescale also drops for heavier envelopes because the planet swells up faster than the addition of envelope mass. Photoevaporation therefore herds planets into either bare cores (˜1.3 R ⊕), or those with double the core’s radius (˜2.6 R ⊕). This process mostly occurs during the first 100 Myr when the stars’ high-energy fluxes are high and nearly constant. The observed radius distribution further requires the Kepler planets to be clustered around 3 M ⊕ in mass, born with H/He envelopes more than a few percent in mass, and that their cores are similar to the Earth in composition. Such envelopes must have been accreted before the dispersal of the gas disks, while the core composition indicates formation inside the ice line. Lastly, the photoevaporation model fails to account for bare planets beyond ˜30-60 days; if these planets are abundant, they may point to a significant second channel for planet formation, resembling the solar system terrestrial planets.

Kepler Planet Detection Metrics: Per-Target Flux-Level Transit Injection Tests of TPS for Data Release 25

NASA Technical Reports Server (NTRS)

Burke, Christopher J.; Catanzarite, Joseph

2017-01-01

the recovered signals can be further classified as planet candidates or false positives in the exact same manner as detections from the nominal (i.e., observed) pipeline run (Twicken et al., 2016, Thompson et al., in preparation). To date, the PLTI test has been the standard means of measuring pipeline completeness averaged over large samples of targets (Christiansen et al., 2015, 2016; Christiansen, 2017). However, since the PLTI test uses only one injection per target, it does not elucidate individual-target variations in pipeline completeness due to differences in stellar properties or astrophysical variability. Thus, we developed the FLTI test to provide a numerically efficient way to fully map individual targets and explore the performance of the pipeline in greater detail. The FLTI tests thereby allow a thorough validation of the pipeline completeness models (such as window function (Burke and Catanzarite, 2017a), detection efficiency (Burke Catanzarite, 2017b), etc.) across the spectrum of Kepler targets (i.e., various astrophysical phenomena and differences in instrumental noise). Tests during development of the FLTI capability revealed that there are significant target-to-target variations in the detection efficiency.

HABITABILITY OF EARTH-MASS PLANETS AND MOONS IN THE KEPLER-16 SYSTEM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quarles, B.; Musielak, Z. E.; Cuntz, M., E-mail: billyq@uta.edu, E-mail: zmusielak@uta.edu, E-mail: cuntz@uta.edu

2012-05-01

We demonstrate that habitable Earth-mass planets and moons can exist in the Kepler-16 system, known to host a Saturn-mass planet around a stellar binary, by investigating their orbital stability in the standard and extended habitable zone (HZ). We find that Earth-mass planets in satellite-like (S-type) orbits are possible within the standard HZ in direct vicinity of Kepler-16b, thus constituting habitable exomoons. However, Earth-mass planets cannot exist in planetary-like (P-type) orbits around the two stellar components within the standard HZ. Yet, P-type Earth-mass planets can exist superior to the Saturnian planet in the extended HZ pertaining to considerably enhanced back-warming inmore » the planetary atmosphere if facilitated. We briefly discuss the potential detectability of such habitable Earth-mass moons and planets positioned in satellite and planetary orbits, respectively. The range of inferior and superior P-type orbits in the HZ is between 0.657-0.71 AU and 0.95-1.02 AU, respectively.« less

New Constraints on the False Positive Rate for Short-Period Kepler Planet Candidates

NASA Astrophysics Data System (ADS)

Colón, Knicole D.; Morehead, Robert C.; Ford, Eric B.

2015-01-01

The Kepler space mission has discovered thousands of potential planets orbiting other stars, thereby setting the stage for in-depth studies of different populations of planets. We present new multi-wavelength transit photometry of small (Rp < 6 Earth radii), short-period (P < 6 days) Kepler planet candidates acquired with the Gran Telescopio Canarias. Multi-wavelength transit photometry allows us to search for wavelength-dependent transit depths and subsequently identify eclipsing binary false positives (which are especially prevalent at the shortest orbital periods). We combine these new observations of three candidates with previous results for five other candidates (Colón & Ford 2011 and Colón, Ford, & Morehead 2012) to provide new constraints on the false positive rate for small, close-in candidates. In our full sample, we identify four candidates as viable planets and four as eclipsing binary false positives. We therefore find a higher false positive rate for small, close-in candidates compared to the lower false positive rate of ~10% determined by other studies for the full sample of Kepler planet candidates (e.g. Fressin et al. 2013). We also discuss the dearth of known planets with periods less than ~2.5 days and radii between ~3 and 11 Earth radii (the so-called 'sub-Jovian desert'), since the majority of the candidates in our study are located in or around this 'desert.' The lack of planets with these orbital and physical properties is not expected to be due to observational bias, as short-period planets are generally easier to detect (especially if they are larger or more massive than Earth). We consider the implications of our results for the other ~20 Kepler planet candidates located in this desert. Characterizing these candidates will allow us to better understand the formation processes of this apparently rare class of planets.

PLANET OCCURRENCE WITHIN 0.25 AU OF SOLAR-TYPE STARS FROM KEPLER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howard, Andrew W.; Marcy, Geoffrey W.; Bryson, Stephen T.

We report the distribution of planets as a function of planet radius, orbital period, and stellar effective temperature for orbital periods less than 50 days around solar-type (GK) stars. These results are based on the 1235 planets (formally 'planet candidates') from the Kepler mission that include a nearly complete set of detected planets as small as 2 R{sub Circled-Plus }. For each of the 156,000 target stars, we assess the detectability of planets as a function of planet radius, R{sub p}, and orbital period, P, using a measure of the detection efficiency for each star. We also correct for themore » geometric probability of transit, R{sub *}/a. We consider first Kepler target stars within the 'solar subset' having T{sub eff} = 4100-6100 K, log g 4.0-4.9, and Kepler magnitude Kp < 15 mag, i.e., bright, main-sequence GK stars. We include only those stars having photometric noise low enough to permit detection of planets down to 2 R{sub Circled-Plus }. We count planets in small domains of R{sub p} and P and divide by the included target stars to calculate planet occurrence in each domain. The resulting occurrence of planets varies by more than three orders of magnitude in the radius-orbital period plane and increases substantially down to the smallest radius (2 R{sub Circled-Plus }) and out to the longest orbital period (50 days, {approx}0.25 AU) in our study. For P < 50 days, the distribution of planet radii is given by a power law, df/dlog R = k{sub R}R{sup {alpha}} with k{sub R} = 2.9{sup +0.5}{sub -0.4}, {alpha} = -1.92 {+-} 0.11, and R {identical_to} R{sub p}/R{sub Circled-Plus }. This rapid increase in planet occurrence with decreasing planet size agrees with the prediction of core-accretion formation but disagrees with population synthesis models that predict a desert at super-Earth and Neptune sizes for close-in orbits. Planets with orbital periods shorter than 2 days are extremely rare; for R{sub p} > 2 R{sub Circled-Plus} we measure an occurrence of less

A Search for Lost Planets in the Kepler Multi-Planet Systems and the Discovery of the Long-Period, Neptune-Sized Exoplanet Kepler-150 f

NASA Technical Reports Server (NTRS)

Schmitt, Joseph R.; Jenkins, Jon M.; Fischer, Debra A.

2017-01-01

The vast majority of the 4700 confirmed planets and planet candidates discovered by the Kepler space telescope were first found by the Kepler pipeline. In the pipeline, after a transit signal is found, all data points associated with those transits are removed, creating a Swiss cheese-like light curve full of holes, which is then used for subsequent transit searches. These holes could render an additional planet undetectable (or lost). We examine a sample of 114 stars with 3+ confirmed planets to see the effect that this Swiss cheesing may have. A simulation determined that the probability that a transiting planet is lost due to the transit masking is low, but non-neglible, reaching a plateau at approximately 3.3% lost in the period range of P = 400 - 500 days. We then model the transits in all quarters of each star and subtract out the transit signals, restoring the in-transit data points, and use the Kepler pipeline to search the transit-subtracted (i.e., transit-cleaned) light curves. However, the pipeline did not discover any credible new transit signals. This demonstrates the validity and robustness of the Kepler pipelines choice to use transit masking over transit subtraction. However, a follow-up visual search through all the transit-subtracted data, which allows for easier visual identification of new transits, revealed the existence of a new, Neptune-sized exoplanet. Kepler-150 f (P = 637.2 days, RP = 3.86 R earth) is confirmed using a combination of false positive probability analysis, transit duration analysis, and the planet multiplicity argument.

A SEARCH FOR LOST PLANETS IN THE KEPLER MULTI-PLANET SYSTEMS AND THE DISCOVERY OF A LONG PERIOD, NEPTUNE-SIZED EXOPLANET KEPLER-150 F.

PubMed

Schmitt, Joseph R; Jenkins, Jon M; Fischer, Debra A

2017-04-01

The vast majority of the 4700 confirmed planets and planet candidates discovered by the Kepler space telescope were first found by the Kepler pipeline. In the pipeline, after a transit signal is found, all data points associated with those transits are removed, creating a "Swiss cheese"-like light curve full of holes, which is then used for subsequent transit searches. These holes could render an additional planet undetectable (or "lost"). We examine a sample of 114 stars with 3+ confirmed planets to see the effect that this "Swiss cheesing" may have. A simulation determined that the probability that a transiting planet is lost due to the transit masking is low, but non-neglible, reaching a plateau at ~3.3% lost in the period range of P = 400 - 500 days. We then model the transits in all quarters of each star and subtract out the transit signals, restoring the in-transit data points, and use the Kepler pipeline to search the transit-subtracted (i.e., transit-cleaned) light curves. However, the pipeline did not discover any credible new transit signals. This demonstrates the validity and robustness of the Kepler pipeline's choice to use transit masking over transit subtraction. However, a follow-up visual search through all the transit-subtracted data, which allows for easier visual identification of new transits, revealed the existence of a new, Neptune-sized exoplanet. Kepler-150 f ( P = 637.2 days, R P = 3.86 R ⊕ ) is confirmed using a combination of false positive probability analysis, transit duration analysis, and the planet multiplicity argument.

A SEARCH FOR LOST PLANETS IN THE KEPLER MULTI-PLANET SYSTEMS AND THE DISCOVERY OF A LONG PERIOD, NEPTUNE-SIZED EXOPLANET KEPLER-150 F

PubMed Central

Schmitt, Joseph R.; Jenkins, Jon M.; Fischer, Debra A.

2018-01-01

The vast majority of the 4700 confirmed planets and planet candidates discovered by the Kepler space telescope were first found by the Kepler pipeline. In the pipeline, after a transit signal is found, all data points associated with those transits are removed, creating a “Swiss cheese”-like light curve full of holes, which is then used for subsequent transit searches. These holes could render an additional planet undetectable (or “lost”). We examine a sample of 114 stars with 3+ confirmed planets to see the effect that this “Swiss cheesing” may have. A simulation determined that the probability that a transiting planet is lost due to the transit masking is low, but non-neglible, reaching a plateau at ~3.3% lost in the period range of P = 400 – 500 days. We then model the transits in all quarters of each star and subtract out the transit signals, restoring the in-transit data points, and use the Kepler pipeline to search the transit-subtracted (i.e., transit-cleaned) light curves. However, the pipeline did not discover any credible new transit signals. This demonstrates the validity and robustness of the Kepler pipeline’s choice to use transit masking over transit subtraction. However, a follow-up visual search through all the transit-subtracted data, which allows for easier visual identification of new transits, revealed the existence of a new, Neptune-sized exoplanet. Kepler-150 f (P = 637.2 days, RP = 3.86 R⊕) is confirmed using a combination of false positive probability analysis, transit duration analysis, and the planet multiplicity argument. PMID:29375142

PLANET HUNTERS. V. A CONFIRMED JUPITER-SIZE PLANET IN THE HABITABLE ZONE AND 42 PLANET CANDIDATES FROM THE KEPLER ARCHIVE DATA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Ji; Fischer, Debra A.; Boyajian, Tabetha S.

We report the latest Planet Hunter results, including PH2 b, a Jupiter-size (R{sub PL} = 10.12 ± 0.56 R{sub ⊕}) planet orbiting in the habitable zone of a solar-type star. PH2 b was elevated from candidate status when a series of false-positive tests yielded a 99.9% confidence level that transit events detected around the star KIC 12735740 had a planetary origin. Planet Hunter volunteers have also discovered 42 new planet candidates in the Kepler public archive data, of which 33 have at least 3 transits recorded. Most of these transit candidates have orbital periods longer than 100 days and 20more » are potentially located in the habitable zones of their host stars. Nine candidates were detected with only two transit events and the prospective periods are longer than 400 days. The photometric models suggest that these objects have radii that range between those of Neptune and Jupiter. These detections nearly double the number of gas-giant planet candidates orbiting at habitable-zone distances. We conducted spectroscopic observations for nine of the brighter targets to improve the stellar parameters and we obtained adaptive optics imaging for four of the stars to search for blended background or foreground stars that could confuse our photometric modeling. We present an iterative analysis method to derive the stellar and planet properties and uncertainties by combining the available spectroscopic parameters, stellar evolution models, and transiting light curve parameters, weighted by the measurement errors. Planet Hunters is a citizen science project that crowd sources the assessment of NASA Kepler light curves. The discovery of these 43 planet candidates demonstrates the success of citizen scientists at identifying planet candidates, even in longer period orbits with only two or three transit events.« less

Stability Limits of Circumbinary Planets: Is There a Pile-up in the Kepler CBPs?

NASA Astrophysics Data System (ADS)

Quarles, B.; Satyal, S.; Kostov, V.; Kaib, N.; Haghighipour, N.

2018-04-01

The stability limit for circumbinary planets (CBPs) is not well defined and can depend on initial parameters defining either the planetary orbit and/or the inner binary orbit. We expand on the work of Holman & Wiegert (1999) to develop numerical tools for quick, easy, and accurate determination of the stability limit. The results of our simulations, as well as our numerical tools, are available to the community through Zenodo and GitHub, respectively. We employ a grid interpolation method based on ∼150 million full N-body simulations of initially circular, coplanar systems and compare to the nine known Kepler CBP systems. Using a formalism from planet packing studies, we find that 55% of the Kepler CBP systems allow for an additional equal-mass planet to potentially exist on an interior orbit relative to the observed planet. Therefore, we do not find strong evidence for a pile-up in the Kepler CBP systems and more detections are needed to adequately characterize the formation mechanisms for the CBP population. Observations from the Transiting Exoplanet Survey Satellite are expected to substantially increase the number of detections using the unique geometry of CBP systems, where multiple transits can occur during a single conjunction.

Planet Hunters: Kepler by Eye

NASA Astrophysics Data System (ADS)

Schwamb, Megan E.; Lintott, C.; Fischer, D.; Smith, A. M.; Boyajian, T. S.; Brewer, J. M.; Giguere, M. J.; Lynn, S.; Parrish, M.; Schawinski, K.; Schmitt, J.; Simpson, R.; Wang, J.

2014-01-01

Planet Hunters (http://www.planethunters.org), part of the Zooniverse's (http://www.zooniverse.org) collection of online citizen science projects, uses the World Wide Web to enlist the general public to identify transits in the pubic Kepler light curves. Planet Hunters utilizes human pattern recognition to identify planet transits that may be missed by automated detection algorithms looking for periodic events. Referred to as ‘crowdsourcing’ or ‘citizen science’, the combined assessment of many non-expert human classifiers with minimal training can often equal or best that of a trained expert and in many cases outperform the best machine-learning algorithm. Visitors to the Planet Hunters' website are presented with a randomly selected ~30-day light curve segment from one of Kepler’s ~160,000 target stars and are asked to draw boxes to mark the locations of visible transits in the web interface. 5-10 classifiers review each 30-day light curve segment. Since December 2010, more than 260,000 volunteers world wide have participated, contributing over 20 million classifications. We have demonstrated the success of a citizen science approach with the project’s more than 20 planet candidates, the discovery of PH1b, a transiting circumbinary planet in a quadruple star system, and the discovery of PH2-b, a confirmed Jupiter-sized planet in the habitable zone of a Sun-like star. I will provide an overview of Planet Hunters, highlighting several of project's most recent exoplanet and astrophysical discoveries. Acknowledgements: MES was supported in part by a NSF AAPF under award AST-1003258 and a American Philosophical Society Franklin Grant. We acknowledge support from NASA ADAP12-0172 grant to PI Fischer.

The California-Kepler Survey. I. High-resolution Spectroscopy of 1305 Stars Hosting Kepler Transiting Planets

NASA Astrophysics Data System (ADS)

Petigura, Erik A.; Howard, Andrew W.; Marcy, Geoffrey W.; Johnson, John Asher; Isaacson, Howard; Cargile, Phillip A.; Hebb, Leslie; Fulton, Benjamin J.; Weiss, Lauren M.; Morton, Timothy D.; Winn, Joshua N.; Rogers, Leslie A.; Sinukoff, Evan; Hirsch, Lea A.; Crossfield, Ian J. M.

2017-09-01

The California-Kepler Survey (CKS) is an observational program developed to improve our knowledge of the properties of stars found to host transiting planets by NASA’s Kepler Mission. The improvement stems from new high-resolution optical spectra obtained using HIRES at the W. M. Keck Observatory. The CKS stellar sample comprises 1305 stars classified as Kepler objects of interest, hosting a total of 2075 transiting planets. The primary sample is magnitude-limited ({Kp}< 14.2) and contains 960 stars with 1385 planets. The sample was extended to include some fainter stars that host multiple planets, ultra-short period planets, or habitable zone planets. The spectroscopic parameters were determined with two different codes, one based on template matching and the other on direct spectral synthesis using radiative transfer. We demonstrate a precision of 60 K in {T}{eff}, 0.10 dex in {log}g, 0.04 dex in [{Fe}/{{H}}], and 1.0 {km} {{{s}}}-1 in V\\sin I. In this paper, we describe the CKS project and present a uniform catalog of spectroscopic parameters. Subsequent papers in this series present catalogs of derived stellar properties such as mass, radius, and age; revised planet properties; and statistical explorations of the ensemble. CKS is the largest survey to determine the properties of Kepler stars using a uniform set of high-resolution, high signal-to-noise ratio spectra. The HIRES spectra are available to the community for independent analyses. Based on observations obtained at the W. M. Keck Observatory, which is operated jointly by the University of California and the California Institute of Technology. Keck time was granted for this project by the University of California, and California Institute of Technology, the University of Hawaii, and NASA.

VALFAST: Secure Probabilistic Validation of Hundreds of Kepler Planet Candidates

NASA Astrophysics Data System (ADS)

Morton, Tim; Petigura, E.; Johnson, J. A.; Howard, A.; Marcy, G. W.; Baranec, C.; Law, N. M.; Riddle, R. L.; Ciardi, D. R.; Robo-AO Team

2014-01-01

The scope, scale, and tremendous success of the Kepler mission has necessitated the rapid development of probabilistic validation as a new conceptual framework for analyzing transiting planet candidate signals. While several planet validation methods have been independently developed and presented in the literature, none has yet come close to addressing the entire Kepler survey. I present the results of applying VALFAST---a planet validation code based on the methodology described in Morton (2012)---to every Kepler Object of Interest. VALFAST is unique in its combination of detail, completeness, and speed. Using the transit light curve shape, realistic population simulations, and (optionally) diverse follow-up observations, it calculates the probability that a transit candidate signal is the result of a true transiting planet or any of a number of astrophysical false positive scenarios, all in just a few minutes on a laptop computer. In addition to efficiently validating the planetary nature of hundreds of new KOIs, this broad application of VALFAST also demonstrates its ability to reliably identify likely false positives. This extensive validation effort is also the first to incorporate data from all of the largest Kepler follow-up observing efforts: the CKS survey of ~1000 KOIs with Keck/HIRES, the Robo-AO survey of >1700 KOIs, and high-resolution images obtained through the Kepler Follow-up Observing Program. In addition to enabling the core science that the Kepler mission was designed for, this methodology will be critical to obtain statistical results from future surveys such as TESS and PLATO.

The mass of the super-Earth orbiting the brightest Kepler planet hosting star

NASA Astrophysics Data System (ADS)

Lopez-Morales, Mercedes; HARPS-N Team

2016-01-01

HD 179070, aka Kepler-21, is a V = 8.25 oscillating F6IV star and the brightest exoplanet host discovered by Kepler. An early analysis of the Q0 - Q5 Kepler light curves by Howell et al. (2012) revealed transits of a planetary companion, Kepler-21b, with a radius of 1.6 R_Earth and an orbital period of 2.7857 days. However, they could not determine the mass of the planet from the initial radial velocity observations with Keck-HIRES, and were only able to impose a 2s upper limit of about 10 M_Earth. Here we present 82 new radial velocity observations of this system obtained with the HARPS-N spectrograph. We detect the Doppler shift signal of Kepler-21b at the 3.6s level, and measure a planetary mass of 5.9 ± 1.6 M_Earth. We also update the radius of the planet to 1.65 ± 0.08 R_Earth, using the now available Kepler Q0 - Q17 photometry for this target. The mass of Kepler-21b appears to fall on the apparent dividing line between super-Earths that have lost all the material in their outer layers and those that have retained a significant amount of volatiles. Based on our results Kepler-21b belongs to the first group. Acknowledgement: This work was supported by funding from the NASA XRP Program and the John Templeton Foundation.

NASA KEPLER OPENS THE STUDY OF THE GALAXY’S PLANET POPULATION

NASA Image and Video Library

2017-06-20

NASA's Kepler mission released its eighth Kepler Candidate Catalog, which contains the best measured and most reliable planet candidates from the space telescope's final survey of the Cygnus Field. In the data are 219 new planet candidates, of which 10 are less than twice the size of the Earth and orbit in the habitable zone.

A Dynamical Analysis of the Kepler-80 System of Five Transiting Planets

NASA Astrophysics Data System (ADS)

MacDonald, Mariah G.; Ragozzine, Darin; Fabrycky, Daniel C.; Ford, Eric B.; Holman, Matthew J.; Isaacson, Howard T.; Lissauer, Jack J.; Lopez, Eric D.; Mazeh, Tsevi; Rogers, Leslie; Rowe, Jason F.; Steffen, Jason H.; Torres, Guillermo

2016-10-01

Kepler has discovered hundreds of systems with multiple transiting exoplanets which hold tremendous potential both individually and collectively for understanding the formation and evolution of planetary systems. Many of these systems consist of multiple small planets with periods less than ∼50 days known as Systems with Tightly spaced Inner Planets, or STIPs. One especially intriguing STIP, Kepler-80 (KOI-500), contains five transiting planets: f, d, e, b, and c with periods of 1.0, 3.1, 4.6, 7.1, and 9.5 days, respectively. We provide measurements of transit times and a transit timing variation (TTV) dynamical analysis. We find that TTVs cannot reliably detect eccentricities for this system, though mass estimates are not affected. Restricting the eccentricity to a reasonable range, we infer masses for the outer four planets (d, e, b, and c) to be {6.75}-0.51+0.69, {4.13}-0.95+0.81, {6.93}-0.70+1.05, and {6.74}-0.86+1.23 Earth masses, respectively. The similar masses but different radii are consistent with terrestrial compositions for d and e and ∼2% H/He envelopes for b and c. We confirm that the outer four planets are in a rare dynamical configuration with four interconnected three-body resonances that are librating with few degree amplitudes. We present a formation model that can reproduce the observed configuration by starting with a multi-resonant chain and introducing dissipation. Overall, the information-rich Kepler-80 planets provide an important perspective into exoplanetary systems.

Kepler-91b: a planet at the end of its life. Planet and giant host star properties via light-curve variations

NASA Astrophysics Data System (ADS)

Lillo-Box, J.; Barrado, D.; Moya, A.; Montesinos, B.; Montalbán, J.; Bayo, A.; Barbieri, M.; Régulo, C.; Mancini, L.; Bouy, H.; Henning, T.

2014-02-01

Context. The evolution of planetary systems is intimately linked to the evolution of their host stars. Our understanding of the whole planetary evolution process is based on the wide planet diversity observed so far. Only a few tens of planets have been discovered orbiting stars ascending the red giant branch. Although several theories have been proposed, the question of how planets die remains open owing to the small number statistics, making it clear that the sample of planets around post-main sequence stars needs to be enlarged. Aims: In this work we study the giant star Kepler-91 (KOI-2133) in order to determine the nature of a transiting companion. This system was detected by the Kepler Space Telescope, which identified small dims in its light curve with a period of 6.246580 ± 0.000082 days. However, its planetary confirmation is needed due to the large pixel size of the Kepler camera, which can hide other stellar configurations able to mimic planet-like transit events. Methods: We analysed Kepler photometry to 1) re-calculate transit parameters; 2) study the light-curve modulations; and 3) to perform an asteroseismic analysis (accurate stellar parameter determination) by identifying solar-like oscillations on the periodogram. We also used a high-resolution and high signal-to-noise ratio spectrum obtained with the Calar Alto Fiber-fed Échelle spectrograph (CAFE) to measure stellar properties. Additionally, false-positive scenarios were rejected by obtaining high-resolution images with the AstraLux lucky imaging camera on the 2.2 m telescope at the Calar Alto Observatory. Results: We confirm the planetary nature of the object transiting the star Kepler-91 by deriving a mass of Mp=0.88+0.17-0.33 MJup and a planetary radius of Rp=1.384+0.011-0.054 RJup. Asteroseismic analysis produces a stellar radius of R⋆ = 6.30 ± 0.16 R⊙ and a mass of M⋆ = 1.31 ± 0.10 M⊙. We find that its eccentric orbit (e=0.066+0.013-0.017) is just 1.32+0.07-0.22 R⋆ away from

Rotational Synchronization May Enhance Habitability for Circumbinary Planets: Kepler Binary Case Studies

NASA Astrophysics Data System (ADS)

Mason, Paul A.; Zuluaga, Jorge I.; Clark, Joni M.; Cuartas-Restrepo, Pablo A.

2013-09-01

We report a mechanism capable of reducing (or increasing) stellar activity in binary stars, thereby potentially enhancing (or destroying) circumbinary habitability. In single stars, stellar aggression toward planetary atmospheres causes mass-loss, which is especially detrimental for late-type stars, because habitable zones are very close and activity is long lasting. In binaries, tidal rotational breaking reduces magnetic activity, thus reducing harmful levels of X-ray and ultraviolet (XUV) radiation and stellar mass-loss that are able to erode planetary atmospheres. We study this mechanism for all confirmed circumbinary (p-type) planets. We find that main sequence twins provide minimal flux variation and in some cases improved environments if the stars rotationally synchronize within the first Gyr. Solar-like twins, like Kepler 34 and Kepler 35, provide low habitable zone XUV fluxes and stellar wind pressures. These wide, moist, habitable zones may potentially support multiple habitable planets. Solar-type stars with lower mass companions, like Kepler 47, allow for protected planets over a wide range of secondary masses and binary periods. Kepler 38 and related binaries are marginal cases. Kepler 64 and analogs have dramatically reduced stellar aggression due to synchronization of the primary, but are limited by the short lifetime. Kepler 16 appears to be inhospitable to planets due to extreme XUV flux. These results have important implications for estimates of the number of stellar systems containing habitable planets in the Galaxy and allow for the selection of binaries suitable for follow-up searches for habitable planets.

ROTATIONAL SYNCHRONIZATION MAY ENHANCE HABITABILITY FOR CIRCUMBINARY PLANETS: KEPLER BINARY CASE STUDIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mason, Paul A.; Zuluaga, Jorge I.; Cuartas-Restrepo, Pablo A.

2013-09-10

We report a mechanism capable of reducing (or increasing) stellar activity in binary stars, thereby potentially enhancing (or destroying) circumbinary habitability. In single stars, stellar aggression toward planetary atmospheres causes mass-loss, which is especially detrimental for late-type stars, because habitable zones are very close and activity is long lasting. In binaries, tidal rotational breaking reduces magnetic activity, thus reducing harmful levels of X-ray and ultraviolet (XUV) radiation and stellar mass-loss that are able to erode planetary atmospheres. We study this mechanism for all confirmed circumbinary (p-type) planets. We find that main sequence twins provide minimal flux variation and in somemore » cases improved environments if the stars rotationally synchronize within the first Gyr. Solar-like twins, like Kepler 34 and Kepler 35, provide low habitable zone XUV fluxes and stellar wind pressures. These wide, moist, habitable zones may potentially support multiple habitable planets. Solar-type stars with lower mass companions, like Kepler 47, allow for protected planets over a wide range of secondary masses and binary periods. Kepler 38 and related binaries are marginal cases. Kepler 64 and analogs have dramatically reduced stellar aggression due to synchronization of the primary, but are limited by the short lifetime. Kepler 16 appears to be inhospitable to planets due to extreme XUV flux. These results have important implications for estimates of the number of stellar systems containing habitable planets in the Galaxy and allow for the selection of binaries suitable for follow-up searches for habitable planets.« less

Two Earth-sized planets orbiting Kepler-20.

PubMed

Fressin, Francois; Torres, Guillermo; Rowe, Jason F; Charbonneau, David; Rogers, Leslie A; Ballard, Sarah; Batalha, Natalie M; Borucki, William J; Bryson, Stephen T; Buchhave, Lars A; Ciardi, David R; Désert, Jean-Michel; Dressing, Courtney D; Fabrycky, Daniel C; Ford, Eric B; Gautier, Thomas N; Henze, Christopher E; Holman, Matthew J; Howard, Andrew; Howell, Steve B; Jenkins, Jon M; Koch, David G; Latham, David W; Lissauer, Jack J; Marcy, Geoffrey W; Quinn, Samuel N; Ragozzine, Darin; Sasselov, Dimitar D; Seager, Sara; Barclay, Thomas; Mullally, Fergal; Seader, Shawn E; Still, Martin; Twicken, Joseph D; Thompson, Susan E; Uddin, Kamal

2011-12-20

Since the discovery of the first extrasolar giant planets around Sun-like stars, evolving observational capabilities have brought us closer to the detection of true Earth analogues. The size of an exoplanet can be determined when it periodically passes in front of (transits) its parent star, causing a decrease in starlight proportional to its radius. The smallest exoplanet hitherto discovered has a radius 1.42 times that of the Earth's radius (R(⊕)), and hence has 2.9 times its volume. Here we report the discovery of two planets, one Earth-sized (1.03R(⊕)) and the other smaller than the Earth (0.87R(⊕)), orbiting the star Kepler-20, which is already known to host three other, larger, transiting planets. The gravitational pull of the new planets on the parent star is too small to measure with current instrumentation. We apply a statistical method to show that the likelihood of the planetary interpretation of the transit signals is more than three orders of magnitude larger than that of the alternative hypothesis that the signals result from an eclipsing binary star. Theoretical considerations imply that these planets are rocky, with a composition of iron and silicate. The outer planet could have developed a thick water vapour atmosphere.

Modeling circumbinary planets: The case of Kepler-38

NASA Astrophysics Data System (ADS)

Kley, Wilhelm; Haghighipour, Nader

2014-04-01

Context. Recently, a number of planets orbiting binary stars have been discovered by the Kepler space telescope. In a few systems the planets reside close to the dynamical stability limit. Owing to the difficulty of forming planets in such close orbits, it is believed that they have formed farther out in the disk and migrated to their present locations. Aims: Our goal is to construct more realistic models of planet migration in circumbinary disks and to determine the final position of these planets more accurately. In our work, we focus on the system Kepler-38 where the planet is close to the stability limit. Methods: The evolution of the circumbinary disk is studied using two-dimensional hydrodynamical simulations. We study locally isothermal disks as well as more realistic models that include full viscous heating, radiative cooling from the disk surfaces, and radiative diffusion in the disk midplane. After the disk has been brought into a quasi-equilibrium state, a 115 Earth-mass planet is embedded and its evolution is followed. Results: In all cases the planets stop inward migration near the inner edge of the disk. In isothermal disks with a typical disk scale height of H/r = 0.05, the final outcome agrees very well with the observed location of planet Kepler-38b. For the radiative models, the disk thickness and location of the inner edge is determined by the mass in the system. For surface densities on the order of 3000 g/cm2 at 1 AU, the inner gap lies close to the binary and planets stop in the region between the 5:1 and 4:1 mean-motion resonances with the binary. A model with a disk with approximately a quarter of the mass yields a final position very close to the observed one. Conclusions: For planets migrating in circumbinary disks, the final position is dictated by the structure of the disk. Knowing the observed orbits of circumbinary planets, radiative disk simulations with embedded planets can provide important information on the physical state of the

Constraining the Radiation and Plasma Environment of the Kepler Circumbinary Habitable-zone Planets

NASA Astrophysics Data System (ADS)

Zuluaga, Jorge I.; Mason, Paul A.; Cuartas-Restrepo, Pablo A.

2016-02-01

The discovery of many planets using the Kepler telescope includes 10 planets orbiting eight binary stars. Three binaries, Kepler-16, Kepler-47, and Kepler-453, have at least one planet in the circumbinary habitable zone (BHZ). We constrain the level of high-energy radiation and the plasma environment in the BHZ of these systems. With this aim, BHZ limits in these Kepler binaries are calculated as a function of time, and the habitability lifetimes are estimated for hypothetical terrestrial planets and/or moons within the BHZ. With the time-dependent BHZ limits established, a self-consistent model is developed describing the evolution of stellar activity and radiation properties as proxies for stellar aggression toward planetary atmospheres. Modeling binary stellar rotation evolution, including the effect of tidal interaction between stars in binaries, is key to establishing the environment around these systems. We find that Kepler-16 and its binary analogs provide a plasma environment favorable for the survival of atmospheres of putative Mars-sized planets and exomoons. Tides have modified the rotation of the stars in Kepler-47, making its radiation environment less harsh in comparison to the solar system. This is a good example of the mechanism first proposed by Mason et al. Kepler-453 has an environment similar to that of the solar system with slightly better than Earth radiation conditions at the inner edge of the BHZ. These results can be reproduced and even reparameterized as stellar evolution and binary tidal models progress, using our online tool http://bhmcalc.net.

CONSTRAINING THE RADIATION AND PLASMA ENVIRONMENT OF THE KEPLER CIRCUMBINARY HABITABLE-ZONE PLANETS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zuluaga, Jorge I.; Mason, Paul A.; Cuartas-Restrepo, Pablo A.

The discovery of many planets using the Kepler telescope includes 10 planets orbiting eight binary stars. Three binaries, Kepler-16, Kepler-47, and Kepler-453, have at least one planet in the circumbinary habitable zone (BHZ). We constrain the level of high-energy radiation and the plasma environment in the BHZ of these systems. With this aim, BHZ limits in these Kepler binaries are calculated as a function of time, and the habitability lifetimes are estimated for hypothetical terrestrial planets and/or moons within the BHZ. With the time-dependent BHZ limits established, a self-consistent model is developed describing the evolution of stellar activity and radiation propertiesmore » as proxies for stellar aggression toward planetary atmospheres. Modeling binary stellar rotation evolution, including the effect of tidal interaction between stars in binaries, is key to establishing the environment around these systems. We find that Kepler-16 and its binary analogs provide a plasma environment favorable for the survival of atmospheres of putative Mars-sized planets and exomoons. Tides have modified the rotation of the stars in Kepler-47, making its radiation environment less harsh in comparison to the solar system. This is a good example of the mechanism first proposed by Mason et al. Kepler-453 has an environment similar to that of the solar system with slightly better than Earth radiation conditions at the inner edge of the BHZ. These results can be reproduced and even reparameterized as stellar evolution and binary tidal models progress, using our online tool http://bhmcalc.net.« less

High-resolution multi-band imaging for validation and characterization of small Kepler planets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Everett, Mark E.; Silva, David R.; Barclay, Thomas

2015-02-01

High-resolution ground-based optical speckle and near-infrared adaptive optics images are taken to search for stars in close angular proximity to host stars of candidate planets identified by the NASA Kepler Mission. Neighboring stars are a potential source of false positive signals. These stars also blend into Kepler light curves, affecting estimated planet properties, and are important for an understanding of planets in multiple star systems. Deep images with high angular resolution help to validate candidate planets by excluding potential background eclipsing binaries as the source of the transit signals. A study of 18 Kepler Object of Interest stars hosting amore » total of 28 candidate and validated planets is presented. Validation levels are determined for 18 planets against the likelihood of a false positive from a background eclipsing binary. Most of these are validated at the 99% level or higher, including five newly validated planets in two systems: Kepler-430 and Kepler-431. The stellar properties of the candidate host stars are determined by supplementing existing literature values with new spectroscopic characterizations. Close neighbors of seven of these stars are examined using multi-wavelength photometry to determine their nature and influence on the candidate planet properties. Most of the close neighbors appear to be gravitationally bound secondaries, while a few are best explained as closely co-aligned field stars. Revised planet properties are derived for each candidate and validated planet, including cases where the close neighbors are the potential host stars.« less

NASA's Kepler Mission Discovers Its Smallest Habitable Zone Planets (Reporter Pkg)

NASA Image and Video Library

2013-04-18

NASA's Kepler mission has discovered two new planetary systems that include three super-Earth-size planets in the 'habitable zone,' the range of distance from a star where the surface temperature of an orbiting planet might be suitable for liquid water. Scientists do not know whether life could exist on the newfound planets, but their discovery signals we are another step closer to finding a world similar to Earth around a star like our sun. Kepler-62 and -69 systems

Planet hunters. VII. Discovery of a new low-mass, low-density planet (PH3 C) orbiting Kepler-289 with mass measurements of two additional planets (PH3 B and D)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmitt, Joseph R.; Fischer, Debra A.; Wang, Ji

2014-11-10

We report the discovery of one newly confirmed planet (P = 66.06 days, R {sub P} = 2.68 ± 0.17 R {sub ⊕}) and mass determinations of two previously validated Kepler planets, Kepler-289 b (P = 34.55 days, R {sub P} = 2.15 ± 0.10 R {sub ⊕}) and Kepler-289-c (P = 125.85 days, R {sub P} = 11.59 ± 0.10 R {sub ⊕}), through their transit timing variations (TTVs). We also exclude the possibility that these three planets reside in a 1:2:4 Laplace resonance. The outer planet has very deep (∼1.3%), high signal-to-noise transits, which puts extremely tight constraintsmore » on its host star's stellar properties via Kepler's Third Law. The star PH3 is a young (∼1 Gyr as determined by isochrones and gyrochronology), Sun-like star with M {sub *} = 1.08 ± 0.02 M {sub ☉}, R {sub *} = 1.00 ± 0.02 R {sub ☉}, and T {sub eff} = 5990 ± 38 K. The middle planet's large TTV amplitude (∼5 hr) resulted either in non-detections or inaccurate detections in previous searches. A strong chopping signal, a shorter period sinusoid in the TTVs, allows us to break the mass-eccentricity degeneracy and uniquely determine the masses of the inner, middle, and outer planets to be M = 7.3 ± 6.8 M {sub ⊕}, 4.0 ± 0.9M {sub ⊕}, and M = 132 ± 17 M {sub ⊕}, which we designate PH3 b, c, and d, respectively. Furthermore, the middle planet, PH3 c, has a relatively low density, ρ = 1.2 ± 0.3 g cm{sup –3} for a planet of its mass, requiring a substantial H/He atmosphere of 2.1{sub −0.3}{sup +0.8}% by mass, and joins a growing population of low-mass, low-density planets.« less

Passing NASA's Planet Quest Baton from Kepler to TESS

NASA Astrophysics Data System (ADS)

Jenkins, J.

Kepler vaulted into the heavens on March 7, 2009, initiating NASAs search for Earth- size planets orbiting Sun-like stars in the habitable zone, where liquid water could exist on a rocky planetary surface. In the 4 years since Kepler began science operations, a flood of photometric data on upwards of 190,000 stars of unprecedented precision and continuity has provoked a watershed of 134+ confirmed or validated planets, 3200+ planetary candidates (most sub-Neptune in size and many compara- ble to or smaller than Earth), and a resounding revolution in asteroseismology and astrophysics. The most recent discoveries include Kepler-62 with 5 planets total of which 2 are in the habitable zone with radii of 1.4 and 1.7 Re. The focus of the mission is shifting towards how to rapidly vet the 18,000+ threshold crossing events produced with each transiting planet search, and towards those studies that will allow us to understand what the data are saying about the prevalence of planets in the solar neighborhood and throughout the galaxy. This talk will provide an overview of the science results from the Kepler Mission and the work ahead to derive the frequency of Earth-size planets in the habitable zone of solar-like stars from the treasure trove of Kepler data. NASAs quest for exoplanets continues with the Transiting Exoplanet Survey Satel- lite (TESS) mission, slated for launch in May 2017 by NASAs Explorer Program. TESS will conduct an all-sky transit survey to identify the 1000 best small exoplanets in the solar neighborhood for follow up observations and characterization. TESSs targets will include all F, G, K dwarfs from +4 to +12 magnitude and all M dwarfs known within ˜200 light-years. 500,000 target stars will be observed over two years with ˜500 square degrees observed continuously for a year in each hemisphere in the James Webb Space Telescopes continuously viewable zones. Since the typical TESS target star is 5 magnitudes brighter than Kepler’s and 10 times

Advances in the Kepler Transit Search Engine and Automated Approaches to Identifying Likely Planet Candidates in Transit Surveys

NASA Astrophysics Data System (ADS)

Jenkins, Jon Michael

2015-08-01

Twenty years ago, no planets were known outside our own solar system. Since then, the discoveries of ~1500 exoplanets have radically altered our views of planets and planetary systems. This revolution is due in no small part to the Kepler Mission, which has discovered >1000 of these planets and >4000 planet candidates. While Kepler has shown that small rocky planets and planetary systems are quite common, the quest to find Earth’s closest cousins and characterize their atmospheres presses forward with missions such as NASA Explorer Program’s Transiting Exoplanet Survey Satellite (TESS) slated for launch in 2017 and ESA’s PLATO mission scheduled for launch in 2024.These future missions pose daunting data processing challenges in terms of the number of stars, the amount of data, and the difficulties in detecting weak signatures of transiting small planets against a roaring background. These complications include instrument noise and systematic effects as well as the intrinsic stellar variability of the subjects under scrutiny. In this paper we review recent developments in the Kepler transit search pipeline improving both the yield and reliability of detected transit signatures.Many of the phenomena in light curves that represent noise can also trigger transit detection algorithms. The Kepler Mission has expended great effort in suppressing false positives from its planetary candidate catalogs. While over 18,000 transit-like signatures can be identified for a search across 4 years of data, most of these signatures are artifacts, not planets. Vetting all such signatures historically takes several months’ effort by many individuals. We describe the application of machine learning approaches for the automated vetting and production of planet candidate catalogs. These algorithms can improve the efficiency of the human vetting effort as well as quantifying the likelihood that each candidate is truly a planet. This information is crucial for obtaining valid planet

Kepler's Final Survey Catalog

NASA Astrophysics Data System (ADS)

Mullally, S. E.

2017-12-01

The Kepler mission was designed to detect transiting exoplanets and has succeeded in finding over 4000 candidates. These candidates include approximately 50 terrestrial-sized worlds near to the habitable zone of their GKM dwarf stars (shown in figure against the stellar temperature). However not all transit detections are created equal. False positives, such as background eclipsing binaries, can mimic the signal of a transiting planet. Additionally, at Kepler's detection limit noise, either from the star or from the detector, can create signals that also mimic a transiting planet. For the data release 25 Kepler catalog we simulated these false alarms and determined how often known false alarms are called candidates. When this reliability information is combined with our studies of catalog completeness, this catalog can be used to understand the occurrence rate of exoplanets, even for the small, temperate planet candidates found by Kepler. I will discuss the automated methods we used to create and characterize this latest catalog, highlighting how we balanced the completeness and reliability of the long period candidates. While Kepler has been very successful at detecting transiting terrestrial-sized exoplanets, many of these detections are around stars that are too dim for successful follow-up work. Future missions will pick up where Kepler left off and find small planets around some of the brightest and smallest stars.

Orbital alignment of circumbinary planets that form in misaligned circumbinary discs: the case of Kepler-413b

NASA Astrophysics Data System (ADS)

Pierens, A.; Nelson, R. P.

2018-06-01

Although most of the circumbinary planets detected by the Kepler spacecraft are on orbits that are closely aligned with the binary orbital plane, the systems Kepler-413 and Kepler-453 exhibit small misalignments of ˜2.5°. One possibility is that these planets formed in a circumbinary disc whose midplane was inclined relative to the binary orbital plane. Such a configuration is expected to lead to a warped and twisted disc, and our aim is to examine the inclination evolution of planets embedded in these discs. We employed 3D hydrodynamical simulations that examine the disc response to the presence of a modestly inclined binary with parameters that match the Kepler-413 system, as a function of disc parameters and binary inclinations. The discs all develop slowly varying warps, and generally display very small amounts of twist. Very slow solid body precession occurs because a large outer disc radius is adopted. Simulations of planets embedded in these discs resulted in the planet aligning with the binary orbit plane for disc masses close to the minimum mass solar nebular, such that nodal precession of the planet was controlled by the binary. For higher disc masses, the planet maintains near coplanarity with the local disc midplane. Our results suggest that circumbinary planets born in tilted circumbinary discs should align with the binary orbit plane as the disc ages and loses mass, even if the circumbinary disc remains misaligned from the binary orbit. This result has important implications for understanding the origins of the known circumbinary planets.

The Kepler-10 planetary system revisited by HARPS-N: A hot rocky world and a solid Neptune-mass planet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dumusque, Xavier; Buchhave, Lars A.; Latham, David W.

Kepler-10b was the first rocky planet detected by the Kepler satellite and confirmed with radial velocity follow-up observations from Keck-HIRES. The mass of the planet was measured with a precision of around 30%, which was insufficient to constrain models of its internal structure and composition in detail. In addition to Kepler-10b, a second planet transiting the same star with a period of 45 days was statistically validated, but the radial velocities were only good enough to set an upper limit of 20 M{sub ⊕} for the mass of Kepler-10c. To improve the precision on the mass for planet b, themore » HARPS-N Collaboration decided to observe Kepler-10 intensively with the HARPS-N spectrograph on the Telescopio Nazionale Galileo on La Palma. In total, 148 high-quality radial-velocity measurements were obtained over two observing seasons. These new data allow us to improve the precision of the mass determination for Kepler-10b to 15%. With a mass of 3.33 ± 0.49 M{sub ⊕} and an updated radius of 1.47{sub −0.02}{sup +0.03} R{sub ⊕}, Kepler-10b has a density of 5.8 ± 0.8 g cm{sup –3}, very close to the value predicted by models with the same internal structure and composition as the Earth. We were also able to determine a mass for the 45-day period planet Kepler-10c, with an even better precision of 11%. With a mass of 17.2 ± 1.9 M{sub ⊕} and radius of 2.35{sub −0.04}{sup +0.09} R{sub ⊕}, Kepler-10c has a density of 7.1 ± 1.0 g cm{sup –3}. Kepler-10c appears to be the first strong evidence of a class of more massive solid planets with longer orbital periods.« less

Kepler Mission: A Search for Habitable Planets

NASA Technical Reports Server (NTRS)

Koch, David; Fonda, Mark (Technical Monitor)

2002-01-01

The Kepler Mission was selected by NASA as one of the next two Discovery Missions. The mission design is based on the search for Earth-size planets in the habitable zone of solar-like stars, but does not preclude the discovery of larger or smaller planets in other orbits of non-solar-like stars. An overview of the mission, the scientific goals and the anticipated results will be presented.

Kepler-432: A Red Giant Interacting with One of its Two Long-period Giant Planets

NASA Astrophysics Data System (ADS)

Quinn, Samuel N.; White, Timothy. R.; Latham, David W.; Chaplin, William J.; Handberg, Rasmus; Huber, Daniel; Kipping, David M.; Payne, Matthew J.; Jiang, Chen; Silva Aguirre, Victor; Stello, Dennis; Sliski, David H.; Ciardi, David R.; Buchhave, Lars A.; Bedding, Timothy R.; Davies, Guy R.; Hekker, Saskia; Kjeldsen, Hans; Kuszlewicz, James S.; Everett, Mark E.; Howell, Steve B.; Basu, Sarbani; Campante, Tiago L.; Christensen-Dalsgaard, Jørgen; Elsworth, Yvonne P.; Karoff, Christoffer; Kawaler, Steven D.; Lund, Mikkel N.; Lundkvist, Mia; Esquerdo, Gilbert A.; Calkins, Michael L.; Berlind, Perry

2015-04-01

We report the discovery of Kepler-432b, a giant planet ({{M}b}=5.41-0.18+0.32 {{M}Jup}, {{R}b}=1.145-0.039+0.036 {{R}Jup}) transiting an evolved star ({{M}\\star }=1.32-0.07+0.10 {{M}⊙ },{{R}\\star }=4.06-0.08+0.12 {{R}⊙ }) with an orbital period of {{P}b}=52.501129-0.000053+0.000067 days. Radial velocities (RVs) reveal that Kepler-432b orbits its parent star with an eccentricity of e=0.5134-0.0089+0.0098, which we also measure independently with asterodensity profiling (AP; e=0.507-0.114+0.039), thereby confirming the validity of AP on this particular evolved star. The well-determined planetary properties and unusually large mass also make this planet an important benchmark for theoretical models of super-Jupiter formation. Long-term RV monitoring detected the presence of a non-transiting outer planet (Kepler-432c; {{M}c}sin {{i}c}=2.43-0.24+0.22 {{M}Jup}, {{P}c}=406.2-2.5+3.9 days), and adaptive optics imaging revealed a nearby (0\\buildrel{\\prime\\prime}\\over{.} 87), faint companion (Kepler-432B) that is a physically bound M dwarf. The host star exhibits high signal-to-noise ratio asteroseismic oscillations, which enable precise measurements of the stellar mass, radius, and age. Analysis of the rotational splitting of the oscillation modes additionally reveals the stellar spin axis to be nearly edge-on, which suggests that the stellar spin is likely well aligned with the orbit of the transiting planet. Despite its long period, the obliquity of the 52.5 day orbit may have been shaped by star-planet interaction in a manner similar to hot Jupiter systems, and we present observational and theoretical evidence to support this scenario. Finally, as a short-period outlier among giant planets orbiting giant stars, study of Kepler-432b may help explain the distribution of massive planets orbiting giant stars interior to 1 AU.

Validation and Initial Characterization of the Long-period Planet Kepler-1654 b

NASA Astrophysics Data System (ADS)

Beichman, C. A.; Giles, H. A. C.; Akeson, R.; Ciardi, D.; Christiansen, J.; Isaacson, H.; Marcy, G. M.; Sinukoff, E.; Greene, T.; Fortney, J. J.; Crossfield, I.; Hu, R.; Howard, A. W.; Petigura, E. A.; Knutson, H. A.

2018-04-01

Fewer than 20 transiting Kepler planets have periods longer than one year. Our early search of the Kepler light curves revealed one such system, Kepler-1654b (originally KIC 8410697b), which shows exactly two transit events and whose second transit occurred only five days before the failure of the second of two reaction wheels brought the primary Kepler mission to an end. A number of authors have also examined light curves from the Kepler mission searching for long-period planets and identified this candidate. Starting in 2014 September, we began an observational program of imaging, reconnaissance spectroscopy, and precision radial velocity (RV) measurements that confirm with a high degree of confidence that Kepler-1654b is a bona fide transiting planet orbiting a mature G5V star (T eff = 5580 K, [Fe/H] = ‑0.08) with a semimajor axis of 2.03 au, a period of 1047.84 days, and a radius of 0.82 ± 0.02 R Jup. RV measurements using Keck’s HIRES spectrometer obtained over 2.5 years set a limit to the planet’s mass of <0.5 (3σ) M Jup. The bulk density of the planet is similar to that of Saturn or possibly lower. We assess the suitability of temperate gas giants like Kepler-1654b for transit spectroscopy with the James Webb Space Telescope, as their relatively cold equilibrium temperatures (T pl ∼ 200 K) make them interesting from the standpoint of exoplanet atmospheric physics. Unfortunately, these low temperatures also make the atmospheric scale heights small and thus transmission spectroscopy challenging. Finally, the long time between transits can make scheduling JWST observations difficult—as is the case with Kepler-1654b.

DENSITY AND ECCENTRICITY OF KEPLER PLANETS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu Yanqin; Lithwick, Yoram

2013-07-20

We analyze the transit timing variations (TTV) obtained by the Kepler mission for 22 sub-Jovian planet pairs (19 published, 3 new) that lie close to mean motion resonances. We find that the TTV phases for most of these pairs lie close to zero, consistent with an eccentricity distribution that has a very low root-mean-squared value of e {approx} 0.01; but about a quarter of the pairs possess much higher eccentricities, up to e {approx} 0.1-0.4. For the low-eccentricity pairs, we are able to statistically remove the effect of eccentricity to obtain planet masses from TTV data. These masses, together withmore » those measured by radial velocity, yield a best-fit mass-radius relation M {approx} 3 M{sub Circled-Plus }(R/R{sub Circled-Plus }). This corresponds to a constant surface escape velocity of {approx}20 km s{sup -1}. We separate the planets into two distinct groups: ''mid-sized'' (those greater than 3 R{sub Circled-Plus }) and 'compact' (those smaller). All mid-sized planets are found to be less dense than water and therefore must contain extensive H/He envelopes that are comparable in mass to that of their cores. We argue that these planets have been significantly sculpted by photoevaporation. Surprisingly, mid-sized planets, a minority among Kepler candidates, are discovered exclusively around stars more massive than 0.8 M{sub Sun }. The compact planets, on the other hand, are often denser than water. Combining our density measurements with those from radial velocity studies, we find that hotter compact planets tend to be denser, with the hottest ones reaching rock density. Moreover, hotter planets tend to be smaller in size. These results can be explained if the compact planets are made of rocky cores overlaid with a small amount of hydrogen, {<=}1% in mass, with water contributing little to their masses or sizes. Photoevaporation has exposed bare rocky cores in cases of the hottest planets. Our conclusion that these planets are likely not water worlds

Kepler Planet Reliability Metrics: Astrophysical Positional Probabilities for Data Release 25

NASA Technical Reports Server (NTRS)

Bryson, Stephen T.; Morton, Timothy D.

2017-01-01

This document is very similar to KSCI-19092-003, Planet Reliability Metrics: Astrophysical Positional Probabilities, which describes the previous release of the astrophysical positional probabilities for Data Release 24. The important changes for Data Release 25 are:1. The computation of the astrophysical positional probabilities uses the Data Release 25 processed pixel data for all Kepler Objects of Interest.2. Computed probabilities now have associated uncertainties, whose computation is described in x4.1.3.3. The scene modeling described in x4.1.2 uses background stars detected via ground-based high-resolution imaging, described in x5.1, that are not in the Kepler Input Catalog or UKIRT catalog. These newly detected stars are presented in Appendix B. Otherwise the text describing the algorithms and examples is largely unchanged from KSCI-19092-003.

Systems engingeering for the Kepler Mission : a search for terrestrial planets

NASA Technical Reports Server (NTRS)

Duren, Riley M.; Dragon, Karen; Gunter, Steve Z.; Gautier, Nick; Koch, Dave; Harvey, Adam; Enos, Alan; Borucki, Bill; Sobeck, Charlie; Mayer, Dave;

Leveraging the power of a planet population: Mass-radius relation, host star multiplicity, and composition distribution of Kepler's sub-Neptunes

NASA Astrophysics Data System (ADS)

Wolfgang, Angie K.

With the advent of large, dedicated planet hunting surveys, the search for extrasolar planets has evolved into an effort to understand the properties and formation of a planet population whose characteristics continue to surprise the provincial perspective we've derived from our own Solar System. The Kepler Mission in particular has enabled a large number of these studies, as it was designed to stare simultaneously at thousands of stars for several years and its automated transit search pipeline enables fairly uniform detection criteria and characterizable completeness and false positive rates. With the detection of nearly 5000 planet candidates, 80% of which are smaller than 4 REarth, Kepler has especially illuminated the unexpectedly vast sub-Neptune population. Such a rich dataset provides an unprecedented opportunity for rigorous statistical study of the physics of these planets that have no analogs in our Solar System. Contributing to this endeavor, I present the statistical characterization of several aspects of this population, including the comparison between Kepler's planet candidates and low-mass occurrence rates inferred from radial velocity detections, the relationship between a sub-Neptune's mass and its radius, the frequency of Kepler planet candidate host stars which have nearby visual companions as revealed by follow-up high resolution imaging, and the distribution of gaseous mass fractions that these sub-Neptunes could possess given a rock-plus-hydrogen composition. To do so, I have used sophisticated statistical analyses such as Monte Carlo simulations and hierarchical Bayesian modeling to tie theory more closely to observations and have acquired near infrared laser guide star adaptive optics imaging of 196 Kepler Objects of Interest. I find that even within this sub-Neptune population these planets are very diverse in nature: there is intrinsic scatter in masses at a given radius, the planet host stars have visual companions at a wide range of

A Catalog of Transit Timing Posterior Distributions for all Kepler Planet Candidate Events

NASA Astrophysics Data System (ADS)

Montet, Benjamin Tyler; Becker, Juliette C.; Johnson, John

2015-08-01

Kepler has ushered in a new era of planetary dynamics, enabling the detection of interactions between multiple planets in transiting systems for hundreds of systems. These interactions, observed as transit timing variations (TTVs), have been used to find non-transiting companions to transiting systems and to measure masses, eccentricities, and inclinations of transiting planets. Often, physical parameters are inferred by comparing the observed light curve to the result of a photodynamical model, a time-intensive process that often ignores the effects of correlated noise in the light curve. Catalogs of transit timing observations have previously neglected non-Gaussian uncertainties in the times of transit, uncertainties in the transit shape, and short cadence data. Here, we present a catalog of not only times of transit centers, but also posterior distributions on the time of transit for every planet candidate transit event in the Kepler data, developed through importance sampling of each transit. This catalog allows us to marginalize over uncertainties in the transit shape and incorporate short cadence data, the effects of correlated noise, and non-Gaussian posteriors. Our catalog will enable dynamical studies that reflect accurately the precision of Kepler and its limitations without requiring the computational power to model the light curve completely with every integration.

Kepler: NASA's First Mission Capable of Finding Earth-Size Planets

NASA Technical Reports Server (NTRS)

Borucki, William J.

2009-01-01

Kepler, a NASA Discovery mission, is a spaceborne telescope designed to search a nearby region of our galaxy for Earth-size planets orbiting in the habitable zone of stars like our sun. The habitable zone is that region around a start where the temperature permits water to be liquid on the surface of a planet. Liquid water is considered essential forth existence of life. Mission Phases: Six mission phases have been defined to describe the different periods of activity during Kepler's mission. These are: launch; commissioning; early science operations, science operations: and decommissioning

The Dynamics of Tightly-packed Planetary Systems in the Presence of an Outer Planet: Case Studies Using Kepler-11 and Kepler-90

NASA Astrophysics Data System (ADS)

Granados Contreras, A. P.; Boley, A. C.

2018-03-01

We explore the effects of an undetected outer giant planet on the dynamics, observability, and stability of Systems with Tightly-packed Inner Planets (STIPs). We use direct numerical simulations along with secular theory and synthetic secular frequency spectra to analyze how analogues of Kepler-11 and Kepler-90 behave in the presence of a nearly co-planar, Jupiter-like outer perturber with semimajor axes between 1 and 5.2 au. Most locations of the outer perturber do not affect the evolution of the inner planetary systems, apart from altering precession frequencies. However, there are locations at which an outer planet causes system instability due to, in part, secular eccentricity resonances. In Kepler-90, there is a range of orbital distances for which the outer perturber drives planets b and c, through secular interactions, onto orbits with inclinations that are ∼16° away from the rest of the planets. Kepler-90 is stable in this configuration. Such secular resonances can thus affect the observed multiplicity of transiting systems. We also compare the synthetic apsidal and nodal precession frequencies with the secular theory and find some misalignment between principal frequencies, indicative of strong interactions between the planets (consistent with the system showing TTVs). First-order libration angles are calculated to identify MMRs in the systems, for which two near-MMRs are shown in Kepler-90, with a 5:4 between b and c, as well as a 3:2 between g and h.

ARE THE KEPLER NEAR-RESONANCE PLANET PAIRS DUE TO TIDAL DISSIPATION?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Man Hoi; Fabrycky, D.; Lin, D. N. C., E-mail: mhlee@hku.hk, E-mail: daniel.fabrycky@gmail.com, E-mail: lin@ucolick.org

The multiple-planet systems discovered by the Kepler mission show an excess of planet pairs with period ratios just wide of exact commensurability for first-order resonances like 2:1 and 3:2. In principle, these planet pairs could have both resonance angles associated with the resonance librating if the orbital eccentricities are sufficiently small, because the width of first-order resonances diverges in the limit of vanishingly small eccentricity. We consider a widely held scenario in which pairs of planets were captured into first-order resonances by migration due to planet-disk interactions, and subsequently became detached from the resonances, due to tidal dissipation in themore » planets. In the context of this scenario, we find a constraint on the ratio of the planet's tidal dissipation function and Love number that implies that some of the Kepler planets are likely solid. However, tides are not strong enough to move many of the planet pairs to the observed separations, suggesting that additional dissipative processes are at play.« less

Kepler-423b: a half-Jupiter mass planet transiting a very old solar-like star

NASA Astrophysics Data System (ADS)

Gandolfi, D.; Parviainen, H.; Deeg, H. J.; Lanza, A. F.; Fridlund, M.; Prada Moroni, P. G.; Alonso, R.; Augusteijn, T.; Cabrera, J.; Evans, T.; Geier, S.; Hatzes, A. P.; Holczer, T.; Hoyer, S.; Kangas, T.; Mazeh, T.; Pagano, I.; Tal-Or, L.; Tingley, B.

2015-04-01

We report the spectroscopic confirmation of the Kepler object of interest KOI-183.01 (Kepler-423b), a half-Jupiter mass planet transiting an old solar-like star every 2.7 days. Our analysis is the first to combine the full Kepler photometry (quarters 1-17) with high-precision radial velocity measurements taken with the FIES spectrograph at the Nordic Optical Telescope. We simultaneously modelled the photometric and spectroscopic data-sets using Bayesian approach coupled with Markov chain Monte Carlo sampling. We found that the Kepler pre-search data conditioned light curve of Kepler-423 exhibits quarter-to-quarter systematic variations of the transit depth, with a peak-to-peak amplitude of ~4.3% and seasonal trends reoccurring every four quarters. We attributed these systematics to an incorrect assessment of the quarterly variation of the crowding metric. The host star Kepler-423 is a G4 dwarf with M⋆ = 0.85 ± 0.04 M⊙, R⋆ = 0.95 ± 0.04 R⊙, Teff= 5560 ± 80 K, [M/H] = - 0.10 ± 0.05 dex, and with an age of 11 ± 2 Gyr. The planet Kepler-423b has a mass of Mp= 0.595 ± 0.081MJup and a radius of Rp= 1.192 ± 0.052RJup, yielding a planetary bulk density of ρp = 0.459 ± 0.083 g cm-3. The radius of Kepler-423b is consistent with both theoretical models for irradiated coreless giant planets and expectations based on empirical laws. The inclination of the stellar spin axis suggests that the system is aligned along the line of sight. We detected a tentative secondary eclipse of the planet at a 2σ confidence level (ΔFec = 14.2 ± 6.6 ppm) and found that the orbit might have asmall non-zero eccentricity of 0.019+0.028-0.014. With a Bond albedo of AB = 0.037 ± 0.019, Kepler-423b is one of the gas-giant planets with the lowest albedo known so far. Based on observations obtained with the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of

The California- Kepler Survey. II. Precise Physical Properties of 2025 Kepler Planets and Their Host Stars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, John Asher; Cargile, Phillip A.; Sinukoff, Evan

We present stellar and planetary properties for 1305 Kepler Objects of Interest hosting 2025 planet candidates observed as part of the California- Kepler Survey. We combine spectroscopic constraints, presented in Paper I, with stellar interior modeling to estimate stellar masses, radii, and ages. Stellar radii are typically constrained to 11%, compared to 40% when only photometric constraints are used. Stellar masses are constrained to 4%, and ages are constrained to 30%. We verify the integrity of the stellar parameters through comparisons with asteroseismic studies and Gaia parallaxes. We also recompute planetary radii for 2025 planet candidates. Because knowledge of planetarymore » radii is often limited by uncertainties in stellar size, we improve the uncertainties in planet radii from typically 42% to 12%. We also leverage improved knowledge of stellar effective temperature to recompute incident stellar fluxes for the planets, now precise to 21%, compared to a factor of two when derived from photometry.« less

Motions of Kepler circumbinary planets in restricted three-body problem under radiating primaries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dermawan, B., E-mail: budider@as.itb.ac.id; Hidayat, T., E-mail: taufiq@as.itb.ac.id; Huda, I. N., E-mail: ibnu.nurul@students.itb.ac.id

2015-09-30

By observing continuously a single field of view in the sky, Kepler mission reveals outstanding results on discoveries of exoplanets. One of its recent progress is the discoveries of circumbinary planets. A circumbinary planet is an exoplanet that moves around a binary system. In this study we investigate motions of Kepler circumbinary planets belong to six binary systems, namely Kepler-16, -34, -35, -38, -47, and -413. The motions are considered to follow the Restricted Three-Body Problem (RTBP). Because the primaries (central massive objects) are stars, they are both radiatives, while the planet is an infinitesimal object. The primaries move inmore » nearly circular and elliptic orbits with respect to their center of masses. We describe, in general, motions of the circumbinary planets in RTBP under radiating primaries. With respect to the averaged zero velocity curves, we show that motions of the exoplanets are stable, in accordance with their Hill stabilities.« less

A 1.9 Earth Radius Rocky Planet and the Discovery of a Non-transiting Planet in the Kepler-20 System

NASA Astrophysics Data System (ADS)

Buchhave, Lars A.; Dressing, Courtney D.; Dumusque, Xavier; Rice, Ken; Vanderburg, Andrew; Mortier, Annelies; Lopez-Morales, Mercedes; Lopez, Eric; Lundkvist, Mia S.; Kjeldsen, Hans; Affer, Laura; Bonomo, Aldo S.; Charbonneau, David; Collier Cameron, Andrew; Cosentino, Rosario; Figueira, Pedro; Fiorenzano, Aldo F. M.; Harutyunyan, Avet; Haywood, Raphaëlle D.; Johnson, John Asher; Latham, David W.; Lovis, Christophe; Malavolta, Luca; Mayor, Michel; Micela, Giusi; Molinari, Emilio; Motalebi, Fatemeh; Nascimbeni, Valerio; Pepe, Francesco; Phillips, David F.; Piotto, Giampaolo; Pollacco, Don; Queloz, Didier; Sasselov, Dimitar; Ségransan, Damien; Sozzetti, Alessandro; Udry, Stéphane; Watson, Chris

2016-12-01

Kepler-20 is a solar-type star (V = 12.5) hosting a compact system of five transiting planets, all packed within the orbital distance of Mercury in our own solar system. A transition from rocky to gaseous planets with a planetary transition radius of ˜1.6 {R}\\oplus has recently been proposed by several articles in the literature. Kepler-20b ({R}p ˜ 1.9 {R}\\oplus ) has a size beyond this transition radius; however, previous mass measurements were not sufficiently precise to allow definite conclusions to be drawn regarding its composition. We present new mass measurements of three of the planets in the Kepler-20 system that are facilitated by 104 radial velocity measurements from the HARPS-N spectrograph and 30 archival Keck/HIRES observations, as well as an updated photometric analysis of the Kepler data and an asteroseismic analysis of the host star ({M}\\star = 0.948+/- 0.051 {M}⊙ and {R}\\star = 0.964+/- 0.018 {R}⊙ ). Kepler-20b is a {1.868}-0.034+0.066 {R}\\oplus planet in a 3.7 day period with a mass of {9.70}-1.44+1.41 {M}\\oplus , resulting in a mean density of {8.2}-1.3+1.5 {{g}} {{cm}}-3, indicating a rocky composition with an iron-to-silicate ratio consistent with that of the Earth. This makes Kepler-20b the most massive planet with a rocky composition found to date. Furthermore, we report the discovery of an additional non-transiting planet with a minimum mass of {19.96}-3.61+3.08 {M}\\oplus and an orbital period of ˜34 days in the gap between Kepler-20f (P ˜ 11 days) and Kepler-20d (P ˜ 78 days). Based on observations made with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Fundación Galileo Galilei of the INAF (Istituto Nazionale di Astrofísica) at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.

Know the Planet, Know the Star: Precise Stellar Parameters with Kepler

NASA Astrophysics Data System (ADS)

Sandford, Emily; Kipping, David M.

2017-01-01

The Kepler space telescope has revolutionized exoplanetary science with unprecedentedly precise photometric measurements of the light curves of transiting planets. In addition to information about the planet and its orbit, encoded in each Kepler transiting planet light curve are certain properties of the host star, including the stellar density and the limb darkening profile. For planets with strong prior constraints on orbital eccentricity (planets to which we refer as “stellar anchors”), we may measure these stellar properties directly from the light curve. This method promises to aid greatly in the characterization of transiting planet host stars targeted by the upcoming NASA TESS mission and any long-period, singly-transiting planets discovered in the same systems. Using Bayesian inference, we fit a transit model, including a nonlinear limb darkening law, to a large sample of transiting planet hosts to measure their stellar properties. We present the results of our analysis, including posterior stellar density distributions for each stellar host, and show how the method yields superior precision to literature stellar properties in the majority of cases studied.

Kepler Small Habitable Zone Planets

NASA Image and Video Library

2015-07-23

Of the 1,030 confirmed planets from Kepler, a dozen are less than twice the size of Earth and reside in the habitable zone of their host stars. In this diagram, the sizes of the exoplanets are represented by the size of each sphere. These are arranged by size from left to right, and by the type of star they orbit, from the M stars that are significantly cooler and smaller than the sun, to the K stars that are somewhat cooler and smaller than the sun, to the G stars that include the sun. The sizes of the planets are enlarged by 25 times compared to the stars. The Earth is shown for reference. http://photojournal.jpl.nasa.gov/catalog/PIA19827

Identifying Young Kepler Planet Host Stars from Keck–HIRES Spectra of Lithium

NASA Astrophysics Data System (ADS)

Berger, Travis A.; Howard, Andrew W.; Boesgaard, Ann Merchant

2018-03-01

The lithium doublet at 6708 Å provides an age diagnostic for main sequence FGK dwarfs. We measured the abundance of lithium in 1305 stars with detected transiting planets from the Kepler mission using high-resolution spectroscopy. Our catalog of lithium measurements from this sample has a range of abundance from A(Li) = 3.11 ± 0.07 to an upper limit of ‑0.84 dex. For a magnitude-limited sample that comprises 960 of the 1305 stars, our Keck–HIRES spectra have a median signal-to-noise ratio of 45 per pixel at ∼6700 Å with spectral resolution \\tfrac{λ }{{{Δ }}λ } = R = 55,000. We identify 80 young stars that have A(Li) values greater than the Hyades at their respective effective temperatures; these stars are younger than ∼650 Myr, the approximate age of the Hyades. We then compare the distribution of A(Li) with planet size, multiplicity, orbital period, and insolation flux. We find larger planets preferentially in younger systems, with an A–D two-sided test p-value = 0.002, a > 3σ confidence that the older and younger planet samples do not come from the same parent distribution. This is consistent with planet inflation/photoevaporation at early ages. The other planet parameters (Kepler planet multiplicity, orbital period, and insolation flux) are uncorrelated with age. Based on observations obtained at the W. M. Keck Observatory, which is operated jointly by the University of California and the California Institute of Technology. Keck time has been granted by the University of Hawaii, the University of California, and Caltech.

A Planet Detection Tutorial and Simulator

NASA Technical Reports Server (NTRS)

Knoch, David; DeVincenzi, Donald (Technical Monitor)

2001-01-01

Detection of extra-solar planets has been a very popular topic with the general public for years. Considerable media coverage of recent detections (currently at about 50) has only heightened the interest in the topic. School children are particularly interested in learning about recent astronomical discoveries. Scientists have the knowledge and responsibility to present this information in both an understandable and interesting format. Most classrooms and homes are now connected to the internet, which can be utilized to provide more than a traditional 'flat' presentation. An interactive software package on planet detection has been developed. The major topics include: "1996 - The Break Through Year In Planet Detection"; "What Determines If A Planet Is Habitable?"; "How Can We Find Other Planets (Search Methods)"; "All About the Kepler Mission: How To Find Terrestrial Planets"; and "A Planet Detection Simulator". Using the simulator, the student records simulated observations and then analyzes and interprets the data within the program. One can determine the orbit and planet size, the planet's temperature and surface gravity, and finally determine if the planet is habitable. Originally developed for the Macintosh, a web based browser version is being developed.

VizieR Online Data Catalog: Detection of 715 Kepler planet candidates host stars (Law+, 2014)

NASA Astrophysics Data System (ADS)

Law, N. M.; Morton, T.; Baranec, C.; Riddle, R.; Ravichandran, G.; Ziegler, C.; Johnson, J. A.; Tendulkar, S. P.; Bui, K.; Burse, M. P.; Das, H. K.; Dekany, R. G.; Kulkarni, S.; Punnadi, S.; Ramaprakash, A. N.

2017-03-01

We selected targets from the KOIs catalog based on a Q1-Q6 Kepler data search (Batalha et al. 2013, J/ApJS/204/24). Our initial targets were selected randomly from the Q1-Q6 KOIs, requiring only that the targets are brighter than mi = 16.0, a restriction which removed only 2% of the KOIs. While it is our intent to observe every KOI with Robo-AO, this initial target selection provides a wide coverage of the range of KOI properties. Given Robo-AO's low time overheads, we took the time to re-observe KOIs which already had detected companions, to produce a complete and homogenous survey. We obtained high-angular-resolution images of the 715 Kepler targeted planet candidate host stars in summer 2012. We performed all the observations in a queue-scheduled mode with the Robo-AO laser adaptive optics system (Baranec et al. 2012SPIE.8447E..04B; 2013, J. Visualized Exp., 72, e50021; Riddle et al. 2012SPIE.8447E..2OR) mounted on the robotic Palomar 60 inch telescope (Cenko et al. 2006PASP..118.1396C). (4 data files).

NASA's Kepler Mission Discovers Multiple Planets Orbiting Twin Suns (Reporter Pkg)

NASA Image and Video Library

2012-08-28

NASA's Kepler mission has discovered the first transiting circumbinary system -- multiple planets orbiting two suns -- 4,900 light-years from Earth, in the constellation Cygnus, proving that more than one planets can form and survive in orbit around a binary star.

An independent planet search in the Kepler dataset. I. One hundred new candidates and revised Kepler objects of interest

NASA Astrophysics Data System (ADS)

Ofir, A.; Dreizler, S.

2013-07-01

Aims: We present first results of our efforts to re-analyze the Kepler photometric dataset, searching for planetary transits using an alternative processing pipeline to the one used by the Kepler mission Methods: The SARS pipeline was tried and tested extensively by processing all available CoRoT mission data. For this first paper of the series we used this pipeline to search for (additional) planetary transits only in a small subset of stars - the Kepler objects of interest (KOIs), which are already known to include at least one promising planet candidate. Results: Although less than 1% of the Kepler dataset are KOIs we are able to significantly update the overall statistics of planetary multiplicity: we find 84 new transit signals on 64 systems on these light curves (LCs) only, nearly doubling the number of transit signals in these systems. Forty-one of the systems were singly-transiting systems that are now multiply-transiting. This significantly reduces the chances of false positive in them. Notable among the new discoveries are KOI 435 as a new six-candidate system (of which kind only Kepler-11 was known before), KOI 277 (which includes two candidates in a 6:7 period commensurability that has anti-correlated transit timing variations) - all but validating the system, KOIs 719, 1574, and 1871 that have small planet candidates (1.15,2.05 and 1.71 R⊕) in the habitable zone of their host star, and KOI 1843 that exhibits the shortest period (4.25 h) and is among the smallest (0.63 R⊕) of all planet candidates. We are also able to reject 11 KOIs as eclipsing binaries based on photometry alone, update the ephemeris for five KOIs and otherwise discuss a number of other objects, which brings the total of new signals and revised KOIs in this study to more than one hundred. Interestingly, a large fraction, about ~1/3, of the newly detected candidates participate in period commensurabilities. Finally, we discuss the possible overestimation of parameter errors in the

NASA's Kepler Mission Discovers First Earth-size Planet in Habitable Zone of Another Star (Reporter Package)

NASA Image and Video Library

2014-04-17

NASA's Kepler mission has discovered the first Earth-size planet orbiting in the habitable zone of a star outside our solar system. The newly discovered planet is called Kepler-186f and is about 10 percent larger than Earth.

Constraints on the Obliquities of Kepler Planet-hosting Stars

NASA Astrophysics Data System (ADS)

Winn, Joshua N.; Petigura, Erik A.; Morton, Timothy D.; Weiss, Lauren M.; Dai, Fei; Schlaufman, Kevin C.; Howard, Andrew W.; Isaacson, Howard; Marcy, Geoffrey W.; Justesen, Anders Bo; Albrecht, Simon

2017-12-01

Stars with hot Jupiters have obliquities ranging from 0° to 180°, but relatively little is known about the obliquities of stars with smaller planets. Using data from the California-Kepler Survey, we investigate the obliquities of stars with planets spanning a wide range of sizes, most of which are smaller than Neptune. First, we identify 156 planet hosts for which measurements of the projected rotation velocity (v\\sin i) and rotation period are both available. By combining estimates of v and v\\sin i, we find nearly all the stars to be compatible with high inclination, and hence, low obliquity (≲20°). Second, we focus on a sample of 159 hot stars ({T}{eff}> 6000 K) for which v\\sin i is available but not necessarily the rotation period. We find six stars for which v\\sin i is anomalously low, an indicator of high obliquity. Half of these have hot Jupiters, even though only 3% of the stars that were searched have hot Jupiters. We also compare the v\\sin i distribution of the hot stars with planets to that of 83 control stars selected without prior knowledge of planets. The mean v\\sin i of the control stars is lower than that of the planet hosts by a factor of approximately π /4, as one would expect if the planet hosts have low obliquities. All these findings suggest that the Kepler planet-hosting stars generally have low obliquities, with the exception of hot stars with hot Jupiters.

The Final Kepler Planet Candidate Catalog (DR25)

NASA Astrophysics Data System (ADS)

Coughlin, Jeffrey; Thompson, Susan E.; Kepler Team

2017-06-01

We present Kepler's final planet candidate catalog, which is based on the Q1--Q17 DR25 data release and was created to allow for accurate calculations of planetary occurrence rates. We discuss improvements made to our fully automated candidate vetting procedure, which yields specific categories of false positives and a disposition score value to indicate decision confidence. We present the use of light curve inversion and scrambling, in addition to our continued use of pixel-level transit injection, to produce artificial planet candidates and false positives. Since these simulated data sets were subjected to the same automated vetting procedure as the real data set, we are able to measure both the completeness and reliability of the catalog. The DR25 catalog, source code, and a multitude of completeness and reliability data products are available at the Exoplanet Archive (http://exoplanetarchive.ipac.caltech.edu). The DR25 light curves and pixel-level data are available at MAST (http://archive.stsci.edu/kepler).

Kepler Planets Tend to Have Siblings of the Same Size

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2017-11-01

After 8.5 years of observations with the Kepler space observatory, weve discovered a large number of close-in, tightly-spaced, multiple-planet systems orbiting distant stars. In the process, weve learned a lot about the properties about these systems and discovered some unexpected behavior. A new study explores one of the properties that has surprised us: planets of the same size tend to live together.Orbital architectures for 25 of the authors multiplanet systems. The dots are sized according to the planets relative radii and colored according to mass. Planets of similar sizes and masses tend to live together in the same system. [Millholland et al. 2017]Ordering of SystemsFrom Keplers observations of extrasolar multiplanet systems, we have seen that the sizes of planets in a given system arent completely random. Systems that contain a large planet, for example, are more likely to contain additional large planets rather than additional planets of random size. So though there is a large spread in the radii weve observed for transiting exoplanets, the spread within any given multiplanet system tends to be much smaller.This odd behavior has led us to ask whether this clustering occurs not just for radius, but also for mass. Since the multiplanet systems discovered by Kepler most often contain super-Earths and mini-Neptunes, which have an extremely large spread in densities, the fact that two such planets have similar radii does not guarantee that they have similar masses.If planets dont cluster in mass within a system, this would raise the question of why planets coordinate only their radii within a given system. If they do cluster in mass, it implies that planets within the same system tend to have similar densities, potentially allowing us to predict the sizes and masses of planets we might find in a given system.Insight into MassesLed by NSF graduate research fellow Sarah Millholland, a team of scientists at Yale University used recently determined masses for

Modeling Kepler Transit Light Curves as False Positives: Rejection of Blend Scenarios for Kepler-9, and Validation of Kepler-9 d, a Super-Earth-Size Planet in a Multiple System

NASA Technical Reports Server (NTRS)

Torres, Guillermo; Fressin, Francois; Batalha, Natalie M.; Borucki, William J.; Brown, Timothy M.; Bryson, Stephen T.; Buchhave, Lars A.; Charbonneau, David; Ciardi, David R.; Dunham, Edward W.;

Confirmation of an exoplanet using the transit color signature: Kepler-418b, a blended giant planet in a multiplanet system

NASA Astrophysics Data System (ADS)

Tingley, B.; Parviainen, H.; Gandolfi, D.; Deeg, H. J.; Palle, E.; Montañés Rodriguez, P.; Murgas, F.; Alonso, R.; Bruntt, H.; Fridlund, M.

2014-07-01

Aims: We announce confirmation of Kepler-418b, one of two proposed planets in this system. This is the first confirmation of an exoplanet based primarily on the transit color signature technique. Methods: We used the Kepler public data archive combined with multicolor photometry from the Gran Telescopio de Canarias and radial velocity follow-up using FIES at the Nordic Optical Telescope for confirmation. Results: We report a confident detection of a transit color signature that can only be explained by a compact occulting body, entirely ruling out a contaminating eclipsing binary, a hierarchical triple, or a grazing eclipsing binary. Those findings are corroborated by our radial velocity measurements, which put an upper limit of ~1 MJup on the mass of Kepler-418b. We also report that the host star is significantly blended, confirming the ~10% light contamination suspected from the crowding metric in the Kepler light curve measured by the Kepler team. We report detection of an unresolved light source that contributes an additional ~30% to the target star, which would not have been detected without multicolor photometric analysis. The resulting planet-star radius ratio is 0.110 ± 0.0025, more than 25% more than the 0.087 measured by Kepler leading to a radius of 1.20 ± 0.16 RJup instead of the 0.94 RJup measured by the Kepler team. Conclusions: This is the first confirmation of an exoplanet candidate based primarily on the transit color signature, demonstrating that this technique is viable from ground for giant planets. It is particularly useful for planets with long periods such as Kepler-418b, which tend to have long transit durations. While this technique is limited to candidates with deep transits from the ground, it may be possible to confirm earth-like exoplanet candidates with a few hours of observing time with an instrument like the James Webb Space Telescope. Additionally, multicolor photometric analysis of transits can reveal unknown stellar neighbors

BIRTH LOCATIONS OF THE KEPLER CIRCUMBINARY PLANETS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silsbee, Kedron; Rafikov, Roman R., E-mail: ksilsbee@astro.princeton.edu

2015-07-20

The Kepler mission has discovered about a dozen circumbinary planetary systems, all containing planets on ∼1 AU orbits. We place bounds on the locations in the circumbinary protoplanetary disk, where these planets could have formed through collisional agglomeration starting from small (kilometer-sized or less) planetesimals. We first present a model of secular planetesimal dynamics that accounts for the (1) perturbation due to the eccentric precessing binary, as well as the (2) gravity and (3) gas drag from a precessing eccentric disk. Their simultaneous action leads to rich dynamics, with (multiple) secular resonances emerging in the disk. We derive analytic resultsmore » for size-dependent planetesimal eccentricity and demonstrate the key role of the disk gravity for circumbinary dynamics. We then combine these results with a simple model for collisional outcomes and find that in systems like Kepler-16, planetesimal growth starting with 10–100 m planetesimals is possible outside a few AU. The exact location exterior to which this happens is sensitive to disk eccentricity, density, and precession rate, as well as to the size of the first generation of planetesimals. Strong perturbations from the binary in the inner part of the disk, combined with a secular resonance at a few AU, inhibit the growth of kilometer-sized planetesimals within 2–4 AU of the binary. In situ planetesimal growth in the Kepler circumbinary systems is possible only starting from large initial planetesimals (few-kilometer-sized even assuming favorable disk properties, i.e., low surface density)« less

Robo-AO Kepler Planetary Candidate Survey. III. Adaptive Optics Imaging of 1629 Kepler Exoplanet Candidate Host Stars

NASA Astrophysics Data System (ADS)

Ziegler, Carl; Law, Nicholas M.; Morton, Tim; Baranec, Christoph; Riddle, Reed; Atkinson, Dani; Baker, Anna; Roberts, Sarah; Ciardi, David R.

2017-02-01

The Robo-AO Kepler Planetary Candidate Survey is observing every Kepler planet candidate host star with laser adaptive optics imaging to search for blended nearby stars, which may be physically associated companions and/or responsible for transit false positives. In this paper, we present the results of our search for stars nearby 1629 Kepler planet candidate hosts. With survey sensitivity to objects as close as ˜0.″15, and magnitude differences Δm ≤slant 6, we find 223 stars in the vicinity of 206 target KOIs; 209 of these nearby stars have not been previously imaged in high resolution. We measure an overall nearby-star probability for Kepler planet candidates of 12.6 % +/- 0.9 % at separations between 0.″15 and 4.″0. Particularly interesting KOI systems are discussed, including 26 stars with detected companions that host rocky, habitable zone candidates and five new candidate planet-hosting quadruple star systems. We explore the broad correlations between planetary systems and stellar binarity, using the combined data set of Baranec et al. and this paper. Our previous 2σ result of a low detected nearby star fraction of KOIs hosting close-in giant planets is less apparent in this larger data set. We also find a significant correlation between detected nearby star fraction and KOI number, suggesting possible variation between early and late Kepler data releases.

THE MASS OF Kepler-93b AND THE COMPOSITION OF TERRESTRIAL PLANETS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dressing, Courtney D.; Charbonneau, David; Dumusque, Xavier

Kepler-93b is a 1.478 ± 0.019 R {sub ⊕} planet with a 4.7 day period around a bright (V = 10.2), astroseismically characterized host star with a mass of 0.911 ± 0.033 M {sub ☉} and a radius of 0.919 ± 0.011 R {sub ☉}. Based on 86 radial velocity observations obtained with the HARPS-N spectrograph on the Telescopio Nazionale Galileo and 32 archival Keck/HIRES observations, we present a precise mass estimate of 4.02 ± 0.68 M {sub ⊕}. The corresponding high density of 6.88 ± 1.18 g cm{sup –3} is consistent with a rocky composition of primarily iron andmore » magnesium silicate. We compare Kepler-93b to other dense planets with well-constrained parameters and find that between 1 and 6 M {sub ⊕}, all dense planets including the Earth and Venus are well-described by the same fixed ratio of iron to magnesium silicate. There are as of yet no examples of such planets with masses >6 M {sub ⊕}. All known planets in this mass regime have lower densities requiring significant fractions of volatiles or H/He gas. We also constrain the mass and period of the outer companion in the Kepler-93 system from the long-term radial velocity trend and archival adaptive optics images. As the sample of dense planets with well-constrained masses and radii continues to grow, we will be able to test whether the fixed compositional model found for the seven dense planets considered in this paper extends to the full population of 1-6 M {sub ⊕} planets.« less

A Catalog of Transit Timing Posterior Distributions for all Kepler Planet Candidate Transit Events

NASA Astrophysics Data System (ADS)

Montet, Benjamin Tyler; Becker, Juliette C.; Johnson, John Asher

2015-12-01

Kepler has ushered in a new era of planetary dynamics, enabling the detection of interactions between multiple planets in transiting systems for hundreds of systems. These interactions, observed as transit timing variations (TTVs), have been used to find non-transiting companions to transiting systems and to measure masses, eccentricities, and inclinations of transiting planets. Often, physical parameters are inferred by comparing the observed light curve to the result of a photodynamical model, a time-intensive process that often ignores the effects of correlated noise in the light curve. Catalogs of transit timing observations have previously neglected non-Gaussian uncertainties in the times of transit, uncertainties in the transit shape, and short cadence data. Here, I present a catalog of not only times of transit centers, but also posterior distributions on the time of transit for every planet candidate transit event in the Kepler data, developed through importance sampling of each transit. This catalog allows one to marginalize over uncertainties in the transit shape and incorporate short cadence data, the effects of correlated noise, and non-Gaussian posteriors. Our catalog will enable dynamical studies that reflect accurately the precision of Kepler and its limitations without requiring the computational power to model the light curve completely with every integration. I will also present our open-source N-body photodynamical modeling code, which integrates planetary and stellar orbits accounting for the effects of GR, tidal effects, and Doppler beaming.

VALIDATION OF 12 SMALL KEPLER TRANSITING PLANETS IN THE HABITABLE ZONE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Torres, Guillermo; Kipping, David M.; Fressin, Francois

We present an investigation of 12 candidate transiting planets from Kepler with orbital periods ranging from 34 to 207 days, selected from initial indications that they are small and potentially in the habitable zone (HZ) of their parent stars. Few of these objects are known. The expected Doppler signals are too small to confirm them by demonstrating that their masses are in the planetary regime. Here we verify their planetary nature by validating them statistically using the BLENDER technique, which simulates large numbers of false positives and compares the resulting light curves with the Kepler photometry. This analysis was supplemented withmore » new follow-up observations (high-resolution optical and near-infrared spectroscopy, adaptive optics imaging, and speckle interferometry), as well as an analysis of the flux centroids. For 11 of them (KOI-0571.05, 1422.04, 1422.05, 2529.02, 3255.01, 3284.01, 4005.01, 4087.01, 4622.01, 4742.01, and 4745.01) we show that the likelihood they are true planets is far greater than that of a false positive, to a confidence level of 99.73% (3σ) or higher. For KOI-4427.01 the confidence level is about 99.2% (2.6σ). With our accurate characterization of the GKM host stars, the derived planetary radii range from 1.1 to 2.7 R {sub ⊕}. All 12 objects are confirmed to be in the HZ, and nine are small enough to be rocky. Excluding three of them that have been previously validated by others, our study doubles the number of known rocky planets in the HZ. KOI-3284.01 (Kepler-438b) and KOI-4742.01 (Kepler-442b) are the planets most similar to the Earth discovered to date when considering their size and incident flux jointly.« less

Kepler-77b: a very low albedo, Saturn-mass transiting planet around a metal-rich solar-like star

NASA Astrophysics Data System (ADS)

Gandolfi, D.; Parviainen, H.; Fridlund, M.; Hatzes, A. P.; Deeg, H. J.; Frasca, A.; Lanza, A. F.; Prada Moroni, P. G.; Tognelli, E.; McQuillan, A.; Aigrain, S.; Alonso, R.; Antoci, V.; Cabrera, J.; Carone, L.; Csizmadia, Sz.; Djupvik, A. A.; Guenther, E. W.; Jessen-Hansen, J.; Ofir, A.; Telting, J.

2013-09-01

We report the discovery of Kepler-77b (alias KOI-127.01), a Saturn-mass transiting planet in a 3.6-day orbit around a metal-rich solar-like star. We combined the publicly available Kepler photometry (quarters 1-13) with high-resolution spectroscopy from the Sandiford at McDonald and FIES at NOT spectrographs. We derived the system parameters via a simultaneous joint fit to the photometric and radial velocity measurements. Our analysis is based on the Bayesian approach and is carried out by sampling the parameter posterior distributions using a Markov chain Monte Carlo simulation. Kepler-77b is a moderately inflated planet with a mass of Mp = 0.430 ± 0.032 MJup, a radius of Rp = 0.960 ± 0.016 RJup, and a bulk density of ρp = 0.603 ± 0.055 g cm-3. It orbits a slowly rotating (Prot = 36 ± 6 days) G5 V star with M⋆ = 0.95 ± 0.04 M⊙, R⋆ = 0.99 ± 0.02 R⊙, Teff = 5520 ± 60 K, [M/H] = 0.20 ± 0.05 dex, that has an age of 7.5 ± 2.0 Gyr. The lack of detectable planetary occultation with a depth higher than ~10 ppm implies a planet geometric and Bond albedo of Ag ≤ 0.087 ± 0.008 and AB ≤ 0.058 ± 0.006, respectively, placing Kepler-77b among the gas-giant planets with the lowest albedo known so far. We found neither additional planetary transit signals nor transit-timing variations at a level of ~0.5 min, in accordance with the trend that close-in gas giant planets seem to belong to single-planet systems. The 106 transitsobserved in short-cadence mode by Kepler for nearly 1.2 years show no detectable signatures of the planet's passage in front of starspots. We explored the implications of the absence of detectable spot-crossing events for the inclination of the stellar spin-axis, the sky-projected spin-orbit obliquity, and the latitude of magnetically active regions. Based on observations obtained with the 2.1-m Otto Struve telescope at McDonald Observatory, Texas, USA.Based on observations obtained with the Nordic Optical Telescope, operated on the

A study of the shortest-period planets found with Kepler

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanchis-Ojeda, Roberto; Rappaport, Saul; Winn, Joshua N.

2014-05-20

We present the results of a survey aimed at discovering and studying transiting planets with orbital periods shorter than one day (ultra-short-period, or USP, planets), using data from the Kepler spacecraft. We computed Fourier transforms of the photometric time series for all 200,000 target stars, and detected transit signals based on the presence of regularly spaced sharp peaks in the Fourier spectrum. We present a list of 106 USP candidates, of which 18 have not previously been described in the literature. This list of candidates increases the number of planet candidates with orbital periods shorter than about six hours frommore » two to seven. In addition, among the objects we studied, there are 26 USP candidates that had been previously reported in the literature which do not pass our various tests. All 106 of our candidates have passed several standard tests to rule out false positives due to eclipsing stellar systems. A low false positive rate is also implied by the relatively high fraction of candidates for which more than one transiting planet signal was detected. By assuming these multi-transit candidates represent coplanar multi-planet systems, we are able to infer that the USP planets are typically accompanied by other planets with periods in the range 1-50 days, in contrast with hot Jupiters which very rarely have companions in that same period range. Another clear pattern is that almost all USP planets are smaller than 2 R {sub ⊕}, possibly because gas giants in very tight orbits would lose their atmospheres by photoevaporation when subject to extremely strong stellar irradiation. Based on our survey statistics, USP planets exist around approximately (0.51 ± 0.07)% of G-dwarf stars, and (0.83 ± 0.18)% of K-dwarf stars.« less

One Hundred Thousand Eyes: Analysis of Kepler Archival Data

NASA Astrophysics Data System (ADS)

Fischer, Debra

We are using a powerful resource, more than 100,000 eyes of users on the successful Planet Hunters Web project, who will identify the best follow-up science targets for this ADAP proposal among the Kepler public archive light curves. Planet Hunters is a Citizen Science program with a user base of more than 50,000 individuals who have already contributed the 24/7 cumulative equivalent of 200 human years assessing Kepler data. They independently identified most of the Kepler candidates with radii greater than 3-4 REARTH and they detected ten transiting planet candidates that were missed by the Kepler pipeline algorithms, including two circumbinary transiting planet candidates. These detections have provided important feedback for the Kepler algorithms about possible leaks where candidates might be lost. Our scientific follow up program will use Planet Hunter classifications of archival data from the Kepler Mission to: "Detect and model new transiting planets: for radii greater than 3 4 REARTH and orbital periods longer than one year, the Planet Hunters should be quite competitive with automated pipelines that require at least 3 transits for a detection and fill in the parameter space for Neptune-size planets over a wide range of orbital periods. For stars where a single transit can be modeled as a long period planet, we will establish a watch list for future transits. We will carry out checks for false positives (pixel centroiding analysis, AO observations, Doppler measurements where appropriate). "Analyze the completeness statistics for Kepler transits and independently determine a corrected planet occurrence rate as a function of planet radius and orbital period. This will be done by injecting synthetic transits into real Kepler light curves and calculating the efficiency with which the transits are detected by Planet Hunters. "Model the full spectroscopic and photometric orbital solutions for a set of ~60 detached eclipsing binary systems with low mass K and M

THE DISTRIBUTION OF TRANSIT DURATIONS FOR KEPLER PLANET CANDIDATES AND IMPLICATIONS FOR THEIR ORBITAL ECCENTRICITIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moorhead, Althea V.; Ford, Eric B.; Morehead, Robert C.

Doppler planet searches have discovered that giant planets follow orbits with a wide range of orbital eccentricities, revolutionizing theories of planet formation. The discovery of hundreds of exoplanet candidates by NASA's Kepler mission enables astronomers to characterize the eccentricity distribution of small exoplanets. Measuring the eccentricity of individual planets is only practical in favorable cases that are amenable to complementary techniques (e.g., radial velocities, transit timing variations, occultation photometry). Yet even in the absence of individual eccentricities, it is possible to study the distribution of eccentricities based on the distribution of transit durations (relative to the maximum transit duration formore » a circular orbit). We analyze the transit duration distribution of Kepler planet candidates. We find that for host stars with T{sub eff} > 5100 K we cannot invert this to infer the eccentricity distribution at this time due to uncertainties and possible systematics in the host star densities. With this limitation in mind, we compare the observed transit duration distribution with models to rule out extreme distributions. If we assume a Rayleigh eccentricity distribution for Kepler planet candidates, then we find best fits with a mean eccentricity of 0.1-0.25 for host stars with T{sub eff} {<=} 5100 K. We compare the transit duration distribution for different subsets of Kepler planet candidates and discuss tentative trends with planetary radius and multiplicity. High-precision spectroscopic follow-up observations for a large sample of host stars will be required to confirm which trends are real and which are the results of systematic errors in stellar radii. Finally, we identify planet candidates that must be eccentric or have a significantly underestimated stellar radius.« less

A Universal Break in the Planet-to-star Mass-ratio Function of Kepler MKG Stars

NASA Astrophysics Data System (ADS)

Pascucci, Ilaria; Mulders, Gijs D.; Gould, Andrew; Fernandes, Rachel

2018-04-01

We follow the microlensing approach and quantify the occurrence of Kepler exoplanets as a function of planet-to-star mass ratio, q, rather than planet radius or mass. For planets with radii ∼1–6 R ⊕ and periods <100 days, we find that, except for a normalization factor, the occurrence rate versus q can be described by the same broken power law with a break at ∼3 × 10‑5 independent of host type for hosts below 1 M ⊙. These findings indicate that the planet-to-star mass ratio is a more fundamental quantity in planet formation than planet mass. We then compare our results to those from microlensing for which the overwhelming majority satisfies the M host < 1 M ⊙ criterion. The break in q for the microlensing planet population, which mostly probes the region outside the snowline, is ∼3–10 times higher than that inferred from Kepler. Thus, the most common planet inside the snowline is ∼3–10 times less massive than the one outside. With rocky planets interior to gaseous planets, the solar system broadly follows the combined mass-ratio function inferred from Kepler and microlensing. However, the exoplanet population has a less extreme radial distribution of planetary masses than the solar system. Establishing whether the mass-ratio function beyond the snowline is also host type independent will be crucial to build a comprehensive theory of planet formation.

Obliquity Variations of Habitable Zone Planets Kepler-62f and Kepler-186f

NASA Astrophysics Data System (ADS)

Shan, Yutong; Li, Gongjie

2018-06-01

Obliquity variability could play an important role in the climate and habitability of a planet. Orbital modulations caused by planetary companions and the planet’s spin axis precession due to the torque from the host star may lead to resonant interactions and cause large-amplitude obliquity variability. Here we consider the spin axis dynamics of Kepler-62f and Kepler-186f, both of which reside in the habitable zone around their host stars. Using N-body simulations and secular numerical integrations, we describe their obliquity evolution for particular realizations of the planetary systems. We then use a generalized analytic framework to characterize regions in parameter space where the obliquity is variable with large amplitude. We find that the locations of variability are fine-tuned over the planetary properties and system architecture in the lower-obliquity regimes (≲40°). As an example, assuming a rotation period of 24 hr, the obliquities of both Kepler-62f and Kepler-186f are stable below ∼40°, whereas the high-obliquity regions (60°–90°) allow moderate variabilities. However, for some other rotation periods of Kepler-62f or Kepler-186f, the lower-obliquity regions could become more variable owing to resonant interactions. Even small deviations from coplanarity (e.g., mutual inclinations ∼3°) could stir peak-to-peak obliquity variations up to ∼20°. Undetected planetary companions and/or the existence of a satellite could also destabilize the low-obliquity regions. In all cases, the high-obliquity region allows for moderate variations, and all obliquities corresponding to retrograde motion (i.e., >90°) are stable.

Had the Planet Mars Not Existed: Kepler's Equant Model and Its Physical Consequences

ERIC Educational Resources Information Center

Bracco, C.; Provost, J.P.

2009-01-01

We examine the equant model for the motion of planets, which was the starting point of Kepler's investigations before he modified it because of Mars observations. We show that, up to first order in eccentricity, this model implies for each orbit a velocity, which satisfies Kepler's second law and Hamilton's hodograph, and a centripetal…

Asymmetric orbital distribution near mean motion resonance: Application to planets observed by Kepler and radial velocities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, Ji-Wei, E-mail: jwxie@nju.edu.cn, E-mail: jwxie@astro.utoronto.ca

2014-05-10

Many multiple-planet systems have been found by the Kepler transit survey and various radial velocity (RV) surveys. Kepler planets show an asymmetric feature, namely, there are small but significant deficits/excesses of planet pairs with orbital period spacing slightly narrow/wide of the exact resonance, particularly near the first order mean motion resonance (MMR), such as 2:1 and 3:2 MMR. Similarly, if not exactly the same, an asymmetric feature (pileup wide of 2:1 MMR) is also seen in RV planets, but only for massive ones. We analytically and numerically study planets' orbital evolutions near and in the MMR. We find that theirmore » orbital period ratios could be asymmetrically distributed around the MMR center regardless of dissipation. In the case of no dissipation, Kepler planets' asymmetric orbital distribution could be partly reproduced for 3:2 MMR but not for 2:1 MMR, implying that dissipation might be more important to the latter. The pileup of massive RV planets just wide of 2:1 MMR is found to be consistent with the scenario that planets formed separately then migrated toward the MMR. The location of the pileup infers a K value of 1-100 on the order of magnitude for massive planets, where K is the damping rate ratio between orbital eccentricity and semimajor axis during planet migration.« less

Kepler-539: A young extrasolar system with two giant planets on wide orbits and in gravitational interaction

NASA Astrophysics Data System (ADS)

Mancini, L.; Lillo-Box, J.; Southworth, J.; Borsato, L.; Gandolfi, D.; Ciceri, S.; Barrado, D.; Brahm, R.; Henning, Th.

2016-05-01

We confirm the planetary nature of Kepler-539 b (aka Kepler object of interest K00372.01), a giant transiting exoplanet orbiting a solar-analogue G2 V star. The mass of Kepler-539 b was accurately derived thanks to a series of precise radial velocity measurements obtained with the CAFE spectrograph mounted on the CAHA 2.2-m telescope. A simultaneous fit of the radial-velocity data and Kepler photometry revealed that Kepler-539 b is a dense Jupiter-like planet with a mass of Mp = 0.97 ± 0.29 MJup and a radius of Rp = 0.747 ± 0.018 RJup, making a complete circular revolution around its parent star in 125.6 days. The semi-major axis of the orbit is roughly 0.5 au, implying that the planet is at ≈0.45 au from the habitable zone. By analysing the mid-transit times of the 12 transit events of Kepler-539 b recorded by the Kepler spacecraft, we found a clear modulated transit time variation (TTV), which is attributable to the presence of a planet c in a wider orbit. The few timings available do not allow us to precisely estimate the properties of Kepler-539 c and our analysis suggests that it has a mass between 1.2 and 3.6 MJup, revolving on a very eccentric orbit (0.4 planet c is the probable cause of the TTV modulation of planet b. The analysis of the CAFE spectra revealed a relatively high photospheric lithium content, A(Li) = 2.48 ± 0.12 dex, which, together with both a gyrochronological and isochronal analysis, suggests that the parent star is relatively young. RV/BVS measurements are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/590/A112

The Mass of Kepler-93b and The Composition of Terrestrial Planets

NASA Astrophysics Data System (ADS)

Dressing, Courtney D.; Charbonneau, David; Dumusque, Xavier; Gettel, Sara; Pepe, Francesco; Collier Cameron, Andrew; Latham, David W.; Molinari, Emilio; Udry, Stéphane; Affer, Laura; Bonomo, Aldo S.; Buchhave, Lars A.; Cosentino, Rosario; Figueira, Pedro; Fiorenzano, Aldo F. M.; Harutyunyan, Avet; Haywood, Raphaëlle D.; Johnson, John Asher; Lopez-Morales, Mercedes; Lovis, Christophe; Malavolta, Luca; Mayor, Michel; Micela, Giusi; Motalebi, Fatemeh; Nascimbeni, Valerio; Phillips, David F.; Piotto, Giampaolo; Pollacco, Don; Queloz, Didier; Rice, Ken; Sasselov, Dimitar; Ségransan, Damien; Sozzetti, Alessandro; Szentgyorgyi, Andrew; Watson, Chris

2015-02-01

Kepler-93b is a 1.478 ± 0.019 R ⊕ planet with a 4.7 day period around a bright (V = 10.2), astroseismically characterized host star with a mass of 0.911 ± 0.033 M ⊙ and a radius of 0.919 ± 0.011 R ⊙. Based on 86 radial velocity observations obtained with the HARPS-N spectrograph on the Telescopio Nazionale Galileo and 32 archival Keck/HIRES observations, we present a precise mass estimate of 4.02 ± 0.68 M ⊕. The corresponding high density of 6.88 ± 1.18 g cm-3 is consistent with a rocky composition of primarily iron and magnesium silicate. We compare Kepler-93b to other dense planets with well-constrained parameters and find that between 1 and 6 M ⊕, all dense planets including the Earth and Venus are well-described by the same fixed ratio of iron to magnesium silicate. There are as of yet no examples of such planets with masses >6 M ⊕. All known planets in this mass regime have lower densities requiring significant fractions of volatiles or H/He gas. We also constrain the mass and period of the outer companion in the Kepler-93 system from the long-term radial velocity trend and archival adaptive optics images. As the sample of dense planets with well-constrained masses and radii continues to grow, we will be able to test whether the fixed compositional model found for the seven dense planets considered in this paper extends to the full population of 1-6 M ⊕ planets. Based on observations made with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Fundación Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias.

Chaos in Kepler's Multiple Planet Systems and K2s Observations of the Atmospheres of Uranus Neptune

NASA Technical Reports Server (NTRS)

Lissauer, Jack J.

2016-01-01

More than one-third of the 4700 planet candidates found by NASA's Kepler spacecraft during its prime mission are associated with target stars that have more than one planet candidate, and such "multis" account for the vast majority of candidates that have been verified as true planets. The large number of multis tells us that flat multiplanet systems like our Solar System are common. Virtually all of the candidate planetary systems are stable, as tested by numerical integrations that assume a physically motivated mass-radius relationship, but some of the systems lie in chaotic regions close to instability. The characteristics of some of the most interesting confirmed Kepler multi-planet systems will be discussed. The Kepler spacecraft's 'second life' in theK2 mission has allowed it to obtain long time-series observations of Solar System targets, including the giant planets Uranus & Neptune. These observations show variability caused by the chaotic weather patterns on Uranus & Neptune.

Characterization of Exoplanet Atmospheres and Kepler Planet Candidates with Multi-Color Photometry from the Gran Telescopio Canarias

NASA Astrophysics Data System (ADS)

Colon, Knicole; Ford, E. B.

2012-01-01

With over 180 confirmed transiting exoplanets and NASA's Kepler mission's recent discovery of over 1200 transiting exoplanet candidates, we can conduct detailed investigations into the (i) properties of exoplanet atmospheres and (ii) false positive rates for planet search surveys. To aid these investigations, we developed a novel technique of using the Optical System for Imaging and low Resolution Integrated Spectroscopy (OSIRIS) installed on the 10.4-meter Gran Telescopio Canarias (GTC) to acquire near-simultaneous multi-color photometry of (i) HD 80606b in bandpasses around the potassium (K I) absorption feature, (ii) GJ 1214b in bandpasses around a possible methane absorption feature and (iii) several Kepler planet candidates. For HD 80606b, we measure a significant color change during transit between wavelengths that probe the K I line core and the K I wing, equivalent to a 4.2% change in the apparent planetary radius. We hypothesize that the excess absorption may be due to K I in a high-speed wind being driven from the exoplanet's exosphere. This is one of the first detections of K I in an exoplanet atmosphere. For GJ 1214b, we compare the transit depths measured "on” and "off” a possible methane absorption feature and use our results to help resolve conflicting results from other studies regarding the composition of this super-Earth-size planet's atmosphere. For Kepler candidates, we use the color change during transit to reject candidates that are false positives (e.g., a blend with an eclipsing binary either in the background/foreground or bound to the target star). We target small planets (<6 Earth radii) with short orbital periods (<6 days), since eclipsing binaries can mimic planets in this regime. Our results include identification of two false positives and test recent predictions of the false positive rates for the Kepler sample. This research demonstrates the value of the GTC for exoplanet follow-up.

Kepler-186f, the First Earth-size Planet in the Habitable Zone Artist Concept

NASA Image and Video Library

2014-04-17

This artist concept depicts Kepler-186f, the first validated Earth-size planet to orbit a distant star in the habitable zone, a range of distance from a star where liquid water might pool on the planet surface.

THE HUNT FOR EXOMOONS WITH KEPLER (HEK). II. ANALYSIS OF SEVEN VIABLE SATELLITE-HOSTING PLANET CANDIDATES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kipping, D. M.; Hartman, J.; Bakos, G. A.

2013-06-20

From the list of 2321 transiting planet candidates announced by the Kepler Mission, we select seven targets with favorable properties for the capacity to dynamically maintain an exomoon and present a detectable signal. These seven candidates were identified through our automatic target selection (TSA) algorithm and target selection prioritization (TSP) filtering, whereby we excluded systems exhibiting significant time-correlated noise and focused on those with a single transiting planet candidate of radius less than 6 R{sub Circled-Plus }. We find no compelling evidence for an exomoon around any of the seven Kepler Objects of Interest (KOIs) but constrain the satellite-to-planet massmore » ratios for each. For four of the seven KOIs, we estimate a 95% upper quantile of M{sub S} /M{sub P} < 0.04, which given the radii of the candidates, likely probes down to sub-Earth masses. We also derive precise transit times and durations for each candidate and find no evidence for dynamical variations in any of the KOIs. With just a few systems analyzed thus far in the ongoing ''Hunt for Exomoons with Kepler'' (HEK) project, projections on eta-moon would be premature, but a high frequency of large moons around Super-Earths/Mini-Neptunes would be premature, but a high frequency of large moons around Super-Earths/Mini-Neptunes would appear to be incommensurable with our results so far.« less

SETI Searches for Radio Transients from Kepler Field Planets and Astropulse Candidates

NASA Astrophysics Data System (ADS)

Gautam, Abhimat Krishna; Siemion, Andrew; Korpela, Eric J.; Cobb, Jeff; Lebofsky, Matt; Werthimer, Dan

2014-06-01

We present a search for fast radio transients in targeted observations of planet candidates in the Kepler Field and candidate Astropulse sources.Kepler Field observations were conducted in the band 1.1 and 1.9 GHz using the Green Bank Telescope in Green Bank, West Virginia and are centered on 86 stars hosting candidate planets identified by the Kepler spacecraft. These stars were chosen based on the properties of their putative planetary system thought to be conducive to the development of advanced life, including all systems known (as of May 2011) hosting a Kepler Object of Interest (KOI) with a calculated equilibrium temperature between 230 and 380 K, at least 4 KOIs or a KOI with an inferred radius < 3.0 r_earth and a period > 50 d. The Kepler Field is centered at an intermediate galactic latitude, b = 13.5°, which presents an additional opportunity to detect signals from the older population of millisecond and recycled pulsars located above the galactic plane.The Astropulse radio survey searches for brief wide-band pulses in a 2.5 MHz band centered at 1420 MHz using commensal data recorded from the Arecibo ALFA receiver. In early Astropulse analysis, 108 candidate sources were identified that passed a series of tests designed to eliminate potential sources of radio frequency interference (RFI). We have performed targeted re-observations of these sources at Arecibo over the full (1214-1536 MHz) ALFA band.We have developed a software pipeline to locate fast dispersed transients in these observations, leveraging components of the PRESTO software library. This pipeline consists of finding and removing RFI, conducting de-dispersion to remove the effects of dispersion from the interstellar medium (ISM) on the signal and identifying over- threshold events. We also perform de-dispersion at negative dispersion measures, proposed to be a potential technique for intelligent civilizations to distinguish their emission from natural sources. We carry out both a periodicity

The dynamics of the multi-planet system orbiting Kepler-56

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Gongjie; Naoz, Smadar; Johnson, John Asher

2014-10-20

Kepler-56 is a multi-planet system containing two coplanar inner planets that are in orbits misaligned with respect to the spin axis of the host star, and an outer planet. Various mechanisms have been proposed to explain the broad distribution of spin-orbit angles among exoplanets, and these theories fall under two broad categories. The first is based on dynamical interactions in a multi-body system, while the other assumes that disk migration is the driving mechanism in planetary configuration and that the star (or disk) is titled with respect to the planetary plane. Here we show that the large observed obliquity ofmore » Kepler 56 system is consistent with a dynamical origin. In addition, we use observations by Huber et al. to derive the obliquity's probability distribution function, thus improving the constrained lower limit. The outer planet may be the cause of the inner planets' large obliquities, and we give the probability distribution function of its inclination, which depends on the initial orbital configuration of the planetary system. We show that even in the presence of precise measurement of the true obliquity, one cannot distinguish the initial configurations. Finally we consider the fate of the system as the star continues to evolve beyond the main sequence, and we find that the obliquity of the system will not undergo major variations as the star climbs the red giant branch. We follow the evolution of the system and find that the innermost planet will be engulfed in ∼129 Myr. Furthermore we put an upper limit of ∼155 Myr for the engulfment of the second planet. This corresponds to ∼3% of the current age of the star.« less

VizieR Online Data Catalog: Final Kepler transiting planet search (DR25) (Twicken+, 2016)

NASA Astrophysics Data System (ADS)

Twicken, J. D.; Jenkins, J. M.; Seader, S. E.; Tenenbaum, P.; Smith, J. C.; Brownston, L. S.; Burke, C. J.; Catanzarite, J. H.; Clarke, B. D.; Cote, M. T.; Girouard, F. R.; Klaus, T. C.; Li, J.; McCauliff, S. D.; Morris, R. L.; Wohler, B.; Campbell, J. R.; Uddin, A. K.; Zamudio, K. A.; Sabale, A.; Bryson, S. T.; Caldwell, D. A.; Christiansen, J. L.; Coughlin, J. L.; Haas, M. R.; Henze, C. E.; Sanderfer, D. T.; Thompson, S. E.

2017-01-01

The Kepler spacecraft is in an Earth-trailing heliocentric orbit and maintained a boresight pointing centered on α=19h22m40s, δ=+44.5° during the primary mission. The Kepler photometer acquired data on a 115-square-degree region of the sky. The data were acquired on 29.4-minute intervals, colloquially known as "long cadences". Long-cadence pixel values were obtained by accumulating 270 consecutive 6.02s exposures. Science acquisition of Q1 data began at 2009-05-13 00:01:07Z, and acquisition of Q17 data concluded at 2013-05-11 12:16:22Z. This time period contains 71427 long-cadence intervals. A total of 198709 targets observed by Kepler were searched for evidence of transiting planets in the final Q1-Q17 pipeline run (see Table1). The results of past Kepler Mission transiting planet searches have been presented in Tenenbaum et al. 2012 (Cat. J/ApJS/199/24) for Quarter 1 through Quarter 3 (i.e., Q1-Q3), Tenenbaum et al. 2013ApJS..206....5T for Q1-Q12, Tenenbaum et al. 2014ApJS..211....6T for Q1-Q16, and Seader et al. 2015 (Cat. J/ApJS/217/18) for Q1-Q17. We now present results of the final Kepler transiting planet search encompassing the complete 17-quarter primary mission. The data release for the final Q1-Q17 pipeline processing is referred to as Data Release 25 (DR25). (3 data files).

Kepler-454b: Rocky or Not?

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2016-02-01

Small exoplanets tend to fall into two categories: the smallest ones are predominantly rocky, like Earth, and the larger ones have a lower-density, more gaseous composition, similar to Neptune. The planet Kepler-454b was initially estimated to fall between these two groups in radius. So what is its composition?Small-Planet DichotomyThough Kepler has detected thousands of planet candidates with radii between 1 and 2.7 Earth radii, we have only obtained precise mass measurements for 12 of these planets.Mass-radius diagram (click for a closer look!) for planets with radius 2.7 Earth radii and well-measured masses. The six smallest planets (and Venus and Earth) fall along a single mass-radius curve of Earth-like composition. The six larger planets (including Kepler-454b) have lower-density compositions. [Gettel et al. 2016]These measurements, however, show an interesting dichotomy: planets with radii less than 1.6 Earth radii have rocky, Earth-like compositions, following a single relation between their mass and radius. Planets between 2 and 2.7 Earth radii, however, have lower densities and dont follow a single mass-radius relation. Their low densities suggest they contain a significant fraction of volatiles, likely in the form of a thick gas envelope of water, hydrogen, and/or helium.The planet Kepler-454b, discovered transiting a Sun-like star, was initially estimated to have a radius of 1.86 Earth radii placing it in between these two categories. A team of astronomers led by Sara Gettel (Harvard-Smithsonian Center for Astrophysics) have since followed up on the initial Kepler detection, hoping to determine the planets composition.Low-Density OutcomeGettel and collaborators obtained 63 observations of the host stars radial velocity with the HARPS-N spectrograph on the Telescopio Nazionale Galileo, and another 36 observations with the HIRES spectrograph at Keck Observatory. These observations allowed them to do several things:Obtain a more accurate radius estimate

Exploring Kepler Giant Planets in the Habitable Zone

NASA Astrophysics Data System (ADS)

Hill, Michelle L.; Kane, Stephen R.; Seperuelo Duarte, Eduardo; Kopparapu, Ravi K.; Gelino, Dawn M.; Wittenmyer, Robert A.

2018-06-01

The Kepler mission found hundreds of planet candidates within the Habitable Zones (HZ) of their host star, including over 70 candidates with radii larger than three Earth radii (R ⊕) within the optimistic HZ (OHZ). These giant planets are potential hosts to large terrestrial satellites (or exomoons) which would also exist in the HZ. We calculate the occurrence rates of giant planets (R p = 3.0–25 R ⊕) in the OHZ, and find a frequency of (6.5 ± 1.9)% for G stars, (11.5 ± 3.1)% for K stars, and (6 ± 6)% for M stars. We compare this with previously estimated occurrence rates of terrestrial planets in the HZ of G, K, and M stars and find that if each giant planet has one large terrestrial moon then these moons are less likely to exist in the HZ than terrestrial planets. However, if each giant planet holds more than one moon, then the occurrence rates of moons in the HZ would be comparable to that of terrestrial planets, and could potentially exceed them. We estimate the mass of each planet candidate using the mass–radius relationship developed by Chen & Kipping. We calculate the Hill radius of each planet to determine the area of influence of the planet in which any attached moon may reside, then calculate the estimated angular separation of the moon and planet for future imaging missions. Finally, we estimate the radial velocity semi-amplitudes of each planet for use in follow-up observations.

A STATISTICAL RECONSTRUCTION OF THE PLANET POPULATION AROUND KEPLER SOLAR-TYPE STARS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silburt, Ari; Wu, Yanqin; Gaidos, Eric

2015-02-01

Using the cumulative catalog of planets detected by the NASA Kepler mission, we reconstruct the intrinsic occurrence of Earth- to Neptune-size (1-4 R {sub ⊕}) planets and their distributions with radius and orbital period. We analyze 76,711 solar-type (0.8 < R {sub *}/R {sub ☉} < 1.2) stars with 430 planets on 20-200 day orbits, excluding close-in planets that may have been affected by the proximity to the host star. Our analysis considers errors in planet radii and includes an ''iterative simulation'' technique that does not bin the data. We find a radius distribution that peaks at 2-2.8 Earth radii, with lowermore » numbers of smaller and larger planets. These planets are uniformly distributed with logarithmic period, and the mean number of such planets per star is 0.46 ± 0.03. The occurrence is ∼0.66 if planets interior to 20 days are included. We estimate the occurrence of Earth-size planets in the ''habitable zone'' (defined as 1-2 R {sub ⊕}, 0.99-1.7 AU for solar-twin stars) as 6.4{sub −1.1}{sup +3.4}%. Our results largely agree with those of Petigura et al., although we find a higher occurrence of 2.8-4 Earth-radii planets. The reasons for this excess are the inclusion of errors in planet radius, updated Huber et al. stellar parameters, and also the exclusion of planets that may have been affected by proximity to the host star.« less

Influence of Stellar Multiplicity On Planet Formation. III. Adaptive Optics Imaging of Kepler Stars With Gas Giant Planets

NASA Astrophysics Data System (ADS)

Wang, Ji; Fischer, Debra A.; Horch, Elliott P.; Xie, Ji-Wei

2015-06-01

As hundreds of gas giant planets have been discovered, we study how these planets form and evolve in different stellar environments, specifically in multiple stellar systems. In such systems, stellar companions may have a profound influence on gas giant planet formation and evolution via several dynamical effects such as truncation and perturbation. We select 84 Kepler Objects of Interest (KOIs) with gas giant planet candidates. We obtain high-angular resolution images using telescopes with adaptive optics (AO) systems. Together with the AO data, we use archival radial velocity data and dynamical analysis to constrain the presence of stellar companions. We detect 59 stellar companions around 40 KOIs for which we develop methods of testing their physical association. These methods are based on color information and galactic stellar population statistics. We find evidence of suppressive planet formation within 20 AU by comparing stellar multiplicity. The stellar multiplicity rate (MR) for planet host stars is {0}-0+5% within 20 AU. In comparison, the stellar MR is 18% ± 2% for the control sample, i.e., field stars in the solar neighborhood. The stellar MR for planet host stars is 34% ± 8% for separations between 20 and 200 AU, which is higher than the control sample at 12% ± 2%. Beyond 200 AU, stellar MRs are comparable between planet host stars and the control sample. We discuss the implications of the results on gas giant planet formation and evolution.

The Kepler-454 System: A Small, Not-rocky Inner Planet, a Jovian World, and a Distant Companion

NASA Astrophysics Data System (ADS)

Gettel, Sara; Charbonneau, David; Dressing, Courtney D.; Buchhave, Lars A.; Dumusque, Xavier; Vanderburg, Andrew; Bonomo, Aldo S.; Malavolta, Luca; Pepe, Francesco; Collier Cameron, Andrew; Latham, David W.; Udry, Stéphane; Marcy, Geoffrey W.; Isaacson, Howard; Howard, Andrew W.; Davies, Guy R.; Silva Aguirre, Victor; Kjeldsen, Hans; Bedding, Timothy R.; Lopez, Eric; Affer, Laura; Cosentino, Rosario; Figueira, Pedro; Fiorenzano, Aldo F. M.; Harutyunyan, Avet; Johnson, John Asher; Lopez-Morales, Mercedes; Lovis, Christophe; Mayor, Michel; Micela, Giusi; Molinari, Emilio; Motalebi, Fatemeh; Phillips, David F.; Piotto, Giampaolo; Queloz, Didier; Rice, Ken; Sasselov, Dimitar; Ségransan, Damien; Sozzetti, Alessandro; Watson, Chris; Basu, Sarbani; Campante, Tiago L.; Christensen-Dalsgaard, Jørgen; Kawaler, Steven D.; Metcalfe, Travis S.; Handberg, Rasmus; Lund, Mikkel N.; Lundkvist, Mia S.; Huber, Daniel; Chaplin, William J.

2016-01-01

Kepler-454 (KOI-273) is a relatively bright (V = 11.69 mag), Sun-like star that hosts a transiting planet candidate in a 10.6 day orbit. From spectroscopy, we estimate the stellar temperature to be 5687 ± 50 K, its metallicity to be [m/H] = 0.32 ± 0.08, and the projected rotational velocity to be v sin I < 2.4 km s-1. We combine these values with a study of the asteroseismic frequencies from short cadence Kepler data to estimate the stellar mass to be {1.028}-0.03+0.04{M}⊙ , the radius to be 1.066 ± 0.012 R⊙, and the age to be {5.25}-1.39+1.41 Gyr. We estimate the radius of the 10.6 day planet as 2.37 ± 0.13 R⊕. Using 63 radial velocity observations obtained with the HARPS-N spectrograph on the Telescopio Nazionale Galileo and 36 observations made with the HIRES spectrograph at the Keck Observatory, we measure the mass of this planet to be 6.8 ± 1.4 M⊕. We also detect two additional non-transiting companions, a planet with a minimum mass of 4.46 ± 0.12 MJ in a nearly circular 524 day orbit and a massive companion with a period >10 years and mass >12.1 MJ. The 12 exoplanets with radii <2.7 R⊕ and precise mass measurements appear to fall into two populations, with those <1.6 R⊕ following an Earth-like composition curve and larger planets requiring a significant fraction of volatiles. With a density of 2.76 ± 0.73 g cm-3, Kepler-454b lies near the mass transition between these two populations and requires the presence of volatiles and/or H/He gas.

Kepler-22b: A 2.4 EARTH-RADIUS PLANET IN THE HABITABLE ZONE OF A SUN-LIKE STAR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borucki, William J.; Koch, David G.; Bryson, Stephen T.

A search of the time-series photometry from NASA's Kepler spacecraft reveals a transiting planet candidate orbiting the 11th magnitude G5 dwarf KIC 10593626 with a period of 290 days. The characteristics of the host star are well constrained by high-resolution spectroscopy combined with an asteroseismic analysis of the Kepler photometry, leading to an estimated mass and radius of 0.970 {+-} 0.060 M{sub Sun} and 0.979 {+-} 0.020 R{sub Sun }. The depth of 492 {+-} 10 ppm for the three observed transits yields a radius of 2.38 {+-} 0.13 Re for the planet. The system passes a battery of testsmore » for false positives, including reconnaissance spectroscopy, high-resolution imaging, and centroid motion. A full BLENDER analysis provides further validation of the planet interpretation by showing that contamination of the target by an eclipsing system would rarely mimic the observed shape of the transits. The final validation of the planet is provided by 16 radial velocities (RVs) obtained with the High Resolution Echelle Spectrometer on Keck I over a one-year span. Although the velocities do not lead to a reliable orbit and mass determination, they are able to constrain the mass to a 3{sigma} upper limit of 124 M{sub Circled-Plus }, safely in the regime of planetary masses, thus earning the designation Kepler-22b. The radiative equilibrium temperature is 262 K for a planet in Kepler-22b's orbit. Although there is no evidence that Kepler-22b is a rocky planet, it is the first confirmed planet with a measured radius to orbit in the habitable zone of any star other than the Sun.« less

ARCHITECTURE AND DYNAMICS OF KEPLER'S CANDIDATE MULTIPLE TRANSITING PLANET SYSTEMS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lissauer, Jack J.; Jenkins, Jon M.; Borucki, William J.

About one-third of the {approx}1200 transiting planet candidates detected in the first four months of Kepler data are members of multiple candidate systems. There are 115 target stars with two candidate transiting planets, 45 with three, 8 with four, and 1 each with five and six. We characterize the dynamical properties of these candidate multi-planet systems. The distribution of observed period ratios shows that the vast majority of candidate pairs are neither in nor near low-order mean-motion resonances. Nonetheless, there are small but statistically significant excesses of candidate pairs both in resonance and spaced slightly too far apart to bemore » in resonance, particularly near the 2:1 resonance. We find that virtually all candidate systems are stable, as tested by numerical integrations that assume a nominal mass-radius relationship. Several considerations strongly suggest that the vast majority of these multi-candidate systems are true planetary systems. Using the observed multiplicity frequencies, we find that a single population of planetary systems that matches the higher multiplicities underpredicts the number of singly transiting systems. We provide constraints on the true multiplicity and mutual inclination distribution of the multi-candidate systems, revealing a population of systems with multiple super-Earth-size and Neptune-size planets with low to moderate mutual inclinations.« less

Tatooines Future: The Eccentric Response of Keplers Circumbinary Planets to Common-Envelope Evolution of their Host Stars

NASA Technical Reports Server (NTRS)

Kostov, Veselin B.; Moore, Keavin; Tamayo, Daniel; Jayawardhana, Ray; Rinehart, Stephen A.

2016-01-01

Inspired by the recent Kepler discoveries of circumbinary planets orbiting nine close binary stars, we explore the fate of the former as the latter evolve off the main sequence. We combine binary star evolution models with dynamical simulations to study the orbital evolution of these planets as their hosts undergo common-envelope stages, losing in the process a tremendous amount of mass on dynamical timescales. Five of the systems experience at least one Roche-lobe overflow and common-envelope stages (Kepler-1647 experiences three), and the binary stars either shrink to very short orbits or coalesce; two systems trigger a double-degenerate supernova explosion. Kepler's circumbinary planets predominantly remain gravitationally bound at the end of the common-envelope phase, migrate to larger orbits, and may gain significant eccentricity; their orbital expansion can be more than an order of magnitude and can occur over the course of a single planetary orbit. The orbits these planets can reach are qualitatively consistent with those of the currently known post-common-envelope, eclipse-time variations circumbinary candidates. Our results also show that circumbinary planets can experience both modes of orbital expansion (adiabatic and non-adiabatic) if their host binaries undergo more than one common-envelope stage; multiplanet circumbinary systems like Kepler-47 can experience both modes during the same common-envelope stage. Additionally, unlike Mercury orbiting the Sun, a circumbinary planet with the same semi-major axis can survive the common envelope evolution of a close binary star with a total mass of 1 Solar Mass.

On the Detection of Non-transiting Hot Jupiters in Multiple-planet Systems

NASA Astrophysics Data System (ADS)

Millholland, Sarah; Wang, Songhu; Laughlin, Gregory

2016-05-01

We outline a photometric method for detecting the presence of a non-transiting short-period giant planet in a planetary system harboring one or more longer-period transiting planets. Within a prospective system of the type that we consider, a hot Jupiter on an interior orbit inclined to the line of sight signals its presence through approximately sinusoidal full-phase photometric variations in the stellar light curve, correlated with astrometrically induced transit timing variations for exterior transiting planets. Systems containing a hot Jupiter along with a low-mass outer planet or planets on inclined orbits are a predicted hallmark of in situ accretion for hot Jupiters, and their presence can thus be used to test planetary formation theories. We outline the prospects for detecting non-transiting hot Jupiters using photometric data from typical Kepler objects of interest (KOIs). As a demonstration of the technique, we perform a brief assessment of Kepler candidates and identify a potential non-transiting hot Jupiter in the KOI-1822 system. Candidate non-transiting hot Jupiters can be readily confirmed with a small number of Doppler velocity observations, even for stars with V ≳ 14.

A Statistical Characterization of Reflection and Refraction in the Atmospheres of sub-Saturn Kepler Planet Candidates

NASA Astrophysics Data System (ADS)

Sheets, Holly A.; Deming, Drake; Arney, Giada; Meadows, Victoria

2016-01-01

We present the results of our method to detect small atmospheric signals in Kepler's close-in, sub-Saturn planet candidate light curves. We detect an average secondary eclipse for groups of super-Earth, Neptune-like, and other sub-Saturn-sized candidates by scaling and combining photometric data of the groups of candidates such that the eclipses add constructively. This greatly increases the signal-to-noise compared to combining eclipses for individual planets. We have modified our method for averaging short cadence light curves of multiple planet candidates (2014, ApJ, 794, 133), and have applied it to long cadence data, accounting for the broadening of the eclipse due to the 30 minute cadence. We then use the secondary eclipse depth to determine the average albedo for the group. In the short cadence data, we found that a group of close-in sub-Saturn candidates (1 to 6 Earth radii) was more reflective (geometric A ~ 0.22) than typical hot Jupiters (geometric A ~ 0.06 to 0.11: Demory 2014, ApJL, 789, L20). With the larger number of candidates available in long cadence, we improve the resolution in radius and consider groups of candidates with radii between 1 and 2, 2 and 4, and 4 and 6 Earth radii. We also modify our averaging technique to search for refracted light just before and after transit in the Kepler candidate light curves, as modelled by Misra and Meadows (2014, ApJL, 795, L14).

An Introduction to Exoplanets and the Kepler Mission

NASA Technical Reports Server (NTRS)

Lissauer, Jack

2014-01-01

A quarter century ago, the only planets known to humanity were the familiar objects that orbit our Sun. But improved observational techniques allowed astronomers to begin detecting planets around other stars in the 1990s. The first extrasolar planets (often referred to as exoplanets) to be discovered were quite exotic and unfamiliar objects. Most were giant objects that are hundreds of times as massive as the Earth and orbit so close to their star that they are hotter than pizza ovens. But as observational capabilities improved, smaller and cooler planets were found. The most capable planet-hunting tool developed to date is NASA's Kepler telescope, which was launched in 2009. Kepler has found that planets similar in size to our Earth are quite abundant within our galaxy. Results of Kepler's research will be summarized and placed into context within the new and growing discipline of exoplanet studies.

The architecture and formation of the Kepler-30 planetary system

NASA Astrophysics Data System (ADS)

Panichi, F.; Goździewski, K.; Migaszewski, C.; Szuszkiewicz, E.

2018-04-01

We study the orbital architecture, physical characteristics of planets, formation and long-term evolution of the Kepler-30 planetary system, detected and announced in 2012 by the KEPLER team. We show that the Kepler-30 system belongs to a particular class of very compact and quasi-resonant, yet long-term stable planetary systems. We re-analyse the light curves of the host star spanning Q1-Q17 quarters of the KEPLER mission. A huge variability of the Transit Timing Variations (TTV) exceeding 2 days is induced by a massive Jovian planet located between two Neptune-like companions. The innermost pair is near to the 2:1 mean motion resonance (MMR), and the outermost pair is close to higher order MMRs, such as 17:7 and 7:3. Our re-analysis of photometric data allows us to constrain, better than before, the orbital elements, planets' radii and masses, which are 9.2 ± 0.1, 536 ± 5, and 23.7 ± 1.3 Earth masses for Kepler-30b, Kepler-30c and Kepler-30d, respectively. The masses of the inner planets are determined within ˜1% uncertainty. We infer the internal structures of the Kepler-30 planets and their bulk densities in a wide range from (0.19 ± 0.01) g.cm-3 for Kepler-30d, (0.96 ± 0.15) g.cm-3 for Kepler-30b, to (1.71 ± 0.13) g.cm-3 for the Jovian planet Kepler-30c. We attempt to explain the origin of this unique planetary system and a deviation of the orbits from exact MMRs through the planetary migration scenario. We anticipate that the Jupiter-like planet plays an important role in determining the present dynamical state of this system.

The detection and characterization of a nontransiting planet by transit timing variations.

PubMed

Nesvorný, David; Kipping, David M; Buchhave, Lars A; Bakos, Gáspár Á; Hartman, Joel; Schmitt, Allan R

2012-06-01

The Kepler mission is monitoring the brightness of ~150,000 stars, searching for evidence of planetary transits. As part of the Hunt for Exomoons with Kepler (HEK) project, we report a planetary system with two confirmed planets and one candidate planet discovered with the publicly available data for KOI-872. Planet b transits the host star with a period P(b) = 33.6 days and exhibits large transit timing variations indicative of a perturber. Dynamical modeling uniquely detects an outer nontransiting planet c near the 5:3 resonance (P(c) = 57.0 days) with a mass 0.37 times that of Jupiter. Transits of a third planetary candidate are also found: a 1.7-Earth radius super-Earth with a 6.8-day period. Our analysis indicates a system with nearly coplanar and circular orbits, reminiscent of the orderly arrangement within the solar system.

Advances in the Kepler Transit Search Engine

NASA Astrophysics Data System (ADS)

Jenkins, Jon M.

2016-10-01

Twenty years ago, no planets were known outside our own solar system. Since then, the discoveries of ~1500 exoplanets have radically altered our views of planets and planetary systems. This revolution is due in no small part to the Kepler Mission, which has discovered >1000 of these planets and >4000 planet candidates. While Kepler has shown that small rocky planets and planetary systems are quite common, the quest to find Earth's closest cousins and characterize their atmospheres presses forward with missions such as NASA Explorer Program's Transiting Exoplanet Survey Satellite (TESS) slated for launch in 2017 and ESA's PLATO mission scheduled for launch in 2024. These future missions pose daunting data processing challenges in terms of the number of stars, the amount of data, and the difficulties in detecting weak signatures of transiting small planets against a roaring background. These complications include instrument noise and systematic effects as well as the intrinsic stellar variability of the subjects under scrutiny. In this paper we review recent developments in the Kepler transit search pipeline improving both the yield and reliability of detected transit signatures. Many of the phenomena in light curves that represent noise can also trigger transit detection algorithms. The Kepler Mission has expended great effort in suppressing false positives from its planetary candidate catalogs. Over 18,000 transit-like signatures can be identified for a search across 4 years of data. Most of these signatures are artifacts, not planets. Vetting all such signatures historically takes several months' effort by many individuals. We describe the application of machine learning approaches for the automated vetting and production of planet candidate catalogs. These algorithms can improve the efficiency of the human vetting effort as well as quantifying the likelihood that each candidate is truly a planet. This information is crucial for obtaining valid planet occurrence

The California-Kepler Survey. V. Peas in a Pod: Planets in a Kepler Multi-planet System Are Similar in Size and Regularly Spaced

NASA Astrophysics Data System (ADS)

Weiss, Lauren M.; Marcy, Geoffrey W.; Petigura, Erik A.; Fulton, Benjamin J.; Howard, Andrew W.; Winn, Joshua N.; Isaacson, Howard T.; Morton, Timothy D.; Hirsch, Lea A.; Sinukoff, Evan J.; Cumming, Andrew; Hebb, Leslie; Cargile, Phillip A.

2018-01-01

We have established precise planet radii, semimajor axes, incident stellar fluxes, and stellar masses for 909 planets in 355 multi-planet systems discovered by Kepler. In this sample, we find that planets within a single multi-planet system have correlated sizes: each planet is more likely to be the size of its neighbor than a size drawn at random from the distribution of observed planet sizes. In systems with three or more planets, the planets tend to have a regular spacing: the orbital period ratios of adjacent pairs of planets are correlated. Furthermore, the orbital period ratios are smaller in systems with smaller planets, suggesting that the patterns in planet sizes and spacing are linked through formation and/or subsequent orbital dynamics. Yet, we find that essentially no planets have orbital period ratios smaller than 1.2, regardless of planet size. Using empirical mass–radius relationships, we estimate the mutual Hill separations of planet pairs. We find that 93% of the planet pairs are at least 10 mutual Hill radii apart, and that a spacing of ∼20 mutual Hill radii is most common. We also find that when comparing planet sizes, the outer planet is larger in 65% ± 0.4% of cases, and the typical ratio of the outer to inner planet size is positively correlated with the temperature difference between the planets. This could be the result of photo-evaporation. Based on observations obtained at the W. M. Keck Observatory, which is operated jointly by the University of California and the California Institute of Technology. Keck time has been granted by the University of California, and California Institute of Technology, and the University of Hawaii.

Robotic laser adaptive optics imaging of 715 Kepler exoplanet candidates using Robo-AO

DOE Office of Scientific and Technical Information (OSTI.GOV)

Law, Nicholas M.; Ziegler, Carl; Morton, Tim

2014-08-10

The Robo-AO Kepler Planetary Candidate Survey is observing every Kepler planet candidate host star with laser adaptive optics imaging to search for blended nearby stars, which may be physically associated companions and/or responsible for transit false positives. In this paper, we present the results from the 2012 observing season, searching for stars close to 715 Kepler planet candidate hosts. We find 53 companions, 43 of which are new discoveries. We detail the Robo-AO survey data reduction methods including a method of using the large ensemble of target observations as mutual point-spread-function references, along with a new automated companion-detection algorithm designedmore » for large adaptive optics surveys. Our survey is sensitive to objects from ≈0.''15 to 2.''5 separation, with magnitude differences up to Δm ≈ 6. We measure an overall nearby-star probability for Kepler planet candidates of 7.4% ± 1.0%, and calculate the effects of each detected nearby star on the Kepler-measured planetary radius. We discuss several Kepler Objects of Interest (KOIs) of particular interest, including KOI-191 and KOI-1151, which are both multi-planet systems with detected stellar companions whose unusual planetary system architecture might be best explained if they are 'coincident multiple' systems, with several transiting planets shared between the two stars. Finally, we find 98% confidence evidence that short-period giant planets are two to three times more likely than longer-period planets to be found in wide stellar binaries.« less

Influence of stellar multiplicity on planet formation. I. Evidence of suppressed planet formation due to stellar companions within 20 au and validation of four planets from the Kepler multiple planet candidates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Ji; Fischer, Debra A.; Xie, Ji-Wei

2014-03-01

The planet occurrence rate for multiple stars is important in two aspects. First, almost half of stellar systems in the solar neighborhood are multiple systems. Second, the comparison of the planet occurrence rate for multiple stars to that for single stars sheds light on the influence of stellar multiplicity on planet formation and evolution. We developed a method of distinguishing planet occurrence rates for single and multiple stars. From a sample of 138 bright (K{sub P} < 13.5) Kepler multi-planet candidate systems, we compared the stellar multiplicity rate of these planet host stars to that of field stars. Using dynamicalmore » stability analyses and archival Doppler measurements, we find that the stellar multiplicity rate of planet host stars is significantly lower than field stars for semimajor axes less than 20 AU, suggesting that planet formation and evolution are suppressed by the presence of a close-in companion star at these separations. The influence of stellar multiplicity at larger separations is uncertain because of search incompleteness due to a limited Doppler observation time baseline and a lack of high-resolution imaging observation. We calculated the planet confidence for the sample of multi-planet candidates and find that the planet confidences for KOI 82.01, KOI 115.01, KOI 282.01, and KOI 1781.02 are higher than 99.7% and thus validate the planetary nature of these four planet candidates. This sample of bright Kepler multi-planet candidates with refined stellar and orbital parameters, planet confidence estimation, and nearby stellar companion identification offers a well-characterized sample for future theoretical and observational study.« less

Kepler-444 Planetary System Artist Concept

NASA Image and Video Library

2015-01-28

The tightly packed system, named Kepler-444, is home to five small planets in very compact orbits. The planets were detected from the dimming that occurs when they transit the disk of their parent star, as shown in this artist conception.

Validating the Presence of a Moon Orbiting Kepler-1625b

NASA Astrophysics Data System (ADS)

Teachey, Alex

2017-08-01

The Hunt for Exomoons with Kepler (HEK) project has been engaged in the search for exomoons for the past several years, but so far no reliable exomoon detection can be found in the literature. After our largest survey to date, we have recently detected a strong candidate moon signal in the light curve of Kepler-1625b. The planet exhibits three transits in the Kepler data (P 287 days), in which we detect out-of-transit flux dips consistent with the presence of a large moon to greater than 4 sigma confidence. We propose to observe the next transit of the planet, which will occur October 29th, 2017 (Cycle-25), in the near-infrared using the Wide Field Camera 3 instrument on HST. We request 26 orbits of the telescope, which will allow us to capture the full planet-moon transit event and provide an opportunity to measure the transmission spectra of both the planet and the moon. We anticipate that the proposed measurements would be sufficient to confirm the first unambiguous detection of a moon beyond our Solar System.

Kepler-90 system (Artist's Concept)

NASA Image and Video Library

2017-12-14

Our solar system now is tied for most number of planets around a single star, with the recent discovery of an eighth planet circling Kepler-90, a Sun-like star 2,545 light years from Earth. The planet was discovered in data from NASA's Kepler Space Telescope. The newly-discovered Kepler-90i -- a sizzling hot, rocky planet that orbits its star once every 14.4 days -- was found using machine learning from Google. Machine learning is an approach to artificial intelligence in which computers "learn." In this case, computers learned to identify planets by finding in Kepler data instances where the telescope recorded changes in starlight caused by planets beyond our solar system, known as exoplanets. https://photojournal.jpl.nasa.gov/catalog/PIA22192

Kepler

NASA Technical Reports Server (NTRS)

Howell, Steve B.

2011-01-01

The NASA Kepler mission recently announced over 1200 exoplanet candidates. While some are common Hot Jupiters, a large number are Neptune size and smaller, transit depths suggest sizes down to the radius of Earth. The Kepler project has a fairly high confidence that most of these candidates are real exoplanets. Many analysis steps and lessons learned from Kepler light curves are used during the vetting process. This talk will cover some new results in the areas of stellar variability, solar systems with multiple planets, and how transit-like signatures are vetted for false positives, especially those indicative of small planets.

EXTRASOLAR BINARY PLANETS. II. DETECTABILITY BY TRANSIT OBSERVATIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lewis, K. M.; Ida, S.; Ochiai, H.

2015-05-20

We discuss the detectability of gravitationally bound pairs of gas-giant planets (which we call “binary planets”) in extrasolar planetary systems that are formed through orbital instability followed by planet–planet dynamical tides during their close encounters, based on the results of N-body simulations by Ochiai et al. (Paper I). Paper I showed that the formation probability of a binary is as much as ∼10% for three giant planet systems that undergo orbital instability, and after post-capture long-term tidal evolution, the typical binary separation is three to five times the sum of the physical radii of the planets. The binary planets aremore » stable during the main-sequence lifetime of solar-type stars, if the stellarcentric semimajor axis of the binary is larger than 0.3 AU. We show that detecting modulations of transit light curves is the most promising observational method to detect binary planets. Since the likely binary separations are comparable to the stellar diameter, the shape of the transit light curve is different from transit to transit, depending on the phase of the binary’s orbit. The transit durations and depth for binary planet transits are generally longer and deeper than those for the single planet case. We point out that binary planets could exist among the known inflated gas-giant planets or objects classified as false positive detections at orbital radii ≳0.3 AU, propose a binary planet explanation for the CoRoT candidate SRc01 E2 1066, and show that binary planets are likely to be present in, and could be detected using, Kepler-quality data.« less

The Kepler End-to-End Model: Creating High-Fidelity Simulations to Test Kepler Ground Processing

NASA Technical Reports Server (NTRS)

Bryson, Stephen T.; Jenkins, Jon M.; Peters, Dan J.; Tenenbaum, Peter P.; Klaus, Todd C.; Gunter, Jay P.; Cote, Miles T.; Caldwell, Douglas A.

2010-01-01

The Kepler mission is designed to detect the transit of Earth-like planets around Sun-like stars by observing 100,000 stellar targets. Developing and testing the Kepler ground-segment processing system, in particular the data analysis pipeline, requires high-fidelity simulated data. This simulated data is provided by the Kepler End-to-End Model (ETEM). ETEM simulates the astrophysics of planetary transits and other phenomena, properties of the Kepler spacecraft and the format of the downlinked data. Major challenges addressed by ETEM include the rapid production of large amounts of simulated data, extensibility and maintainability.

Improving the Accuracy of Planet Occurrence Rates from Kepler Using Approximate Bayesian Computation

NASA Astrophysics Data System (ADS)

Hsu, Danley C.; Ford, Eric B.; Ragozzine, Darin; Morehead, Robert C.

2018-05-01

We present a new framework to characterize the occurrence rates of planet candidates identified by Kepler based on hierarchical Bayesian modeling, approximate Bayesian computing (ABC), and sequential importance sampling. For this study, we adopt a simple 2D grid in planet radius and orbital period as our model and apply our algorithm to estimate occurrence rates for Q1–Q16 planet candidates orbiting solar-type stars. We arrive at significantly increased planet occurrence rates for small planet candidates (R p < 1.25 R ⊕) at larger orbital periods (P > 80 day) compared to the rates estimated by the more common inverse detection efficiency method (IDEM). Our improved methodology estimates that the occurrence rate density of small planet candidates in the habitable zone of solar-type stars is {1.6}-0.5+1.2 per factor of 2 in planet radius and orbital period. Additionally, we observe a local minimum in the occurrence rate for strong planet candidates marginalized over orbital period between 1.5 and 2 R ⊕ that is consistent with previous studies. For future improvements, the forward modeling approach of ABC is ideally suited to incorporating multiple populations, such as planets, astrophysical false positives, and pipeline false alarms, to provide accurate planet occurrence rates and uncertainties. Furthermore, ABC provides a practical statistical framework for answering complex questions (e.g., frequency of different planetary architectures) and providing sound uncertainties, even in the face of complex selection effects, observational biases, and follow-up strategies. In summary, ABC offers a powerful tool for accurately characterizing a wide variety of astrophysical populations.

Kepler Mission Website: Portal to the International Year of Astronomy

NASA Astrophysics Data System (ADS)

Harman, Pamela; DeVore, E.; Gould, A.; Koch, D.

2008-05-01

The 400th anniversary of Galileo's telescope is an opportunity to turn the public's eyes skyward and to the universe beyond the solar system. The Kepler Mission, launching in 2009, the International Year of Astronomy (IYA) will is specifically designed to survey our region of the Milky Way galaxy to detect and characterize hundreds of Earth-size and smaller planets in or near the habitable zone, using the transit method of detection. The habitable zone encompasses the distances from a star where liquid water can exist on a planet's surface. Results from this mission will allow us to place our solar system within the continuum of planetary systems in the Galaxy. The Kepler Mission is a NASA Discovery Program Mission. The Kepler Mission website http://www.kepler.arc.nasa.gov/ offers classroom activity lesson plans Detecting Planet Transits, The Human Orrery, and Morning Star and Evening Star. The activities are suitable for the informal science education realm. The spacecraft paper model and LEGO model orrerey can be used in the classroom by teachers or at home by families. The mission simulation and animation, as well as lessons and models highlight the science concepts critical to employing the transit method of detection, Kepler's Laws. The Send Your Name to Space on Kepler Spacecraft provides a certificate of participation for all individuals that submit there name to be listed on a DVD placed on the spacecraft. This poster will provide details on each of the items described.

Had the planet Mars not existed: Kepler's equant model and its physical consequences

NASA Astrophysics Data System (ADS)

Bracco, C.; Provost, J.-P.

2009-09-01

We examine the equant model for the motion of planets, which was the starting point of Kepler's investigations before he modified it because of Mars observations. We show that, up to first order in eccentricity, this model implies for each orbit a velocity, which satisfies Kepler's second law and Hamilton's hodograph, and a centripetal acceleration with an r-2 dependence on the distance to the Sun. If this dependence is assumed to be universal, Kepler's third law follows immediately. This elementary exercise in kinematics for undergraduates emphasizes the proximity of the equant model coming from ancient Greece with our present knowledge. It adds to its historical interest a didactical relevance concerning, in particular, the discussion of the Aristotelian or Newtonian conception of motion.

The Kepler Mission and the International Year of Astronomy

NASA Astrophysics Data System (ADS)

Harman, Pamela; DeVore, E.; Gould, A.; Koch, D.

2008-05-01

Johannes Kepler was one of Galileo's contemporaries, publishing New Astronomy defining his first two laws, nearly 400 years ago, in 1609. It is a fitting tribute that the Kepler Mission launches in 2009. Kepler continued his studies of motion and made observations of satellites of Jupiter, and published his third law. We now recognize Kepler's laws as 1. Planets move in elliptical; 2. The planets move such that the line between the Sun and the Planet sweeps out equal areas in equal time no matter where in the orbit; and 3. The square of the period of the orbit of a planet is proportional to the mean distance from the Sun cubed. Kepler's laws were deduced empirically from the motions of the planet Mars in the early 17th century, before Newton deduced the law of gravity and his laws of motion. The Kepler Mission, a NASA Discovery mission, is specifically designed to survey our region of the Milky Way galaxy to detect and characterize hundreds of Earth-size and smaller planets in or near the habitable zone. The habitable zone encompasses the distances from a star where liquid water can exist on a planet's surface. Results from this mission will allow us to place our solar system within the continuum of planetary systems in the Galaxy. The Mission Education and Public Outreach (EPO) Program has developed a Night Sky Network (NSN) outreach kit, Shadows and Silhouettes. This NSN kit is used by amateur astronomers at school and public observing events to illustrate a transit, and explain eclipses.

Know the Planet, Know the Star: Precise Stellar Densities from Kepler Transit Light Curves

NASA Astrophysics Data System (ADS)

Sandford, Emily; Kipping, David

2017-12-01

The properties of a transiting planet’s host star are written in its transit light curve. The light curve can reveal the stellar density ({ρ }* ) and the limb-darkening profile in addition to the characteristics of the planet and its orbit. For planets with strong prior constraints on orbital eccentricity, we may measure these stellar properties directly from the light curve; this method promises to aid greatly in the characterization of transiting planet host stars targeted by the upcoming NASA Transiting Exoplanet Survey Satellite mission and any long-period, singly transiting planets discovered in the same systems. Using Bayesian inference, we fit a transit model, including a nonlinear limb-darkening law, to 66 Kepler transiting planet hosts to measure their stellar properties. We present posterior distributions of ρ *, limb-darkening coefficients, and other system parameters for these stars. We measure densities to within 5% for the majority of our target stars, with the dominant precision-limiting factor being the signal-to-noise ratio of the transits. Of our measured stellar densities, 95% are in 3σ or better agreement with previously published literature values. We make posterior distributions for all of our target Kepler objects of interest available online at 10.5281/zenodo.1028515.

Detectability of the Reflection Signal from Inner Planets

NASA Technical Reports Server (NTRS)

Borucki, W. J.; Jenkins, J. M.; Scargle, J.; Koch, D.; Doyle, L. R.; Cuzzi, Jeffrey (Technical Monitor)

1996-01-01

Mayor and Queloz (1996) and Marcy and Butler (1996) have found massive planets with orbital periods Tp=approx.4 days around two solar-like stars (51 Pegasi and v Andromeda). These planets are most likely similar in size and composition to the gas giants in our solar system (Burrows et al 1996). Based on this expectation and assuming the same albedo as Jupiter, we examined the feasibility of searching for similar planets with a dedicated space-based 1-m telescope. The Kepler mission will survey approximately 70,000 main-sequence dwarf stars from 9 to 14 mag continuously for four years to detect transiting Earthlike planets. Based on the detection statistics of Marcy and Butler, we expect to detect 1400 inner-orbit giant planets. Such planets in a much wider range of orbital inclinations (i) will produce nearly sinusoidal modulations of the star light flux due to the varying planetary phases. The relative signal amplitudes are of order 2x10(exp -5) and decrease as Tp(exp 4/3) for i >> 0deg. We estimated the expected signal to noise ratio (SNR) using the solar irradiance measurements from the ACRIM 1 experiment along with expected shot and detector noises. The figure shows SNR as a function of Tp for a 12 mag star, and indicates the planet radius required for detection. The survey will be sensitive to planets with periods from 12 hr to approx.8 days at the 6 sigma level.

Measurements of Kepler Planet Masses and Eccentricities from Transit Timing Variations: Analytic and N-body Results

NASA Astrophysics Data System (ADS)

Hadden, Sam; Lithwick, Yoram

2015-12-01

Several Kepler planets reside in multi-planet systems where gravitational interactions result in transit timing variations (TTVs) that provide exquisitely sensitive probes of their masses of and orbits. Measuring these planets' masses and orbits constrains their bulk compositions and can provide clues about their formation. However, inverting TTV measurements in order to infer planet properties can be challenging: it involves fitting a nonlinear model with a large number of parameters to noisy data, often with significant degeneracies between parameters. I present results from two complementary approaches to TTV inversion: Markov chain Monte Carlo simulations that use N-body integrations to compute transit times and a simplified analytic model for computing the TTVs of planets near mean motion resonances. The analytic model allows for straightforward interpretations of N-body results and provides an independent estimate of parameter uncertainties that can be compared to MCMC results which may be sensitive to factors such as priors. We have conducted extensive MCMC simulations along with analytic fits to model the TTVs of dozens of Kepler multi-planet systems. We find that the bulk of these sub-Jovian planets have low densities that necessitate significant gaseous envelopes. We also find that the planets' eccentricities are generally small but often definitively non-zero.

BEER ANALYSIS OF KEPLER AND CoRoT LIGHT CURVES. I. DISCOVERY OF KEPLER-76b: A HOT JUPITER WITH EVIDENCE FOR SUPERROTATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Faigler, S.; Tal-Or, L.; Mazeh, T.

We present the first case in which the BEER algorithm identified a hot Jupiter in the Kepler light curve, and its reality was confirmed by orbital solutions based on follow-up spectroscopy. The companion Kepler-76b was identified by the BEER algorithm, which detected the BEaming (sometimes called Doppler boosting) effect together with the Ellipsoidal and Reflection/emission modulations (BEER), at an orbital period of 1.54 days, suggesting a planetary companion orbiting the 13.3 mag F star. Further investigation revealed that this star appeared in the Kepler eclipsing binary catalog with estimated primary and secondary eclipse depths of 5 Multiplication-Sign 10{sup -3} andmore » 1 Multiplication-Sign 10{sup -4}, respectively. Spectroscopic radial velocity follow-up observations with Tillinghast Reflector Echelle Spectrograph and SOPHIE confirmed Kepler-76b as a transiting 2.0 {+-} 0.26 M{sub Jup} hot Jupiter. The mass of a transiting planet can be estimated from either the beaming or the ellipsoidal amplitude. The ellipsoidal-based mass estimate of Kepler-76b is consistent with the spectroscopically measured mass while the beaming-based estimate is significantly inflated. We explain this apparent discrepancy as evidence for the superrotation phenomenon, which involves eastward displacement of the hottest atmospheric spot of a tidally locked planet by an equatorial superrotating jet stream. This phenomenon was previously observed only for HD 189733b in the infrared. We show that a phase shift of 10. Degree-Sign 3 {+-} 2. Degree-Sign 0 of the planet reflection/emission modulation, due to superrotation, explains the apparently inflated beaming modulation, resolving the ellipsoidal/beaming amplitude discrepancy. Kepler-76b is one of very few confirmed planets in the Kepler light curves that show BEER modulations and the first to show superrotation evidence in the Kepler band. Its discovery illustrates for the first time the ability of the BEER algorithm to detect

The Kepler Follow-up Observation Program. I. A Catalog of Companions to Kepler Stars from High-Resolution Imaging

NASA Astrophysics Data System (ADS)

Furlan, E.; Ciardi, D. R.; Everett, M. E.; Saylors, M.; Teske, J. K.; Horch, E. P.; Howell, S. B.; van Belle, G. T.; Hirsch, L. A.; Gautier, T. N., III; Adams, E. R.; Barrado, D.; Cartier, K. M. S.; Dressing, C. D.; Dupree, A. K.; Gilliland, R. L.; Lillo-Box, J.; Lucas, P. W.; Wang, J.

2017-02-01

We present results from high-resolution, optical to near-IR imaging of host stars of Kepler Objects of Interest (KOIs), identified in the original Kepler field. Part of the data were obtained under the Kepler imaging follow-up observation program over six years (2009-2015). Almost 90% of stars that are hosts to planet candidates or confirmed planets were observed. We combine measurements of companions to KOI host stars from different bands to create a comprehensive catalog of projected separations, position angles, and magnitude differences for all detected companion stars (some of which may not be bound). Our compilation includes 2297 companions around 1903 primary stars. From high-resolution imaging, we find that ˜10% (˜30%) of the observed stars have at least one companion detected within 1″ (4″). The true fraction of systems with close (≲4″) companions is larger than the observed one due to the limited sensitivities of the imaging data. We derive correction factors for planet radii caused by the dilution of the transit depth: assuming that planets orbit the primary stars or the brightest companion stars, the average correction factors are 1.06 and 3.09, respectively. The true effect of transit dilution lies in between these two cases and varies with each system. Applying these factors to planet radii decreases the number of KOI planets with radii smaller than 2 {R}\\oplus by ˜2%-23% and thus affects planet occurrence rates. This effect will also be important for the yield of small planets from future transit missions such as TESS.

Kepler-424 b: A 'lonely' hot Jupiter that found A companion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Endl, Michael; Caldwell, Douglas A.; Barclay, Thomas

Hot Jupiter systems provide unique observational constraints for migration models in multiple systems and binaries. We report on the discovery of the Kepler-424 (KOI-214) two-planet system, which consists of a transiting hot Jupiter (Kepler-424b) in a 3.31 day orbit accompanied by a more massive outer companion in an eccentric (e = 0.3) 223 day orbit. The outer giant planet, Kepler-424c, is not detected transiting the host star. The masses of both planets and the orbital parameters for the second planet were determined using precise radial velocity (RV) measurements from the Hobby-Eberly Telescope (HET) and its High Resolution Spectrograph (HRS). Inmore » stark contrast to smaller planets, hot Jupiters are predominantly found to be lacking any nearby additional planets; they appear to be {sup l}onely{sup .} This might be a consequence of these systems having a highly dynamical past. The Kepler-424 planetary system has a hot Jupiter in a multiple system, similar to υ Andromedae. We also present our results for Kepler-422 (KOI-22), Kepler-77 (KOI-127), Kepler-43 (KOI-135), and Kepler-423 (KOI-183). These results are based on spectroscopic data collected with the Nordic Optical Telescope (NOT), the Keck 1 telescope, and HET. For all systems, we rule out false positives based on various follow-up observations, confirming the planetary nature of these companions. We performed a comparison with planetary evolutionary models which indicate that these five hot Jupiters have heavy element contents between 20 and 120 M {sub ⊕}.« less

VizieR Online Data Catalog: Kepler multiple transiting planet systems (Wang+, 2015)

NASA Astrophysics Data System (ADS)

Wang, J.; Fischer, D. A.; Xie, J.-W.; Ciardi, D. R.

2017-10-01

The sample of MTPSs remains the same as that in Wang et al. (2014, J/ApJ/783/4). From the NASA Exoplanet Archive (http://exoplanetarchive.ipac.caltech.edu), we select Kepler objects of interest (KOIs) that satisfy the following criteria: (1) disposition of either Candidate or Confirmed; (2) with at least two planet candidates; (3) Kepler magnitude (KP) brighter than 13.5. The above selection criteria resulted in 138 MTPSs in Wang et al. (2014, J/ApJ/783/4). With the updated Exoplanet Archive, the selection criteria resulted in 208 MTPSs. In this paper, we focus on the 138 MTPSs to be consistent with previous work. (4 data files).

Kepler: A Search for Terrestrial Planets - Kepler Data Characterization Handbook

NASA Technical Reports Server (NTRS)

Van Cleve, Jeffrey; Christiansen, J. L.; Jenkins, J. M.; Caldwell, D. A.; Barclay, T.; Bryson, S. T.; Burke, C. J.; Campbell, J.; Catanzarite, J.; Clarke, B. D.;

Optimizing the TESS Planet Finding Pipeline

NASA Astrophysics Data System (ADS)

Chitamitara, Aerbwong; Smith, Jeffrey C.; Tenenbaum, Peter; TESS Science Processing Operations Center

2017-10-01

The Transiting Exoplanet Survey Satellite (TESS) is a new NASA planet finding all-sky survey that will observe stars within 200 light years and 10-100 times brighter than that of the highly successful Kepler mission. TESS is expected to detect ~1000 planets smaller than Neptune and dozens of Earth size planets. As in the Kepler mission, the Science Processing Operations Center (SPOC) processing pipeline at NASA Ames Research center is tasked with calibrating the raw pixel data, generating systematic error corrected light curves and then detecting and validating transit signals. The Transiting Planet Search (TPS) component of the pipeline must be modified and tuned for the new data characteristics in TESS. For example, due to each sector being viewed for as little as 28 days, the pipeline will be identifying transiting planets based on a minimum of two transit signals rather than three, as in the Kepler mission. This may result in a significantly higher false positive rate. The study presented here is to measure the detection efficiency of the TESS pipeline using simulated data. Transiting planets identified by TPS are compared to transiting planets from the simulated transit model using the measured epochs, periods, transit durations and the expected detection statistic of injected transit signals (expected MES). From the comparisons, the recovery and false positive rates of TPS is measured. Measurements of recovery in TPS are then used to adjust TPS configuration parameters to maximize the planet recovery rate and minimize false detections. The improvements in recovery rate between initial TPS conditions and after various adjustments will be presented and discussed.

Microlensing of Kepler stars as a method of detecting primordial black hole dark matter.

PubMed

Griest, Kim; Lehner, Matthew J; Cieplak, Agnieszka M; Jain, Bhuvnesh

2011-12-02

If the dark matter consists of primordial black holes (PBHs), we show that gravitational lensing of stars being monitored by NASA's Kepler search for extrasolar planets can cause significant numbers of detectable microlensing events. A search through the roughly 150,000 light curves would result in large numbers of detectable events for PBHs in the mass range 5×10(-10) M(⊙) to 10(-4) M(⊙). Nondetection of these events would close almost 2 orders of magnitude of the mass window for PBH dark matter. The microlensing rate is higher than previously noticed due to a combination of the exceptional photometric precision of the Kepler mission and the increase in cross section due to the large angular sizes of the relatively nearby Kepler field stars. We also present a new formalism for calculating optical depth and microlensing rates in the presence of large finite-source effects. © 2011 American Physical Society

PLANET HUNTERS. VIII. CHARACTERIZATION OF 41 LONG-PERIOD EXOPLANET CANDIDATES FROM KEPLER ARCHIVAL DATA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Ji; Fischer, Debra A.; Picard, Alyssa

2015-12-20

The census of exoplanets is incomplete for orbital distances larger than 1 AU. Here, we present 41 long-period planet candidates in 38 systems identified by Planet Hunters based on Kepler archival data (Q0–Q17). Among them, 17 exhibit only one transit, 14 have two visible transits, and 10 have more than three visible transits. For planet candidates with only one visible transit, we estimate their orbital periods based on transit duration and host star properties. The majority of the planet candidates in this work (75%) have orbital periods that correspond to distances of 1–3 AU from their host stars. We conduct follow-up imaging and spectroscopic observationsmore » to validate and characterize planet host stars. In total, we obtain adaptive optics images for 33 stars to search for possible blending sources. Six stars have stellar companions within 4″. We obtain high-resolution spectra for 6 stars to determine their physical properties. Stellar properties for other stars are obtained from the NASA Exoplanet Archive and the Kepler Stellar Catalog by Huber et al. We validate 7 planet candidates that have planet confidence over 0.997 (3σ level). These validated planets include 3 single-transit planets (KIC-3558849b, KIC-5951458b, and KIC-8540376c), 3 planets with double transits (KIC-8540376b, KIC-9663113b, and KIC-10525077b), and 1 planet with four transits (KIC-5437945b). This work provides assessment regarding the existence of planets at wide separations and the associated false positive rate for transiting observation (17%–33%). More than half of the long-period planets with at least three transits in this paper exhibit transit timing variations up to 41 hr, which suggest additional components that dynamically interact with the transiting planet candidates. The nature of these components can be determined by follow-up radial velocity and transit observations.« less

Towards a Comprehensive Understanding of Planet Occurrence Rates: Extending the Kepler Legacy Across a Wide Stellar Parameter Space with K2

NASA Astrophysics Data System (ADS)

Akeson, Rachel

Measuring the occurrence rate of extrasolar planets is one of the most fundamental constraints on our understanding of planets throughout the Galaxy. By studying planet populations across a wide parameter space in stellar age, type, metallicity, and multiplicity, we can inform planet formation, migration and evolution theories. The ground-based ELTs and the flagship space missions that NASA is planning in the next decades and beyond will be designed to make the first observations of potential biomarkers in the atmospheres of extrasolar planets understanding how common these planets and how they are distributed will be crucial for this effort. One of the most important results of the main Kepler mission was a measurement of the frequency of planets orbiting FGK dwarfs. Although that result is crucial for estimating the frequency of planetary systems orbiting middle-aged Sun-like stars, the majority of stars in the galaxy have lower masses. We propose to extend the Kepler occurrence rates to lower stellar masses by using publicly available data from the second-generation K2 mission to estimate the frequency of planets orbiting low-mass stars. The confluence of the lower temperature, smaller size, and relative abundance of M dwarfs makes them attractive and efficient targets for habitable planet detection and characterization. The archived K2 data contain nearly an order of magnitude more M dwarfs than the original Kepler data set ( 30,000 compared to 3700), allowing us to constrain occurrence rates both more precisely and with more granularity across the M dwarf parameter range. We will also take advantage of the wide variety of stellar environments sampled by the community-driven K2 mission to estimate the frequency of planets orbiting stars with a range of metallicities and ages. The K2 mission has observed several clusters across a wide range of ages, including the Upper Scorpius OB association (10My old), the Pleiades cluster (115My old), and the Hyades and

A SEMI-ANALYTICAL MODEL OF VISIBLE-WAVELENGTH PHASE CURVES OF EXOPLANETS AND APPLICATIONS TO KEPLER- 7 B AND KEPLER- 10 B

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Renyu; Demory, Brice-Olivier; Seager, Sara

2015-03-20

Kepler has detected numerous exoplanet transits by measuring stellar light in a single visible-wavelength band. In addition to detection, the precise photometry provides phase curves of exoplanets, which can be used to study the dynamic processes on these planets. However, the interpretation of these observations can be complicated by the fact that visible-wavelength phase curves can represent both thermal emission and scattering from the planets. Here we present a semi-analytical model framework that can be applied to study Kepler and future visible-wavelength phase curve observations of exoplanets. The model efficiently computes reflection and thermal emission components for both rocky andmore » gaseous planets, considering both homogeneous and inhomogeneous surfaces or atmospheres. We analyze the phase curves of the gaseous planet Kepler- 7 b and the rocky planet Kepler- 10 b using the model. In general, we find that a hot exoplanet’s visible-wavelength phase curve having a significant phase offset can usually be explained by two classes of solutions: one class requires a thermal hot spot shifted to one side of the substellar point, and the other class requires reflective clouds concentrated on the same side of the substellar point. Particularly for Kepler- 7 b, reflective clouds located on the west side of the substellar point can best explain its phase curve. The reflectivity of the clear part of the atmosphere should be less than 7% and that of the cloudy part should be greater than 80%, and the cloud boundary should be located at 11° ± 3° to the west of the substellar point. We suggest single-band photometry surveys could yield valuable information on exoplanet atmospheres and surfaces.« less

Densities and eccentricities of 139 Kepler planets from transit time variations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hadden, Sam; Lithwick, Yoram

2014-05-20

We extract densities and eccentricities of 139 sub-Jovian planets by analyzing transit time variations (TTVs) obtained by the Kepler mission through Quarter 12. We partially circumvent the degeneracies that plague TTV inversion with the help of an analytical formula for the TTV. From the observed TTV phases, we find that most of these planets have eccentricities of the order of a few percent. More precisely, the rms eccentricity is 0.018{sub −0.004}{sup +0.005}, and planets smaller than 2.5 R {sub ⊕} are around twice as eccentric as those bigger than 2.5 R {sub ⊕}. We also find a best-fit density-radius relationshipmore » ρ ≈ 3 g cm{sup –3} × (R/3 R {sub ⊕}){sup –2.3} for the 56 planets that likely have small eccentricity and hence small statistical correction to their masses. Many planets larger than 2.5 R {sub ⊕} are less dense than water, implying that their radii are largely set by a massive hydrogen atmosphere.« less

Prevalence of Earth-size planets orbiting Sun-like stars.

PubMed

Petigura, Erik A; Howard, Andrew W; Marcy, Geoffrey W

2013-11-26

Determining whether Earth-like planets are common or rare looms as a touchstone in the question of life in the universe. We searched for Earth-size planets that cross in front of their host stars by examining the brightness measurements of 42,000 stars from National Aeronautics and Space Administration's Kepler mission. We found 603 planets, including 10 that are Earth size ( ) and receive comparable levels of stellar energy to that of Earth (1 - 2 R[Symbol: see text] ). We account for Kepler's imperfect detectability of such planets by injecting synthetic planet-caused dimmings into the Kepler brightness measurements and recording the fraction detected. We find that 11 ± 4% of Sun-like stars harbor an Earth-size planet receiving between one and four times the stellar intensity as Earth. We also find that the occurrence of Earth-size planets is constant with increasing orbital period (P), within equal intervals of logP up to ~200 d. Extrapolating, one finds 5.7(-2.2)(+1.7)% of Sun-like stars harbor an Earth-size planet with orbital periods of 200-400 d.

Kepler Discovery

NASA Image and Video Library

2011-02-02

Jack Lissauer, a planetary scientist and a Kepler science team member at NASA's Ames Research Center, speaks during a news conference, Wednesday, Feb. 2, 2010, at NASA Headquarters in Washington. Scientists using NASA's Kepler, a space telescope, recently discovered six planets made of a mix of rock and gases orbiting a single sun-like star, known as Kepler-11, which is located approximately 2,000 light years from Earth. "It’s amazingly compact, it’s amazingly flat, there’s an amazingly large number of big planets orbiting close to their star - we didn’t know such systems could even exist," he said. Photo Credit: (NASA/Paul E. Alers)

Kepler Discovery

NASA Image and Video Library

2011-02-02

Jack Lissauer, a planetary scientist and a Kepler science team member at NASA's Ames Research Center, speaks during a news conference, Wednesday, Feb. 2, 2010, at NASA Headquarters in Washington. Scientists using NASA's Kepler, a space telescope, recently discovered six planets made of a mix of rock and gases orbiting a single sun-like star, known as Kepler-11, which is located approximately 2,000 light years from Earth."It’s amazingly compact, it’s amazingly flat, there’s an amazingly large number of big planets orbiting close to their star - we didn’t know such systems could even exist." Photo Credit: (NASA/Paul E. Alers)

ATMOSPHERE AND SPECTRAL MODELS OF THE KEPLER-FIELD PLANETS HAT-P-7b AND TrES-2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spiegel, David S.; Burrows, Adam, E-mail: dsp@astro.princeton.ed, E-mail: burrows@astro.princeton.ed

2010-10-10

We develop atmosphere models of two of the three Kepler-field planets that were known prior to the start of the Kepler mission (HAT-P-7b and TrES-2). We find that published Kepler and Spitzer data for HAT-P-7b appear to require an extremely hot upper atmosphere on the dayside, with a strong thermal inversion and little day-night redistribution. The Spitzer data for TrES-2 suggest a mild thermal inversion with moderate day-night redistribution. We examine the effect of nonequilibrium chemistry on TrES-2 model atmospheres and find that methane levels must be adjusted by extreme amounts in order to cause even mild changes in atmosphericmore » structure and emergent spectra. Our best-fit models to the Spitzer data for TrES-2 lead us to predict a low secondary eclipse planet-star flux ratio ({approx}<2 x 10{sup -5}) in the Kepler bandpass, which is consistent with what very recent observations have found. Finally, we consider how the Kepler-band optical flux from a hot exoplanet depends on the strength of a possible extra optical absorber in the upper atmosphere. We find that the optical flux is not monotonic in optical opacity, and the non-monotonicity is greater for brighter, hotter stars.« less

Kepler-447b: a hot-Jupiter with an extremely grazing transit

NASA Astrophysics Data System (ADS)

Lillo-Box, J.; Barrado, D.; Santos, N. C.; Mancini, L.; Figueira, P.; Ciceri, S.; Henning, Th.

2015-05-01

We present the radial velocity confirmation of the extrasolar planet Kepler-447b, initially detected as a candidate by the Kepler mission. In this work, we analyzeits transit signal and the radial velocity data obtained with the Calar Alto Fiber-fed Echelle spectrograph (CAFE). By simultaneously modeling both datasets, we obtain the orbital and physical properties of the system. According to our results, Kepler-447b is a Jupiter-mass planet (Mp = 1.37+0.48-0.46 MJup), with an estimated radius of Rp = 1.65+0.59-0.56 RJup (uncertainties provided in this work are 3σ unless specified). This translates into a sub-Jupiter density. The planet revolves every ~7.8 days in a slightly eccentric orbit (e = 0.123+0.037-0.036) around a G8V star with detected activity in the Kepler light curve. Kepler-447b transits its host with a large impact parameter (b = 1.076+0.112-0.086), which is one of the few planetary grazing transits confirmed so far and the first in the Kepler large crop of exoplanets. We estimate that only around 20% of the projected planet disk occults the stellar disk. The relatively large uncertainties in the planet radius are due to the large impact parameter and short duration of the transit. Planetary transits with large impact parameters (and in particular grazing transits) can be used to detect and analyze interesting configurations, such as additional perturbing bodies, stellar pulsations, rotation of a non-spherical planet, or polar spot-crossing events. All these scenarios will periodically modify the transit properties (depth, duration, and time of mid-transit), which could be detectable with sufficiently accurate photometry. Short-cadence photometric data (at the 1-min level) would help in the search for these exotic configurations in grazing planetary transits like that of Kepler-447b. This system could then be an excellent target for the forthcoming missions TESS and CHEOPS, which will provide the required photometric precision and cadence to study

Kepler-424 b: A "Lonely" Hot Jupiter that Found a Companion

NASA Astrophysics Data System (ADS)

Endl, Michael; Caldwell, Douglas A.; Barclay, Thomas; Huber, Daniel; Isaacson, Howard; Buchhave, Lars A.; Brugamyer, Erik; Robertson, Paul; Cochran, William D.; MacQueen, Phillip J.; Havel, Mathieu; Lucas, Phillip; Howell, Steve B.; Fischer, Debra; Quintana, Elisa; Ciardi, David R.

2014-11-01

Hot Jupiter systems provide unique observational constraints for migration models in multiple systems and binaries. We report on the discovery of the Kepler-424 (KOI-214) two-planet system, which consists of a transiting hot Jupiter (Kepler-424b) in a 3.31 day orbit accompanied by a more massive outer companion in an eccentric (e = 0.3) 223 day orbit. The outer giant planet, Kepler-424c, is not detected transiting the host star. The masses of both planets and the orbital parameters for the second planet were determined using precise radial velocity (RV) measurements from the Hobby-Eberly Telescope (HET) and its High Resolution Spectrograph (HRS). In stark contrast to smaller planets, hot Jupiters are predominantly found to be lacking any nearby additional planets; they appear to be "lonely". This might be a consequence of these systems having a highly dynamical past. The Kepler-424 planetary system has a hot Jupiter in a multiple system, similar to \\upsilon Andromedae. We also present our results for Kepler-422 (KOI-22), Kepler-77 (KOI-127), Kepler-43 (KOI-135), and Kepler-423 (KOI-183). These results are based on spectroscopic data collected with the Nordic Optical Telescope (NOT), the Keck 1 telescope, and HET. For all systems, we rule out false positives based on various follow-up observations, confirming the planetary nature of these companions. We performed a comparison with planetary evolutionary models which indicate that these five hot Jupiters have heavy element contents between 20 and 120 M ⊕. Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Stanford University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen.

Kepler-432 b: a massive planet in a highly eccentric orbit transiting a red giant

NASA Astrophysics Data System (ADS)

Ciceri, S.; Lillo-Box, J.; Southworth, J.; Mancini, L.; Henning, Th.; Barrado, D.

2015-01-01

We report the first disclosure of the planetary nature of Kepler-432 b (aka Kepler object of interest KOI-1299.01). We accurately constrained its mass and eccentricity by high-precision radial velocity measurements obtained with the CAFE spectrograph at the CAHA 2.2-m telescope. By simultaneously fitting these new data and Kepler photometry, we found that Kepler-432 b is a dense transiting exoplanet with a mass of Mp = 4.87 ± 0.48MJup and radius of Rp = 1.120 ± 0.036RJup. The planet revolves every 52.5 d around a K giant star that ascends the red giant branch, and it moves on a highly eccentric orbit with e = 0.535 ± 0.030. By analysing two near-IR high-resolution images, we found that a star is located at 1.1'' from Kepler-432, but it is too faint to cause significant effects on the transit depth. Together with Kepler-56 and Kepler-91, Kepler-432 occupies an almost-desert region of parameter space, which is important for constraining the evolutionary processes of planetary systems. RV data (Table A.1) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/573/L5

A New Way to Confirm Planet Candidates

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2016-05-01

What was the big deal behind the Kepler news conference yesterday? Its not just that the number of confirmed planets found by Kepler has more than doubled (though thats certainly exciting news!). Whats especially interesting is the way in which these new planets were confirmed.Number of planet discoveries by year since 1995, including previous non-Kepler discoveries (blue), previous Kepler discoveries (light blue) and the newly validated Kepler planets (orange). [NASA Ames/W. Stenzel; Princeton University/T. Morton]No Need for Follow-UpBefore Kepler, the way we confirmed planet candidates was with follow-up observations. The candidate could be validated either by directly imaging (which is rare) or obtaining a large number radial-velocity measurements of the wobble of the planets host star due to the planets orbit. But once Kepler started producing planet candidates, these approaches to validation became less feasible. A lot of Kepler candidates are small and orbit faint stars, making follow-up observations difficult or impossible.This problem is what inspired the development of whats known as probabilistic validation, an analysis technique that involves assessing the likelihood that the candidates signal is caused by various false-positive scenarios. Using this technique allows astronomers to estimate the likelihood of a candidate signal being a true planet detection; if that likelihood is high enough, the planet candidate can be confirmed without the need for follow-up observations.A breakdown of the catalog of Kepler Objects of Interest. Just over half had previously been identified as false positives or confirmed as candidates. 1284 are newly validated, and another 455 have FPP of1090%. [Morton et al. 2016]Probabilistic validation has been used in the past to confirm individual planet candidates in Kepler data, but now Timothy Morton (Princeton University) and collaborators have taken this to a new level: they developed the first code thats designed to do fully

Atmospheres of Two Super-Puffs: Transmission Spectra of Kepler 51b and Kepler 51d

NASA Astrophysics Data System (ADS)

Roberts, Jessica; Berta-Thompson, Zachory K.; Desert, Jean-Michel; Deck, Katherine; Fabrycky, Daniel; Fortney, Jonathan J.; Line, Michael R.; Lopez, Eric; Masuda, Kento; Morley, Caroline; Sanchis Ojeda, Roberto; Winn, Joshua N.

2018-06-01

The Kepler 51 system hosts three transiting, extremely low-mass, low-density exoplanets. These planets orbit a young G type star at periods of 45, 85 and 130 days, placing them outside of the regime for the inflated hot-Jupiters. Instead, the Kepler 51 planets are part of a rare class of exoplanets: the super-puffs. Models suggest these H/He-rich planets formed outside of the snow-line and migrated inwards, which might imply abundant water in their atmospheres. Because Kepler 51b and 51d have low surface gravities, they also have scale heights 10x larger than a typical hot-Jupiter, making them prime targets for atmospheric investigation. Kepler 51c, while also possessing a large scale height, only grazes its star during transit. We are also presented with a unique opportunity to study two super-puffs in very different temperature regimes around the same star. Therefore, we observed two transits each of both Kepler 51b and 51d with the Hubble Space Telescope’s Wide Field Camera 3 G141 grism spectroscopy. Using these data we created spectroscopic light curves that allow us to compute a transmission spectrum for each planet. We conclude that both planets have a flat transmission spectrum with a precision better than 0.6 scale heights between 1.1 and 1.7 microns. We also analyzed the transit timing variations of each planet by combining re-fitted Kepler mid-transit times with our measured HST times. From these additional timing points, we are able to better constrain the planetary masses and the dynamics of the system. With these updated masses and revisited stellar parameters, we determine precise measurements on the densities of these planets. We will present these results as well as discuss the implications for high altitude aerosols in both Kepler 51b and 51d.

Management and systems engineering of the Kepler mission

NASA Astrophysics Data System (ADS)

Fanson, James; Livesay, Leslie; Frerking, Margaret; Cooke, Brian

2010-07-01

Kepler is the National Aeronautics and Space Administration's (NASA's) first mission capable of detecting Earth-size planets orbiting in the habitable zones around stars other than the sun. Selected for implementation in 2001 and launched in 2009, Kepler seeks to determine whether Earth-like planets are common or rare in the galaxy. The investigation requires a large, space-based photometer capable of simultaneously measuring the brightnesses of 100,000 stars at partper- million level of precision. This paper traces the development of the mission from the perspective of project management and systems engineering and describes various methodologies and tools that were found to be effective. The experience of the Kepler development is used to illuminate lessons that can be applied to future missions.

Management and Systems Engineering of the Kepler Mission

NASA Technical Reports Server (NTRS)

Fanson, James; Livesay, Leslie; Frerking, Margaret; Cooke, Brian

2010-01-01

Kepler is the National Aeronautics and Space Administration's (NASA's) first mission capable of detecting Earth-size planets orbiting in the habitable zones around stars other than the sun. Selected for implementation in 2001 and launched in 2009, Kepler seeks to determine whether Earth-like planets are common or rare in the galaxy. The investigation requires a large, space-based photometer capable of simultaneously measuring the brightnesses of 100,000 stars at part-per-million level of precision. This paper traces the development of the mission from the perspective of project management and systems engineering and describes various methodologies and tools that were found to be effective. The experience of the Kepler development is used to illuminate lessons that can be applied to future missions.

An Earth-sized planet in the habitable zone of a cool star.

PubMed

Quintana, Elisa V; Barclay, Thomas; Raymond, Sean N; Rowe, Jason F; Bolmont, Emeline; Caldwell, Douglas A; Howell, Steve B; Kane, Stephen R; Huber, Daniel; Crepp, Justin R; Lissauer, Jack J; Ciardi, David R; Coughlin, Jeffrey L; Everett, Mark E; Henze, Christopher E; Horch, Elliott; Isaacson, Howard; Ford, Eric B; Adams, Fred C; Still, Martin; Hunter, Roger C; Quarles, Billy; Selsis, Franck

2014-04-18

The quest for Earth-like planets is a major focus of current exoplanet research. Although planets that are Earth-sized and smaller have been detected, these planets reside in orbits that are too close to their host star to allow liquid water on their surfaces. We present the detection of Kepler-186f, a 1.11 ± 0.14 Earth-radius planet that is the outermost of five planets, all roughly Earth-sized, that transit a 0.47 ± 0.05 solar-radius star. The intensity and spectrum of the star's radiation place Kepler-186f in the stellar habitable zone, implying that if Kepler-186f has an Earth-like atmosphere and water at its surface, then some of this water is likely to be in liquid form.

Validation of Small Kepler Transiting Planet Candidates in or near the Habitable Zone

NASA Astrophysics Data System (ADS)

Torres, Guillermo; Kane, Stephen R.; Rowe, Jason F.; Batalha, Natalie M.; Henze, Christopher E.; Ciardi, David R.; Barclay, Thomas; Borucki, William J.; Buchhave, Lars A.; Crepp, Justin R.; Everett, Mark E.; Horch, Elliott P.; Howard, Andrew W.; Howell, Steve B.; Isaacson, Howard T.; Jenkins, Jon M.; Latham, David W.; Petigura, Erik A.; Quintana, Elisa V.

2017-12-01

A main goal of NASA’s Kepler Mission is to establish the frequency of potentially habitable Earth-size planets ({η }\\oplus ). Relatively few such candidates identified by the mission can be confirmed to be rocky via dynamical measurement of their mass. Here we report an effort to validate 18 of them statistically using the BLENDER technique, by showing that the likelihood they are true planets is far greater than that of a false positive. Our analysis incorporates follow-up observations including high-resolution optical and near-infrared spectroscopy, high-resolution imaging, and information from the analysis of the flux centroids of the Kepler observations themselves. Although many of these candidates have been previously validated by others, the confidence levels reported typically ignore the possibility that the planet may transit a star different from the target along the same line of sight. If that were the case, a planet that appears small enough to be rocky may actually be considerably larger and therefore less interesting from the point of view of habitability. We take this into consideration here and are able to validate 15 of our candidates at a 99.73% (3σ) significance level or higher, and the other three at a slightly lower confidence. We characterize the GKM host stars using available ground-based observations and provide updated parameters for the planets, with sizes between 0.8 and 2.9 R ⊕. Seven of them (KOI-0438.02, 0463.01, 2418.01, 2626.01, 3282.01, 4036.01, and 5856.01) have a better than 50% chance of being smaller than 2 R ⊕ and being in the habitable zone of their host stars.

Kepler Mission: A Mission to Find Earth-size Planets in the Habitable Zone

NASA Technical Reports Server (NTRS)

Borucki, W. J.

2003-01-01

The Kepler Mission is a Discovery-class mission designed to continuously monitor the brightness of 100,000 solar-like stars to detect the transits of Earth-size and larger planets. It is a wide field of view photometer Schmidt-type telescope with an array of 42 CCDs. It has a 0.95 m aperture and 1.4 m primary and is designed to attain a photometric precision of 2 parts in 10(exp 5) for 12th magnitude solar-like stars for a 6 hr transit duration. It will continuously observe 100,000 main-sequence stars from 9th to 14th magnitude in the Cygnus constellation for a period of four years with a cadence of 4/hour. An additional 250 stars can be monitored at a cadence of l/minute to do astro-seismology of stars brighter than 11.5 mv. The photometer is scheduled to be launched into heliocentric orbit in 2007. When combined with ground-based spectrometric observations of these stars, the positions of the planets relative to the habitable zone can be found. The spectra of the stars are also used to determine the relationships between the characteristics of terrestrial planets and the characteristics of the stars they orbit. In particular, the association of planet size and occurrence frequency with stellar mass and metallicity will be investigated. Based on the results of the current Doppler-velocity discoveries, over a thousand giant planets will also be found. Information on the albedos and densities of those giants showing transits will be obtained. At the end of the four year mission, hundreds of Earth-size planets should be discovered in and near the HZ of their stars if such planets are common. A null result would imply that terrestrial planets in the HZ are very rare and that life might also be quite rare.

Earth-class Planets Line Up

NASA Image and Video Library

2011-12-20

This chart compares the first Earth-size planets found around a sun-like star to planets in our own solar system, Earth and Venus. NASA Kepler mission discovered the newfound planets, called Kepler-20e and Kepler-20f.

KEPLER Mission: development and overview

NASA Astrophysics Data System (ADS)

Borucki, William J.

2016-03-01

The Kepler Mission is a space observatory launched in 2009 by NASA to monitor 170 000 stars over a period of four years to determine the frequency of Earth-size and larger planets in and near the habitable zone of Sun-like stars, the size and orbital distributions of these planets, and the types of stars they orbit. Kepler is the tenth in the series of NASA Discovery Program missions that are competitively-selected, PI-directed, medium-cost missions. The Mission concept and various instrument prototypes were developed at the Ames Research Center over a period of 18 years starting in 1983. The development of techniques to do the 10 ppm photometry required for Mission success took years of experimentation, several workshops, and the exploration of many ‘blind alleys’ before the construction of the flight instrument. Beginning in 1992 at the start of the NASA Discovery Program, the Kepler Mission concept was proposed five times before its acceptance for mission development in 2001. During that period, the concept evolved from a photometer in an L2 orbit that monitored 6000 stars in a 50 sq deg field-of-view (FOV) to one that was in a heliocentric orbit that simultaneously monitored 170 000 stars with a 105 sq deg FOV. Analysis of the data to date has detected over 4600 planetary candidates which include several hundred Earth-size planetary candidates, over a thousand confirmed planets, and Earth-size planets in the habitable zone (HZ). These discoveries provide the information required for estimates of the frequency of planets in our galaxy. The Mission results show that most stars have planets, many of these planets are similar in size to the Earth, and that systems with several planets are common. Although planets in the HZ are common, many are substantially larger than Earth.

KEPLER Mission: development and overview.

PubMed

Borucki, William J

2016-03-01

The Kepler Mission is a space observatory launched in 2009 by NASA to monitor 170,000 stars over a period of four years to determine the frequency of Earth-size and larger planets in and near the habitable zone of Sun-like stars, the size and orbital distributions of these planets, and the types of stars they orbit. Kepler is the tenth in the series of NASA Discovery Program missions that are competitively-selected, PI-directed, medium-cost missions. The Mission concept and various instrument prototypes were developed at the Ames Research Center over a period of 18 years starting in 1983. The development of techniques to do the 10 ppm photometry required for Mission success took years of experimentation, several workshops, and the exploration of many 'blind alleys' before the construction of the flight instrument. Beginning in 1992 at the start of the NASA Discovery Program, the Kepler Mission concept was proposed five times before its acceptance for mission development in 2001. During that period, the concept evolved from a photometer in an L2 orbit that monitored 6000 stars in a 50 sq deg field-of-view (FOV) to one that was in a heliocentric orbit that simultaneously monitored 170,000 stars with a 105 sq deg FOV. Analysis of the data to date has detected over 4600 planetary candidates which include several hundred Earth-size planetary candidates, over a thousand confirmed planets, and Earth-size planets in the habitable zone (HZ). These discoveries provide the information required for estimates of the frequency of planets in our galaxy. The Mission results show that most stars have planets, many of these planets are similar in size to the Earth, and that systems with several planets are common. Although planets in the HZ are common, many are substantially larger than Earth.

Lifting Transit Signals from the Kepler Noise Floor. I. Discovery of a Warm Neptune

NASA Astrophysics Data System (ADS)

Kunimoto, Michelle; Matthews, Jaymie M.; Rowe, Jason F.; Hoffman, Kelsey

2018-01-01

Light curves from the 4-year Kepler exoplanet hunting mission have been searched for transits by NASA’s Kepler team and others, but there are still important discoveries to be made. We have searched the light curves of 400 Kepler Objects of Interest (KOIs) to find transit signals down to signal-to-noise ratio (S/N) ∼ 6, which is under the limit of S/N ∼ 7.1 that has been commonly adopted as a strict threshold to distinguish between a transit candidate and false alarm. We detect four new and convincing planet candidates ranging in radius from near-Mercury-size to slightly larger than Neptune. We highlight the discovery of KOI-408.05 (period = 637 days; radius = 4.9 R ⊕ incident flux = 0.6 S ⊕), a planet candidate within its host star’s Habitable Zone. We dub this planet a “warm Neptune,” a likely volatile-rich world that deserves closer inspection. KOI-408.05 joins 21 other confirmed and candidate planets in the current Kepler sample with semimajor axes a > 1.4 au. These discoveries are significant as a demonstration that the S/N threshold for detection used by the Kepler project is open to debate.

Kepler Discovery

NASA Image and Video Library

2011-02-02

Douglas Hudgins, a Kepler Program Scientist, speaks during a news conference, Wednesday, Feb. 2, 2010, at NASA Headquarters in Washington. Scientists using NASA's Kepler, a space telescope, recently discovered six planets made of a mix of rock and gases orbiting a single sun-like star, known as Kepler-11, which is located approximately 2,000 light years from Earth. Photo Credit: (NASA/Paul E. Alers)

Data Validation in the Kepler Science Operations Center Pipeline

NASA Technical Reports Server (NTRS)

Wu, Hayley; Twicken, Joseph D.; Tenenbaum, Peter; Clarke, Bruce D.; Li, Jie; Quintana, Elisa V.; Allen, Christopher; Chandrasekaran, Hema; Jenkins, Jon M.; Caldwell, Douglas A.;

The Kepler Mission: A Mission to Determine the Frequency of Inner Planets Near the Habitable Zone of a Wide Range of Stars

NASA Technical Reports Server (NTRS)

Borucki, W. J.; Koch, D. G.; Dunham, E. W.; Jenkins, J. M.

1997-01-01

The surprising discovery of giant planets in inner orbits around solar-like stars has brought into question our understanding of the development and evolution of planetary systems, including our solar system. To make further progress, it is critical to detect and obtain data on the frequency and characteristics of Earth-class planets. The Kepler Mission is designed to be a quick, low-cost approach to accomplish that objective. Transits by Earth-class planets produce a fractional change. in stellar brightness of 5 x 10(exp -5) to 40 x 10(exp -5) lasting for 4 to 16 hours. From the period and depth of the transits, the orbit and size of the planets can be calculated. The proposed instrument is a one-meter aperture photometer with a 12 deg. field-of-view (FOV). To obtain the required precision and to avoid interruptions caused by day-night and seasonal cycles, the photometer will be launched into a heliocentric orbit. It will continuously and simultaneously monitor the flux from 80,000 dwarf stars brighter than 14th magnitude in the Cygnus constellation. The mission tests the hypothesis that the formation of most stars produces Earth-class planets in inner orbits. Based on this assumption and the recent observations that 2% of the stars have giant planets in inner orbits, several types of results are expected from the mission: 1. From transits of Earth-class planets, about 480 planet detections and 60 cases where two or more planets are found in the same system. 2. From transits of giant planets, about 160 detections of inner-orbit planets and 24 detections of outer-orbit planets. 3. From the phase modulation of the reflected light from giant planets, about 1400 planet detections with periods less than a week, albedos for 160 of these giant planets, and densities for seven planets.

The Kepler Mission: A Mission to Determine the Frequency of Inner Planets Neat the Habitable Zone of a Wide Range of Stars

NASA Technical Reports Server (NTRS)

Borucki, W. J.; Koch, D. G.; Dunham, E. W.; Jenkins, J. M.; Young, Richard E. (Technical Monitor)

1997-01-01

The surprising discovery of giant planets in inner orbits around solar-like stars has brought into question our understanding of the development and evolution of planetary systems, including our solar system. To make further progress, it is critical to detect and obtain data on the frequency and characteristics of Earth-class planets. The Kepler Mission is designed to be a quick, low-cost approach to accomplish that objective. Transits by Earth-class planets produce a fractional change in stellar brightness of 5 x 10(exp -5) to 40 x 10(exp -5) lasting for 4 to 16 hours, From the period and depth of the transits, the orbit and size of the planets can be calculated. The proposed instrument is a one-meter aperture photometer with a 12 deg field-of-view (FOV). To obtain the required precision and to avoid interruptions caused by day-night and seasonal cycles, the photometer will be launched into a heliocentric orbit. It will continuously and simultaneously monitor the flux from 80,000 dwarf stars brighter than 14th magnitude in the Cygnus constellation. The mission tests the hypothesis that the formation of most stars produces Earth-class planets in inner orbits. Based on this assumption and the recent observations that 2% of the stars have giant planets in inner orbits, several types of results are expected from the mission: 1. From transits of Earth-class planets, about 480 planet detections and 60 cases where two or more planets are found in the same system. 2. From transits of giant planets, about 160 detections of inner-orbit planets and 24 detections of outer-orbit planets. 3. From the phase modulation of the reflected light from giant planets, about 1400 planet detections with periods less than a week, albedos for 160 of these giant planets, and densities for seven planets.

Kepler Discovery

NASA Image and Video Library

2011-02-02

A scale model of the Kepler space telescope is seen at a news conference, Wednesday, Feb. 2, 2010, at NASA Headquarters in Washington. Scientists using NASA's Kepler, a space telescope, recently discovered six planets made of a mix of rock and gases orbiting a single sun-like star, known as Kepler-11, which is located approximately 2,000 light years from Earth. Photo Credit: (NASA/Paul E. Alers)

No Metallicity Correlation Associated with the Kepler Dichotomy

NASA Astrophysics Data System (ADS)

Munoz Romero, Carlos Eduardo; Kempton, Eliza

2018-01-01

NASA’s Kepler mission has discovered thousands of planetary systems, ∼ 20% of which are found to host multiple transiting planets. This relative paucity (compared to the high fraction of single transiting systems) is postulated to result from a distinction in the architecture between multi-transiting systems and those hosting a single transiting planet: a phenomenon usually referred to as the Kepler dichotomy. We investigate the hypothesis that external giant planets are the main cause behind the over-abundance of single- relative to multi-transiting systems, which would be signaled by higher metallicities in the former sample. To this end, we perform a statistical analysis on the stellar metallicity distribution with respect to planet multiplicity in the Kepler data. We perform our analysis on a variety of samples taken from a population of 1062 Kepler main sequence planetary hosts, using precisely determined metallicities from the California-Kepler survey. Contrary to some predictions, we do not find a significant difference between the stellar metallicities of the single- and multiple-transiting planet systems. However, we do find a 43% upper bound for systems with a single non-giant planet that could also host a hidden giant planet, based on metallicity considerations. While the presence of external giant planets might be one factor behind the Kepler dichotomy, our results also favor alternative explanations. We suggest that additional radial velocity and direct imaging measurements are necessary to constrain the presence of gas giants in systems with a single transiting planet.

100-year DASCH Light Curves of Kepler Planet-Candidate Host Stars

NASA Astrophysics Data System (ADS)

Tang, Sumin; Sasselov, Dimitar; Grindlay, Jonathan; Los, Edward; Servillat, Mathieu

2013-07-01

We present 100 year light curves of Kepler planet-candidate host stars from the Digital Access to a Sky Century at Harvard (DASCH) project. 261 out of 997 host stars have at least 10 good measurements on DASCH scans of the Harvard plates. 109 of them have at least 100 good measurements, including 70% (73 out of 104) of all host stars with g ≤ 13 mag, and 44% (100 out of 228) of all host stars with g ≤ 14 mag. Our typical photometric uncertainty is ˜0.1-0.15 mag. No variation is found at 3σ level for these host stars, including 21 confirmed or candidate hot Jupiter systems which might be expected to show enhanced flares from magnetic interactions between dwarf primaries and their close and relatively massive planet companions.

Kepler constraints on planets near hot Jupiters

PubMed Central

Steffen, Jason H.; Ragozzine, Darin; Fabrycky, Daniel C.; Carter, Joshua A.; Ford, Eric B.; Holman, Matthew J.; Rowe, Jason F.; Welsh, William F.; Borucki, William J.; Boss, Alan P.; Ciardi, David R.; Quinn, Samuel N.

2012-01-01

We present the results of a search for planetary companions orbiting near hot Jupiter planet candidates (Jupiter-size candidates with orbital periods near 3 d) identified in the Kepler data through its sixth quarter of science operations. Special emphasis is given to companions between the 2∶1 interior and exterior mean-motion resonances. A photometric transit search excludes companions with sizes ranging from roughly two-thirds to five times the size of the Earth, depending upon the noise properties of the target star. A search for dynamically induced deviations from a constant period (transit timing variations) also shows no significant signals. In contrast, comparison studies of warm Jupiters (with slightly larger orbits) and hot Neptune-size candidates do exhibit signatures of additional companions with these same tests. These differences between hot Jupiters and other planetary systems denote a distinctly different formation or dynamical history. PMID:22566651

Kepler constraints on planets near hot Jupiters.

PubMed

Steffen, Jason H; Ragozzine, Darin; Fabrycky, Daniel C; Carter, Joshua A; Ford, Eric B; Holman, Matthew J; Rowe, Jason F; Welsh, William F; Borucki, William J; Boss, Alan P; Ciardi, David R; Quinn, Samuel N

2012-05-22

We present the results of a search for planetary companions orbiting near hot Jupiter planet candidates (Jupiter-size candidates with orbital periods near 3 d) identified in the Kepler data through its sixth quarter of science operations. Special emphasis is given to companions between the 21 interior and exterior mean-motion resonances. A photometric transit search excludes companions with sizes ranging from roughly two-thirds to five times the size of the Earth, depending upon the noise properties of the target star. A search for dynamically induced deviations from a constant period (transit timing variations) also shows no significant signals. In contrast, comparison studies of warm Jupiters (with slightly larger orbits) and hot Neptune-size candidates do exhibit signatures of additional companions with these same tests. These differences between hot Jupiters and other planetary systems denote a distinctly different formation or dynamical history.

The Kepler Data Processing Handbook: A Field Guide to Prospecting for Habitable Worlds

NASA Technical Reports Server (NTRS)

Jenkins, Jon M.

2017-01-01

The Kepler telescope hurtled into orbit in March 2009, initiating NASA's first mission to discover Earth-size planets orbiting Sun-like stars. Kepler simultaneously collected data for approximately 165,000 target stars at a time over its four-year mission, identifying over 4700 planet candidates, over 2300 confirmed or validated planets, and over 2100 eclipsing binaries. While Kepler was designed to discover exoplanets, the long-term, ultrahigh photometric precision measurements it achieved made it a premier observational facility for stellar astrophysics, especially in the field of asteroseismology, and for variable stars, such as RR Lyrae. The Kepler Science Operations Center (SOC) was developed at NASA Ames Research Center to process the data acquired by Kepler from pixel-level calibrations all the way to identifying transiting planet signatures and subjecting them to a suite of diagnostic tests to establish or break confidence in their planetary nature. Detecting small, rocky planets transiting Sun-like stars presents a variety of daunting challenges, including achieving an unprecedented photometric precision of 20 ppm on 6.5-hour timescales, and supporting the science operations, management, processing, and repeated reprocessing of the accumulating data stream. A newly revised and expanded version of the Kepler Data Processing Handbook (KDPH) has been released to support the legacy archival products. The KDPH details the theory, design and performance of the algorithms supporting each data processing step. This paper presents an overview of the KDPH and features illustrations of several key algorithms in the Kepler Science Data Processing Pipeline. Kepler was selected as the 10th mission of the Discovery Program. Funding for this mission is provided by NASA, Science Mission Directorate.

Kepler Media Briefing

NASA Image and Video Library

2009-02-19

Jim Fanson, Kepler project manager, at NASA's Jet Propulsion Laboratory in Pasadena, Calif. holds a model of the Kepler spacecraft as he talks about the Kepler mission during a media briefing, Thursday, Feb. 19, 2008, at NASA Headquarters in Washington. Kepler, the first mission with the ability to find planets like earth, is scheduled to launch on March 5, 2009 from Cape Canaveral Air Force Station, Fla. aboard a Delta II rocket. Photo Credit: (NASA/Paul. E. Alers)

More Planets in the Hyades Cluster

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2017-12-01

A few weeks ago, Astrobites reported on a Neptune-sized planet discovered orbiting a star in the Hyades cluster. A separate study submitted at the same time, however, reveals that there may be even more planets lurking in this system.Thanks, KeplerArtists impression of the Kepler spacecraft and the mapping of the fields of the current K2 mission. [NASA]As we learn about the formation and evolution of planets outside of our own solar system, its important that we search for planets throughout different types of star clusters; observing both old and young clusters, for instance, can tell us about planets in different stages of their evolutionary histories. Luckily for us, we have a tool that has been doing exactly this: the Kepler mission.In true holiday spirit, Kepler is the gift that just keeps on giving. Though two of its reaction wheels have failed, Kepler now as its reincarnation, K2 just keeps detecting more planet transits. Whats more, detailed analysis of past Kepler/K2 data with ever more powerful techniques as well as the addition of high-precision parallaxes for stars from Gaia in the near future ensures that the Kepler data set will continue to reveal new exoplanet transits for many years to come.Image of the Hyades cluster, a star cluster that is only 800 million years old. [NASA/ESA/STScI]Hunting in the Young HyadesTwo studies using K2 data were recently submitted on exoplanet discoveries around EPIC 247589423 in the Hyades cluster, a nearby star cluster that is only 800 million years old. Astrobites reported on the first study in October and discussed details about the newly discovered mini-Neptune presented in that study.The second study, led by Andrew Mann (University of Texas at Austin and NASA Hubble Fellow at Columbia University), was published this week. This study presented a slightly different outcome: the authors detect the presence of not just the one, but three exoplanets orbiting EPIC 247589423.New DiscoveriesMann and collaborators searched

Kepler-90 System Compared to Our Solar System (Artist's Concept)

NASA Image and Video Library

2017-12-14

Our solar system now is tied for most number of planets around a single star, with the recent discovery of an eighth planet circling Kepler-90, a Sun-like star 2,545 light years from Earth. The planet was discovered in data from NASA's Kepler Space Telescope. This artist's concept depicts the Kepler-90 system compared with our own solar system. The newly-discovered Kepler-90i -- a sizzling hot, rocky planet that orbits its star once every 14.4 days -- was found using machine learning from Google. Machine learning is an approach to artificial intelligence in which computers "learn." In this case, computers learned to identify planets by finding in Kepler data instances where the telescope recorded changes in starlight caused by planets beyond our solar system, known as exoplanets. https://photojournal.jpl.nasa.gov/catalog/PIA22193

TESTING IN SITU ASSEMBLY WITH THE KEPLER PLANET CANDIDATE SAMPLE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansen, Brad M. S.; Murray, Norm, E-mail: hansen@astro.ucla.edu, E-mail: murray@cita.utoronto.ca

2013-09-20

We present a Monte Carlo model for the structure of low-mass (total mass <25 M{sub ⊕}) planetary systems that form by the in situ gravitational assembly of planetary embryos into final planets. Our model includes distributions of mass, eccentricity, inclination, and period spacing that are based on the simulation of a disk of 20 M{sub ⊕}, forming planets around a solar-mass star, and assuming a power-law surface density distribution that drops with distance a as ∝ a {sup –1.5}. The output of the Monte Carlo model is then subjected to the selection effects that mimic the observations of a transitingmore » planet search such as that performed by the Kepler satellite. The resulting comparison of the output to the properties of the observed sample yields an encouraging agreement in terms of the relative frequencies of multiple-planet systems and the distribution of the mutual inclinations when moderate tidal circularization is taken into account. The broad features of the period distribution and radius distribution can also be matched within this framework, although the model underpredicts the distribution of small period ratios. This likely indicates that some dissipation is still required in the formation process. The most striking deviation between the model and observations is in the ratio of single to multiple systems in that there are roughly 50% more single-planet candidates observed than are produced in any model population. This suggests that some systems must suffer additional attrition to reduce the number of planets or increase the range of inclinations.« less

Systematic Search for Rings around Kepler Planet Candidates: Constraints on Ring Size and Occurrence Rate

NASA Astrophysics Data System (ADS)

Aizawa, Masataka; Masuda, Kento; Kawahara, Hajime; Suto, Yasushi

2018-05-01

We perform a systematic search for rings around 168 Kepler planet candidates with sufficient signal-to-noise ratios that are selected from all of the short-cadence data. We fit ringed and ringless models to their light curves and compare the fitting results to search for the signatures of planetary rings. First, we identify 29 tentative systems, for which the ringed models exhibit statistically significant improvement over the ringless models. The light curves of those systems are individually examined, but we are not able to identify any candidate that indicates evidence for rings. In turn, we find several mechanisms of false positives that would produce ringlike signals, and the null detection enables us to place upper limits on the size of the rings. Furthermore, assuming the tidal alignment between axes of the planetary rings and orbits, we conclude that the occurrence rate of rings larger than twice the planetary radius is less than 15%. Even though the majority of our targets are short-period planets, our null detection provides statistical and quantitative constraints on largely uncertain theoretical models of the origin, formation, and evolution of planetary rings.

Compositional Constraints on the Best Characterized Rocky Exoplanet, Kepler-36 b

NASA Astrophysics Data System (ADS)

Rogers, Leslie; Deck, Katherine; Lissauer, Jack J.; Carter, Joshua A.

2015-01-01

Kepler-36 is an extreme planetary system, consisting of two transiting sub-Neptune-size planets that revolve around a sub-giant star with orbital periods of 13.84 and 16.24 days. Mutual gravitational interactions between the two planets perturb the planets' transit times, allowing the planets' masses to be measured. Despite the similarity of their masses and orbital radii, the planets show a stark contrast in their mean densities; the inner planet (Kepler-36 b) is more than eight times as dense as its outer companion planet (Kepler-36 c). We perform a photo-dynamical analysis of the Kepler-36 system based on more than three years of Kepler photometry. With N-body integrations of initial conditions sampled from the photo-dynamical fits, we further refine the properties of the system by ruling out solutions that show large-scale instability within 5 Giga-days. Ultimately, we measure the planets' masses within 4.2% precision, and the planets' radii with 1.8% precision. Kepler-36 b is currently the rocky exoplanet with the most precisely measured mass and radius. Kepler-36 b's mass and radius are consistent with an Earth-like composition, and an iron-enhanced Mercury-like composition is ruled out.

Compositional Constraints on the Best Characterized Rocky Exoplanet, Kepler-36 b

NASA Astrophysics Data System (ADS)

Rogers, Leslie Anne; Deck, Katherine; Lissauer, Jack; Carter, Joshua

2015-08-01

Kepler-36 is an extreme planetary system, consisting of two transiting sub-Neptune-size planets that revolve around a sub-giant star with orbital periods of 13.84 and 16.24 days. Mutual gravitational interactions between the two planets perturb the planets' transit times, allowing the planets' masses to be measured. Despite the similarity of their masses and orbital radii, the planets show a stark contrast in their mean densities; the inner planet (Kepler-36 b) is more than eight times as dense as its outer companion planet (Kepler-36 c). We perform a photo-dynamical analysis of the Kepler-36 system based on more than three years of Kepler photometry. With N-body integrations of initial conditions sampled from the photo-dynamical fits, we further refine the properties of the system by ruling out solutions that show large scale instability within 5 Giga-days. Ultimately, we measure the planets' masses within 4.2% precision, and the planets' radii with 1.8% precision. Kepler-36 b is currently the rocky exoplanet with the most precisely measured mass and radius. Kepler-36 b’s mass and radius are consistent with a Earth-like composition, and an iron-enhanced Mercury-like composition is ruled out.

Compositional Constraints on the Best Characterized Rocky Exoplanet, Kepler-36 b

NASA Astrophysics Data System (ADS)

Rogers, L.; Deck, K.; Lissauer, J. J.; Carter, J.

2014-12-01

Kepler-36 is an extreme planetary system, consisting of two transiting sub-Neptune-size planets that revolve around a sub-giant star with orbital periods of 13.84 and 16.24 days. Mutual gravitational interactions between the two planets perturb the planets' transit times, allowing the planets' masses to be measured. Despite the similarity of their masses and orbital radii, the planets show a stark contrast in their mean densities; the inner planet (Kepler-36 b) is more than eight times as dense as its outer companion planet (Kepler-36 c). We perform a photo-dynamical analysis of the Kepler-36 system based on more than three years of Kepler photometry. With N-body integrations of initial conditions sampled from the photo-dynamical fits, we further refine the properties of the system by ruling out solutions that show large scale instability within 5 Giga-days. Ultimately, we measure the planets' masses within 4.2% precision, and the planets' radii with 1.8% precision. Kepler-36 b is currently the rocky exoplanet with the most precisely measured mass and radius. Kepler-36 b's mass and radius are consistent with a Earth-like composition, and an iron-enhanced Mercury-like composition is ruled out.

K2's First Five-Planet System

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2016-08-01

Whats the latest from the Kepler K2 mission? K2 has found its first planetary system containing more than three planets an exciting five-planet system located ~380 light-years from Earth!Opportunities From K2Raw K2 light curve (blue, top) and systematic corrected light curve (orange, bottom) for HIP 41378. The three deepest transits are single transits from the three outermost planet candidates. [Vanderburg et al. 2016]The original Kepler mission was enormously successful, discovering thousands of planet candidates. But one side effect of Keplers original observing technique, in which it studied the same field for four years, is that it was very good at detecting extremely faint systems systems that were often too faint to be followed up with other techniques.After Keplers mechanical failure in 2013, the K2 mission was launched, in which the spacecraft uses solar pressure to stabilize it long enough to perform an 80-day searches of each region it examines. Over the course of the K2 mission, Kepler could potentially survey up to 20 times the sky area of the original mission, providing ample opportunity to find planetary systems around bright stars. These stars may be bright enough to be followed up with other techniques.Multi-Planet SystemsTheres a catch to the 80-day observing program: the K2 mission is less likely to detect multiple planets orbiting the same star, due to the short time spent observing the system. While the original Kepler mission detected systems with up to seven planets, K2 had yet to detect systems with more than three candidates until now.Led by Andrew Vanderburg (NSF Graduate Research Fellow at the Harvard-Smithsonian Center for Astrophysics), a team of scientists recentlyanalyzed K2 observations ofthe bright star HIP 41378. Theteamfound that this F-type star hosts five potential planetary candidates!Phase-folded light curve for each of the five transiting planets in the HIP 41378 system. The outermost planet (bottom panel) may provide an

Seismology of Giant Planets: General Overview and Results from the Kepler K2 Observations of Neptune

NASA Astrophysics Data System (ADS)

Gaulme, Patrick

2017-10-01

For this invited contribution, I was asked to give an overview about the application of helio and aster-oseismic techniques to study the interior of giant planets, and to specifically present the recent observations of Neptune by Kepler K2. Seismology applied to giant planets could drastically change our understanding of their deep interiors, as it has happened with the Earth, the Sun, and many main-sequence and evolved stars. The study of giant planets' composition is important for understanding both the mechanisms enabling their formation and the origins of planetary systems, in particular our own. Unfortunately, its determination is complicated by the fact that their interior is thought not to be homogeneous, so that spectroscopic determinations of atmospheric abundances are probably not representative of the planet as a whole. Instead, the determination of their composition and structure must rely on indirect measurements and interior models. Giant planets are mostly fluid and convective, which makes their seismology much closer to that of solar-like stars than that of terrestrial planets. Hence, helioseismology techniques naturally transfer to giant planets. In addition, two alternative methods can be used: photometry of the solar light reflected by planetary atmospheres, and ring seismology in the specific case of Saturn. The current decade has been promising thanks to the detection of Jupiter's acoustic oscillations with the ground-based imaging-spectrometer SYMPA and indirect detection of Saturn's f-modes in its rings by the NASA Cassini orbiter. This has motivated new projects of ground-based and space-borne instruments that are under development. The K2 observations represented the first opportunity to search for planetary oscillations with visible photometry. Despite the excellent quality of K2 data, the noise level of the power spectrum of the light curve was not low enough to detect Neptune's oscillations. The main results from the K2 observations are

Processing and Managing the Kepler Mission's Treasure Trove of Stellar and Exoplanet Data

NASA Technical Reports Server (NTRS)

Jenkins, Jon M.

2016-01-01

The Kepler telescope launched into orbit in March 2009, initiating NASAs first mission to discover Earth-size planets orbiting Sun-like stars. Kepler simultaneously collected data for 160,000 target stars at a time over its four-year mission, identifying over 4700 planet candidates, 2300 confirmed or validated planets, and over 2100 eclipsing binaries. While Kepler was designed to discover exoplanets, the long term, ultra- high photometric precision measurements it achieved made it a premier observational facility for stellar astrophysics, especially in the field of asteroseismology, and for variable stars, such as RR Lyraes. The Kepler Science Operations Center (SOC) was developed at NASA Ames Research Center to process the data acquired by Kepler from pixel-level calibrations all the way to identifying transiting planet signatures and subjecting them to a suite of diagnostic tests to establish or break confidence in their planetary nature. Detecting small, rocky planets transiting Sun-like stars presents a variety of daunting challenges, from achieving an unprecedented photometric precision of 20 parts per million (ppm) on 6.5-hour timescales, supporting the science operations, management, processing, and repeated reprocessing of the accumulating data stream. This paper describes how the design of the SOC meets these varied challenges, discusses the architecture of the SOC and how the SOC pipeline is operated and is run on the NAS Pleiades supercomputer, and summarizes the most important pipeline features addressing the multiple computational, image and signal processing challenges posed by Kepler.

Kepler Media Briefing

NASA Image and Video Library

2009-02-19

Jim Fanson, Kepler project manager, right, talks about the Kepler mission as William Borucki, left, listens during a media briefing, Thursday, Feb. 19, 2008, at NASA Headquarters in Washington. Kepler, the first mission with the ability to find planets like earth, is scheduled to launch on March 5, 2009 from Cape Canaveral Air Force Station, Fla. aboard a Delta II rocket. Photo Credit: (NASA/Paul. E. Alers)

PEPSI deep spectra. III. Chemical analysis of the ancient planet-host star Kepler-444

NASA Astrophysics Data System (ADS)

Mack, C. E.; Strassmeier, K. G.; Ilyin, I.; Schuler, S. C.; Spada, F.; Barnes, S. A.

2018-04-01

Context. With the Large Binocular Telescope (LBT), we obtained a spectrum with PEPSI, its new optical high-resolution échelle spectrograph. The spectrum has very high resolution and a high signal-to-noise (S/N) and is of the K0V host Kepler-444, which is known to host five sub-Earth-sized rocky planets. The spectrum has a resolution of R ≈ 250 000, a continuous wavelength coverage from 4230 Å to 9120 Å, and an S/N between 150-550:1 (blue to red). Aim. We performed a detailed chemical analysis to determine the photospheric abundances of 18 chemical elements. These were used to place constraints on the bulk composition of the five rocky planets. Methods: Our spectral analysis employs the equivalent-width method for most of our spectral lines, but we used spectral synthesis to fit a small number of lines that required special care. In both cases, we derived our abundances using the MOOG spectral analysis package and Kurucz model atmospheres. Results: We find no correlation between elemental abundance and condensation temperature among the refractory elements (TC > 950 K). In addition, using our spectroscopic stellar parameters and isochrone fitting, we find an age of 10 ± 1.5 Gyr, which is consistent with the asteroseismic age of 11 ± 1 Gyr. Finally, from the photospheric abundances of Mg, Si, and Fe, we estimate that the typical Fe-core mass fraction for the rocky planets in the Kepler-444 system is approximately 24%. Conclusions: If our estimate of the Fe-core mass fraction is confirmed by more detailed modeling of the disk chemistry and simulations of planet formation and evolution in the Kepler-444 system, then this would suggest that rocky planets in more metal-poor and α-enhanced systems may tend to be less dense than their counterparts of comparable size in more metal-rich systems. Based on data acquired with PEPSI using the Large Binocular Telescope (LBT). The LBT is an international collaboration among institutions in the United States, Italy, and

The host stars of Kepler's habitable exoplanets: superflares, rotation and activity

NASA Astrophysics Data System (ADS)

Armstrong, D. J.; Pugh, C. E.; Broomhall, A.-M.; Brown, D. J. A.; Lund, M. N.; Osborn, H. P.; Pollacco, D. L.

2016-01-01

We embark on a detailed study of the light curves of Kepler's most Earth-like exoplanet host stars using the full length of Kepler data. We derive rotation periods, photometric activity indices, flaring energies, mass-loss rates, gyrochronological ages, X-ray luminosities and consider implications for the planetary magnetospheres and habitability. Furthermore, we present the detection of superflares in the light curve of Kepler-438, the exoplanet with the highest Earth Similarity Index to date. Kepler-438b orbits at a distance of 0.166 au to its host star, and hence may be susceptible to atmospheric stripping. Our sample is taken from the Habitable Exoplanet Catalogue, and consists of the stars Kepler-22, Kepler-61, Kepler-62, Kepler-174, Kepler-186, Kepler-283, Kepler-296, Kepler-298, Kepler-438, Kepler-440, Kepler-442, Kepler-443 and KOI-4427, between them hosting 15 of the most habitable transiting planets known to date from Kepler.

The Kepler Mission: Search for Habitable Planets

NASA Technical Reports Server (NTRS)

Borucki, William; Likins, B.; DeVincenzi, Donald L. (Technical Monitor)

1998-01-01

Detecting extrasolar terrestrial planets orbiting main-sequence stars is of great interest and importance. Current ground-based methods are only capable of detecting objects about the size or mass of Jupiter or larger. The difficulties encountered with direct imaging of Earth-size planets from space are expected to be resolved in the next twenty years. Spacebased photometry of planetary transits is currently the only viable method for detection of terrestrial planets (30-600 times less massive than Jupiter). This method searches the extended solar neighborhood, providing a statistically large sample and the detailed characteristics of each individual case. A robust concept has been developed and proposed as a Discovery-class mission. Its capabilities and strengths are presented.

EXTRACTING PLANET MASS AND ECCENTRICITY FROM TTV DATA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lithwick, Yoram; Xie Jiwei; Wu Yanqin

2012-12-20

Most planet pairs in the Kepler data that have measured transit time variations (TTVs) are near first-order mean-motion resonances. We derive analytical formulae for their TTV signals. We separate planet eccentricity into free and forced parts, where the forced part is purely due to the planets' proximity to resonance. This separation yields simple analytical formulae. The phase of the TTV depends sensitively on the presence of free eccentricity: if the free eccentricity vanishes, the TTV will be in phase with the longitude of conjunctions. This effect is easily detectable in current TTV data. The amplitude of the TTV depends onmore » planet mass and free eccentricity, and it determines planet mass uniquely only when the free eccentricity is sufficiently small. We analyze the TTV signals of six short-period Kepler pairs. We find that three of these pairs (Kepler 18, 24, 25) have a TTV phase consistent with zero. The other three (Kepler 23, 28, 32) have small TTV phases, but ones that are distinctly non-zero. We deduce that the free eccentricities of the planets are small, {approx}< 0.01, but not always vanishing. Furthermore, as a consequence of this, we deduce that the true masses of the planets are fairly accurately determined by the TTV amplitudes, within a factor of {approx}< 2. The smallness of the free eccentricities suggests that the planets have experienced substantial dissipation. This is consistent with the hypothesis that the observed pile-up of Kepler pairs near mean-motion resonances is caused by resonant repulsion. But the fact that some of the planets have non-vanishing free eccentricity suggests that after resonant repulsion occurred there was a subsequent phase in the planets' evolution when their eccentricities were modestly excited, perhaps by interplanetary interactions.« less

Kepler Media Briefing

NASA Image and Video Library

2009-02-19

Jim Fanson, Kepler project manager, at NASA's Jet Propulsion Laboratory in Pasadena, Calif. talks about the Kepler mission during a media briefing, Thursday, Feb. 19, 2008, at NASA Headquarters in Washington. Kepler, the first mission with the ability to find planets like earth, is scheduled to launch on March 5, 2009 from Cape Canaveral Air Force Station, Fla. aboard a Delta II rocket. Photo Credit: (NASA/Paul. E. Alers)

Kepler Media Briefing

NASA Image and Video Library

2009-02-19

William Borucki, principal investigator for Kepler Science at Ames Research Center, Moffett Field, Calif., talks about the Kepler mission during a media briefing, Thursday, Feb. 19, 2008, at NASA Headquarters in Washington. Kepler, the first mission with the ability to find planets like earth, is scheduled to launch on March 5, 2009 from Cape Canaveral Air Force Station, Fla. aboard a Delta II rocket. Photo Credit: (NASA/Paul. E. Alers)

Kepler Media Briefing

NASA Image and Video Library

2009-02-19

Jim Fanson, Kepler project manager, center, talks about the Kepler mission as William Borucki, left, and Debra Fischer, right, listen during a media briefing, Thursday, Feb. 19, 2008, at NASA Headquarters in Washington. Kepler, the first mission with the ability to find planets like earth, is scheduled to launch on March 5, 2009 from Cape Canaveral Air Force Station, Fla. aboard a Delta II rocket. Photo Credit: (NASA/Paul. E. Alers)

Kepler Press Conference

NASA Image and Video Library

2009-08-05

William Bo-Ricki, Kepler principal investigator at NASA's Ames Research Center, speaks during a press conference, Thursday, Aug. 6, 2009, at NASA Headquarters in Washington about the scientific observations coming from the Kepler spacecraft that was launched this past March. Kepler is NASA's first mission that is capable of discovering earth-sized planets in the habitable zones of stars like our Sun. Photo Credit: (NASA/Paul E. Alers)

Assessing the Effect of Stellar Companions to Kepler Objects of Interest

NASA Astrophysics Data System (ADS)

Hirsch, Lea; Ciardi, David R.; Howard, Andrew

2017-01-01

Unknown stellar companions to Kepler planet host stars dilute the transit signal, causing the planetary radii to be underestimated. We report on the analysis of 165 stellar companions detected with high-resolution imaging to be within 2" of 159 KOI host stars. The majority of the planets and planet candidates in these systems have nominal radii smaller than 6 REarth. Using multi-filter photometry on each companion, we assess the likelihood that the companion is bound and estimate its stellar properties, including stellar radius and flux. We then recalculate the planet radii in these systems, determining how much each planet's size is underestimated if it is assumed to 1) orbit the primary star, 2) orbit the companion star, or 3) be equally likely to orbit either star in the system. We demonstrate the overall effect of unknown stellar companions on our understanding of Kepler planet sizes.

Educational And Public Outreach Software On Planet Detection For The Macintosh (TM)

NASA Technical Reports Server (NTRS)

Koch, David; Brady, Victoria; Cannara, Rachel; Witteborn, Fred C. (Technical Monitor)

1996-01-01

The possibility of extra-solar planets has been a very popular topic with the general public for years. Considerable media coverage of recent detections has only heightened the interest in the topic. School children are particularly interested in learning about space. Astronomers have the knowledge and responsibility to present this information in both an understandable and interesting format. Since most classrooms and homes are now equipped with computers this media can be utilized to provide more than a traditional "flat" presentation. An interactive "stack" has been developed using Hyperstudio (TM). The major topics include: "1996 - The Break Through Year In Planet Detection"; "What Determines If A Planet Is Habitable?"; "How Can We Find Other Planets (Search Methods)"; "All About the Kepler Mission: How To Find Earth-Sized Planets"; and "A Mission Simulator". Using the simulator, the student records simulated observations and then analyzes and interprets the data within the program stacks to determine the orbit and planet size, the planet's temperature and surface gravity, and finally determines if the planet is habitable. Additional related sections are also included. Many of the figures are animated to assist in comprehension of the material. A set of a dozen lesson plans for the middle school has also been drafted.

A Revised Estimate of the Occurrence Rate of Terrestrial Planets in the Habitable Zones around Kepler M-dwarfs

NASA Astrophysics Data System (ADS)

Kopparapu, Ravi Kumar

2013-04-01

Because of their large numbers, low-mass stars may be the most abundant planet hosts in our Galaxy. Furthermore, terrestrial planets in the habitable zones (HZs) around M-dwarfs can potentially be characterized in the near future and hence may be the first such planets to be studied. Recently, Dressing & Charbonneau used Kepler data and calculated the frequency of terrestrial planets in the HZ of cool stars to be 0.15^{+0.13}_{-0.06} per star for Earth-size planets (0.5-1.4 R ⊕). However, this estimate was derived using the Kasting et al. HZ limits, which were not valid for stars with effective temperatures lower than 3700 K. Here we update their result using new HZ limits from Kopparapu et al. for stars with effective temperatures between 2600 K and 7200 K, which includes the cool M stars in the Kepler target list. The new HZ boundaries increase the number of planet candidates in the HZ. Assuming Earth-size planets as 0.5-1.4 R ⊕, when we reanalyze their results, we obtain a terrestrial planet frequency of 0.48^{+0.12}_{-0.24} and 0.53^{+0.08}_{-0.17} planets per M-dwarf star for conservative and optimistic limits of the HZ boundaries, respectively. Assuming Earth-size planets as 0.5-2 R ⊕, the frequency increases to 0.51^{+0.10}_{-0.20} per star for the conservative estimate and to 0.61^{+0.07}_{-0.15} per star for the optimistic estimate. Within uncertainties, our optimistic estimates are in agreement with a similar optimistic estimate from the radial velocity survey of M-dwarfs (0.41^{+0.54}_{-0.13}). So, the potential for finding Earth-like planets around M stars may be higher than previously reported.

Kepler Discovery

NASA Image and Video Library

2011-02-02

William Borucki, Kepler Science Principal Investigator from NASA's Ames Research Center, second from left, speaks during a news conference, Wednesday, Feb. 2, 2010, at NASA Headquarters in Washington as Douglas Hudgins, left, Jack Lissauer and Debra Fischer, far right, look on. Scientists using NASA's Kepler, a space telescope, recently discovered six planets made of a mix of rock and gases orbiting a single sun-like star, known as Kepler-11, which is located approximately 2,000 light years from Earth. Photo Credit: (NASA/Paul E. Alers)

Masses of Kepler-46b, c from Transit Timing Variations

NASA Astrophysics Data System (ADS)

Saad-Olivera, Ximena; Nesvorný, David; Kipping, David M.; Roig, Fernando

2017-04-01

We use 16 quarters of the Kepler mission data to analyze the transit timing variations (TTVs) of the extrasolar planet Kepler-46b (KOI-872). Our dynamical fits confirm that the TTVs of this planet (period P={33.648}-0.005+0.004 days) are produced by a non-transiting planet Kepler-46c (P={57.325}-0.098+0.116 days). The Bayesian inference tool MultiNest is used to infer the dynamical parameters of Kepler-46b and Kepler-46c. We find that the two planets have nearly coplanar and circular orbits, with eccentricities ≃ 0.03 somewhat higher than previously estimated. The masses of the two planets are found to be {M}b={0.885}-0.343+0.374 and {M}c={0.362}-0.016+0.016 Jupiter masses, with M b being determined here from TTVs for the first time. Due to the precession of its orbital plane, Kepler-46c should start transiting its host star a few decades from now.

Assessing the Effect of Stellar Companions from High-resolution Imaging of Kepler Objects of Interest

NASA Astrophysics Data System (ADS)

Hirsch, Lea A.; Ciardi, David R.; Howard, Andrew W.; Everett, Mark E.; Furlan, Elise; Saylors, Mindy; Horch, Elliott P.; Howell, Steve B.; Teske, Johanna; Marcy, Geoffrey W.

2017-03-01

We report on 176 close (<2″) stellar companions detected with high-resolution imaging near 170 hosts of Kepler Objects of Interest (KOIs). These Kepler targets were prioritized for imaging follow-up based on the presence of small planets, so most of the KOIs in these systems (176 out of 204) have nominal radii <6 {R}\\oplus . Each KOI in our sample was observed in at least two filters with adaptive optics, speckle imaging, lucky imaging, or the Hubble Space Telescope. Multi-filter photometry provides color information on the companions, allowing us to constrain their stellar properties and assess the probability that the companions are physically bound. We find that 60%-80% of companions within 1″ are bound, and the bound fraction is >90% for companions within 0.″5 the bound fraction decreases with increasing angular separation. This picture is consistent with simulations of the binary and background stellar populations in the Kepler field. We also reassess the planet radii in these systems, converting the observed differential magnitudes to a contamination in the Kepler bandpass and calculating the planet radius correction factor, X R = R p (true)/R p (single). Under the assumption that planets in bound binaries are equally likely to orbit the primary or secondary, we find a mean radius correction factor for planets in stellar multiples of X R = 1.65. If stellar multiplicity in the Kepler field is similar to the solar neighborhood, then nearly half of all Kepler planets may have radii underestimated by an average of 65%, unless vetted using high-resolution imaging or spectroscopy.

Kepler Mission: A Wide-FOV Photometer Designed to Determine the Frequency of Earth-Size and Larger Planets Around Solar-like stars

NASA Technical Reports Server (NTRS)

Borucki, William; Koch, David; Lissauer, Jack; Basri, Gibor; Caldwell, John; Cochran, William; Dunham, Edward W.; Gilliland, Ronald; Jenkins, Jon M.; Caldwell, Douglas;

Kepler Press Conference

NASA Image and Video Library

2009-08-05

Jon Morse, NASA's Astrophysics Division Director, left, speaks during a press conference, Thursday, Aug. 6, 2009, at NASA Headquarters in Washington about the scientific observations coming from the Kepler spacecraft that was launched this past March asWilliam Bo-Ricki, Kepler principal investigator at NASA's Ames Research Center, looks on. Kepler is NASA's first mission that is capable of discovering earth-sized planets in the habitable zones of stars like our Sun. Photo Credit: (NASA/Paul E. Alers)

Homogeneous Photodynamical Analysis of Kepler's Multiply-Transiting Systems

NASA Astrophysics Data System (ADS)

Ragozzine, Darin

To search for planets more like our own, NASA s Kepler Space Telescope ( Kepler ) discovered thousands of exoplanet candidates that cross in front of ( transit ) their parent stars (e.g., Twicken et al. 2016). The Kepler exoplanet data represent an incredible observational leap forward as evidenced by hundreds of papers with thousands of citations. In particular, systems with multiple transiting planets combine the determination of physical properties of exoplanets (e.g., radii), the context provided by the system architecture, and insights from orbital dynamics. Such systems are the most information-rich exoplanetary systems (Ragozzine & Holman 2010). Thanks to Kepler s revolutionary dataset, understanding these Multi-Transiting Systems (MTSs) enables a wide variety of major science questions. In conclusion, existing analyses of MTSs are incomplete and suboptimal and our efficient and timely proposal will provide significant scientific gains ( 100 new mass measurements and 100 updated mass measurements). Furthermore, our homogeneous analysis enables future statistical analyses, including those necessary to characterize the small planet mass-radius relation with implications for understanding the formation, evolution, and habitability of planets. The overarching goal of this proposal is a complete homogeneous investigation of Kepler MTSs to provide detailed measurements (or constraints) on exoplanetary physical and orbital properties. Current investigations do not exploit the full power of the Kepler data; here we propose to use better data (Short Cadence observations), better methods (photodynamical modeling), and a better statistical method (Bayesian Differential Evolution Markov Chain Monte Carlo) in a homogenous analysis of all 700 Kepler MTSs. These techniques are particularly valuable for understanding small terrestrial planets. We propose to extract the near-maximum amount of information from these systems through a series of three research objectives

Kepler Reliability and Occurrence Rates

NASA Astrophysics Data System (ADS)

Bryson, Steve

2016-10-01

The Kepler mission has produced tables of exoplanet candidates (``KOI table''), as well as tables of transit detections (``TCE table''), hosted at the Exoplanet Archive (http://exoplanetarchive.ipac.caltech.edu). Transit detections in the TCE table that are plausibly due to a transiting object are selected for inclusion in the KOI table. KOI table entries that have not been identified as false positives (FPs) or false alarms (FAs) are classified as planet candidates (PCs, Mullally et al. 2015). A subset of PCs have been confirmed as planetary transits with greater than 99% probability, but most PCs have <99% probability of being true planets. The fraction of PCs that are true transiting planets is the PC reliability rate. The overall PC population is believed to have a reliability rate >90% (Morton & Johnson 2011).

Secure Mass Measurements from Transit Timing: 10 Kepler Exoplanets between 3 and 8 M⊕ with Diverse Densities and Incident Fluxes

NASA Astrophysics Data System (ADS)

Jontof-Hutter, Daniel; Ford, Eric B.; Rowe, Jason F.; Lissauer, Jack J.; Fabrycky, Daniel C.; Van Laerhoven, Christa; Agol, Eric; Deck, Katherine M.; Holczer, Tomer; Mazeh, Tsevi

2016-03-01

We infer dynamical masses in eight multiplanet systems using transit times measured from Kepler's complete data set, including short-cadence data where available. Of the 18 dynamical masses that we infer, 10 pass multiple tests for robustness. These are in systems Kepler-26 (KOI-250), Kepler-29 (KOI-738), Kepler-60 (KOI-2086), Kepler-105 (KOI-115), and Kepler-307 (KOI-1576). Kepler-105 c has a radius of 1.3 R⊕ and a density consistent with an Earth-like composition. Strong transit timing variation (TTV) signals were detected from additional planets, but their inferred masses were sensitive to outliers or consistent solutions could not be found with independently measured transit times, including planets orbiting Kepler-49 (KOI-248), Kepler-57 (KOI-1270), Kepler-105 (KOI-115), and Kepler-177 (KOI-523). Nonetheless, strong upper limits on the mass of Kepler-177 c imply an extremely low density of ˜0.1 g cm-3. In most cases, individual orbital eccentricities were poorly constrained owing to degeneracies in TTV inversion. For five planet pairs in our sample, strong secular interactions imply a moderate to high likelihood of apsidal alignment over a wide range of possible eccentricities. We also find solutions for the three planets known to orbit Kepler-60 in a Laplace-like resonance chain. However, nonlibrating solutions also match the transit timing data. For six systems, we calculate more precise stellar parameters than previously known, enabling useful constraints on planetary densities where we have secure mass measurements. Placing these exoplanets on the mass-radius diagram, we find that a wide range of densities is observed among sub-Neptune-mass planets and that the range in observed densities is anticorrelated with incident flux.

Finding Kepler's Exoearths

NASA Astrophysics Data System (ADS)

Petigura, Erik; Marcy, G.

2012-05-01

With its unprecedented photometric precision and duty cycle, the Kepler mission offers the first opportunity to detect Earth analog planets. Detecting transits with depths of 0.01%, periods of 1 year, and durations of 10 hours pose a novel challenge, prompting an optimization of both the detrending of the photometry and of the transit search algorithm. We present TERRA, the Transiting Exoearth Robust Reduction Algorithm, designed specifically to find earth analogs. TERRA carefully treats systematic effects with timescales comparable to an exoearth transit and removes features that are not important from the perspective of transit detection. We demonstrate TERRA's detection power through an extensive transit injection and recovery experiment.

Kepler Mission: a Discovery-Class Mission Designed to Determine the Frequency of Earth-Size and Larger Planets Around Solar-Like Stars

NASA Technical Reports Server (NTRS)

Borucki, William; Koch, David; Lissauer, Jack; Basri, Gibor; Caldwell, John; Cochran, William; Dunham, Edward W.; Gilliland, Ronald; Caldwell, Douglas; Kondo, Yoji;

Prevalence of Earth-size planets orbiting Sun-like stars

PubMed Central

Petigura, Erik A.; Howard, Andrew W.; Marcy, Geoffrey W.

2013-01-01

Determining whether Earth-like planets are common or rare looms as a touchstone in the question of life in the universe. We searched for Earth-size planets that cross in front of their host stars by examining the brightness measurements of 42,000 stars from National Aeronautics and Space Administration’s Kepler mission. We found 603 planets, including 10 that are Earth size () and receive comparable levels of stellar energy to that of Earth (). We account for Kepler’s imperfect detectability of such planets by injecting synthetic planet–caused dimmings into the Kepler brightness measurements and recording the fraction detected. We find that 11 ± 4% of Sun-like stars harbor an Earth-size planet receiving between one and four times the stellar intensity as Earth. We also find that the occurrence of Earth-size planets is constant with increasing orbital period (P), within equal intervals of logP up to ∼200 d. Extrapolating, one finds % of Sun-like stars harbor an Earth-size planet with orbital periods of 200–400 d. PMID:24191033

Convection in Cool Stars, as Seen Through Kepler's Eyes

NASA Astrophysics Data System (ADS)

Bastien, Fabienne A.

2015-01-01

Stellar surface processes represent a fundamental limit to the detection of extrasolar planets with the currently most heavily-used techniques. As such, considerable effort has gone into trying to mitigate the impact of these processes on planet detection, with most studies focusing on magnetic spots. Meanwhile, high-precision photometric planet surveys like CoRoT and Kepler have unveiled a wide variety of stellar variability at previously inaccessible levels. We demonstrate that these newly revealed variations are not solely magnetically driven but also trace surface convection through light curve ``flicker.'' We show that ``flicker'' not only yields a simple measurement of surface gravity with a precision of ˜0.1 dex, but it may also improve our knowledge of planet properties, enhance radial velocity planet detection and discovery, and provide new insights into stellar evolution.

Reborn Kepler Discovers First K2 Exoplanet Artist Concept

NASA Image and Video Library

2014-12-18

This artist concept shows NASA planet-hunting Kepler spacecraft operating in a new mission profile called K2. Using publicly available data, astronomers have confirmed K2 first exoplanet discovery proving Kepler can still find planets.

Kepler Press Conference

NASA Image and Video Library

2009-08-05

William Bo-Ricki, Kepler principal investigator at NASA's Ames Research Center, second from left, speaks during a press conference, Thursday, Aug. 6, 2009, at NASA Headquarters in Washington about the scientific observations coming from the Kepler spacecraft that was launched this past March as Jon Morse, NASA's Astrophysics Division Director, left, looks on. Kepler is NASA's first mission that is capable of discovering earth-sized planets in the habitable zones of stars like our Sun. Photo Credit: (NASA/Paul E. Alers)

Kepler Press Conference

NASA Image and Video Library

2009-08-05

William Bo-Ricki, Kepler principal investigator at NASA's Ames Research Center, second from left, is joined by Jon Morse, left, Sara Seager, and Alan Boss while speaking at a press conference, Thursday, Aug. 6, 2009, at NASA Headquarters in Washington about the scientific observations coming from the Kepler spacecraft that was launched this past March. Kepler is NASA's first mission that is capable of discovering earth-sized planets in the habitable zones of stars like our Sun. Photo Credit: (NASA/Paul E. Alers)

Kepler Media Briefing

NASA Image and Video Library

2009-02-19

William Borucki, principal investigator for Kepler Science at Ames Research Center, Moffett Field, Calif., second from left, is seen through a television camer monitor as he talks about the Kepler mission during a media briefing, Thursday, Feb. 19, 2008, at NASA Headquarters in Washington. Kepler, the first mission with the ability to find planets like earth, is scheduled to launch on March 5, 2009 from Cape Canaveral Air Force Station, Fla. aboard a Delta II rocket. Photo Credit: (NASA/Paul. E. Alers)

BEER ANALYSIS OF KEPLER AND CoRoT LIGHT CURVES. II. EVIDENCE FOR SUPERROTATION IN THE PHASE CURVES OF THREE KEPLER HOT JUPITERS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Faigler, S.; Mazeh, T.

We analyzed the Kepler light curves of four transiting hot Jupiter systems—KOI-13, HAT-P-7, TrES-2, and Kepler-76, which show BEaming, Ellipsoidal, and Reflection (BEER) phase modulations. The mass of the four planets can be estimated from either the beaming or the ellipsoidal amplitude, given the mass and radius of their parent stars. For KOI-13, HAT-P-7, and Kepler-76 we find that the beaming-based planetary mass estimate is larger than the mass estimated from the ellipsoidal amplitude, consistent with previous studies. This apparent discrepancy may be explained by equatorial superrotation of the planet atmosphere, which induces an angle shift of the planet reflection/emissionmore » phase modulation, as was suggested for Kepler-76 in the first paper of this series. We propose a modified BEER model that supports superrotation, assuming either a Lambertian or geometric reflection/emission phase function, and provides a photometry-consistent estimate of the planetary mass. Our analysis shows that for Kepler-76 and HAT-P-7, the Lambertian superrotation BEER model is highly preferable over an unshifted null model, while for KOI-13 it is preferable only at a 1.4σ level. For TrES-2 we do not find such preference. For all four systems the Lambertian superrotation model mass estimates are in excellent agreement with the planetary masses derived from, or constrained by, radial velocity measurements. This makes the Lambertian superrotation BEER model a viable tool for estimating the masses of hot Jupiters from photometry alone. We conclude that hot Jupiter superrotation may be a common phenomenon that can be detected in the visual light curves of Kepler.« less

VizieR Online Data Catalog: Transit times of Kepler-448b and Kepler-693b (Masuda, 2017)

NASA Astrophysics Data System (ADS)

Masuda, K.

2017-11-01

I analyzed Transit Timing Variations (TTVs) of 23 confirmed, singly transiting warm Jupiters (WJs; Section 2.1) with an orbital period of 7days8R{Earth} in the DR24 of the KOI catalog (Coughlin et al. 2016, Cat. J/ApJS/224/12). Systems with multiple KOIs are all excluded, even though they consist of only one confirmed planet and false positives. I found clearly non-sinusoidal TTVs for Kepler-448/KOI-12b, Kepler-693/KOI-824b, and Kepler-419/KOI-1474b. The result is consistent with the TTV search by Holczer et al. 2016 (Cat. J/ApJS/225/9), who reported significant long-term TTVs for the same three KOIs in our sample. Of these planets, the TTVs of Kepler-419b have previously been analyzed by Dawson et al. (2014ApJ...791...89D). Therefore, I focus on Kepler-448b and Kepler-693b. (3 data files).

Kepler: A Search for Terrestrial Planets. K2 Handbook

NASA Technical Reports Server (NTRS)

Van Cleve, Jeffrey; Bryson, Steve

2017-01-01

The Kepler spacecraft was repurposed for the K2 mission a year after the failure of the second of Kepler's four reaction wheels in 2013 May. The purpose of this document, the K2 Handbook (K2H), is to describe features of K2 operations, performance, data analysis, and archive products which are common to most K2 campaigns, but different in degree or kind from the corresponding features of the Kepler mission.The K2 Handbook is meant to be read with the following companion documents, which are all publicly available:1. Kepler Instrument Handbook (KSCI-19033) provides information about the design, performance and operational constraints of the instrument and an overview of the types of pixel data that are available.2. Kepler Data Processing Handbook (KSCI-19081) describes how pixels downloaded from the spacecraft are converted by the Kepler Data Processing Pipeline into the data products available at the MAST archive3. Kepler Archive Manual (KDMC-100008) describes the format and content of the data products and how to search for them.4. Kepler Data Characteristics Handbook (KSCI-19040) describes recurring non-astrophysical features of the Kepler data due to instrument signatures, spacecraft events or solar activity and explains how these characteristics are handled by the Kepler pipeline.5. The Ecliptic Plane Input Catalog describes the provenance of the positions and Kepler magnitudes used for target management and aperature photometry.6. K2 Data Release Notes (DRN) are on-line documents available on the K2 science website which describe the data inventory, instrumental signatures and events peculiar to individual observing campaigns.

Dysonian SETI as a "Shortcut" to Detecting Habitable Planets

NASA Astrophysics Data System (ADS)

Wright, J. T.

2016-12-01

The search for habitable planets is ultimately motivated by the search for inhabited planets. On Earth, the most telling signature of life is that of humanity's technology. The Search for Extraterrestrial Intelligence (SETI) is thus the "ultimate" search for habitable planets.In 1960 two seminal papers in SETI were published, providing two visions for SETI. Giuseppe Cocconi and Philip Morrison's proposed detecting deliberate radio signals ("communication SETI"), while Freeman Dyson ("artifact SETI"), proposed detecting the inevitable effects of massive energy supplies and artifacts on their surroundings. While communication SETI has now had many career-long practitioners and major efforts, artifact SETI has, until recently, not been a vibrant field of study. The launch of the Kepler and WISE satellites have greatly renewed interest in the field, however, and the recent Breakthrough Listen Initiative has provided new motivation for finding good targets for communication SETI. I will discuss the progress of the Ĝ Search for Extraterrestrial Civilizations with Large Energy Supplies, including its justification and motivation, waste heat search strategy and first results, and the framework for a search for megastructures via transit light curves. The last of these led to the identification of KIC 8462852 (a.k.a. "Tabby's Star") as a candidate ETI host. This star, discovered by Boyajian and the Zooniverse Planet Hunters, exhibits several apparently unique and so-far unexplained photometric properties, and continues to confound natural explanation.

Kepler Discovery

NASA Image and Video Library

2011-02-02

Debra Fischer, a professor of Astronomy at Yale University, speaks during a news conference, Wednesday, Feb. 2, 2010, at NASA Headquarters in Washington. Scientists using NASA's Kepler, a space telescope, recently discovered six planets made of a mix of rock and gases orbiting a single sun-like star, known as Kepler-11, which is located approximately 2,000 light years from Earth. Photo Credit: (NASA/Paul E. Alers)

A REVISED ESTIMATE OF THE OCCURRENCE RATE OF TERRESTRIAL PLANETS IN THE HABITABLE ZONES AROUND KEPLER M-DWARFS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kopparapu, Ravi Kumar

Because of their large numbers, low-mass stars may be the most abundant planet hosts in our Galaxy. Furthermore, terrestrial planets in the habitable zones (HZs) around M-dwarfs can potentially be characterized in the near future and hence may be the first such planets to be studied. Recently, Dressing and Charbonneau used Kepler data and calculated the frequency of terrestrial planets in the HZ of cool stars to be 0.15{sup +0.13}{sub -0.06} per star for Earth-size planets (0.5-1.4 R{sub Circled-Plus }). However, this estimate was derived using the Kasting et al. HZ limits, which were not valid for stars with effectivemore » temperatures lower than 3700 K. Here we update their result using new HZ limits from Kopparapu et al. for stars with effective temperatures between 2600 K and 7200 K, which includes the cool M stars in the Kepler target list. The new HZ boundaries increase the number of planet candidates in the HZ. Assuming Earth-size planets as 0.5-1.4 R{sub Circled-Plus }, when we reanalyze their results, we obtain a terrestrial planet frequency of 0.48{sup +0.12}{sub -0.24} and 0.53{sup +0.08}{sub -0.17} planets per M-dwarf star for conservative and optimistic limits of the HZ boundaries, respectively. Assuming Earth-size planets as 0.5-2 R{sub Circled-Plus }, the frequency increases to 0.51{sup +0.10}{sub -0.20} per star for the conservative estimate and to 0.61{sup +0.07}{sub -0.15} per star for the optimistic estimate. Within uncertainties, our optimistic estimates are in agreement with a similar optimistic estimate from the radial velocity survey of M-dwarfs (0.41{sup +0.54}{sub -0.13}). So, the potential for finding Earth-like planets around M stars may be higher than previously reported.« less

Exoplanet orbital eccentricities derived from LAMOST-Kepler analysis.

PubMed

Xie, Ji-Wei; Dong, Subo; Zhu, Zhaohuan; Huber, Daniel; Zheng, Zheng; De Cat, Peter; Fu, Jianning; Liu, Hui-Gen; Luo, Ali; Wu, Yue; Zhang, Haotong; Zhang, Hui; Zhou, Ji-Lin; Cao, Zihuang; Hou, Yonghui; Wang, Yuefei; Zhang, Yong

2016-10-11

The nearly circular (mean eccentricity [Formula: see text]) and coplanar (mean mutual inclination [Formula: see text]) orbits of the solar system planets motivated Kant and Laplace to hypothesize that planets are formed in disks, which has developed into the widely accepted theory of planet formation. The first several hundred extrasolar planets (mostly Jovian) discovered using the radial velocity (RV) technique are commonly on eccentric orbits ([Formula: see text]). This raises a fundamental question: Are the solar system and its formation special? The Kepler mission has found thousands of transiting planets dominated by sub-Neptunes, but most of their orbital eccentricities remain unknown. By using the precise spectroscopic host star parameters from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) observations, we measure the eccentricity distributions for a large (698) and homogeneous Kepler planet sample with transit duration statistics. Nearly half of the planets are in systems with single transiting planets (singles), whereas the other half are multiple transiting planets (multiples). We find an eccentricity dichotomy: on average, Kepler singles are on eccentric orbits with [Formula: see text] 0.3, whereas the multiples are on nearly circular [Formula: see text] and coplanar [Formula: see text] degree) orbits similar to those of the solar system planets. Our results are consistent with previous studies of smaller samples and individual systems. We also show that Kepler multiples and solar system objects follow a common relation [[Formula: see text](1-2)[Formula: see text

Herschel/PACS photometry of transiting-planet host stars with candidate warm debris disks

NASA Astrophysics Data System (ADS)

Ardila, David R.; Merin, Bruno; Ribas, Alvaro; Bouy, Herve; Bryden, Geoffrey; Stapelfeldt, Karl R.; Padgett, Deborah

2015-01-01

Dust in debris disks is produced by colliding or evaporating planetesimals, which are remnants of the planet formation process. Warm dust disks, known by their emission at ≤24 μm, are rare (4% of FGK main sequence stars) and especially interesting because they trace material in the region likely to host terrestrial planets, where the dust has a very short dynamical lifetime. Statistical analyses of the source counts of excesses as found with the mid-IR Wide Field Infrared Survey Explorer (WISE) suggest that warm-dust candidates found for the Kepler transiting-planet host-star candidates can be explained by extragalactic or galactic background emission aligned by chance with the target stars. These statistical analyses do not exclude the possibility that a given WISE excess could be due to a transient dust population associated with the target. Here we report Herschel/PACS 100 and 160 micron follow-up observations of a sample of Kepler and non-Kepler transiting-planet candidates' host stars, with candidate WISE warm debris disks, aimed at detecting a possible cold debris disk in any one of them. No clear detections were found in any one of the objects at either wavelength. Our upper limits confirm that most objects in the sample do not have a massive debris disk like that in beta Pic. We also show that the planet-hosting star WASP-33 does not have a debris disk comparable to the one around eta Crv. Although the data cannot be used to rule out rare warm disks around the Kepler planet-hosting candidates, the lack of detections and the characteristics of neighboring emission found at far-IR wavelengths support an earlier result suggesting that most of the WISE-selected IR excesses around Kepler candidate host stars are likely due to either chance alignment with background IR-bright galaxies and/or to interstellar emission.

PHOTOMETRIC ORBITS OF EXTRASOLAR PLANETS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Robert A.

We define and analyze the photometric orbit (PhO) of an extrasolar planet observed in reflected light. In our definition, the PhO is a Keplerian entity with six parameters: semimajor axis, eccentricity, mean anomaly at some particular time, argument of periastron, inclination angle, and effective radius, which is the square root of the geometric albedo times the planetary radius. Preliminarily, we assume a Lambertian phase function. We study in detail the case of short-period giant planets (SPGPs) and observational parameters relevant to the Kepler mission: 20 ppm photometry with normal errors, 6.5 hr cadence, and three-year duration. We define a relevantmore » 'planetary population of interest' in terms of probability distributions of the PhO parameters. We perform Monte Carlo experiments to estimate the ability to detect planets and to recover PhO parameters from light curves. We calibrate the completeness of a periodogram search technique, and find structure caused by degeneracy. We recover full orbital solutions from synthetic Kepler data sets and estimate the median errors in recovered PhO parameters. We treat in depth a case of a Jupiter body-double. For the stated assumptions, we find that Kepler should obtain orbital solutions for many of the 100-760 SPGP that Jenkins and Doyle estimate Kepler will discover. Because most or all of these discoveries will be followed up by ground-based radial velocity observations, the estimates of inclination angle from the PhO may enable the calculation of true companion masses: Kepler photometry may break the 'msin i' degeneracy. PhO observations may be difficult. There is uncertainty about how low the albedos of SPGPs actually are, about their phase functions, and about a possible noise floor due to systematic errors from instrumental and stellar sources. Nevertheless, simple detection of SPGPs in reflected light should be robust in the regime of Kepler photometry, and estimates of all six orbital parameters may be

Kepler Media Briefing

NASA Image and Video Library

2009-02-19

William Borucki, principal investigator for Kepler Science at Ames Research Center, Moffett Field, Calif.,, second from left, talks about the Kepler mission during a media briefing, Thursday, Feb. 19, 2008, at NASA Headquarters in Washington. Kepler, the first mission with the ability to find planets like earth, is scheduled to launch on March 5, 2009 from Cape Canaveral Air Force Station, Fla. aboard a Delta II rocket. Joining Borucki at the briefing were Jon Morse, director, Astrophysics Division, NASA Headquarters, Jim Fanson, Kepler project manager at the Jet Propulsion Laboratory and Debra Fischer, a professor of Astronomy at San Francisco State University. Photo Credit: (NASA/Paul. E. Alers)

AN ANCIENT EXTRASOLAR SYSTEM WITH FIVE SUB-EARTH-SIZE PLANETS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campante, T. L.; Davies, G. R.; Chaplin, W. J.

The chemical composition of stars hosting small exoplanets (with radii less than four Earth radii) appears to be more diverse than that of gas-giant hosts, which tend to be metal-rich. This implies that small, including Earth-size, planets may have readily formed at earlier epochs in the universe's history when metals were more scarce. We report Kepler spacecraft observations of Kepler-444, a metal-poor Sun-like star from the old population of the Galactic thick disk and the host to a compact system of five transiting planets with sizes between those of Mercury and Venus. We validate this system as a true five-planetmore » system orbiting the target star and provide a detailed characterization of its planetary and orbital parameters based on an analysis of the transit photometry. Kepler-444 is the densest star with detected solar-like oscillations. We use asteroseismology to directly measure a precise age of 11.2 ± 1.0 Gyr for the host star, indicating that Kepler-444 formed when the universe was less than 20% of its current age and making it the oldest known system of terrestrial-size planets. We thus show that Earth-size planets have formed throughout most of the universe's 13.8 billion year history, leaving open the possibility for the existence of ancient life in the Galaxy. The age of Kepler-444 not only suggests that thick-disk stars were among the hosts to the first Galactic planets, but may also help to pinpoint the beginning of the era of planet formation.« less

A SUPER-EARTH-SIZED PLANET ORBITING IN OR NEAR THE HABITABLE ZONE AROUND A SUN-LIKE STAR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barclay, Thomas; Burke, Christopher J.; Howell, Steve B.

We present the discovery of a super-Earth-sized planet in or near the habitable zone of a Sun-like star. The host is Kepler-69, a 13.7 mag G4V-type star. We detect two periodic sets of transit signals in the 3-year flux time series of Kepler-69, obtained with the Kepler spacecraft. Using the very high precision Kepler photometry, and follow-up observations, our confidence that these signals represent planetary transits is >99.3%. The inner planet, Kepler-69b, has a radius of 2.24{sup +0.44}{sub -0.29} R{sub Circled-Plus} and orbits the host star every 13.7 days. The outer planet, Kepler-69c, is a super-Earth-sized object with a radiusmore » of 1.7{sup +0.34}{sub -0.23} R{sub Circled-Plus} and an orbital period of 242.5 days. Assuming an Earth-like Bond albedo, Kepler-69c has an equilibrium temperature of 299 {+-} 19 K, which places the planet close to the habitable zone around the host star. This is the smallest planet found by Kepler to be orbiting in or near the habitable zone of a Sun-like star and represents an important step on the path to finding the first true Earth analog.« less

The effects of external planets on inner systems: multiplicities, inclinations and pathways to eccentric warm Jupiters

NASA Astrophysics Data System (ADS)

Mustill, Alexander J.; Davies, Melvyn B.; Johansen, Anders

2017-07-01

We study how close-in systems such as those detected by Kepler are affected by the dynamics of bodies in the outer system. We consider two scenarios: outer systems of giant planets potentially unstable to planet-planet scattering and wide binaries that may be capable of driving Kozai or other secular variations of outer planets' eccentricities. Dynamical excitation of planets in the outer system reduces the multiplicity of Kepler-detectable planets in the inner system in ˜20-25 per cent of our systems. Accounting for the occurrence rates of wide-orbit planets and binary stars, ≈18 per cent of close-in systems could be destabilized by their outer companions in this way. This provides some contribution to the apparent excess of systems with a single transiting planet compared to multiple; however, it only contributes at most 25 per cent of the excess. The effects of the outer dynamics can generate systems similar to Kepler-56 (two coplanar planets significantly misaligned with the host star) and Kepler-108 (two significantly non-coplanar planets in a binary). We also identify three pathways to the formation of eccentric warm Jupiters resulting from the interaction between outer and inner systems: direct inelastic collision between an eccentric outer and an inner planet; secular eccentricity oscillations that may 'freeze out' when scattering resolves in the outer system; and scattering in the inner system followed by 'uplift', where inner planets are removed by interaction with the outer planets. In these scenarios, the formation of eccentric warm Jupiters is a signature of a past history of violent dynamics among massive planets beyond ˜1 au.

DETAILED ABUNDANCES OF STARS WITH SMALL PLANETS DISCOVERED BY KEPLER. I. THE FIRST SAMPLE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schuler, Simon C.; Vaz, Zachary A.; Santrich, Orlando J. Katime

2015-12-10

We present newly derived stellar parameters and the detailed abundances of 19 elements of seven stars with small planets discovered by NASA's Kepler Mission. Each star, save one, has at least one planet with a radius ≤1.6 R{sub ⊕}, suggesting a primarily rocky composition. The stellar parameters and abundances are derived from high signal-to-noise ratio, high-resolution echelle spectroscopy obtained with the 10 m Keck I telescope and High Resolution Echelle Spectrometer using standard spectroscopic techniques. The metallicities of the seven stars range from −0.32 to +0.13 dex, with an average metallicity that is subsolar, supporting previous suggestions that, unlike Jupiter-typemore » giant planets, small planets do not form preferentially around metal-rich stars. The abundances of elements other than iron are in line with a population of Galactic disk stars, and despite our modest sample size, we find hints that the compositions of stars with small planets are similar to stars without known planets and with Neptune-size planets, but not to those of stars with giant planets. This suggests that the formation of small planets does not require exceptional host-star compositions and that small planets may be ubiquitous in the Galaxy. We compare our derived abundances (which have typical uncertainties of ≲0.04 dex) to the condensation temperature of the elements; a correlation between the two has been suggested as a possible signature of rocky planet formation. None of the stars demonstrate the putative rocky planet signature, despite at least three of the stars having rocky planets estimated to contain enough refractory material to produce the signature, if real. More detailed abundance analyses of stars known to host small planets are needed to verify our results and place ever more stringent constraints on planet formation models.« less

Using a generalized version of the Titius-Bode relation to extrapolate the patterns seen in Kepler multi-exoplanet systems, and estimate the average number of planets in circumstellar habitable zones

NASA Astrophysics Data System (ADS)

Lineweaver, Charles H.

2015-08-01

The Titius-Bode (TB) relation’s successful prediction of the period of Uranus was the main motivation that led to the search for another planet between Mars and Jupiter. This search led to the discovery of the asteroid Ceres and the rest of the asteroid belt. The TB relation can also provide useful hints about the periods of as-yet-undetected planets around other stars. In Bovaird & Lineweaver (2013) [1], we used a generalized TB relation to analyze 68 multi-planet systems with four or more detected exoplanets. We found that the majority of exoplanet systems in our sample adhered to the TB relation to a greater extent than the Solar System does. Thus, the TB relation can make useful predictions about the existence of as-yet-undetected planets in Kepler multi-planet systems. These predictions are one way to correct for the main obstacle preventing us from estimating the number of Earth-like planets in the universe. That obstacle is the incomplete sampling of planets of Earth-mass and smaller [2-5]. In [6], we use a generalized Titius-Bode relation to predict the periods of 228 additional planets in 151 of these Kepler multiples. These Titius-Bode-based predictions suggest that there are, on average, 2±1 planets in the habitable zone of each star. We also estimate the inclination of the invariable plane for each system and prioritize our planet predictions by their geometric probability to transit. We highlight a short list of 77 predicted planets in 40 systems with a high geometric probability to transit, resulting in an expected detection rate of ~15 per cent, ~3 times higher than the detection rate of our previous Titius-Bode-based predictions.References: [1] Bovaird, T. & Lineweaver, C.H (2013) MNRAS, 435, 1126-1138. [2] Dong S. & Zhu Z. (2013) ApJ, 778, 53 [3] Fressin F. et al. (2013) ApJ, 766, 81 [4] Petigura E. A. et al. (2013) PNAS, 110, 19273 [5] Silburt A. et al. (2014), ApJ (arXiv:1406.6048v2) [6] Bovaird, T., Lineweaver, C.H. & Jacobsen, S.K. (2015, in

NASA's Kepler Spacecraft Discovers Its First Rocky Planet

NASA Image and Video Library

2011-01-10

Animation narrated by Natalie Batalha, describing the location of Kepler-10b and the possible molten landscape. New Field-of-View animation by Marco Librero and new Kepler-10b animation by Dana Berry.

Kepler Media Briefing

NASA Image and Video Library

2009-02-19

Jon Morse, director, Astrophysics Division at NASA Headquarters talks about the Kepler mission during a media briefing, Thursday, Feb. 19, 2008, at NASA Headquarters in Washington. Kepler, the first mission with the ability to find planets like earth, is scheduled to launch on March 5, 2009 from Cape Canaveral Air Force Station, Fla. aboard a Delta II rocket. Photo Credit: (NASA/Paul. E. Alers)

Kepler Media Briefing

NASA Image and Video Library

2009-02-19

Debra Fischer, a professor of Astronomy at San Francisco State University, talks about the Kepler mission during a media briefing, Thursday, Feb. 19, 2008, at NASA Headquarters in Washington. Kepler, the first mission with the ability to find planets like earth, is scheduled to launch on March 5, 2009 from Cape Canaveral Air Force Station, Fla. aboard a Delta II rocket. Photo Credit: (NASA/Paul. E. Alers)

Finding Optimal Apertures in Kepler Data

NASA Astrophysics Data System (ADS)

Smith, Jeffrey C.; Morris, Robert L.; Jenkins, Jon M.; Bryson, Stephen T.; Caldwell, Douglas A.; Girouard, Forrest R.

2016-12-01

With the loss of two spacecraft reaction wheels precluding further data collection for the Kepler primary mission, even greater pressure is placed on the processing pipeline to eke out every last transit signal in the data. To that end, we have developed a new method to optimize the Kepler Simple Aperture Photometry (SAP) photometric apertures for both planet detection and minimization of systematic effects. The approach uses a per cadence modeling of the raw pixel data and then performs an aperture optimization based on signal-to-noise ratio and the Kepler Combined Differential Photometric Precision (CDPP), which is a measure of the noise over the duration of a reference transit signal. We have found the new apertures to be superior to the previous Kepler apertures. We can now also find a per cadence flux fraction in aperture and crowding metric. The new approach has also been proven to be robust at finding apertures in K2 data that help mitigate the larger motion-induced systematics in the photometry. The method further allows us to identify errors in the Kepler and K2 input catalogs.

Kepler Planetary Systems in Motion Artist Concept

NASA Image and Video Library

2012-01-26

This artist concept shows an overhead view of the orbital position of the planets in systems with multiple transiting planets discovered by NASA Kepler mission. All the colored planets have been verified.

Overview and Status of the Kepler Mission

NASA Technical Reports Server (NTRS)

Koch, D.; Borucki, W.; Dunham, E.; Geary, J.; Gilliland, R.; Jenkins, J.; Latham, D.; Mayer, D.; Sobeck, C.; Duren, R.

2003-01-01

The Kepler Mission is a search for terrestrial planets with the design optimized for detecting Earth-size planets in the habitable zone (HZ) of solar-like stars. In addition, the mission has a broad detection capability for a wide range of planetary sizes, planetary orbits and spectral types of stars. The mission is in the midst of the development phase with good progress leading to the preliminary design review later this year. Long lead procurements are well under way. An overview in all areas is presented including both the flight system (photometer and spacecraft) and the ground system. Launch is on target for 2007 on a Delta II.

Kepler Press Conference

NASA Image and Video Library

2009-08-05

Alan Boss, an astrophyscist at the Carnegie Institution at the Department of Terrestrial Magnetism speaks during a press conference, Thursday, Aug. 6, 2009, at NASA Headquarters in Washington about the scientific observations coming from the Kepler spacecraft that was launched this past March. Kepler is NASA's first mission that is capable of discovering earth-sized planets in the habitable zones of stars like our Sun. Photo Credit: (NASA/Paul E. Alers)

Kepler Press Conference

NASA Image and Video Library

2009-08-05

Sara Seager, Professor of Planetary Science at the Massachusetts Institute of Technology, speaks during a press conference, Thursday, Aug. 6, 2009, at NASA Headquarters in Washington about the scientific observations coming from the Kepler spacecraft that was launched this past March. Kepler is NASA's first mission that is capable of discovering earth-sized planets in the habitable zones of stars like our Sun. Photo Credit: (NASA/Paul E. Alers)

Kepler Diamond Mine of Stars

NASA Image and Video Library

2009-04-16

This image from NASA Kepler mission shows the telescope full field of view an expansive star-rich patch of sky in the constellations Cygnus and Lyra stretching across 100 square degrees, or the equivalent of two side-by-side dips of the Big Dipper. A cluster of stars, called NGC 6791, and a star with a known planet, called TrES-2, are outlined. The cluster is eight billion years old, and located 13,000 light-years from Earth. It is called an open cluster because its stars are loosely bound and have started to spread out. TrES-2 is a hot Jupiter-like planet known to cross in front of, or transit, its star every 2.5 days. Kepler will hunt for transiting planets that are as small as Earth. Kepler was designed to hunt for planets like Earth. Of the approximately 4.5 million stars in the region pictured here, more than 100,000 were selected as candidates for Kepler's search. The mission will spend the next three-and-a-half years staring at these target stars, looking for periodic dips in brightness. Such dips occur when planets cross in front of their stars from our point of view in the galaxy, partially blocking the starlight. The area in the lower right of the image is brighter because it is closer to the plane of our galaxy and is jam-packed with stars. The area in upper left is farther from the galactic plane and contains fewer stars. The image has been color-coded so that brighter stars appear white, and fainter stars, red. It is a 60-second exposure, taken on April 8, 2009, one day after the spacecraft's dust cover was jettisoned. To achieve the level of precision needed to spot planets as small as Earth, Kepler's images are intentionally blurred slightly. This minimizes the number of saturated stars. Saturation, or "blooming," occurs when the brightest stars overload the individual pixels in the detectors, causing the signal to spill out into nearby pixels. These spills can be seen in the image as fine white lines extending above and below some of the brightest

Discovery and Rossiter-Mclaughlin Effect of Exoplanet Kepler-8b

NASA Astrophysics Data System (ADS)

Jenkins, Jon M.; Borucki, William J.; Koch, David G.; Marcy, Geoffrey W.; Cochran, William D.; Welsh, William F.; Basri, Gibor; Batalha, Natalie M.; Buchhave, Lars A.; Brown, Timothy M.; Caldwell, Douglas A.; Dunham, Edward W.; Endl, Michael; Fischer, Debra A.; Gautier, Thomas N., III; Geary, John C.; Gilliland, Ronald L.; Howell, Steve B.; Isaacson, Howard; Johnson, John Asher; Latham, David W.; Lissauer, Jack J.; Monet, David G.; Rowe, Jason F.; Sasselov, Dimitar D.; Howard, Andrew W.; MacQueen, Phillip; Orosz, Jerome A.; Chandrasekaran, Hema; Twicken, Joseph D.; Bryson, Stephen T.; Quintana, Elisa V.; Clarke, Bruce D.; Li, Jie; Allen, Christopher; Tenenbaum, Peter; Wu, Hayley; Meibom, Søren; Klaus, Todd C.; Middour, Christopher K.; Cote, Miles T.; McCauliff, Sean; Girouard, Forrest R.; Gunter, Jay P.; Wohler, Bill; Hall, Jennifer R.; Ibrahim, Khadeejah; Kamal Uddin, AKM; Wu, Michael S.; Bhavsar, Paresh A.; Van Cleve, Jeffrey; Pletcher, David L.; Dotson, Jessie L.; Haas, Michael R.

2010-12-01

We report on the discovery and the Rossiter-McLaughlin (R-M) effect of Kepler-8b, a transiting planet identified by the NASA Kepler Mission. Kepler photometry and Keck-HIRES radial velocities yield the radius and mass of the planet around this F8IV subgiant host star. The planet has a radius R P = 1.419 R J and a mass M P = 0.60 M J, yielding a density of 0.26 g cm-3, one of the lowest planetary densities known. The orbital period is P = 3.523 days and the orbital semimajor axis is 0.0483+0.0006 -0.0012 AU. The star has a large rotational vsin i of 10.5 ± 0.7 km s-1 and is relatively faint (V ≈ 13.89 mag); both properties are deleterious to precise Doppler measurements. The velocities are indeed noisy, with scatter of 30 m s-1, but exhibit a period and phase that are consistent with those implied by transit photometry. We securely detect the R-M effect, confirming the planet's existence and establishing its orbit as prograde. We measure an inclination between the projected planetary orbital axis and the projected stellar rotation axis of λ = -26fdg4 ± 10fdg1, indicating a significant inclination of the planetary orbit. R-M measurements of a large sample of transiting planets from Kepler will provide a statistically robust measure of the true distribution of spin-orbit orientations for hot Jupiters around F and early G stars. Based in part on observations obtained at the W. M. Keck Observatory, which is operated as a scientific partnership between the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

An artificial Kepler dichotomy? Implications for the coplanarity of planetary systems

NASA Astrophysics Data System (ADS)

Bovaird, Timothy; Lineweaver, Charles H.

2016-10-01

We challenge the assumptions present in previous efforts to model the ensemble of detected Kepler systems, which require a dichotomous stellar population of `fertile' and `sterile' planet producing stars. We remove the assumption of Rayleigh distributed mutual inclinations between planets and show that the need for two distinct stellar populations disappears when the inner part of planetary disks are assumed to be flat, rather than flared.

Herschel/PACS photometry of transiting-planet host stars with candidate warm debris disks

NASA Astrophysics Data System (ADS)

Merín, Bruno; Ardila, David R.; Ribas, Álvaro; Bouy, Hervé; Bryden, Geoffrey; Stapelfeldt, Karl; Padgett, Deborah

2014-09-01

Dust in debris disks is produced by colliding or evaporating planetesimals, which are remnants of the planet formation process. Warm dust disks, known by their emission at ≤24 μm, are rare (4% of FGK main sequence stars) and especially interesting because they trace material in the region likely to host terrestrial planets, where the dust has a very short dynamical lifetime. Statistical analyses of the source counts of excesses as found with the mid-IR Wide Field Infrared Survey Explorer (WISE) suggest that warm-dust candidates found for the Kepler transiting-planet host-star candidates can be explained by extragalactic or galactic background emission aligned by chance with the target stars. These statistical analyses do not exclude the possibility that a given WISE excess could be due to a transient dust population associated with the target. Here we report Herschel/PACS 100 and 160 micron follow-up observations of a sample of Kepler and non-Kepler transiting-planet candidates' host stars, with candidate WISE warm debris disks, aimed at detecting a possible cold debris disk in any one of them. No clear detections were found in any one of the objects at either wavelength. Our upper limits confirm that most objects in the sample do not have a massive debris disk like that in β Pic. We also show that the planet-hosting star WASP-33 does not have a debris disk comparable to the one around η Crv. Although the data cannot be used to rule out rare warm disks around the Kepler planet-hosting candidates, the lack of detections and the characteristics of neighboring emission found at far-IR wavelengths support an earlier result suggesting that most of the WISE-selected IR excesses around Kepler candidate host stars are likely due to either chance alignment with background IR-bright galaxies and/or to interstellar emission. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important

THE HUNT FOR EXOMOONS WITH KEPLER (HEK). I. DESCRIPTION OF A NEW OBSERVATIONAL PROJECT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kipping, D. M.; Bakos, G. A.; Buchhave, L.

2012-05-10

Two decades ago, empirical evidence concerning the existence and frequency of planets around stars, other than our own, was absent. Since that time, the detection of extrasolar planets from Jupiter-sized to, most recently, Earth-sized worlds has blossomed and we are finally able to shed light on the plurality of Earth-like, habitable planets in the cosmos. Extrasolar moons may also be frequently habitable worlds, but their detection or even systematic pursuit remains lacking in the current literature. Here, we present a description of the first systematic search for extrasolar moons as part of a new observational project called 'The Hunt formore » Exomoons with Kepler' (HEK). The HEK project distills the entire list of known transiting planet candidates found by Kepler (2326 at the time of writing) down to the most promising candidates for hosting a moon. Selected targets are fitted using a multimodal nested sampling algorithm coupled with a planet-with-moon light curve modeling routine. By comparing the Bayesian evidence of a planet-only model to that of a planet-with-moon, the detection process is handled in a Bayesian framework. In the case of null detections, upper limits derived from posteriors marginalized over the entire prior volume will be provided to inform the frequency of large moons around viable planetary hosts, {eta} leftmoon. After discussing our methodologies for target selection, modeling, fitting, and vetting, we provide two example analyses.« less

A resonant chain of four transiting, sub-Neptune planets.

PubMed

Mills, Sean M; Fabrycky, Daniel C; Migaszewski, Cezary; Ford, Eric B; Petigura, Erik; Isaacson, Howard

2016-05-26

Surveys have revealed many multi-planet systems containing super-Earths and Neptunes in orbits of a few days to a few months. There is debate whether in situ assembly or inward migration is the dominant mechanism of the formation of such planetary systems. Simulations suggest that migration creates tightly packed systems with planets whose orbital periods may be expressed as ratios of small integers (resonances), often in a many-planet series (chain). In the hundreds of multi-planet systems of sub-Neptunes, more planet pairs are observed near resonances than would generally be expected, but no individual system has hitherto been identified that must have been formed by migration. Proximity to resonance enables the detection of planets perturbing each other. Here we report transit timing variations of the four planets in the Kepler-223 system, model these variations as resonant-angle librations, and compute the long-term stability of the resonant chain. The architecture of Kepler-223 is too finely tuned to have been formed by scattering, and our numerical simulations demonstrate that its properties are natural outcomes of the migration hypothesis. Similar systems could be destabilized by any of several mechanisms, contributing to the observed orbital-period distribution, where many planets are not in resonances. Planetesimal interactions in particular are thought to be responsible for establishing the current orbits of the four giant planets in the Solar System by disrupting a theoretical initial resonant chain similar to that observed in Kepler-223.

What's the Kepler Spacecraft Been Up To?

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2016-03-01

Remember back in May 2013 when the second of Keplers reaction wheels failed, rendering it unable to control its precision pointing? As a result of a clever backup plan by intrepid scientists, Kepler is still going strong! This January, a paper was published describing some of the results from the first year of the extended Kepler mission, known as K2.K2: A Second ChanceHistograms of the K2 planet candidate sample (solid yellow) compared with planet candidates from the first four months of Kepler observations (blue diagonal lines). The histograms compare planet radius, orbital period, and brightness. [Vanderburg et al. 2016]After an incredibly successful five years discovering transiting exoplanets, the failure of two of Keplers reaction wheels (which allow it to maintain its orientation) looked like it would shut down the mission. Luckily, the scientific community came up with the ingenious plan of stabilizing the telescope using the radiation pressure exerted by the Sun. Though this solution limits Kepler to observing within the ecliptic plane, it has provided a new life lease for the project.Despite the significantly worsened pointing precision in the K2 mission, new analysis techniques have been developed that decouple the motion of the spacecraft from its observations, resulting in an observational precision for K2 thats within 35% of the original precision achieved by Kepler.Using these techniques, a team of scientists led by Andrew Vanderburg (HarvardSmithsonian Center for Astrophysics) analyzed the publicly released data from the first year of the K2 mission. In a new study, they describe the results from the 59,174 targets that Kepler has observed in that time.Planetary CandidatesVanderburg and collaborators report that K2 has detected 234 planetary candidates around 208 stars in its first year. These candidates span a range of sizes from gas-giant to smaller than the Earth, and have orbital periods that range from hours to more than a month. The list

THE INTERSTELLAR MEDIUM IN THE KEPLER SEARCH VOLUME

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Marshall C.; Redfield, Seth; Jensen, Adam G., E-mail: mjohnson@astro.as.utexas.edu

2015-07-10

The properties of the interstellar medium (ISM) surrounding a planetary system can impact planetary climate through a number of mechanisms, including changing the size of the astrosphere (one of the major shields for cosmic rays) as well as direct deposition of material into planetary atmospheres. In order to constrain the ambient ISM conditions for exoplanetary systems, we present observations of interstellar Na i and K i absorption toward seventeen early type stars in the Kepler prime mission field of view (FOV). We identify 39 Na i and 8 K i velocity components, and attribute these to 11 ISM clouds. Sixmore » of these are detected toward more than one star, and for these clouds we put limits on the cloud properties, including distance and hydrogen number density. We identify one cloud with significant (≳1.5 cm{sup −3}) hydrogen number density located within the nominal ∼100 pc boundary of the Local Bubble. We identify systems with confirmed planets within the Kepler FOV that could lie within these ISM clouds, and estimate upper limits on the astrosphere sizes of these systems under the assumption that they do lie within these clouds. Under this condition, the Kepler-20, 42, and 445 multiplanet systems could have compressed astrospheres much smaller than the present-day heliosphere. Among the known habitable zone planet hosts, Kepler-186 could have an astrosphere somewhat smaller than the heliosphere, while Kepler-437 and KOI-4427 could have astrospheres much larger than the heliosphere. The thick disk star Kepler-444 may have an astrosphere just a few AU in radius.« less

Are we alone? Stories from the frontline of Kepler's search for Earth's twin (Presentation Video)

NASA Astrophysics Data System (ADS)

Jenkins, Jon

2013-10-01

Kepler vaulted into the heavens on March 7, 2009, initiating NASA's search for Earth-size planets orbiting Sun-like stars in the habitable zone, where liquid water could exist on the planetary surface and support alien biology. Never before has there been a photometer capable of reaching a precision near 20 ppm in 6.5 hours while conducting nearly continuous and uninterrupted observations for several years. The flood of exquisite photometric data over the last 4 years on 190,000+ stars has provoked a watershed of results. Over 2,700+ candidate planets have been identified of which an astounding 1171 orbit 467 stars. Over 120+ planets have confirmed or validated and the data have also led to a resounding revolution in asteroseismology. Recent discoveries include Kepler-62 with 5 planets total of which 2 are in the habitable zone, and are 1.4 and 1.7 times the radius of the Earth. Designing and building the Kepler photometer and the software systems that process and analyze the resulting data presented a daunting set of challenges, including how to manage the large data volume, how to detect miniscule transit signatures against stellar variability and instrumental effects, and how to review hundreds of diagnostics produced for each of ~20,000 candidate transit signatures. The challenges continue into flight operations, as the photometer and spacecraft have experienced aging and changes in hardware performance over the course of time. The success of Kepler sets the stage for TESS, NASA's next mission to detect Earth's closest cousins.

Exoplanet orbital eccentricities derived from LAMOST-Kepler analysis

NASA Astrophysics Data System (ADS)

Xie, Ji-Wei; Dong, Subo; Zhu, Zhaohuan; Huber, Daniel; Zheng, Zheng; De Cat, Peter; Fu, Jianning; Liu, Hui-Gen; Luo, Ali; Wu, Yue; Zhang, Haotong; Zhang, Hui; Zhou, Ji-Lin; Cao, Zihuang; Hou, Yonghui; Wang, Yuefei; Zhang, Yong

2016-10-01

The nearly circular (mean eccentricity e¯≈0.06) and coplanar (mean mutual inclination i¯≈3°) orbits of the solar system planets motivated Kant and Laplace to hypothesize that planets are formed in disks, which has developed into the widely accepted theory of planet formation. The first several hundred extrasolar planets (mostly Jovian) discovered using the radial velocity (RV) technique are commonly on eccentric orbits (e¯≈0.3). This raises a fundamental question: Are the solar system and its formation special? The Kepler mission has found thousands of transiting planets dominated by sub-Neptunes, but most of their orbital eccentricities remain unknown. By using the precise spectroscopic host star parameters from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) observations, we measure the eccentricity distributions for a large (698) and homogeneous Kepler planet sample with transit duration statistics. Nearly half of the planets are in systems with single transiting planets (singles), whereas the other half are multiple transiting planets (multiples). We find an eccentricity dichotomy: on average, Kepler singles are on eccentric orbits with e¯≈0.3, whereas the multiples are on nearly circular (e¯=0.04-0.04+0.03) and coplanar (i¯=1.4-1.1+0.8 degree) orbits similar to those of the solar system planets. Our results are consistent with previous studies of smaller samples and individual systems. We also show that Kepler multiples and solar system objects follow a common relation [×i¯] between mean eccentricities and mutual inclinations. The prevalence of circular orbits and the common relation may imply that the solar system is not so atypical in the galaxy after all.

Exoplanet orbital eccentricities derived from LAMOST–Kepler analysis

PubMed Central

Xie, Ji-Wei; Dong, Subo; Zhu, Zhaohuan; Huber, Daniel; Zheng, Zheng; De Cat, Peter; Fu, Jianning; Liu, Hui-Gen; Luo, Ali; Wu, Yue; Zhang, Haotong; Zhang, Hui; Zhou, Ji-Lin; Cao, Zihuang; Hou, Yonghui; Wang, Yuefei; Zhang, Yong

2016-01-01

The nearly circular (mean eccentricity e¯≈0.06) and coplanar (mean mutual inclination i¯≈3°) orbits of the solar system planets motivated Kant and Laplace to hypothesize that planets are formed in disks, which has developed into the widely accepted theory of planet formation. The first several hundred extrasolar planets (mostly Jovian) discovered using the radial velocity (RV) technique are commonly on eccentric orbits (e¯≈0.3). This raises a fundamental question: Are the solar system and its formation special? The Kepler mission has found thousands of transiting planets dominated by sub-Neptunes, but most of their orbital eccentricities remain unknown. By using the precise spectroscopic host star parameters from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) observations, we measure the eccentricity distributions for a large (698) and homogeneous Kepler planet sample with transit duration statistics. Nearly half of the planets are in systems with single transiting planets (singles), whereas the other half are multiple transiting planets (multiples). We find an eccentricity dichotomy: on average, Kepler singles are on eccentric orbits with e¯≈ 0.3, whereas the multiples are on nearly circular (e¯=0.04−0.04+0.03) and coplanar (i¯=1.4−1.1+0.8 degree) orbits similar to those of the solar system planets. Our results are consistent with previous studies of smaller samples and individual systems. We also show that Kepler multiples and solar system objects follow a common relation [e¯≈(1–2)×i¯] between mean eccentricities and mutual inclinations. The prevalence of circular orbits and the common relation may imply that the solar system is not so atypical in the galaxy after all. PMID:27671635

Investigating the Orbital Period Valley of Giant Planets in Kepler Data

NASA Astrophysics Data System (ADS)

Thomas, Brianna P.; Birkby, Jayne L.

2016-01-01

Transit light curves contain a wealth of information about the basic properties of a planet, such as its radius, semi-major axis, and orbital period. For the latter property, there is a distinct lack of planets with periods between 10 to 100 days. This gap could be caused by something as simple as observational bias, or as prominent as planetary formation or migration. Here, we report an investigation into the atmosphere of planets within this orbital period valley, to search for differences that may indicate a different formation mechanism or migration path to those outside of it. We do this by searching for the secondary eclipse of planets in the valley in order to measure their albedos. We determined an optimal target for this: KOI-366 b (P ~ 75 days). However, we find that despite the exquisite precision of Kepler data, it cannot constrain the albedo for this long-orbit planet candidate. We measure a 1σ upper limit on the geometric albedo of Ag,1σ ≤ 2.0. We highlight that additional scatter in the light curve is likely caused by a ~ 2-day pulsation of the giant host star, and that further data is required to measure the secondary eclipse. KOI-366 is one of the best suited of all host stars with long period exoplanet candidates for follow-up due to its relatively bright magnitude (Kp = 11.7 mag), but the full investigation of the reflective properties of long period planets may require space-based observations from future instruments, such as WFIRST, that will be more sensitive to objects further away from their host stars. This work was supported in part by the NSF REU and DoD ASSURE programs under NSF grant no. 1262851 and by the Smithsonian Institution. This work was performed in part under contract with the Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute.

Kepler Press Conference

NASA Image and Video Library

2009-08-05

William Bo-Ricki, Kepler principal investigator at NASA's Ames Research Center, second from left, speaks during a press conference, Thursday, Aug. 6, 2009, at NASA Headquarters in Washington about the scientific observations coming from the Kepler spacecraft that was launched this past March. Others seated include Jon Morse, NASA's Astrophysics Director, Sara Seager, Professor of Planetary Science and Physics at MIT, and Alan Boss, an Astrophysicist at the Carnegie Institution at the Department of Terrestrial Magnetism in Washington, right. Kepler is NASA's first mission that is capable of discovering earth-sized planets in the habitable zones of stars like our Sun. Photo Credit: (NASA/Paul E. Alers)

About 30% of Sun-like Stars Have Kepler-like Planetary Systems: A Study of Their Intrinsic Architecture

NASA Astrophysics Data System (ADS)

Zhu, Wei; Petrovich, Cristobal; Wu, Yanqin; Dong, Subo; Xie, Jiwei

2018-06-01

We constrain the intrinsic architecture of Kepler planetary systems by modeling the observed multiplicities of the transiting planets (tranets) and their transit timing variations (TTVs). We robustly determine that the fraction of Sun-like stars with Kepler-like planets, η Kepler, is 30 ± 3%. Here, Kepler-like planets are planets that have radii R p ≳ R ⊕ and orbital periods P < 400 days. Our result thus significantly revises previous claims that more than 50% of Sun-like stars have such planets. Combined with the average number of Kepler planets per star (∼0.9), we obtain that on average each planetary system has 3.0 ± 0.3 planets within 400 days. We also find that the dispersion in orbital inclinations of planets within a given planetary system, σ i,k , is a steep function of its number of planets, k. This can be parameterized as {σ }i,k\\propto {k}α and we find that ‑4 < α < ‑2 at the 2σ level. Such a distribution well describes the observed multiplicities of both transits and TTVs with no excess of single-tranet systems. Therefore we do not find evidence supporting the so-called “Kepler dichotomy.” Together with a previous study on orbital eccentricities, we now have a consistent picture: the fewer planets in a system, the hotter it is dynamically. We discuss briefly possible scenarios that lead to such a trend. Despite our solar system not belonging to the Kepler club, it is interesting to notice that the solar system also has three planets within 400 days and that the inclination dispersion is similar to Kepler systems of the same multiplicity.

Transit Timing Variation analysis with Kepler light curves of KOI 227 and Kepler 93b

NASA Astrophysics Data System (ADS)

Dulz, Shannon; Reed, Mike

2017-01-01

By searching for transit signals in approximately 150,000 stars, NASA’s Kepler Space telescope found thousands of exoplanets over its primary mission from 2009 to 2013 (Tenenbaum et al. 2014, ApJS, 211, 6). Yet, a detailed follow-up examination of Kepler light curves may contribute more evidence on system dynamics and planetary atmospheres of these objects. Kepler’s continuous observing of these systems over the mission duration produced light curves of sufficient duration to allow for the search for transit timing variations. Transit timing variations over the course of many orbits may indicate a precessing orbit or the existence of a non-transiting third body such as another exoplanet. Flux contributions of the planet just prior to secondary eclipse may provide a measurement of bond albedo from the day-side of the transiting planet. Any asymmetries of the transit shape may indicate thermal asymmetries which can measure upper atmosphere motion of the planet. These two factors can constrain atmospheric models of close orbiting exoplanets. We first establish our procedure with the well-documented TTV system, KOI 227 (Nesvorny et al. 2014, ApJ, 790, 31). Using the test case of KOI 227, we analyze Kepler-93b for TTVs and day-side flux contributions. Kepler-93b is likely a rocky planet with R = 1.50 ± 0.03 Earth Radii and M = 2.59 ± 2.0 Earth Masses (Marcy et al. 2014, ApJS, 210, 20). This research is funded by a NASA EPSCoR grant.

CONSTRAINTS ON PLANET OCCURRENCE AROUND NEARBY MID-TO-LATE M DWARFS FROM THE MEARTH PROJECT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berta, Zachory K.; Irwin, Jonathan; Charbonneau, David, E-mail: zberta@cfa.harvard.edu

The MEarth Project is a ground-based photometric survey intended to find planets transiting the closest and smallest main-sequence stars. In its first four years, MEarth discovered one transiting exoplanet, the 2.7 R{sub ⊕} planet GJ1214b. Here, we answer an outstanding question: in light of the bounty of small planets transiting small stars uncovered by the Kepler mission, should MEarth have found more than just one planet so far? We estimate MEarth's ensemble sensitivity to exoplanets by performing end-to-end simulations of 1.25 × 10{sup 6} observations of 988 nearby mid-to-late M dwarfs, gathered by MEarth between 2008 October and 2012 June.more » For 2-4 R{sub ⊕} planets, we compare this sensitivity to results from Kepler and find that MEarth should have found planets at a rate of 0.05-0.36 planets yr{sup –1} in its first four years. As part of this analysis, we provide new analytic fits to the Kepler early M dwarf planet occurrence distribution. When extrapolating between Kepler's early M dwarfs and MEarth's mid-to-late M dwarfs, we find that assuming the planet occurrence distribution stays fixed with respect to planetary equilibrium temperature provides a good match to our detection of a planet with GJ1214b's observed properties. For larger planets, we find that the warm (600-700 K), Neptune-sized (4 R{sub ⊕}) exoplanets that transit early M dwarfs like Gl436 and GJ3470 occur at a rate of <0.15 star{sup –1} (at 95% confidence) around MEarth's later M dwarf targets. We describe a strategy with which MEarth can increase its expected planet yield by 2.5 × without new telescopes by shifting its sensitivity toward the smaller and cooler exoplanets that Kepler has demonstrated to be abundant.« less

Kepler's Cosmos And The Lathe Of Heaven

NASA Astrophysics Data System (ADS)

Brecher, Kenneth

2011-01-01

Johannes Kepler's Mysterium Cosmographicum, published in 1596, presented his vision of the geometrical structure of the solar system. Kepler sought to account for the number of planets, thought to be six, as well as their orbital radii. He assigned orbits to the planets in three-dimensional space. Kepler proposed that the planets move on six spheres inscribed within and circumscribed around the five platonic solids. How did he arrive at his model? By his own account reported in the book, the central idea occurred to him while giving a lecture about planetary conjunctions. But was this revelation the origin of the model? In this presentation, we discuss the artistic, scientific and mathematical environment in which Kepler was immersed in late 16th century Europe. Examples will be shown of some of the readily available inscribed polyhedra that he may have seen - printed in widely circulated books, included in well-known paintings and engravings, and displayed as three dimensional ornamentally turned sculptures. It is highly likely that he saw such physical models five years later while in the employ of Rudolf II who was an avid ornamental turner. Layered polyhedral ivory turnings were made by the nobility with what were then fairly common lathes. Kepler himself wanted to have his own celestial model made into a punch bowl! Therefore, it seems plausible that Kepler had seen models of inscribed platonic solids well before 1596. Later in life Kepler reprinted the Mysterium Cosmographicum with very little fundamental change in its outlook, even after having found what we now call Kepler's three laws of planetary motion. His interest in nested polyhedra may well have preceded any astronomical evidence or geometrical reasoning, arising from artistic and aesthetic encounters that occurred early in his life. Project LITE is supported by the NSF through DUE Grant # 0715975.

Kepler Mission: Current Status

NASA Astrophysics Data System (ADS)

Borucki, William J.; Koch, D. G.; Lissauer, J. J.; Bryson, S.; Natalie, B.; Caldwell, D. A.; DeVore, E.; Jenkins, J. M.; Christensen-Dalsgaard, J.; Cochran, W. D.; Dunham, E. W.; Gautier, T. N.; Geary, J. C.; Latham, D. W.; Sasselov, D.; Gilliland, R. L.; Gould, A.; Howell, S. B.; Monet, D. G.

2007-12-01

Kepler is a Discovery-class mission designed to determine the frequency of Earth-size planets in and near the habitable zone of solar-like stars. The instrument consists of a high precision photometer with Schmidt-type optics and a focal plane containing 95 million pixels to monitor over 100,000 stars to search for patterns of transits generated by planets as small as Mars. The recent reduction in the mission duration is discussed with regard to the impact on the expected science product and null statistics. Both terrestrial and giant planets discoveries will be followed up with ground-based Doppler-velocity observations to determine mass and density. The first meeting of Kepler Asteroseismic Science Consortium was held in Paris to organize an international team to analyze the Kepler data to determine the characteristics of the brighter target stars including their size and age. Stellar size determinations accurate to a few percent are expected. These will allow very accurate planet sizes to be determined from the depth of the transit signals. NASA HQ received thirty six proposals for the Participating Scientist Program and chose several new members to join the Science Team. Both the 0.95 m Schmidt corrector and 1.4 m aperture primary mirror have been completed and delivered for integration into the photometer. The focal plane with forty-two science CCD detectors and their processing electronics has been assembled and tested. The spacecraft assembly has begun with the mounting of the reaction control system, reaction wheels, attitude determination & control system, and power systems. Both the photometer and spacecraft are nearing final assembly with all subsystems having passed their environmental and performance testing. The photometer to spacecraft integration will begin this spring. The Mission is on schedule for a launch in February 2009. The Kepler Mission is funded by the NASA Astrophysics Division, Science Mission Directorate.

A Population of planetary systems characterized by short-period, Earth-sized planets.

PubMed

Steffen, Jason H; Coughlin, Jeffrey L

2016-10-25

We analyze data from the Quarter 1-17 Data Release 24 (Q1-Q17 DR24) planet candidate catalog from NASA's Kepler mission, specifically comparing systems with single transiting planets to systems with multiple transiting planets, and identify a population of exoplanets with a necessarily distinct system architecture. Such an architecture likely indicates a different branch in their evolutionary past relative to the typical Kepler system. The key feature of these planetary systems is an isolated, Earth-sized planet with a roughly 1-d orbital period. We estimate that at least 24 of the 144 systems we examined ([Formula: see text]17%) are members of this population. Accounting for detection efficiency, such planetary systems occur with a frequency similar to the hot Jupiters.

A Population of planetary systems characterized by short-period, Earth-sized planets

PubMed Central

Steffen, Jason H.; Coughlin, Jeffrey L.

2016-01-01

We analyze data from the Quarter 1–17 Data Release 24 (Q1–Q17 DR24) planet candidate catalog from NASA’s Kepler mission, specifically comparing systems with single transiting planets to systems with multiple transiting planets, and identify a population of exoplanets with a necessarily distinct system architecture. Such an architecture likely indicates a different branch in their evolutionary past relative to the typical Kepler system. The key feature of these planetary systems is an isolated, Earth-sized planet with a roughly 1-d orbital period. We estimate that at least 24 of the 144 systems we examined (≳17%) are members of this population. Accounting for detection efficiency, such planetary systems occur with a frequency similar to the hot Jupiters. PMID:27790984

The Kepler Mission: A Search for Terrestrial Planets - Development Status

NASA Technical Reports Server (NTRS)

Koch, David; Borucki, W.; Mayer, D.; Caldwell, D.; Jenkens, J.; Dunham, E.; Geary, J.; Bachtell, E.; Deininger, W.; Philbrick, R.

2003-01-01

We have embarked on a mission to detect terrestrial planets. The space mission has been optimized to search for earth-size planets (0.5 to 10 earth masses) in the habitable zone (HZ) of solar-like stars. Given this design, the mission will necessarily be capable of not only detecting Earth analogs, but a wide range of planetary types and characteristics ranging from Mercury-size objects with orbital periods of days to gas-giants in decade long orbits that have undeniable signatures even with only one transit detected. The mission is designed to survey the full range of spectral-type dwarf stars. The approach is to detect the periodic signal of transiting planets. Three or more transits of a star exceeding a combined threshold of eight sigma with a statistically consistent period, brightness change and duration provide a rigorous method of detection. From the relative brightness change the planet size can be calculated. From the period the orbital size can be calculated and its location relative to the HZ determined. Presented here are: the mission goals, the top level system design requirements derived from these goals that drive the flight system design, a number of the trades that have lead to the mission concept, expected photometric performance dependence on stellar brightness and spectral type based on the system 'noise tree' analysis. Updated estimates are presented of the numbers of detectable planets versus size, orbit, stellar spectral type and distances based on a planet frequency hypothesis. The current project schedule and organization are given.

The Prevalence of Earth-size Planets Orbiting Sun-like Stars

NASA Astrophysics Data System (ADS)

Petigura, Erik; Marcy, Geoffrey W.; Howard, Andrew

2015-01-01

In less than two decades since the discovery of the first planet orbiting another Sun-like star, the study of extrasolar planets has matured beyond individual discoveries to detailed characterization of the planet population as a whole. No mission has played more of a role in this paradigm shift than NASA's Kepler mission. Kepler photometry has shown that planets like Earth are common throughout the Milky Way Galaxy. Our group performed an independent search of Kepler photometry using our custom transit-finding pipeline, TERRA, and produced our own catalog of planet candidates. We conducted spectroscopic follow-up of their host stars in order to rule out false positive scenarios and to better constrain host star properties. We measured TERRA's sensitivity to planets of different sizes and orbital periods by injecting synthetic planets into raw Kepler photometry and measuring the recovery rate. Correcting for orbital tilt and survey completeness, we found that ~80% of GK stars harbor one or more planets within 1 AU and that ~22% of Sun-like stars harbor an Earth-size planet that receives similar levels of stellar radiation as Earth. I will present the latest results from our efforts to characterize the demographics of small planets revealed by Kepler.

The Kepler Project: Mission Update

NASA Technical Reports Server (NTRS)

Borucki, William J.; Koch, David G.

2009-01-01

Kepler is a Discovery-class mission designed to determine the frequency of Earth-size planets in and near the habitable zone of solar-like stars. The instrument consists of a 0.95 m aperture photometer designed to obtain high precision photometric measurement of > 100,000 stars to search for patterns of transits. The focal plane of the Schmidt-telescope contains 42 CCDs with at total of 95 mega pixels that cover 116 square degrees of sky. The photometer was launched into an Earth-trailing heliocentric orbit on March 6, 2009, finished its commissioning on May 12, and is now in the science operations mode. During the commissioning of the Kepler photometer, data were obtained at a 30 minute cadence for 53,000 stars for 9.7 days. Although the data have not yet been corrected for the presence of systematic errors and artifacts, the data show the presence of hundreds of eclipsing binary stars and variable stars of amazing variety. To provide some estimate of the capability of the photometer, a quick analysis of the photometric precision was made. Analysis of the commissioning data also show transits, occultations and light emitted from the known exoplanet HAT-P7b. The data show a smooth rise and fall of light: from the planet as it orbits its star, punctuated by a drop of 130 +/- 11 ppm in flux when the planet passes behind its star. We interpret this as the phase variation of the dayside thermal emission plus reflected light from the planet as it orbits its star and is occulted. The depth of the occultation is similar in amplitude to that expected from a transiting Earth-size planet and demonstrates that the Mission has the precision necessary to detect such planets.

A Bewildering and Dynamic Picture of Exoplanetary Systems Identified by the Kepler Mission (Invited)

NASA Astrophysics Data System (ADS)

Jenkins, J. M.

2013-12-01

Kepler vaulted into the heavens on March 7, 2009, initiating NASA's search for Earth-size planets orbiting Sun-like stars in the habitable zone, where liquid water could exist on a rocky planetary surface. In the 4 years since, a flood of photometric data of unprecedented precision and continuity on more than 190,000 stars has provoked a watershed of 134+ confirmed or validated planets, 3200+ planetary candidates (most sub-Neptune in size and many comparable to or smaller than Earth), and a revolution in asteroseismology and astrophysics. Recent discoveries include Kepler-62 with 5 planets total, of which 2 are in the habitable zone with radii of 1.4 and 1.7 Re. Approximately 500 of the stars in the Kepler survey with planets host multiple transiting planets: 43% of planet candidates have transiting siblings. Many of these multiple transiting planet systems are dynamically packed and are unlikely, therefore, to have formed in situ. These systems experienced strong migration and evolution to arrive at the configurations we observe today, with important implications for the time-variable habitability of these planets over their histories. The half dozen circumbinary transiting planet systems discovered by Kepler to date highlight the dynamic nature of the habitable zone in systems with multiple host stars where the habitable zone may change significantly on timescales commensurate with the orbital period of the binary. While the catalog of circumbinary planets is small at this point, it already possesses at least one example of an exoplanet in the habitable zone. This implies that the majority of habitable zone planets may be circumbinary planets given the high frequency of multiple star systems and the early detection of Kepler-47b. KIC-12557548 is most likely a disintegrating sub-Mercury-sized planet. While it was probably never habitable, it represents a unique example of the dynamic nature of planetary systems. These amazing discoveries challenge our conventional

Detecting Planet Pairs in Mean Motion Resonances via the Astrometry Method

NASA Astrophysics Data System (ADS)

Wu, Dong-Hong; Liu, Hui-Gen; Yu, Zhou-Yi; Zhang, Hui; Zhou, Ji-Lin

2016-07-01

Gaia is leading us into a new era with a high astrometry precision of ˜10 μas. Under such precision, astrometry can play an important role in detecting and characterizing exoplanets. In particular, we can identify planet pairs in mean motion resonances (MMRs), which constrain the formation and evolution of planetary systems. In accordance with observations, we consider two-Jupiter or two-super-Earth systems in 1:2, 2:3, and 3:4 MMRs. Our simulations show that the false alarm probabilities (FAPs) of a third planet are extremely small, while the two real planets can be fitted well with a signal-to-noise ratio (S/N) \\gt 3. The probability of reconstructing a resonant system is related to the eccentricities and the resonance intensity. Generally, when the S/N ≥slant 10, if the eccentricities of both planets are larger than 0.01 and the resonance is quite strong, the probability of reconstructing the planet pair in MMRs is ≥slant 80 % . Jupiter pairs in MMRs are reconstructed more easily than super-Earth pairs with similar S/N when we consider dynamical stability. FAPs are also calculated when we detect planet pairs in or near MMRs. The FAPs for 1:2 MMRs are the largest, I.e., FAP \\gt 15 % when S/N ≤slant 10. Extrapolating from the Kepler planet pairs near MMRs and assuming a S/N ˜ 3, we discover and reconstruct a few tens of Jupiter pairs and hundreds of super-Earth pairs in 2:3 and 1:2 MMRs within 30 pc. We also compare the differences between even and uneven data cadence and find that planets are better measured with more uniform phase coverage.

Ensemble asteroseismology of solar-type stars with the NASA Kepler mission.

PubMed

Chaplin, W J; Kjeldsen, H; Christensen-Dalsgaard, J; Basu, S; Miglio, A; Appourchaux, T; Bedding, T R; Elsworth, Y; García, R A; Gilliland, R L; Girardi, L; Houdek, G; Karoff, C; Kawaler, S D; Metcalfe, T S; Molenda-Żakowicz, J; Monteiro, M J P F G; Thompson, M J; Verner, G A; Ballot, J; Bonanno, A; Brandão, I M; Broomhall, A-M; Bruntt, H; Campante, T L; Corsaro, E; Creevey, O L; Doğan, G; Esch, L; Gai, N; Gaulme, P; Hale, S J; Handberg, R; Hekker, S; Huber, D; Jiménez, A; Mathur, S; Mazumdar, A; Mosser, B; New, R; Pinsonneault, M H; Pricopi, D; Quirion, P-O; Régulo, C; Salabert, D; Serenelli, A M; Silva Aguirre, V; Sousa, S G; Stello, D; Stevens, I R; Suran, M D; Uytterhoeven, K; White, T R; Borucki, W J; Brown, T M; Jenkins, J M; Kinemuchi, K; Van Cleve, J; Klaus, T C

2011-04-08

In addition to its search for extrasolar planets, the NASA Kepler mission provides exquisite data on stellar oscillations. We report the detections of oscillations in 500 solar-type stars in the Kepler field of view, an ensemble that is large enough to allow statistical studies of intrinsic stellar properties (such as mass, radius, and age) and to test theories of stellar evolution. We find that the distribution of observed masses of these stars shows intriguing differences to predictions from models of synthetic stellar populations in the Galaxy.

STUDYING ATMOSPHERE-DOMINATED HOT JUPITER KEPLER PHASE CURVES: EVIDENCE THAT INHOMOGENEOUS ATMOSPHERIC REFLECTION IS COMMON

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shporer, Avi; Hu, Renyu

2015-10-15

We identify three Kepler transiting planets, Kepler-7b, Kepler-12b, and Kepler-41b, whose orbital phase-folded light curves are dominated by planetary atmospheric processes including thermal emission and reflected light, while the impact of non-atmospheric (i.e., gravitational) processes, including beaming (Doppler boosting) and tidal ellipsoidal distortion, is negligible. Therefore, those systems allow a direct view of their atmospheres without being hampered by the approximations used in the inclusion of both atmospheric and non-atmospheric processes when modeling the phase-curve shape. We present here the analysis of Kepler-12b and Kepler-41b atmosphere based on their Kepler phase curve, while the analysis of Kepler-7b was already presentedmore » elsewhere. The model we used efficiently computes reflection and thermal emission contributions to the phase curve, including inhomogeneous atmospheric reflection due to longitudinally varying cloud coverage. We confirm Kepler-12b and Kepler-41b show a westward phase shift between the brightest region on the planetary surface and the substellar point, similar to Kepler-7b. We find that reflective clouds located on the west side of the substellar point can explain the phase shift. The existence of inhomogeneous atmospheric reflection in all three of our targets, selected due to their atmosphere-dominated Kepler phase curve, suggests this phenomenon is common. Therefore, it is also likely to be present in planetary phase curves that do not allow a direct view of the planetary atmosphere as they contain additional orbital processes. We discuss the implications of a bright-spot shift on the analysis of phase curves where both atmospheric and gravitational processes appear, including the mass discrepancy seen in some cases between the companion’s mass derived from the beaming and ellipsoidal photometric amplitudes. Finally, we discuss the potential detection of non-transiting but otherwise similar planets, whose mass is

Differential rotation of stars with multiple transiting planets

NASA Astrophysics Data System (ADS)

Netto, Yuri; Valio, Adriana

2017-10-01

If a star hosts a planet in an orbit such that it eclipses the star periodically, can be estimated the rotation profile of this star. If planets in multiplanetary system occult different stellar areas, spots in more than one latitude of the stellar disc can be detected. The monitored study of theses starspots in different latitudes allow us to infer the rotation profile of the star. We use the model described in Silva (2003) to characterize the starspots of Kepler-210, an active star with two planets. Kepler-210 is a late K star with an estimated age of 350 +/- 50 Myrs, average rotation period of 12.33 days, mass of 0.63 M⊙ and radius of 0.69 R⊙. The planets that eclipses this star have radii of 0.0498 R s and 0.0635 R s with orbital periods of 2.4532 +/- 0.0007 days and 7.9725 +/- 0.0014 days, respectively, where R s is the star radius.

Eccentric Companions to Kepler-448b and Kepler-693b: Clues to the Formation of Warm Jupiters

NASA Astrophysics Data System (ADS)

Masuda, Kento

2017-08-01

I report the discovery of non-transiting close companions to two transiting warm Jupiters (WJs), Kepler-448/KOI-12b (orbital period P=17.9 {days}, radius {R}{{p}}={1.23}-0.05+0.06 {R}{Jup}) and Kepler-693/KOI-824b (P=15.4 {days}, {R}{{p}}=0.91+/- 0.05 {R}{Jup}), via dynamical modeling of their transit timing and duration variations (TTVs and TDVs). The companions have masses of {22}-5+7 {M}{Jup} (Kepler-448c) and {150}-40+60 {M}{Jup} (Kepler-693c), and both are on eccentric orbits (e={0.65}-0.09+0.13 for Kepler-448c and e={0.47}-0.06+0.11 for Kepler-693c) with periastron distances of 1.5 {au}. Moderate eccentricities are detected for the inner orbits as well (e={0.34}-0.07+0.08 for Kepler-448b and e={0.2}-0.1+0.2 for Kepler-693b). In the Kepler-693 system, a large mutual inclination between the inner and outer orbits ({53}-9+7 \\deg or {134}-10+11 \\deg ) is also revealed by the TDVs. This is likely to induce a secular oscillation in the eccentricity of the inner WJ that brings its periastron close enough to the host star for tidal star-planet interactions to be significant. In the Kepler-448 system, the mutual inclination is weakly constrained, and such an eccentricity oscillation is possible for a fraction of the solutions. Thus these WJs may be undergoing tidal migration to become hot Jupiters (HJs), although the migration via this process from beyond the snow line is disfavored by the close-in and massive nature of the companions. This may indicate that WJs can be formed in situ and could even evolve into HJs via high-eccentricity migration inside the snow line.

Kepler-4b: A Hot Neptune-like Planet of a G0 Star Near Main-sequence Turnoff

NASA Astrophysics Data System (ADS)

Borucki, William J.; Koch, David G.; Brown, Timothy M.; Basri, Gibor; Batalha, Natalie M.; Caldwell, Douglas A.; Cochran, William D.; Dunham, Edward W.; Gautier, Thomas N., III; Geary, John C.; Gilliland, Ronald L.; Howell, Steve B.; Jenkins, Jon M.; Latham, David W.; Lissauer, Jack J.; Marcy, Geoffrey W.; Monet, David; Rowe, Jason F.; Sasselov, Dimitar

2010-04-01

Early time-series photometry from NASA's Kepler spacecraft has revealed a planet transiting the star we term Kepler-4, at R.A. = 19h02m27.s68, δ = +50°08'08farcs7. The planet has an orbital period of 3.213 days and shows transits with a relative depth of 0.87 × 10-3 and a duration of about 3.95 hr. Radial velocity (RV) measurements from the Keck High Resolution Echelle Spectrometer show a reflex Doppler signal of 9.3+1.1 -1.9 m s-1, consistent with a low-eccentricity orbit with the phase expected from the transits. Various tests show no evidence for any companion star near enough to affect the light curve or the RVs for this system. From a transit-based estimate of the host star's mean density, combined with analysis of high-resolution spectra, we infer that the host star is near turnoff from the main sequence, with estimated mass and radius of 1.223+0.053 -0.091 M sun and 1.487+0.071 -0.084 R sun. We estimate the planet mass and radius to be {M P, R P} = {24.5 ± 3.8 M ⊕, 3.99 ± 0.21 R ⊕}. The planet's density is near 1.9 g cm-3 it is thus slightly denser and more massive than Neptune, but about the same size. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

Near Mean-motion Resonances in the System Observed by Kepler: Affected by Mass Accretion and Type I Migration

NASA Astrophysics Data System (ADS)

Wang, Su; Ji, Jianghui

2017-12-01

The Kepler mission has released over 4496 planetary candidates, among which 3483 planets have been confirmed as of 2017 April. The statistical results of the planets show that there are two peaks around 1.5 and 2.0 in the distribution of orbital period ratios. The observations indicate that plenty of planet pairs could have first been captured into mean-motion resonances (MMRs) in planetary formation. Subsequently, these planets depart from exact resonant locations to be near-MMR configurations. Through type I migration, two low-mass planets have a tendency to be trapped in first-order MMRs (2:1 or 3:2 MMRs); however, two scenarios of mass accretion of planets and potential outward migration play important roles in reshaping their final orbital configurations. Under the scenario of mass accretion, the planet pairs can cross 2:1 MMRs and then enter into 3:2 MMRs, especially for the inner pairs. With such a formation scenario, the possibility that two planets are locked into 3:2 MMRs can increase if they are formed in a flat disk. Moreover, the outward migration can make planets have a high likelihood to be trapped into 3:2 MMRs. We perform additional runs to investigate the mass relationship for those planets in three-planet systems, and we show that two peaks near 1.5 and 2.0 for the period ratios of two planets can be easily reproduced through our formation scenario. We further show that the systems in chain resonances (e.g., 4:2:1, 3:2:1, 6:3:2, and 9:6:4 MMRs), have been observed in our simulations. This mechanism can be applicable to understand the formation of systems of Kepler-48, Kepler-53, Kepler-100, Kepler-192, Kepler-297, Kepler-399, and Kepler-450.

Detailed Abundances of Stars with Small Planets Discovered by Kepler. I. The First Sample

NASA Astrophysics Data System (ADS)

Schuler, Simon C.; Vaz, Zachary A.; Katime Santrich, Orlando J.; Cunha, Katia; Smith, Verne V.; King, Jeremy R.; Teske, Johanna K.; Ghezzi, Luan; Howell, Steve B.; Isaacson, Howard

2015-12-01

We present newly derived stellar parameters and the detailed abundances of 19 elements of seven stars with small planets discovered by NASA's Kepler Mission. Each star, save one, has at least one planet with a radius ≤1.6 R⊕, suggesting a primarily rocky composition. The stellar parameters and abundances are derived from high signal-to-noise ratio, high-resolution echelle spectroscopy obtained with the 10 m Keck I telescope and High Resolution Echelle Spectrometer using standard spectroscopic techniques. The metallicities of the seven stars range from -0.32 to +0.13 dex, with an average metallicity that is subsolar, supporting previous suggestions that, unlike Jupiter-type giant planets, small planets do not form preferentially around metal-rich stars. The abundances of elements other than iron are in line with a population of Galactic disk stars, and despite our modest sample size, we find hints that the compositions of stars with small planets are similar to stars without known planets and with Neptune-size planets, but not to those of stars with giant planets. This suggests that the formation of small planets does not require exceptional host-star compositions and that small planets may be ubiquitous in the Galaxy. We compare our derived abundances (which have typical uncertainties of ≲0.04 dex) to the condensation temperature of the elements; a correlation between the two has been suggested as a possible signature of rocky planet formation. None of the stars demonstrate the putative rocky planet signature, despite at least three of the stars having rocky planets estimated to contain enough refractory material to produce the signature, if real. More detailed abundance analyses of stars known to host small planets are needed to verify our results and place ever more stringent constraints on planet formation models. Some of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California

Kepler-62 and the Solar System

NASA Image and Video Library

2013-04-18

This diagram compares the planets of the inner solar system to Kepler-62, a five-planet system about 1,200 light-years from Earth in the constellation Lyra. At seven billion years old, the star is somewhat older than the sun.

TRANSIT TIMING OBSERVATIONS FROM KEPLER. I. STATISTICAL ANALYSIS OF THE FIRST FOUR MONTHS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ford, Eric B.; Rowe, Jason F.; Caldwell, Douglas A.

The architectures of multiple planet systems can provide valuable constraints on models of planet formation, including orbital migration, and excitation of orbital eccentricities and inclinations. NASA's Kepler mission has identified 1235 transiting planet candidates. The method of transit timing variations (TTVs) has already confirmed seven planets in two planetary systems. We perform a transit timing analysis of the Kepler planet candidates. We find that at least {approx}11% of planet candidates currently suitable for TTV analysis show evidence suggestive of TTVs, representing at least {approx}65 TTV candidates. In all cases, the time span of observations must increase for TTVs to providemore » strong constraints on planet masses and/or orbits, as expected based on N-body integrations of multiple transiting planet candidate systems (assuming circular and coplanar orbits). We find the fraction of planet candidates showing TTVs in this data set does not vary significantly with the number of transiting planet candidates per star, suggesting significant mutual inclinations and that many stars with a single transiting planet should host additional non-transiting planets. We anticipate that Kepler could confirm (or reject) at least {approx}12 systems with multiple transiting planet candidates via TTVs. Thus, TTVs will provide a powerful tool for confirming transiting planets and characterizing the orbital dynamics of low-mass planets. If Kepler observations were extended to at least seven years, then TTVs would provide much more precise constraints on the dynamics of systems with multiple transiting planets and would become sensitive to planets with orbital periods extending into the habitable zone of solar-type stars.« less

2014 Summer Series - Jon Jenkins - Chasing Shadow Worlds: Exoplanets from Kepler and Beyond

NASA Image and Video Library

2014-08-14

Twenty years ago, there were no planets known outside our own solar system. Since then, the discoveries of about 1500 planets orbiting other stars have radically altered our views of planets and planetary systems. This revolution in knowledge is due in no small part to the Kepler Mission, which has discovered over 950 of these planets and over 3000 planet candidates. This talk will review the greatest hits of Kepler and peek into the future of exoplanets.

Discourse following award of Kepler Gold Medal. [Kepler Laws, planetary astronomy and physics, and Jupiter studies

NASA Technical Reports Server (NTRS)

Kuiper, G. P.

1973-01-01

Kuiper briefly reviews Kepler's contributions to the field of planetary astronomy and physics, along with references to his own background in the study of stars, planets, and the solar system. He mentions his participation in NASA programs related to planetary astronomy. He concludes his remarks with thanks for being honored by the award of the Kepler Gold Medal.

An Earth-sized planet with an Earth-like density.

PubMed

Pepe, Francesco; Cameron, Andrew Collier; Latham, David W; Molinari, Emilio; Udry, Stéphane; Bonomo, Aldo S; Buchhave, Lars A; Charbonneau, David; Cosentino, Rosario; Dressing, Courtney D; Dumusque, Xavier; Figueira, Pedro; Fiorenzano, Aldo F M; Gettel, Sara; Harutyunyan, Avet; Haywood, Raphaëlle D; Horne, Keith; Lopez-Morales, Mercedes; Lovis, Christophe; Malavolta, Luca; Mayor, Michel; Micela, Giusi; Motalebi, Fatemeh; Nascimbeni, Valerio; Phillips, David; Piotto, Giampaolo; Pollacco, Don; Queloz, Didier; Rice, Ken; Sasselov, Dimitar; Ségransan, Damien; Sozzetti, Alessandro; Szentgyorgyi, Andrew; Watson, Christopher A

2013-11-21

Recent analyses of data from the NASA Kepler spacecraft have established that planets with radii within 25 per cent of the Earth's (R Earth symbol) are commonplace throughout the Galaxy, orbiting at least 16.5 per cent of Sun-like stars. Because these studies were sensitive to the sizes of the planets but not their masses, the question remains whether these Earth-sized planets are indeed similar to the Earth in bulk composition. The smallest planets for which masses have been accurately determined are Kepler-10b (1.42 R Earth symbol) and Kepler-36b (1.49 R Earth symbol), which are both significantly larger than the Earth. Recently, the planet Kepler-78b was discovered and found to have a radius of only 1.16 R Earth symbol. Here we report that the mass of this planet is 1.86 Earth masses. The resulting mean density of the planet is 5.57 g cm(-3), which is similar to that of the Earth and implies a composition of iron and rock.

THE OCCURRENCE RATE OF SMALL PLANETS AROUND SMALL STARS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dressing, Courtney D.; Charbonneau, David, E-mail: cdressing@cfa.harvard.edu

We use the optical and near-infrared photometry from the Kepler Input Catalog to provide improved estimates of the stellar characteristics of the smallest stars in the Kepler target list. We find 3897 dwarfs with temperatures below 4000 K, including 64 planet candidate host stars orbited by 95 transiting planet candidates. We refit the transit events in the Kepler light curves for these planet candidates and combine the revised planet/star radius ratios with our improved stellar radii to revise the radii of the planet candidates orbiting the cool target stars. We then compare the number of observed planet candidates to themore » number of stars around which such planets could have been detected in order to estimate the planet occurrence rate around cool stars. We find that the occurrence rate of 0.5-4 R{sub Circled-Plus} planets with orbital periods shorter than 50 days is 0.90{sup +0.04}{sub -0.03} planets per star. The occurrence rate of Earth-size (0.5-1.4 R{sub Circled-Plus }) planets is constant across the temperature range of our sample at 0.51{sub -0.05}{sup +0.06} Earth-size planets per star, but the occurrence of 1.4-4 R{sub Circled-Plus} planets decreases significantly at cooler temperatures. Our sample includes two Earth-size planet candidates in the habitable zone, allowing us to estimate that the mean number of Earth-size planets in the habitable zone is 0.15{sup +0.13}{sub -0.06} planets per cool star. Our 95% confidence lower limit on the occurrence rate of Earth-size planets in the habitable zones of cool stars is 0.04 planets per star. With 95% confidence, the nearest transiting Earth-size planet in the habitable zone of a cool star is within 21 pc. Moreover, the nearest non-transiting planet in the habitable zone is within 5 pc with 95% confidence.« less

A Census of Habitable Planets around Nearby stars?

NASA Astrophysics Data System (ADS)

Leger, Alain M.

2015-12-01

One day or another, a spectroscopic mission will be launched searching for biosignatures in the atmospheres of Earth-like planets, i.e. planets located in the Habitable Zone (HZ) of their stars and hopefully rocky. This could be done blindly, the expensive spectroscopic mission searching for the candidates before performing their spectroscopy. According to a clear tendency in the Kepler data, the mean number of Earth-like planets, ηEarth, around the Kepler stars is rather low (10% - 20%). It makes this approach pretty inefficient, most of the stars studied (90% - 80%) having no such planets, and the corresponding mission time being essentially lost. This is more severe when the random position of planets on their orbits is taken into account. An exhaustive census of these planets around the nearby stars, the only ones accessible to the mission, appears desirable priorly to its launch.Up to now, the detection of low mas planets in the HZ of their stars by the Radial Velocity technique is limited to stars with very low activity (~ 2% of F,G,K stars). The detection by transits is limited by the low probability the randomly oriented orbits, few of them leading to a transit (0.5% for solar-type stars). On the other hand, ultra accurate astrometry is less sensitive to stellar activity and could detect Earth-like planets around most of the nearby solar-type stars.We present the project of a space mission, Theia+, that could do the job and measure the masses and orbits of these planets, a key piece of information to derive a possible statement about the likelihood of the actual presence of life on a planet. Other capabilities of the mission regarding Dark Matter, Very Compact Object, Cosmology, and Stellar Formation is also rapidly mentioned.

VizieR Online Data Catalog: Detection of Kepler multiple M-star systems (Rappaport+, 2014)

NASA Astrophysics Data System (ADS)

Rappaport, S.; Swift, J.; Levine, A.; Joss, M.; Sanchis-Ojeda, R.; Barclay, T.; Still, M.; Handler, G.; Olah, K.; Muirhead, P. S.; Huber, D.; Vida, K.

2017-07-01

In all, we find 297 of the 3897 targets exhibit the requisite significant Fourier transform (FT) signal comprising a base frequency plus its harmonic, with the base frequency exceeding 0.5 cycles/day (i.e., Prot<2 days). We believe that the majority of these periodicities are likely to be due to stellar rotation manifested via starspots, but a significant number may be due to planet transits and binary eclipses. The individual FTs for these systems were further examined to eliminate those which were clearly not due to rotating starspots. In all cases we folded the data modulo the detected fundamental period, and were readily able to rule out cases due to transiting planets since their well-known sharp, relatively rectangular dipping profiles are characteristic. Of course, we also checked the KOI list for matches. Any of the objects that appear in the Kepler eclipsing binary ("EB") star catalog (e.g., Matijevic et al. 2012AJ....143..123M) were likewise eliminated. (2 data files).

Likely transiting exocomets detected by Kepler

NASA Astrophysics Data System (ADS)

Rappaport, S.; Vanderburg, A.; Jacobs, T.; LaCourse, D.; Jenkins, J.; Kraus, A.; Rizzuto, A.; Latham, D. W.; Bieryla, A.; Lazarevic, M.; Schmitt, A.

2018-02-01

We present the first good evidence for exocomet transits of a host star in continuum light in data from the Kepler mission. The Kepler star in question, KIC 3542116, is of spectral type F2V and is quite bright at Kp = 10. The transits have a distinct asymmetric shape with a steeper ingress and slower egress that can be ascribed to objects with a trailing dust tail passing over the stellar disc. There are three deeper transits with depths of ≃ 0.1 per cent that last for about a day, and three that are several times more shallow and of shorter duration. The transits were found via an exhaustive visual search of the entire Kepler photometric data set, which we describe in some detail. We review the methods we use to validate the Kepler data showing the comet transits, and rule out instrumental artefacts as sources of the signals. We fit the transits with a simple dust-tail model, and find that a transverse comet speed of ˜35-50 km s-1 and a minimum amount of dust present in the tail of ˜1016 g are required to explain the larger transits. For a dust replenishment time of ˜10 d, and a comet lifetime of only ˜300 d, this implies a total cometary mass of ≳3 × 1017 g, or about the mass of Halley's comet. We also discuss the number of comets and orbital geometry that would be necessary to explain the six transits detected over the 4 yr of Kepler prime-field observations. Finally, we also report the discovery of a single comet-shaped transit in KIC 11084727 with very similar transit and host-star properties.

Accurate parameters of the oldest known rocky-exoplanet hosting system: Kepler-10 revisited

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fogtmann-Schulz, Alexandra; Hinrup, Brian; Van Eylen, Vincent

2014-02-01

Since the discovery of Kepler-10, the system has received considerable interest because it contains a small, rocky planet which orbits the star in less than a day. The system's parameters, announced by the Kepler team and subsequently used in further research, were based on only five months of data. We have reanalyzed this system using the full span of 29 months of Kepler photometric data, and obtained improved information about its star and the planets. A detailed asteroseismic analysis of the extended time series provides a significant improvement on the stellar parameters: not only can we state that Kepler-10 ismore » the oldest known rocky-planet-harboring system at 10.41 ± 1.36 Gyr, but these parameters combined with improved planetary parameters from new transit fits gives us the radius of Kepler-10b to within just 125 km. A new analysis of the full planetary phase curve leads to new estimates on the planetary temperature and albedo, which remain degenerate in the Kepler band. Our modeling suggests that the flux level during the occultation is slightly lower than at the transit wings, which would imply that the nightside of this planet has a non-negligible temperature.« less

The Constraint of Coplanarity: Compact multi-planet system outer architectures and formation.-UP

NASA Astrophysics Data System (ADS)

Jontof-Hutter, Daniel

The Kepler mission discovered 92 systems with 4 or more transiting exoplanets. Systems like Kepler-11 with six "mini-Neptunes" on orbital periods well inside that of Venus pose a challenge to planet formation theory which is broadly split into two competing paradigms. One theory invokes the formation of Neptunes beyond the "snow line", followed by inward migration and assembly into compact configurations near the star. The alternative is that low density planets form in situ at all distances in the protoplanetary nebula. The two paradigms disagree on the occurrence of Jovian planets at longer orbital periods than the transiting exoplanets since such massive planets would impede the inward migration of multiple volatile-rich planets to within a fraction of 1 AU. The likelihood of all the known planets at systems like Kepler-11 to be transiting is very sensitive to presence of outer Jovian planets for a wide range in orbital distance and relative inclination of the Jovian planet. This can put upper limits on the occurrence of Jovian planets by the condition that the six known planets have to have low mutual inclinations most of the time in order for their current cotransiting state to be plausible. Most of these systems have little or no RV data. Hence, our upper limits may be the best constraints on the occurrence of Jovian planets in compact co-planar systems for years to come, and may help distinguish the two leading paradigms of planet formation theory. Methodology. We propose to use an established n-body code (MERCURY) to perform long-term simulations of systems like Kepler-11 with the addition of a putative Jovian planet considering a range of orbital distances. These simulations will test for which initial conditions a Jovian planet would prevent the known planets from all transiting at the same time. We will 1) determine at what orbital distances and inclinations an outer Jovian planet would make the observed configuration of Kepler-11 very unlikely. 2) Test

Stability of the Kepler-11 system and its origin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mahajan, Nikhil; Wu, Yanqin

2014-11-01

A significant fraction of Kepler systems are closely packed, largely coplanar, and circular. We study the stability of a six-planet system, Kepler-11, to gain insights on the dynamics and formation history of such systems. Using a technique called 'frequency maps' as fast indicators of long-term stability, we explore the stability of the Kepler-11 system by analyzing the neighborhood space around its orbital parameters. Frequency maps provide a visual representation of chaos and stability, and their dependence on orbital parameters. We find that the current system is stable, but lies within a few percent of several dynamically dangerous two-body mean-motion resonances.more » Planet eccentricities are restricted below a small value, ∼0.04, for long-term stability, but planet masses can be more than twice their reported values (thus allowing for the possibility of mass loss by past photoevaporation). Based on our frequency maps, we speculate on the origin of instability in closely packed systems. We then proceed to investigate how the system could have been assembled. The stability constraints on Kepler-11 (mainly eccentricity constraints) suggest that if the system were assembled in situ, a dissipation mechanism must have been at work to neutralize the eccentricity excitation. On the other hand, if migration was responsible for assembling the planets, there has to be little differential migration among the planets to avoid them either getting trapped into mean motion resonances, or crashing into each other.« less

Johannes Kepler and his contribution to Applied Mathematics

NASA Astrophysics Data System (ADS)

Pichler, Franz

The worldwide renown of Johannes Kepler is based above all on his contribution to astronomy. The 3 Kepler's Laws relating to the planets are well known and will ensure that his name is remembered by future generations. Besides his astronomical work, Kepler also made important contributions in the fields of theology, physics, phylosophy and mathematics. The actual paper discusses the advances by Kepler in the application of mathematics to the solution of "real life problems". The author made a concise account of some of the disciples by Kepler: Klug, Wieleitner, Caspar, Hammer, paying particular attention to works published by Kepler while he was living in Linz (1612-1628). The Kepler's contribution to applied mathematics is an example supremely worthy of emulation, the author concludes.

Average Albedos of Close-in Super-Earths and Super-Neptunes from Statistical Analysis of Long-cadence Kepler Secondary Eclipse Data

NASA Astrophysics Data System (ADS)

Sheets, Holly A.; Deming, Drake

2017-10-01

We present the results of our work to determine the average albedo for small, close-in planets in the Kepler candidate catalog. We have adapted our method of averaging short-cadence light curves of multiple Kepler planet candidates to long-cadence data, in order to detect an average albedo for the group of candidates. Long-cadence data exist for many more candidates than the short-cadence data, and so we separate the candidates into smaller radius bins than in our previous work: 1-2 {R}\\oplus , 2-4 {R}\\oplus , and 4-6 {R}\\oplus . We find that, on average, all three groups appear darker than suggested by the short-cadence results, but not as dark as many hot Jupiters. The average geometric albedos for the three groups are 0.11 ± 0.06, 0.05 ± 0.04, and 0.23 ± 0.11, respectively, for the case where heat is uniformly distributed about the planet. If heat redistribution is inefficient, the albedos are even lower, since there will be a greater thermal contribution to the total light from the planet. We confirm that newly identified false-positive Kepler Object of Interest (KOI) 1662.01 is indeed an eclipsing binary at twice the period listed in the planet candidate catalog. We also newly identify planet candidate KOI 4351.01 as an eclipsing binary, and we report a secondary eclipse measurement for Kepler-4b (KOI 7.01) of ˜7.50 ppm at a phase of ˜0.7, indicating that the planet is on an eccentric orbit.

Absolute densities in exoplanetary systems. Photodynamical modelling of Kepler-138.

NASA Astrophysics Data System (ADS)

Almenara, J. M.; Díaz, R. F.; Dorn, C.; Bonfils, X.; Udry, S.

2018-04-01

In favourable conditions, the density of transiting planets in multiple systems can be determined from photometry data alone. Dynamical information can be extracted from light curves, providing modelling is done self-consistently, i.e. using a photodynamical model, which simulates the individual photometric observations instead of the more generally used transit times. We apply this methodology to the Kepler-138 planetary system. The derived planetary bulk densities are a factor of two more precise than previous determinations, and we find a discrepancy in the stellar bulk density with respect to a previous study. This leads, in turn, to a discrepancy in the determination of masses and radii of the star and the planets. In particular, we find that interior planet, Kepler-138 b, has a size in between Mars and the Earth. Given our mass and density estimates, we characterize the planetary interiors using a generalized Bayesian inference model. This model allows us to quantify for interior degeneracy and calculate confidence regions of interior parameters such as thicknesses of the core, the mantle, and ocean and gas layers. We find that Kepler-138 b and Kepler-138 d have significantly thick volatile layers, and that the gas layer of Kepler-138 b is likely enriched. On the other hand, Kepler-138 c can be purely rocky.

Absolute densities in exoplanetary systems: photodynamical modelling of Kepler-138

NASA Astrophysics Data System (ADS)

Almenara, J. M.; Díaz, R. F.; Dorn, C.; Bonfils, X.; Udry, S.

2018-07-01

In favourable conditions, the density of transiting planets in multiple systems can be determined from photometry data alone. Dynamical information can be extracted from light curves, providing modelling is done self-consistently, i.e. using a photodynamical model, which simulates the individual photometric observations instead of the more generally used transit times. We apply this methodology to the Kepler-138 planetary system. The derived planetary bulk densities are a factor of 2 more precise than previous determinations, and we find a discrepancy in the stellar bulk density with respect to a previous study. This leads, in turn, to a discrepancy in the determination of masses and radii of the star and the planets. In particular, we find that interior planet, Kepler-138b, has a size in between Mars and the Earth. Given our mass and density estimates, we characterize the planetary interiors using a generalized Bayesian inference model. This model allows us to quantify for interior degeneracy and calculate confidence regions of interior parameters such as thicknesses of the core, the mantle, and ocean and gas layers. We find that Kepler-138b and Kepler-138 d have significantly thick volatile layers and that the gas layer of Kepler-138b is likely enriched. On the other hand, Kepler-138c can be purely rocky.

MEASURING TRANSIT SIGNAL RECOVERY IN THE KEPLER PIPELINE. I. INDIVIDUAL EVENTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Christiansen, Jessie L.; Clarke, Bruce D.; Burke, Christopher J.

The Kepler mission was designed to measure the frequency of Earth-size planets in the habitable zone of Sun-like stars. A crucial component for recovering the underlying planet population from a sample of detected planets is understanding the completeness of that sample-the fraction of the planets that could have been discovered in a given data set that actually were detected. Here, we outline the information required to determine the sample completeness, and describe an experiment to address a specific aspect of that question, i.e., the issue of transit signal recovery. We investigate the extent to which the Kepler pipeline preserves individualmore » transit signals by injecting simulated transits into the pixel-level data, processing the modified pixels through the pipeline, and comparing the measured transit signal-to-noise ratio (S/N) to that expected without perturbation by the pipeline. We inject simulated transit signals across the full focal plane for a set of observations for a duration of 89 days. On average, we find that the S/N of the injected signal is recovered at MS = 0.9973({+-} 0.0012) Multiplication-Sign BS - 0.0151({+-} 0.0049), where MS is the measured S/N and BS is the baseline, or expected, S/N. The 1{sigma} width of the distribution around this correlation is {+-}2.64%. This indicates an extremely high fidelity in reproducing the expected detection statistics for single transit events, and provides teams performing their own periodic transit searches the confidence that there is no systematic reduction in transit signal strength introduced by the pipeline. We discuss the pipeline processes that cause the measured S/N to deviate significantly from the baseline S/N for a small fraction of targets; these are primarily the handling of data adjacent to spacecraft re-pointings and the removal of harmonics prior to the measurement of the S/N. Finally, we outline the further work required to characterize the completeness of the Kepler pipeline.« less

Circumbinary planet formation in the Kepler-16 system. II. A toy model for in situ planet formation within a debris belt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meschiari, Stefano, E-mail: stefano@astro.as.utexas.edu

2014-07-20

Recent simulations have shown that the formation of planets in circumbinary configurations (such as those recently discovered by Kepler) is dramatically hindered at the planetesimal accretion stage. The combined action of the binary and the protoplanetary disk acts to raise impact velocities between kilometer-sized planetesimals beyond their destruction threshold, halting planet formation within at least 10 AU from the binary. It has been proposed that a primordial population of 'large' planetesimals (100 km or more in size), as produced by turbulent concentration mechanisms, would be able to bypass this bottleneck; however, it is not clear whether these processes are viablemore » in the highly perturbed circumbinary environments. We perform two-dimensional hydrodynamical and N-body simulations to show that kilometer-sized planetesimals and collisional debris can drift and be trapped in a belt close to the central binary. Within this belt, planetesimals could initially grow by accreting debris, ultimately becoming 'indestructible' seeds that can accrete other planetesimals in situ despite the large impact speeds. We find that large, indestructible planetesimals can be formed close to the central binary within 10{sup 5} yr, therefore showing that even a primordial population of 'small' planetesimals can feasibly form a planet.« less

Kepler-20e -- The Smallest Exoplanet Artist Concept

NASA Image and Video Library

2011-12-20

Kepler-20e is the first planet smaller than the Earth discovered to orbit a star other than the sun. A year on Kepler-20e only lasts 6 days, as it is much closer to its host star than the Earth is to the sun.

Artificial Intelligence and NASA Data Used to Discover Eighth Planet Circling Distant Star

NASA Image and Video Library

2017-12-12

Our solar system now is tied for most number of planets around a single star, with the recent discovery of an eighth planet circling Kepler-90, a Sun-like star 2,545 light years from Earth. The planet was discovered in data from NASA’s Kepler space telescope. The newly-discovered Kepler-90i -- a sizzling hot, rocky planet that orbits its star once every 14.4 days -- was found by researchers from Google and The University of Texas at Austin using machine learning. Machine learning is an approach to artificial intelligence in which computers “learn.” In this case, computers learned to identify planets by finding in Kepler data instances where the telescope recorded signals from planets beyond our solar system, known as exoplanets. Video Credit: NASA Ames Research Center / Google

Captain Cook, the Terrestrial Planet Finder and the search for extraterrestrial intelligence

NASA Technical Reports Server (NTRS)

Beichman, C.

2002-01-01

A recently completed NASA study has concluded that a Terrestrial Planet Finder could be launched within a decade to detect terrestrial planets around nearby stars. Such a mission, complemented by projects (Kepler and Eddington) that will provide statistical information on the frequency of Earth-sized planets in the habitable zone, will determine key terms in the Drake equation that describes the number of intelligent civilizations in the Universe.

Rediscovering Kepler's laws using Newton's gravitation law and NASA data

NASA Astrophysics Data System (ADS)

Springsteen, Paul; Keith, Jason

2010-03-01

Kepler's three laws of planetary motion were originally discovered by using data acquired from Tycho Brache's naked eye observations of the planets. We show how Kepler's third law can be reproduced using planetary data from NASA. We will also be using Newton's Gravitational law to explain why Kepler's three laws exist as they do.

Synergies Between the Kepler, K2 and TESS Missions with the PLATO Mission (Revised)

NASA Technical Reports Server (NTRS)

Jenkins, Jon M.

2017-01-01

Two transit survey missions will have been flown by NASA prior to the launch of ESA's PLATO Mission in 2026, laying the groundwork for exoplanet discovery via the transit method. The Kepler Mission, which launched in 2009, collected data on its 100+ square degree field of view for four years before failure of a reaction wheel ended its primary mission. The results from Kepler include 2300+ confirmed or validated exoplanets, 2200+ planetary candidates, 2100+ eclipsing binaries. Kepler also revolutionized the field of asteroseismology by measuring the pressure mode oscillations of over 15000 solar-like stars spanning the lifecycle of such stars from hydrogen-burning dwarfs to helium-burning red giants. The re-purposed Kepler Mission, dubbed K2, continues to observe fields of view in and near the ecliptic plane for 80 days each, significantly broadening the scope of the astrophysical investigations as well as discovering an additional 156 exoplanets to date. The TESS mission will launch in 2017 to conduct an all-sky survey for small exoplanets orbiting stars 10X closer and 100X brighter than Kepler exoplanet host stars, allowing for far greater follow-up and characterization of their masses as well as their sizes for at least 50 small planets. Future assets such as James Webb Space Telescope, and ground-based assets such as ESOs Very Large Telescope (VLT) array, the Exremely Large Telescope (ELT), and the Thirty Meter Telescope (TMT) will be able to characterize the atmospheric composition and properties of these small planets. TESS will observe each 24 X 96 field of view for 30 days and thereby cover first the southern and then the northern hemisphere over 13 pointings during each year of the primary mission. The pole-most camera will observe the James Webb continuous viewing zone for one year in each hemisphere, permitting much longer period planets to be detected in this region. The PLATO mission will seek to detect habitable Earth-like planets with an instrument

From Pixels to Planets

NASA Technical Reports Server (NTRS)

Brownston, Lee; Jenkins, Jon M.

2015-01-01

The Kepler Mission was launched in 2009 as NASAs first mission capable of finding Earth-size planets in the habitable zone of Sun-like stars. Its telescope consists of a 1.5-m primary mirror and a 0.95-m aperture. The 42 charge-coupled devices in its focal plane are read out every half hour, compressed, and then downlinked monthly. After four years, the second of four reaction wheels failed, ending the original mission. Back on earth, the Science Operations Center developed the Science Pipeline to analyze about 200,000 target stars in Keplers field of view, looking for evidence of periodic dimming suggesting that one or more planets had crossed the face of its host star. The Pipeline comprises several steps, from pixel-level calibration, through noise and artifact removal, to detection of transit-like signals and the construction of a suite of diagnostic tests to guard against false positives. The Kepler Science Pipeline consists of a pipeline infrastructure written in the Java programming language, which marshals data input to and output from MATLAB applications that are executed as external processes. The pipeline modules, which underwent continuous development and refinement even after data started arriving, employ several analytic techniques, many developed for the Kepler Project. Because of the large number of targets, the large amount of data per target and the complexity of the pipeline algorithms, the processing demands are daunting. Some pipeline modules require days to weeks to process all of their targets, even when run on NASA's 128-node Pleiades supercomputer. The software developers are still seeking ways to increase the throughput. To date, the Kepler project has discovered more than 4000 planetary candidates, of which more than 1000 have been independently confirmed or validated to be exoplanets. Funding for this mission is provided by NASAs Science Mission Directorate.

THE POSSIBLE MOON OF KEPLER-90g IS A FALSE POSITIVE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kipping, D. M.; Torres, G.; Buchhave, L. A.

2015-01-20

The discovery of an exomoon would provide deep insights into planet formation and the habitability of planetary systems, with transiting examples being particularly sought after. Of the hundreds of Kepler planets now discovered, the seven-planet system Kepler-90 is unusual for exhibiting an unidentified transit-like signal in close proximity to one of the transits of the long-period gas-giant Kepler-90g, as noted by Cabrera et al. As part of the ''Hunt for Exomoons with Kepler'' project, we investigate this possible exomoon signal and find it passes all conventional photometric, dynamical, and centroid diagnostic tests. However, pixel-level light curves indicate that the moon-like signalmore » occurs on nearly all of the target's pixels, which we confirm using a novel way of examining pixel-level data which we dub the ''transit centroid''. This test reveals that the possible exomoon to Kepler-90g is likely a false positive, perhaps due to a cosmic ray induced sudden pixel sensitivity dropout. This work highlights the extreme care required for seeking non-periodic low-amplitude transit signals, such as exomoons.« less

DETECTION OF KOI-13.01 USING THE PHOTOMETRIC ORBIT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shporer, Avi; Jenkins, Jon M.; Seader, Shawn E.

2011-12-15

We use the KOI-13 transiting star-planet system as a test case for the recently developed BEER algorithm, aimed at identifying non-transiting low-mass companions by detecting the photometric variability induced by the companion along its orbit. Such photometric variability is generated by three mechanisms: the beaming effect, tidal ellipsoidal distortion, and reflection/heating. We use data from three Kepler quarters, from the first year of the mission, while ignoring measurements within the transit and occultation, and show that the planet's ephemeris is clearly detected. We fit for the amplitude of each of the three effects and use the beaming effect amplitude tomore » estimate the planet's minimum mass, which results in M{sub p} sin i = 9.2 {+-} 1.1 M{sub J} (assuming the host star parameters derived by Szabo et al.). Our results show that non-transiting star-planet systems similar to KOI-13.01 can be detected in Kepler data, including a measurement of the orbital ephemeris and the planet's minimum mass. Moreover, we derive a realistic estimate of the amplitudes uncertainties, and use it to show that data obtained during the entire lifetime of the Kepler mission of 3.5 years will allow detecting non-transiting close-in low-mass companions orbiting bright stars, down to the few Jupiter mass level. Data from the Kepler Extended Mission, if funded by NASA, will further improve the detection capabilities.« less