A NEW MERGING DOUBLE DEGENERATE BINARY IN THE SOLAR NEIGHBORHOOD

作者:Debes John H*; Kilic Mukremin; Tremblay Pier Emmanuel; Lopez Morales Mercedes; Anglada Escude Guillem; Napiwotzki Ralph; Osip David; Weinberger Alycia
来源:Astronomical Journal, 2015, 149(5): 176.
DOI:10.1088/0004-6256/149/5/176

摘要

Characterizing the local space density of double degenerate (DD) binary systems is a complementary approach to broad sky surveys of DDs to determine the expected rates of WD binary mergers, in particular those that may evolve into other observable phenomena such as extreme helium stars, Am CVn systems, and SNe Ia. However, there have been few such systems detected in local space. We report here the discovery that WD1242-105, a nearby bright WD, is a double-line spectroscopic binary consisting of two degenerate DA WDs of similar mass and temperature, despite it previously having been spectroscopically characterized as a single degenerate. Follow-up photometry, spectroscopy, and trigonometric parallax have been obtained in an effort to determine the fundamental parameters of each component of this system. The binary has a mass ratio of 0.7 and a trigonometric parallax of 25.5 mas, placing it at a distance of 39 pc. The system's total mass is 0.95 M-circle dot and has an orbital period of 2.85 hr, making it the strongest known gravitational wave source (log h = -20.78) in the mHz regime. Because of its orbital period and total mass, WD1242-105 is predicted to merge via gravitational radiation on a timescale of 740 Myr, which will most likely not result in a catastrophic explosion.

  • 出版日期2015-5