A new bright eclipsing hot subdwarf binary from the ASAS and SuperWASP surveys

Schaffenroth V, Geier S, Drechsel H, Heber U, Wils P, Ostensen RH, Maxted PFL, Di Scala G (2013)

Publication Type: Journal article

Publication year: 2013

Journal

Astronomy & Astrophysics EDP Sciences

Book Volume: 553

Article Number: A18

DOI: 10.1051/0004-6361/201220929

Abstract

We report the discovery of a bright (mV = 11.6 mag), eclipsing, hot subdwarf binary of spectral type B with a late main sequence companion from the All Sky Automated Survey (ASAS 102322-3737.0). Such systems are called HW Vir stars after the prototype. The lightcurve shows a grazing eclipse and a strong reflection effect. An orbital period of P = 0.13927 d, an inclination of i = 65.86, a mass ratio q = 0.34, a radial velocity semiamplitude K1 = 81.0 km s-1, and other parameters were derived from a combined spectroscopic and photometric analysis. The short period can only be explained by a common envelope origin of the system. The atmospheric parameters (T eff = 28 400 K, log g = 5.60) are consistent with a core helium-burning star located on the extreme horizontal branch. In agreement with that we derived the most likely sdB mass to be MsdB = 0.46 M ⊙, close to the canonical mass of such objects. The companion is a late M-dwarf with a mass of Mcomp = 0.16 M⊙. ASAS 102322-3737.0 is the third brightest of only 12 known HW Virginis systems, which makes it an ideal target for detailed spectroscopic studies and long-term photometric monitoring to search for period variations, e.g., those caused by a substellar companion. © 2013 ESO.

Authors with CRIS profile

Veronika Schaffenroth Dr.Karl-Remeis-Sternwarte Bamberg, Astronomisches Institut Stephan Geier Dr.Karl-Remeis-Sternwarte Bamberg, Astronomisches Institut Horst Drechsel Dr.Karl-Remeis-Sternwarte Bamberg, Astronomisches Institut Ulrich Heber Naturwissenschaftliche Fakultät

Involved external institutions

Katholieke Universiteit Leuven (KUL) / Catholic University of Leuven BE Belgium (BE) University of Keele GB United Kingdom (GB) Carnes Hill Observatory AU Australia (AU)

How to cite

APA:

Schaffenroth, V., Geier, S., Drechsel, H., Heber, U., Wils, P., Ostensen, R.H.,... Di Scala, G. (2013). A new bright eclipsing hot subdwarf binary from the ASAS and SuperWASP surveys. Astronomy & Astrophysics, 553. https://doi.org/10.1051/0004-6361/201220929

MLA:

Schaffenroth, Veronika, et al. "A new bright eclipsing hot subdwarf binary from the ASAS and SuperWASP surveys." Astronomy & Astrophysics 553 (2013).

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