PHOTOMETRIC VARIABILITY IN<i>KEPLER</i>TARGET STARS. II. AN OVERVIEW OF AMPLITUDE, PERIODICITY, AND ROTATION IN FIRST QUARTER DATA

Basri, Gibor; Walkowicz, Lucianne M.; Batalha, Natalie M.; Gilliland, Ronald L.; Jenkins, Jon M.; Borucki, W. J.; Koch, David; Caldwell, Douglas A.; Dupree, A. K.; Latham, David W.; Marcy, Geoffrey W.; Meibom, S.; Brown, T. M.

doi:10.1088/0004-6256/141/1/20

Cited by 199 publications

(66 citation statements)

References 14 publications

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“…We then tested our period-finding procedure using solar data, inspired by the approach outlined in Basri et al (2011). In particular, we chose 2 four-year segments of SOHO Virgo g+r data to sample the Sun around both solar maximum and solar minimum.…”

Section: Discussionmentioning

confidence: 99%

“…2); in both cases, we successfully recovered the solar rotation period. Interestingly, Nielsen et al (2013) applied a similar approach and failed to reliably recover the solar rotation, while Basri et al (2011) found only that P ~2 0 d, primarily due to their use of only one quarter of data. Both pointed out that, as variability is expected to decrease as rotation period increases, such failure implies a bias in that stars with long rotation periods are less likely to be detected.…”

Section: Discussionmentioning

confidence: 99%

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Rotation, activity, and stellar obliquities in a large uniform sample ofKeplersolar analogs

Buzasi

Lezcano

Preston³

2016

J. Space Weather Space Clim.

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In this study, we undertook a deep photometric examination of a narrowly-defined sample of solar analogs in the Kepler field, with the goals of producing a uniform and statistically meaningful sample of such stars, comparing the properties of planet hosts to those of the general stellar population, and examining the behavior of rotation and photometric activity among stars with similar overall physical parameters. We successfully derived photometric activity indicators and rotation periods for 95 planet hosts (Kepler objects of interest [KOIs]) and 954 solar analogs without detected planets; 573 of these rotation periods are reported here for the first time. Rotation periods average roughly 20 d, but the distribution has a wide dispersion, with a tail extending to P > 35 d which appears to be inconsistent with published gyrochronological relations. We observed a weak rotation-activity relation for stars with rotation periods less than about 12 d; for slower rotators, the relation is dominated by scatter. However, we are able to state that the solar activity level derived from Virgo data is consistent with the majority of stars with similar rotation periods in our sample. Finally, our KOI sample is consistently approximately 0.3 dex more variable than our non-KOIs; we ascribe the difference to a selection effect due to low orbital obliquity in the planet-hosting stars and derive a mean obliquity for our sample of v ¼ 6 þ5 À6 , similar to that seen in the solar system.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Rotation, activity, and stellar obliquities in a large uniform sample ofKeplersolar analogs

Buzasi

Lezcano

Preston³

2016

J. Space Weather Space Clim.

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“…Indeed, the dimming produced by these spots leads to a measurable modulation in the photometry with a period corresponding to the surface rotation at the active latitudes (e.g. Basri et al 2011;Garcia et al 2014;Walkowicz and Basri 2013;Nielsen et al 2013;Reinhold et al 2013;McQuillan et al 2014) in which the spots develop. One must keep in mind that on the Sun faculae and the small-scale field around over-compensate this dimming effect, leading to a net brightening at solar maximum (Spruit 2000;Fröhlich 2012).…”

Section: New Asteroseismic Diagnostics Of Global Stellar Convection mentioning

confidence: 99%

“…Examples of the latter include the extensive MONITOR program (Aigrain et al 2007) (see Moraux et al 2013, for the most recent results), the SuperWASP data for the Hyades and Praesepe (Delorme et al 2011) and the large (Hartman et al 2009(Hartman et al , 2010 M37 and Pleiades data sets. The Kepler and CoRoT missions reach lower amplitudes and can detect stars with longer rotation periods, pushing stellar rotation measurements into the solar regime (Basri et al 2011;Garcia et al 2014;Walkowicz and Basri 2013;Nielsen et al 2013;Reinhold et al 2013;McQuillan et al 2014). With the aid of these samples, a standard empirical picture of angular momentum evolution has emerged, with the following basic ingredients.…”

Section: Stellar Rotation and Spin Downmentioning

confidence: 99%

The Solar-Stellar Connection

Brun¹,

García²,

Houdek³

et al. 2017

Space Sciences Series of ISSI

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We discuss how recent advances in observations, theory and numerical simulations have allowed the stellar community to progress in its understanding of stellar convection, rotation and magnetism and to assess the degree to which the Sun and other stars share similar dynamical properties. Ensemble asteroseismology has become a reality with the advent of large time domain studies, especially from space missions. This new capability has provided improved constraints on stellar rotation and activity, over and above that obtained via traditional techniques such as spectropolarimetry or CaII H&K observations. New data and surveys covering large mass and age ranges have provided a wide parameter space to confront theories of stellar magnetism. These new empirical databases are complemented by theoretical advances and improved multi-D simulations of stellar dynamos. We trace these pathways through which a lucid and more detailed picture of magnetohydrodynamics of solar-like stars is beginning to emerge and discuss future prospects.

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“…Our goal is to monitor the spectral shape of the TF as well as its absolute level to a precision better than a few times 10 −5 , such that uncertainties in the TF do not significantly affect the final quality of the science spectra obtained. The Kepler mission is generating an unprecedented set of lightcurves for stars, with the best precision and coverage ever achieved [64]. Detailed modeling of optical light curves measured by the Kepler satellite using stellar model atmospheres shows that the vast majority of G-dwarfs and selected A-dwarfs have Fig.…”

Section: Justification Of Wavelength Coverage and Spectral Resolutionmentioning

confidence: 99%

EChO - Exoplanet Characterisation Observatory

Tessenyi¹

2017

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A dedicated mission to investigate exoplanetary atmospheres represents a major milestone in our quest to understand our place in the universe by placing our Solar System in context and by addressing the suitability of planets for the presence of life. EChO -the Exoplanet Characterisation Observatory -is a mission concept specifically geared for this purpose.EChO will provide simultaneous, multi-wavelength spectroscopic observations on a stable platform that will allow very long exposures. The use of passive cooling, few moving parts and well established technology gives a low-risk and potentially long-lived mission. EChO will build on observations by Hubble, Spitzer and groundbased telescopes, which discovered the first molecules and atoms in exoplanetary atmospheres. However, EChO's configuration and specifications are designed to study a number of systems in a consistent manner that will eliminate the ambiguities affecting prior observations. EChO will simultaneously observe a broad enough spectral region -from the visible to the mid-infrared -to constrain from one single spectrum the temperature structure of the atmosphere, the abundances of the major carbon and oxygen bearing species, the expected photochemically-produced species and magnetospheric signatures. The spectral range and resolution are tailored to separate bands belonging to up to 30 molecules and retrieve the composition and temperature structure of planetary atmospheres.The target list for EChO includes planets ranging from Jupiter-sized with equilibrium temperatures T eq up to 2000 K, to those of a few Earth masses, with T eq ∼300 K. The list will include planets with no Solar System analog, such as the recently discovered planets GJ1214b, whose density lies between that of terrestrial and gaseous planets, or the rocky-iron planet 55 Cnc e, with day-side temperature close to 3000 K. As the number of detected exoplanets is growing rapidly each year, and the mass and radius of those detected steadily decreases, the target list will be constantly adjusted to include the most interesting systems.We have baselined a dispersive spectrograph design covering continuously the 0.4-16 µm spectral range in 6 channels (1 in the visible, 5 in the InfraRed), which allows the spectral resolution to be adapted from several tens to several hundreds, depending on the target brightness. The instrument will be mounted behind a 1.5 m class telescope, passively cooled to 50 K, with the instrument structure and optics passively cooled to ∼45 K. EChO will be placed in a grand halo orbit around L2. This orbit, in combination with an optimised thermal shield design, provides a highly stable thermal environment and a high degree of visibility of the sky to observe repeatedly several tens of targets over the year. Both the baseline and alternative designs have been evaluated and no critical items with Technology Readiness Level (TRL) less than 4 to 5 have been identified. We have also undertaken a first-order cost and development plan analysis and find that EChO ...

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PHOTOMETRIC VARIABILITY INKEPLERTARGET STARS. II. AN OVERVIEW OF AMPLITUDE, PERIODICITY, AND ROTATION IN FIRST QUARTER DATA

Cited by 199 publications

References 14 publications

Rotation, activity, and stellar obliquities in a large uniform sample ofKeplersolar analogs

Rotation, activity, and stellar obliquities in a large uniform sample ofKeplersolar analogs

The Solar-Stellar Connection

EChO - Exoplanet Characterisation Observatory

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