Evidence from K2 for rapid rotation in the descendant of an intermediate-mass star

Abstract

Using patterns in the oscillation frequencies of a white dwarf observed by K2, we have measured the fastest rotation rate, 1.13(02) hr, of any isolated pulsating white dwarf known to date. Balmer-line fits to follow-up spectroscopy from the SOAR telescope show that the star (SDSSJ0837+1856, EPIC 211914185) is a 13,590(340) K, 0.87(03) solar-mass white dwarf. This is the highest mass measured for any pulsating white dwarf with known rotation, suggesting a possible link between high mass and fast rotation. If it is the product of single-star evolution, its progenitor was a roughly 4.0 solar-mass main-sequence B star; we know very little about the angular momentum evolution of such intermediate-mass stars. We explore the possibility that this rapidly rotating white dwarf is the byproduct of a binary merger, which we conclude is unlikely given the pulsation periods observed.

5 pages, 4 figure, 1 table; accepted for publication in The Astrophysical Journal Letters

References in corpus (10)

• A Technique for Extracting Highly Precise Photometry for the Two-Wheeled Kepler Mission
• The interior rotation of a sample of gamma Doradus stars from ensemble modelling of their gravity mode period spacings
• Signatures of internal rotation discovered in the Kepler data of five slowly pulsating B stars
• A new asteroseismic diagnostic for internal rotation in $\gamma$ Doradus stars
• The Field White Dwarf Mass Distribution
• On the effect of rotation on populations of classical Cepheids I. Predictions at solar metallicity
• Why should we correct reported pulsation frequencies for stellar line-of-sight Doppler velocity shifts?
• A deep test of radial differential rotation in a helium-atmosphere white dwarf: I. Discovery of pulsations in PG 0112+104
• Comparison of Atmospheric Parameters Determined from Spectroscopy and Photometry for DA White Dwarfs in the Sloan Digital Sky Survey
• A fast spinning magnetic white dwarf in the double-degenerate, super-Chandrasekhar system NLTT 12758

Cited by in corpus (23)

• Probing the interior physics of stars through asteroseismology
• White Dwarf Rotation as a Function of Mass and a Dichotomy of Mode Linewidths: Kepler Observations of 27 Pulsating DA White Dwarfs Through K2 Campaign 8
• Gaia Data Release 2: Variable stars in the colour-absolute magnitude diagram
• Forward asteroseismic modeling of stars with a convective core from gravity-mode oscillations: parameter estimation and stellar model selection
• Lense-Thirring frame dragging induced by a fast-rotating white dwarf in a binary pulsar system
• An Isolated White Dwarf with a 70 second Spin Period
• Eating Planets for Lunch and Dinner: Signatures of Planet Consumption by Evolving Stars
• Discovery of 74 new bright ZZ Ceti stars in the first three years of TESS
• The Merger Fraction of Ultramassive White Dwarfs
• Magnetism, X-rays, and Accretion Rates in WD 1145+017 and other Polluted White Dwarf Systems
• Orbital relaxation and excitation of planets tidally interacting with white dwarfs
• Destroying Aliases from the Ground and Space: Super-Nyquist ZZ Cetis in K2 Long Cadence Data
• Probing the structure of Kepler ZZ Ceti stars with full evolutionary models-based asteroseismology
• Magnetospherically-trapped dust and a possible model for the unusual transits at WD 1145+017
• Survivability of radio-loud planetary cores orbiting white dwarfs
• The Rapid Rotation of the Strongly Magnetic Ultramassive White Dwarf EGGR 156
• Pulsating White Dwarfs
• A comment on "Lense-Thirring frame dragging induced by a fast-rotating white dwarf in a binary pulsar system" by V. Venkatraman Krishnan et al
• Asteroseismology of PG 1541$+$651 and BPM 31594 with TESS
• Exploring the pulsational properties of two ZZ Ceti stars
• 84 Second and 169 Second Rotation of Two Isolated, Ultramassive, Strongly Magnetic White Dwarfs
• An observer's view on the future of asteroseismology
• The unreasonable effectiveness of the $n\Sigma v$ approximation