Detailed follow up studies of three ultracompact sdB binaries

Eric Stringer; Thomas Kupfer; Matti Dorsch

Detailed follow up studies of three ultracompact sdB binaries

Solar and Stellar Astrophysics 2023-03-13 v1

Authors: Eric Stringer , Thomas Kupfer , Matti Dorsch

Abstract

We present follow-up studies of three ultracompact hot subdwarf binaries. Using data from the Zwicky Transient Facility, we find orbital periods of 33.6, 37.3, and 36.9 minutes for ZTF 1946+3203, ZTF 0640+1738, and ZTF 0643+0318 respectively. The light curves show ellipsoidal variability of the hot subdwarf star with potential eclipses of an accretion disc. Phase-resolved spectroscopic observations with Keck were used to measure a radial velocity curve and atmospheric parameters of the hot subdwarf stars. ZTF J0643 shows evidence of accretion disc emission lines in the average spectrum. Combining light curve and spectroscopic fits will allow us to measure precise system properties such as masses, to determine the evolutionary history and future evolution of the system.

Keywords

hot subdwarf binaries ultracompact systems orbital periods ellipsoidal variability spectroscopic observations accretion discs

Cite

@article{arxiv.2303.05523,
  title  = {Detailed follow up studies of three ultracompact sdB binaries},
  author = {Eric Stringer and Thomas Kupfer and Matti Dorsch},
  journal= {arXiv preprint arXiv:2303.05523},
  year   = {2023}
}

Comments

Accepted for publication in Bulletin de la Soci\'et\'e Royale des Sciences de Li\`ege, proceedings for the sdOB10 conference, 10 pages, 1 figure

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