Bulletin de la Société Royale des Sciences de Liège Bulletin de la Société Royale des Sciences de Liège -  Volume 92 - Année 2023  Numéro 2 - Proceedings of the 10th Meeting on Hot Subdwarfs and Related Objects 

Detailed follow up studies of three ultracompact sdB binaries

Eric Stringer
Department of Physics and Astronomy, Texas Tech University, PO Box 41051, Lubbock, TX 79409, USA. Corresponding author: erstring@ttu.edu
Thomas Kupfer
Department of Physics and Astronomy, Texas Tech University, PO Box 41051, Lubbock, TX 79409, USA
Matti Dorsch
Dr. Karl Remeis-Observatory & ECAP, Friedrich-Alexander University Erlangen-Nürnberg, Sternwartstr. 7, 96049 Bamberg, Germany

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 el-lipsoidal 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.

Pour citer cet article

Eric Stringer, Thomas Kupfer & Matti Dorsch, «Detailed follow up studies of three ultracompact sdB binaries», Bulletin de la Société Royale des Sciences de Liège [En ligne], Volume 92 - Année 2023, Numéro 2 - Proceedings of the 10th Meeting on Hot Subdwarfs and Related Objects, 103-111 URL : https://popups.uliege.be/0037-9565/index.php?id=11283.