Kepler rapidly rotating giant stars

Abstract

Rapidly rotating giant stars are relatively rare and may represent important stages of stellar evolution, resulting from stellar coalescence of close binary systems or accretion of sub-stellar companions by their hosting stars. In the present letter we report 17 giant stars observed in the scope of the Kepler space mission exhibiting rapid rotation behavior. For the first time the abnormal rotational behavior for this puzzling family of stars is revealed by direct measurements of rotation, namely from photometric rotation period, exhibiting very short rotation period with values ranging from 13 to 55 days. This finding points for remarkable surface rotation rates, up to 18 times the Sun rotation. These giants are combined with 6 other recently listed in the literature for mid-IR diagnostic based on WISE information, from which a trend for an infrared excess is revealed for at least a half of the stars, but at a level far lower than the dust excess emission shown by planet-bearing main-sequence stars.

17 pages, 4 figures and 1 table, Accepted for publication in the Astrophysical Journal Letters

References in corpus (16)

• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• Evolutionary tracks and isochrones for low- and intermediate-mass stars: from 0.15 to 7 M_sun, and from Z=0.0004 to 0.03
• Kepler Mission Design, Realized Photometric Performance, and Early Science
• Defining and cataloging exoplanets: The exoplanet.eu database
• Overview of the Kepler Science Processing Pipeline
• The APOKASC Catalog: An Asteroseismic and Spectroscopic Joint Survey of Targets in the Kepler Fields
• The accretion of planets and brown dwarfs by giant stars -- II. solar mass stars on the red giant branch
• The Accretion of Brown Dwarfs and Planets by Giant Stars -- I. AGB Stars
• Observable Signatures of Planet Accretion in Red Giant Stars I: Rapid Rotation and Light Element Replenishment
• The Frequency of Rapid Rotation Among K Giant Stars
• Wavelets: a powerful tool for studying rotation, activity, and pulsation in Kepler and CoRoT stellar light curves
• Overview of semi-sinusoidal stellar variability with the CoRoT satellite
• The rotational behavior of Kepler Stars with Planets
• Bright 22 $\mu$m Excess Candidates from WISE All-Sky Catalog and Hipparcos Main Catalog
• Debris Disks in Kepler Exoplanet Systems
• On the Nature of Rapidly Rotating Single Evolved Stars

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• Is Betelgeuse the Outcome of a Past Merger?
• The Active Chromospheres of Lithium-Rich Red Giant Stars
• An extremely hot white dwarf with a rapidly rotating K-type subgiant companion: UCAC2 46706450
• The Betelgeuse Project III: Merger Characteristics
• Rapidly Rotating, X-ray Bright Stars in the Kepler Field
• A wavelet analysis of photometric variability in Kepler white dwarf stars
• On the nature of the candidate T-Tauri star V501 Aurigae