X-ray observation of the Roche-lobe filling white dwarf plus hot subdwarf system ZTF J213056.71+442046.5

Abstract

ZTF J213056.71+442046.5 is the prototype of a small class of recently discovered compact binaries composed of a white dwarf and a hot subdwarf that fills its Roche-lobe. Its orbital period of only 39 min is the shortest known for the objects in this class. Evidence for a high orbital inclination (i=86 deg) and for the presence of an accretion disk has been inferred from a detailed modeling of its optical photometric and spectroscopic data. We report the results of an XMM-Newton observation carried out on 2021 January 7. ZTF J213056.71+442046.5 was clearly detected by the Optical Monitor, which showed a periodic variability in the UV band (200-400 nm), with a light curve similar to that seen at longer wavelengths. Despite accretion on the white dwarf at an estimated rate of the order of 10^{-9} M_sun/yr, no X-rays were detected with the EPIC instrument, with a limit of ~10^{30} erg/s on the 0.2-12 keV luminosity. We discuss possible explanations for the lack of a strong X-ray emission from this system.

arXiv commentAccepted for publication on The Astrophysical Journal

References in corpus (32)

• The Gaia mission
• The European Photon Imaging Camera on XMM-Newton: The MOS Cameras
• The Zwicky Transient Facility: System Overview, Performance, and First Results
• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• HI4PI: A full-sky HI survey based on EBHIS and GASS
• A 3D Dust Map Based on Gaia, Pan-STARRS 1 and 2MASS
• The Origin of Subdwarf B Star (I): the Formation Channels
• The origin of sdB stars (II)
• The XMM-Newton Optical/UV Monitor Telescope
• The Second-Generation Guide Star Catalog: Description and Properties
• Hot subluminous stars
• The XMM-Newton serendipitous survey. VII. The third XMM-Newton serendipitous source catalogue
• X-ray Emissions from Accreting White Dwarfs: a Review
• LISA verification binaries with updated distances from Gaia Data Release 2
• Close binary EHB stars from SPY
• Orbital periods of twenty two subdwarf B stars
• The hot subdwarf B + white dwarf binary KPD 1930+2752 - a Supernova Type Ia progenitor candidate
• Hot subdwarf binaries from the MUCHFUSS project - Analysis of 12 new systems and a study of the short-period binary population
• The population of hot subdwarf stars studied with Gaia II. The Gaia DR2 catalogue of hot subluminous stars
• An ultra-massive fast-spinning white dwarf in a peculiar binary system
• Evolution of Low-Mass Helium Stars in Semidetached Binaries
• Hard X-ray view on intermediate polars in the Gaia era
• The shortest period sdB plus white dwarf binary CD-30 11223 (GALEX J1411-3053)
• The first ultracompact Roche lobe-filling hot subdwarf binary
• A hot subdwarf-white dwarf super-Chandrasekhar candidate supernova Ia progenitor
• Confirmation of Eclipses in KPD 0422+5421, A Binary Containing a White Dwarf and a Subdwarf B Star
• A new class of Roche lobe-filling hot subdwarf binaries
• PTF1 J082340.04+081936.5: A hot subdwarf B star with a low mass white dwarf companion in an 87 minute orbit
• Discovery of a double detonation thermonuclear supernova progenitor
• Phases of Mass Transfer from Hot Subdwarfs to White Dwarf Companions and Their Photometric Properties
• The OmegaWhite survey for short-period variable stars - V. Discovery of an ultracompact hot subdwarf binary with a compact companion in a 44 minute orbit
• Constraints on the winds of hot subdwarf stars from X-ray observations of two sdB binaries with compact companions: CD -30 11223 and PG 1232-136

Cited by in corpus (2)

• Limiting the accretion disk light in two mass transferring hot subdwarf binaries
• Discovery of the first outbursting hot subdwarf binary: ZTF J0007+4804