Rapidly Rotating, X-ray Bright Stars in the Kepler Field
arXiv:1608.07828 · doi:10.3847/0004-637X/831/1/27
Abstract
We present Kepler light curves and optical spectroscopy of twenty X-ray bright stars located in the Kepler field of view. The stars, spectral type FK, show evidence for rapid rotation including chromospheric activity 100 times or more above the Sun at maximum and flaring behavior in their light curves. Eighteen of our objects appear to be (sub)giants and may belong to the class of FK Com variables, that is evolved rapidly spinning single stars with no excretion disk and high levels of chromospheric activity. Such stars are rare and are likely the result of W UMa binary mergers, a process believed to produce the FK Com class of variable and their descendants. The FK Com stage, including the presence of an excretion disk, is short-lived but leads to longer-lived stages consisting of single, rapidly rotating evolved (sub)giants with high levels of stellar activity.
arXiv comment34 pages, Accepted in ApJ
References in corpus (24)
- Kepler Input Catalog: Photometric Calibration and Stellar Classification
- Rotation Periods of 34,030 Kepler Main-Sequence Stars: The Full Autocorrelation Sample
- V1309 Scorpii: merger of a contact binary
- Revised Stellar Properties of Kepler Targets for the Quarter 1-16 Transit Detection Run
- Spin down of the core rotation in red giants
- Local kinematics of K and M giants from Coravel/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters
- Rotation and differential rotation of active Kepler stars
- The APOKASC Catalog: An Asteroseismic and Spectroscopic Joint Survey of Targets in the Kepler Fields
- Paper II: Calibration of the Swift ultraviolet/optical telescope
- Characterizing the Variability of Stars with Early-Release Kepler Data
- Stellar Mergers Are Common
- Accurate early positions for Swift GRBS: enhancing X-ray positions with UVOT astrometry
- Atmospheric Parameters of 169 F, G, K and M-type Stars in the Kepler Field
- A UBV Photometric Survey of the Kepler Field
- Initial data release of the Kepler-INT Survey
- Rapid Rotation of Low-Mass Red Giants Using APOKASC: A Measure of Interaction Rates on the Post-main-sequence
- A spectroscopic survey of the youngest field stars in the solar neighbourhood. I. The optically bright sample
- Post-outburst spectra of a stellar-merger remnant of V1309 Scorpii: from a twin of V838 Monocerotis to a clone of V4332 Sagittarii
- Overview of semi-sinusoidal stellar variability with the CoRoT satellite
- Kepler rapidly rotating giant stars
- KSwAGS: A Swift X-ray and UV Survey of the Kepler Field. I
- FK Comae Berenices, King of Spin: The COCOA-PUFS Project
- Study of FK Comae Berenices: VII. Correlating photospheric and chromospheric activity
- On the Nature of Rapidly Rotating Single Evolved Stars
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- Gaia Data Release 3: Cross-match of Gaia sources with variable objects from the literature
- Active red giants: close binaries versus single rapid rotators
- The Pseudosynchronization of Binary Stars Undergoing Strong Tidal Interactions
- Spectropolarimetric follow-up of 8 rapidly rotating, X-ray bright FK Comae candidates
- A multi-wavelength view of the open cluster NGC 2527: Discovery of active stars