Rotation periods of 12 000 main-sequence Kepler stars: Dependence on stellar spectral type and comparison with v sin i observations
TL;DR: In this paper, the Lomb-Scargle periodogram was used to measure the rotation periods of active stars in the Kepler field as a function of spectral type and to extend reliable rotation measurements from F-, G-, and K-type to M-type stars.
Abstract: Aims. We aim to measure the starspot rotation periods of active stars in the Kepler field as a function of spectral type and to extend reliable rotation measurements from F-, G-, and K-type to M-type stars. Methods. Using the Lomb-Scargle periodogram we searched more than 150 000 stellar light curves for periodic brightness variations. We analyzed periods between 1 and 30 days in eight consecutive Kepler quarters, where 30 days is an estimated maximum for the validity of the PDC_MAP data correction pipeline. We selected stable rotation periods, i.e., periods that do not vary from the median by more than one day in at least six of the eight quarters. We averaged the periods for each stellar spectral class according to B−V color and compared the results to archival v sini data, using stellar radii estimates from the Kepler Input Catalog. Results. We report on the stable starspot rotation periods of 12 151 Kepler stars. We find good agreement between starspot velocities and v sini data for all F-, G- and early K-type stars. The 795 M-type stars in our sample have a median rotation period of 15. 4d ays. We find an excess of M-type stars with periods less than 7.5 days that are potentially fast-rotating and fully convective. Measuring photometric variability in multiple Kepler quarters appears to be a straightforward and reliable way to determine the rotation periods of a large sample of active stars, including late-type stars.
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TL;DR: The PLATO 2.0 mission as discussed by the authors has been selected for ESA's M3 launch opportunity (2022/24) to provide accurate key planet parameters (radius, mass, density and age) in statistical numbers.
Abstract: PLATO 2.0 has recently been selected for ESA’s M3 launch opportunity (2022/24). Providing accurate key planet parameters (radius, mass, density and age) in statistical numbers, it addresses fundamental questions such as: How do planetary systems form and evolve? Are there other systems with planets like ours, including potentially habitable planets? The PLATO 2.0 instrument consists of 34 small aperture telescopes (32 with 25 s readout cadence and 2 with 2.5 s candence) providing a wide field-of-view (2232 deg 2) and a large photometric magnitude range (4–16 mag). It focusses on bright (4–11 mag) stars in wide fields to detect and characterize planets down to Earth-size by photometric transits, whose masses can then be determined by ground-based radial-velocity follow-up measurements. Asteroseismology will be performed for these bright stars to obtain highly accurate stellar parameters, including masses and ages. The combination of bright targets and asteroseismology results in high accuracy for the bulk planet parameters: 2 %, 4–10 % and 10 % for planet radii, masses and ages, respectively. The planned baseline observing strategy includes two long pointings (2–3 years) to detect and bulk characterize planets reaching into the habitable zone (HZ) of solar-like stars and an additional step-and-stare phase to cover in total about 50 % of the sky. PLATO 2.0 will observe up to 1,000,000 stars and detect and characterize hundreds of small planets, and thousands of planets in the Neptune to gas giant regime out to the HZ. It will therefore provide the first large-scale catalogue of bulk characterized planets with accurate radii, masses, mean densities and ages. This catalogue will include terrestrial planets at intermediate orbital distances, where surface temperatures are moderate. Coverage of this parameter range with statistical numbers of bulk characterized planets is unique to PLATO 2.0. The PLATO 2.0 catalogue allows us to e.g.: - complete our knowledge of planet diversity for low-mass objects, - correlate the planet mean density-orbital distance distribution with predictions from planet formation theories,- constrain the influence of planet migration and scattering on the architecture of multiple systems, and - specify how planet and system parameters change with host star characteristics, such as type, metallicity and age. The catalogue will allow us to study planets and planetary systems at different evolutionary phases. It will further provide a census for small, low-mass planets. This will serve to identify objects which retained their primordial hydrogen atmosphere and in general the typical characteristics of planets in such low-mass, low-density range. Planets detected by PLATO 2.0 will orbit bright stars and many of them will be targets for future atmosphere spectroscopy exploring their atmosphere. Furthermore, the mission has the potential to detect exomoons, planetary rings, binary and Trojan planets. The planetary science possible with PLATO 2.0 is complemented by its impact on stellar and galactic science via asteroseismology as well as light curves of all kinds of variable stars, together with observations of stellar clusters of different ages. This will allow us to improve stellar models and study stellar activity. A large number of well-known ages from red giant stars will probe the structure and evolution of our Galaxy. Asteroseismic ages of bright stars for different phases of stellar evolution allow calibrating stellar age-rotation relationships. Together with the results of ESA’s Gaia mission, the results of PLATO 2.0 will provide a huge legacy to planetary, stellar and galactic science.
965 citations
TL;DR: In this article, the authors analyzed three years of data from the Kepler space mission to derive rotation periods of main-sequence stars below 6500 K. They found typically higher amplitudes for shorter periods and lower effective temperatures, with an excess of low-amplitude stars above ∼5400 K.
Abstract: We analyzed three years of data from the Kepler space mission to derive rotation periods of main-sequence stars below 6500 K. Our automated autocorrelation-based method detected rotation periods between 0.2 and 70 days for 34,030 (25.6%) of the 133,030 main-sequence Kepler targets (excluding known eclipsing binaries and Kepler Objects of Interest), making this the largest sample of stellar rotation periods to date. In this paper we consider the detailed features of the now well-populated period-temperature distribution and demonstrate that the period bimodality, first seen by McQuillan et al. in the M-dwarf sample, persists to higher masses, becoming less visible above 0.6 M {sub ☉}. We show that these results are globally consistent with the existing ground-based rotation-period data and find that the upper envelope of the period distribution is broadly consistent with a gyrochronological age of 4.5 Gyr, based on the isochrones of Barnes, Mamajek, and Hillenbrand and Meibom et al. We also performed a detailed comparison of our results to those of Reinhold et al. and Nielsen et al., who measured rotation periods of field stars observed by Kepler. We examined the amplitude of periodic variability for the stars with detection rotation periods, and found a typical range betweenmore » ∼950 ppm (5th percentile) and ∼22,700 ppm (95th percentile), with a median of ∼5600 ppm. We found typically higher amplitudes for shorter periods and lower effective temperatures, with an excess of low-amplitude stars above ∼5400 K.« less
704 citations
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01 May 2011TL;DR: In this paper, the authors present an overview of the solar system and its evolution, including the formation and evolution of stars, asteroids, and free-floating planets, as well as their internal and external structures.
Abstract: 1. Introduction 2. Radial velocities 3. Astrometry 4. Timing 5. Microlensing 6. Transits 7. Imaging 8. Host stars 9. Brown dwarfs and free-floating planets 10. Formation and evolution 11. Interiors and atmospheres 12. The Solar System Appendixes References Index.
527 citations
TL;DR: In this paper, the authors analyzed 3 years of data from the Kepler space mission to derive rotation periods of main-sequence stars below 6500 K. Their automated autocorrelation-based method detected rotation periods between 0.2 and 70 days for 34,030 (25.6%) of the 133,030 Kepler targets (excluding known eclipsing binaries and Kepler Objects of Interest).
Abstract: We analyzed 3 years of data from the Kepler space mission to derive rotation periods of main-sequence stars below 6500 K. Our automated autocorrelation-based method detected rotation periods between 0.2 and 70 days for 34,030 (25.6%) of the 133,030 main-sequence Kepler targets (excluding known eclipsing binaries and Kepler Objects of Interest), making this the largest sample of stellar rotation periods to date. In this paper we consider the detailed features of the now well-populated period-temperature distribution and demonstrate that the period bimodality, first seen by McQuillan, Aigrain & Mazeh (2013) in the M-dwarf sample, persists to higher masses, becoming less visible above 0.6 M_sun. We show that these results are globally consistent with the existing ground-based rotation-period data and find that the upper envelope of the period distribution is broadly consistent with a gyrochronological age of 4.5 Gyrs, based on the isochrones of Barnes (2007), Mamajek & Hillenbrand (2008) and Meibom et al. (2009). We also performed a detailed comparison of our results to those of Reinhold et al. (2013) and Nielsen et al. (2013), who have measured rotation periods of field stars observed by Kepler. We examined the amplitude of periodic variability for the stars with detected rotation periods, and found a typical range between ~950 ppm (5th percentile) and ~22,700 ppm (95th percentile), with a median of ~5,600 ppm. We found typically higher amplitudes for shorter periods and lower effective temperatures, with an excess of low-amplitude stars above ~5400 K.
432 citations
Cites background or methods or result from "Rotation periods of 12 000 main-seq..."
...To directly compare our periods with those detected by Reinhold et al. (2013) and Nielsen et al. (2013), for the stars where both methods report periods, we plotted their periods versus ours in Figure 7....
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...We then compared our results to those of Reinhold et al. (2013) and Nielsen et al. (2013) who have also performed rotation period studies of the Kepler sample....
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...Two previous studies focussing on the broader Kepler sample are those of Reinhold et al. (2013), with an emphasis on differential rotation, who derive ∼ 24, 000 periods using Q3, and Nielsen et al. (2013), who measured ∼ 12, 000 periods from Q2–Q9, and compare to previous spectroscopic studies....
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...For the alternative methods there are ∼ 85 cases where AutoACF detects a short period and Reinhold et al. (2013) or Nielsen et al. (2013) detect a considerably longer period....
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...The panels show AutoACF compared to Reinhold et al. (2013) (R13, left) and Nielsen et al. (2013) (N13, right), with the number of stars in each group denoted as N ....
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References
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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
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01 Jan 1976TL;DR: In this paper, the authors present a model of the photosphere of the black body and its radiation, and the measurement of stellar continua, spectral lines, and photospheric pressure.
Abstract: 1. Background 2. Fourier transforms 3. Spectroscopic tools 4. Light detectors 5. Radiation terms and definitions 6. The black body and its radiation 7. Radiative and convective energy transport 8. The continuous absorption coefficient 9. The model photosphere 10. The measurement of stellar continua 11. The line absorption coefficient 12. The measurement of spectral lines 13. The behavior of spectral lines 14. The measurement of stellar radii and temperatures 15. The measurement of photospheric pressure 16. Chemical analysis 17. Velocity fields in stellar photospheres 18. Stellar rotation.
1,924 citations
1,732 citations
01 Jan 1992
TL;DR: In this article, the authors present a model of the photosphere of the black body and its radiation, and the measurement of stellar continua, spectral lines, and photospheric pressure.
Abstract: 1. Background 2. Fourier transforms 3. Spectroscopic tools 4. Light detectors 5. Radiation terms and definitions 6. The black body and its radiation 7. Radiative and convective energy transport 8. The continuous absorption coefficient 9. The model photosphere 10. The measurement of stellar continua 11. The line absorption coefficient 12. The measurement of spectral lines 13. The behavior of spectral lines 14. The measurement of stellar radii and temperatures 15. The measurement of photospheric pressure 16. Chemical analysis 17. Velocity fields in stellar photospheres 18. Stellar rotation.
1,109 citations