Multiband light-curve analysis of the 40.5-min period eclipsing double-degenerate binary SDSS J082239.54+304857.19. Issue 4 (18th November 2020)

• Record Type: Journal Article
• Authors: Kosakowski, Alekzander; Kilic, Mukremin; Brown, Warren
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 500:Issue 4(2021)
• Page Start: 5098
• Page End: 5105
• Publication Date: 2020-11-18
• Subjects: binaries: eclipsing -- stars: individual: J082239.54+304857.19 -- stars: individual: J0822+3048 -- white dwarfs; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/staa3571
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We present the Apache Point Observatory BG40 broad-band and simultaneous Gemini r -band and i -band high-speed follow-up photometry observations and analysis of the 40.5-min period eclipsing detached double-degenerate binary SDSS J082239.54+304857.19. Our APO data spans over 318 d and includes 13 primary eclipses, from which we precisely measure the system's orbital period and improve the time of mid-eclipse measurement. We fit the light curves for each filter individually and show that this system contains a low-mass DA white dwarf with radius RA = 0.031 ± 0.006 R⊙ and a RB = 0.013 ± 0.005 R⊙ companion at an inclination of i = 87.7 ± 0.2 ○ . We use the best-fitting eclipsing light curve model to estimate the temperature of the secondary star as T eff = 5200 ± 100 K. Finally, while we do not record significant offsets to the expected time of mid-eclipse caused by the emission of gravitational waves with our 1-yr baseline, we show that a 3σ significant measurement of the orbital decay due to gravitational waves will be possible in 2023, at which point the eclipse will occur about 8 s earlier than expected.