Author
Jill Tarter
Other affiliations: Ames Research Center
Bio: Jill Tarter is an academic researcher from Search for extraterrestrial intelligence. The author has contributed to research in topics: Search for extraterrestrial intelligence & Allen Telescope Array. The author has an hindex of 27, co-authored 86 publications receiving 13412 citations. Previous affiliations of Jill Tarter include Ames Research Center.
Papers published on a yearly basis
Papers
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Ames Research Center1, University of California, Berkeley2, San Jose State University3, Las Cumbres Observatory Global Telescope Network4, Search for extraterrestrial intelligence5, York University6, Aarhus University7, University of Texas at Austin8, Lowell Observatory9, Harvard University10, California Institute of Technology11, Space Telescope Science Institute12, Lawrence Hall of Science13, Goddard Space Flight Center14, United States Department of the Navy15, Carnegie Institution for Science16, University of Washington17, University of Hawaii at Hilo18, University of California, Santa Cruz19, Massachusetts Institute of Technology20, Fermilab21, San Diego State University22, Southern Connecticut State University23, Planetary Science Institute24, Yale University25, Marshall Space Flight Center26, The Catholic University of America27, University of Idaho28, Villanova University29
TL;DR: The Kepler mission was designed to determine the frequency of Earth-sized planets in and near the habitable zone of Sun-like stars, which is the region where planetary temperatures are suitable for water to exist on a planet's surface.
Abstract: The Kepler mission was designed to determine the frequency of Earth-sized planets in and near the habitable zone of Sun-like stars. The habitable zone is the region where planetary temperatures are suitable for water to exist on a planet’s surface. During the first 6 weeks of observations, Kepler monitored 156,000 stars, and five new exoplanets with sizes between 0.37 and 1.6 Jupiter radii and orbital periods from 3.2 to 4.9 days were discovered. The density of the Neptune-sized Kepler-4b is similar to that of Neptune and GJ 436b, even though the irradiation level is 800,000 times higher. Kepler-7b is one of the lowest-density planets (~0.17 gram per cubic centimeter) yet detected. Kepler-5b, -6b, and -8b confirm the existence of planets with densities lower than those predicted for gas giant planets.
3,663 citations
Ames Research Center1, University of California, Berkeley2, San Jose State University3, Las Cumbres Observatory Global Telescope Network4, Search for extraterrestrial intelligence5, Aarhus University6, University of Texas at Austin7, Lowell Observatory8, California Institute of Technology9, Harvard University10, Space Telescope Science Institute11, Lawrence Hall of Science12, Carnegie Institution for Science13, University of Florida14, University of California, Santa Cruz15, Massachusetts Institute of Technology16, Fermilab17, San Diego State University18, Southern Connecticut State University19, Marshall Space Flight Center20, University of Arizona21, University of Hertfordshire22, Centre National D'Etudes Spatiales23, Villanova University24
TL;DR: In this article, the Kepler mission released data for 156,453 stars observed from the beginning of the science observations on 2009 May 2 through September 16, and there are 1235 planetary candidates with transit-like signatures detected in this period.
Abstract: On 2011 February 1 the Kepler mission released data for 156,453 stars observed from the beginning of the science observations on 2009 May 2 through September 16. There are 1235 planetary candidates with transit-like signatures detected in this period. These are associated with 997 host stars. Distributions of the characteristics of the planetary candidates are separated into five class sizes: 68 candidates of approximately Earth-size (R_p < 1.25 R_⊕), 288 super-Earth-size (1.25 R_⊕ ≤ R_p < 2 R_⊕), 662 Neptune-size (2 R_⊕ ≤ R_p < 6 R_⊕), 165 Jupiter-size (6 R_⊕ ≤ R_p < 15 R_⊕), and 19 up to twice the size of Jupiter (15 R_⊕ ≤ R_p < 22 R_⊕). In the temperature range appropriate for the habitable zone, 54 candidates are found with sizes ranging from Earth-size to larger than that of Jupiter. Six are less than twice the size of the Earth. Over 74% of the planetary candidates are smaller than Neptune. The observed number versus size distribution of planetary candidates increases to a peak at two to three times the Earth-size and then declines inversely proportional to the area of the candidate. Our current best estimates of the intrinsic frequencies of planetary candidates, after correcting for geometric and sensitivity biases, are 5% for Earth-size candidates, 8% for super-Earth-size candidates, 18% for Neptune-size candidates, 2% for Jupiter-size candidates, and 0.1% for very large candidates; a total of 0.34 candidates per star. Multi-candidate, transiting systems are frequent; 17% of the host stars have multi-candidate systems, and 34% of all the candidates are part of multi-candidate systems.
1,241 citations
San Jose State University1, Ames Research Center2, Las Cumbres Observatory Global Telescope Network3, Harvard University4, University of California, Berkeley5, University of Florida6, Pennsylvania State University7, Georgia State University8, NASA Exoplanet Science Institute9, California Institute of Technology10, Carnegie Institution for Science11, University of Copenhagen12, Aarhus University13, University of Texas at Austin14, Massachusetts Institute of Technology15, Search for extraterrestrial intelligence16, Lawrence Hall of Science17, University of Hertfordshire18, Villanova University19, Fermilab20, Princeton University21, San Diego State University22
TL;DR: In this paper, the authors used the noise-weighted robust averaging of multi-quarter photo-center offsets derived from difference image analysis, which identifies likely background eclipsing binaries.
Abstract: New transiting planet candidates are identified in sixteen months (May 2009 - September 2010) of data from the Kepler spacecraft. Nearly five thousand periodic transit-like signals are vetted against astrophysical and instrumental false positives yielding 1,091 viable new planet candidates, bringing the total count up to over 2,300. Improved vetting metrics are employed, contributing to higher catalog reliability. Most notable is the noise-weighted robust averaging of multi-quarter photo-center offsets derived from difference image analysis which identifies likely background eclipsing binaries. Twenty-two months of photometry are used for the purpose of characterizing each of the new candidates. Ephemerides (transit epoch, T_0, and orbital period, P) are tabulated as well as the products of light curve modeling: reduced radius (Rp/R*), reduced semi-major axis (d/R*), and impact parameter (b). The largest fractional increases are seen for the smallest planet candidates (197% for candidates smaller than 2Re compared to 52% for candidates larger than 2Re) and those at longer orbital periods (123% for candidates outside of 50-day orbits versus 85% for candidates inside of 50-day orbits). The gains are larger than expected from increasing the observing window from thirteen months (Quarter 1-- Quarter 5) to sixteen months (Quarter 1 -- Quarter 6). This demonstrates the benefit of continued development of pipeline analysis software. The fraction of all host stars with multiple candidates has grown from 17% to 20%, and the paucity of short-period giant planets in multiple systems is still evident. The progression toward smaller planets at longer orbital periods with each new catalog release suggests that Earth-size planets in the Habitable Zone are forthcoming if, indeed, such planets are abundant.
1,162 citations
University of California, Berkeley1, Ames Research Center2, San Jose State University3, Lowell Observatory4, Jet Propulsion Laboratory5, University of Texas at Austin6, Harvard University7, Las Cumbres Observatory Global Telescope Network8, Space Telescope Science Institute9, Niels Bohr Institute10, National Center for Atmospheric Research11, Aarhus University12, NASA Exoplanet Science Institute13, Massachusetts Institute of Technology14, Fermilab15, University of California, Santa Cruz16, Yale University17, University of Florida18, California Institute of Technology19, University of California, Santa Barbara20, University of Hertfordshire21, San Diego State University22, Carnegie Institution for Science23, Lawrence Hall of Science24, Villanova University25
TL;DR: In this paper, the authors 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.
Abstract: 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_⊕. For each of the 156,000 target stars, we assess the detectability of planets as a function of planet radius, R_p, and orbital period, P, using a measure of the detection efficiency for each star. We also correct for the geometric probability of transit, R_*/a. We consider first Kepler target stars within the "solar subset" having T_eff = 4100-6100 K, log g = 4.0-4.9, and Kepler magnitude K_p 2 R_⊕ we measure an occurrence of less than 0.001 planets per star. For all planets with orbital periods less than 50 days, we measure occurrence of 0.130 ± 0.008, 0.023 ± 0.003, and 0.013 ± 0.002 planets per star for planets with radii 2-4, 4-8, and 8-32 R_⊕, in agreement with Doppler surveys. We fit occurrence as a function of P to a power-law model with an exponential cutoff below a critical period P_0. For smaller planets, P_0 has larger values, suggesting that the "parking distance" for migrating planets moves outward with decreasing planet size. We also measured planet occurrence over a broader stellar T_eff range of 3600-7100 K, spanning M0 to F2 dwarfs. Over this range, the occurrence of 2-4 R_⊕ planets in the Kepler field increases with decreasing T_eff, with these small planets being seven times more abundant around cool stars (3600-4100 K) than the hottest stars in our sample (6600-7100 K).
1,159 citations
TL;DR: In this article, the authors report the distribution of planets as a function of planet radius (R_p), orbital period (P), and stellar effective temperature (Teff) for P < 50 day orbits around GK stars.
Abstract: We report the distribution of planets as a function of planet radius (R_p), orbital period (P), and stellar effective temperature (Teff) for P < 50 day orbits around GK stars. These results are based on the 1,235 planets (formally "planet candidates") from the Kepler mission that include a nearly complete set of detected planets as small as 2 Earth radii (Re). For each of the 156,000 target stars we assess the detectability of planets as a function of R_p and P. We also correct for the geometric probability of transit, R*/a. We consider first stars within the "solar subset" having Teff = 4100-6100 K, logg = 4.0-4.9, and Kepler magnitude Kp < 15 mag. We include only those stars having noise low enough to permit detection of planets down to 2 Re. We count planets in small domains of R_p and P and divide by the included target stars to calculate planet occurrence in each domain. Occurrence of planets varies by more than three orders of magnitude and increases substantially down to the smallest radius (2 Re) and out to the longest orbital period (50 days, ~0.25 AU) in our study. For P < 50 days, the radius distribution is given by a power law, df/dlogR= k R^\alpha. This rapid increase in planet occurrence with decreasing planet size agrees with core-accretion, but disagrees with population synthesis models. We fit occurrence as a function of P to a power law model with an exponential cutoff below a critical period P_0. For smaller planets, P_0 has larger values, suggesting that the "parking distance" for migrating planets moves outward with decreasing planet size. We also measured planet occurrence over Teff = 3600-7100 K, spanning M0 to F2 dwarfs. The occurrence of 2-4 Re planets in the Kepler field increases with decreasing Teff, making these small planets seven times more abundant around cool stars than the hottest stars in our sample. [abridged]
1,134 citations
Cited by
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Ames Research Center1, University of California, Berkeley2, San Jose State University3, Las Cumbres Observatory Global Telescope Network4, Search for extraterrestrial intelligence5, York University6, Aarhus University7, University of Texas at Austin8, Lowell Observatory9, Harvard University10, California Institute of Technology11, Space Telescope Science Institute12, Lawrence Hall of Science13, Goddard Space Flight Center14, United States Department of the Navy15, Carnegie Institution for Science16, University of Washington17, University of Hawaii at Hilo18, University of California, Santa Cruz19, Massachusetts Institute of Technology20, Fermilab21, San Diego State University22, Southern Connecticut State University23, Planetary Science Institute24, Yale University25, Marshall Space Flight Center26, The Catholic University of America27, University of Idaho28, Villanova University29
TL;DR: The Kepler mission was designed to determine the frequency of Earth-sized planets in and near the habitable zone of Sun-like stars, which is the region where planetary temperatures are suitable for water to exist on a planet's surface.
Abstract: The Kepler mission was designed to determine the frequency of Earth-sized planets in and near the habitable zone of Sun-like stars. The habitable zone is the region where planetary temperatures are suitable for water to exist on a planet’s surface. During the first 6 weeks of observations, Kepler monitored 156,000 stars, and five new exoplanets with sizes between 0.37 and 1.6 Jupiter radii and orbital periods from 3.2 to 4.9 days were discovered. The density of the Neptune-sized Kepler-4b is similar to that of Neptune and GJ 436b, even though the irradiation level is 800,000 times higher. Kepler-7b is one of the lowest-density planets (~0.17 gram per cubic centimeter) yet detected. Kepler-5b, -6b, and -8b confirm the existence of planets with densities lower than those predicted for gas giant planets.
3,663 citations
Massachusetts Institute of Technology1, Harvard University2, Princeton University3, University of Chicago4, Las Cumbres Observatory Global Telescope Network5, University of Copenhagen6, Arizona State University7, Carnegie Institution for Science8, University of Birmingham9, Aarhus University10, Goddard Space Flight Center11, University of Maryland, College Park12, Vanderbilt University13, Northern Kentucky University14, Lowell Observatory15, University of Texas at Austin16, University of Florida17, Max Planck Society18, Tokyo Institute of Technology19, University of California, Berkeley20, University of California, Santa Cruz21, Space Telescope Science Institute22, Johns Hopkins University23, Spanish National Research Council24, Lehigh University25, INAF26, Fisk University27
TL;DR: The Transiting Exoplanet Survey Satellite (TESS) as discussed by the authors will search for planets transiting bright and nearby stars using four wide-field optical charge-coupled device cameras to monitor at least 200,000 main-sequence dwarf stars.
Abstract: The Transiting Exoplanet Survey Satellite (TESS) will search for planets transiting bright and nearby stars. TESS has been selected by NASA for launch in 2017 as an Astrophysics Explorer mission. The spacecraft will be placed into a highly elliptical 13.7-day orbit around the Earth. During its 2-year mission, TESS will employ four wide-field optical charge-coupled device cameras to monitor at least 200,000 main-sequence dwarf stars with I C ≈4−13 for temporary drops in brightness caused by planetary transits. Each star will be observed for an interval ranging from 1 month to 1 year, depending mainly on the star’s ecliptic latitude. The longest observing intervals will be for stars near the ecliptic poles, which are the optimal locations for follow-up observations with the James Webb Space Telescope. Brightness measurements of preselected target stars will be recorded every 2 min, and full frame images will be recorded every 30 min. TESS stars will be 10 to 100 times brighter than those surveyed by the pioneering Kepler mission. This will make TESS planets easier to characterize with follow-up observations. TESS is expected to find more than a thousand planets smaller than Neptune, including dozens that are comparable in size to the Earth. Public data releases will occur every 4 months, inviting immediate community-wide efforts to study the new planets. The TESS legacy will be a catalog of the nearest and brightest stars hosting transiting planets, which will endure as highly favorable targets for detailed investigations.
2,604 citations
Kavli Institute for Theoretical Physics1, University of Bonn2, University of California, Berkeley3, University of California, Santa Barbara4, University of Nice Sophia Antipolis5, Arizona State University6, Netherlands Institute for Space Research7, University of Wisconsin-Madison8, University of Alabama9
TL;DR: Modules for Experiments in Stellar Astrophysics (MESA) as discussed by the authors can now simultaneously evolve an interacting pair of differentially rotating stars undergoing transfer and loss of mass and angular momentum, greatly enhancing the prior ability to model binary evolution.
Abstract: We substantially update the capabilities of the open-source software instrument Modules for Experiments in Stellar Astrophysics (MESA). MESA can now simultaneously evolve an interacting pair of differentially rotating stars undergoing transfer and loss of mass and angular momentum, greatly enhancing the prior ability to model binary evolution. New MESA capabilities in fully coupled calculation of nuclear networks with hundreds of isotopes now allow MESA to accurately simulate advanced burning stages needed to construct supernova progenitor models. Implicit hydrodynamics with shocks can now be treated with MESA, enabling modeling of the entire massive star lifecycle, from pre-main sequence evolution to the onset of core collapse and nucleosynthesis from the resulting explosion. Coupling of the GYRE non-adiabatic pulsation instrument with MESA allows for new explorations of the instability strips for massive stars while also accelerating the astrophysical use of asteroseismology data. We improve treatment of mass accretion, giving more accurate and robust near-surface profiles. A new MESA capability to calculate weak reaction rates "on-the-fly" from input nuclear data allows better simulation of accretion induced collapse of massive white dwarfs and the fate of some massive stars. We discuss the ongoing challenge of chemical diffusion in the strongly coupled plasma regime, and exhibit improvements in MESA that now allow for the simulation of radiative levitation of heavy elements in hot stars. We close by noting that the MESA software infrastructure provides bit-for-bit consistency for all results across all the supported platforms, a profound enabling capability for accelerating MESA's development.
2,166 citations
TL;DR: The Transiting Exoplanet Survey Satellite (TESS) as mentioned in this paper was selected by NASA for launch in 2017 as an Astrophysics Explorer mission to search for planets transiting bright and nearby stars.
Abstract: The Transiting Exoplanet Survey Satellite (TESS) will search for planets transiting bright and nearby stars. TESS has been selected by NASA for launch in 2017 as an Astrophysics Explorer mission. The spacecraft will be placed into a highly elliptical 13.7-day orbit around the Earth. During its two-year mission, TESS will employ four wide-field optical CCD cameras to monitor at least 200,000 main-sequence dwarf stars with I = 4-13 for temporary drops in brightness caused by planetary transits. Each star will be observed for an interval ranging from one month to one year, depending mainly on the star's ecliptic latitude. The longest observing intervals will be for stars near the ecliptic poles, which are the optimal locations for follow-up observations with the James Webb Space Telescope. Brightness measurements of preselected target stars will be recorded every 2 min, and full frame images will be recorded every 30 min. TESS stars will be 10-100 times brighter than those surveyed by the pioneering Kepler mission. This will make TESS planets easier to characterize with follow-up observations. TESS is expected to find more than a thousand planets smaller than Neptune, including dozens that are comparable in size to the Earth. Public data releases will occur every four months, inviting immediate community-wide efforts to study the new planets. The TESS legacy will be a catalog of the nearest and brightest stars hosting transiting planets, which will endure as highly favorable targets for detailed investigations.
1,728 citations
TL;DR: The K2 mission as discussed by the authors uses an innovative way of operating the Kepler spacecraft to observe target fields along the ecliptic for the next 2-3 years, with an estimated photometric precision near 400 ppm in a single 30 minute observation.
Abstract: The K2 mission will make use of the Kepler spacecraft and its assets to expand upon Kepler's groundbreaking discoveries in the fields of exoplanets and astrophysics through new and exciting observations. K2 will use an innovative way of operating the spacecraft to observe target fields along the ecliptic for the next 2-3 years. Early science commissioning observations have shown an estimated photometric precision near 400 ppm in a single 30 minute observation, and a 6-hr photometric precision of 80 ppm (both at V = 12). The K2 mission offers long-term, simultaneous optical observation of thousands of objects at a precision far better than is achievable from ground-based telescopes. Ecliptic fields will be observed for approximately 75 days enabling a unique exoplanet survey which fills the gaps in duration and sensitivity between the Kepler and TESS missions, and offers pre-launch exoplanet target identification for JWST transit spectroscopy. Astrophysics observations with K2 will include studies of young open clusters, bright stars, galaxies, supernovae, and asteroseismology.
1,672 citations