NOAO >   Observing Info >   Approved Programs >   2015A-0601

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Program Information for 2015A-0601


PI: Donald Terndrup, Ohio State U., terndrup.1@osu.edu
Address: Departmentt of Astronomy, 140 W 18th Ave, Columbus, OH 43210 USA

CoI: Zachary Hartman, Ohio State U.

Title: Spectroscopy of dwarf secondary stars in post-common envelope binaries

Abstract: Many detached post-common envelope binaries, such as the HW Virginis stars, have short-period (P ∼ 0.1 day) orbits but are not in the domain where gravitational radiation dominates the angular momentum loss. HW Vir stars consist of a hot horizontal branch primary and a low-mass (0.1 – 0.2 Msun) dwarf secondary, and exhibit a strong reflection effect from the dwarf star. A few of these have been studied in detail through eclipse timing and often show complicated behavior, sometimes indicating the presence of planets, superimposed on a (possible) signal of steady angular momentum loss from winds. To date, all are single-lined binaries, and the properties of the dwarf secondary stars are very poorly determined; all that is known is that they have the radii that are similar to dwarf M stars at the bottom of the main sequence. We will obtain time-series spectroscopy of several of these binary systems to detect absorption or emission lines from the secondary, as a first step to future radial velocity studies of both components and the measurement of the mass/radius relation in the dwarf secondaries.

Program Type: Payback

Scheduled Nights:
Run 1 (2015A):  KP-4m/KOSMOS -- 4.5n on May 01 - May 05 2015
Run 2 (2016A):  KP-4m/KOSMOS -- 3n on Jun 17 - Jun 19 2016


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2015A-0601

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