PSR J1738+0333: The First Millisecond Pulsar + Pulsating White Dwarf Binary

Abstract

We report the discovery of the first millisecond pulsar with a pulsating white dwarf companion. Following the recent discoveries of pulsations in extremely low-mass (ELM, <0.3 Msol) white dwarfs (WDs), we targeted ELM WD companions to two millisecond pulsars with high-speed Gemini photometry. We find significant optical variability in PSR J1738+0333 with periods between roughly 1790-3060 s, consistent in timescale with theoretical and empirical observations of pulsations in 0.17 Msol He-core ELM WDs. We additionally put stringent limits on a lack of variability in PSR J1909-3744, showing this ELM WD is not variable to <0.1 per cent amplitude. Thanks to the accurate distance and radius estimates from radio timing measurements, PSR J1738+0333 becomes a benchmark for low-mass, pulsating WDs. Future, more extensive time-series photometry of this system offers an unprecedented opportunity to constrain the physical parameters (including the cooling age) and interior structure of this ELM WD, and in turn, the mass and spin-down age of its pulsar companion.

MNRAS Letters, in press. Fixed a small error at the end of section 5.1

References in corpus (8)

• A Massive Pulsar in a Compact Relativistic Binary
• The relativistic pulsar-white dwarf binary PSR J1738+0333 II. The most stringent test of scalar-tensor gravity
• Pulsating White Dwarf Stars and Precision Asteroseismology
• Formation of millisecond pulsars with CO white dwarf companions - II. Accretion, spin-up, true ages and comparison to MSPs with He white dwarf companions
• The relativistic pulsar-white dwarf binary PSR J1738+0333 I. Mass determination and evolutionary history
• The masses of PSR J1911-5958A and its white dwarf companion
• Precise Atmospheric Parameters for the Shortest Period Binary White Dwarfs: Gravitational Waves, Metals, and Pulsations
• Radius constraints from high-speed photometry of 20 low-mass white dwarf binaries

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• A double white dwarf with a paradoxical origin?
• Probing the structure of Kepler ZZ Ceti stars with full evolutionary models-based asteroseismology
• Pulsating low-mass white dwarfs in the frame of new evolutionary sequences: V. Asteroseismology of ELMV white dwarf stars
• The DECam Minute Cadence Survey I