Ultra-short Period Binaries from the Catalina Surveys

Abstract

We investigate the properties of 367 ultra-short period binary candidates selected from 31,000 sources recently identified from Catalina Surveys data. Based on light curve morphology, along with WISE, SDSS and GALEX multi-colour photometry, we identify two distinct groups of binaries with periods below the 0.22 day contact binary minimum. In contrast to most recent work, we spectroscopically confirm the existence of M-dwarf+M-dwarf contact binary systems. By measuring the radial velocity variations for five of the shortest-period systems, we find examples of rare cool-white dwarf+M-dwarf binaries. Only a few such systems are currently known. Unlike warmer white dwarf systems, their UV flux and their optical colours and spectra are dominated by the M-dwarf companion. We contrast our discoveries with previous photometrically-selected ultra-short period contact binary candidates, and highlight the ongoing need for confirmation using spectra and associated radial velocity measurements. Overall, our analysis increases the number of ultra-short period contact binary candidates by more than an order of magnitude.

12 pages, 12 figures, accepted ApJ

References in corpus (9)

• The Catalina Surveys Periodic Variable Star Catalog
• Low-Mass Dwarf Template Spectra from the Sloan Digital Sky Survey
• New periodic variable stars coincident with ROSAT sources discovered using SuperWASP
• Contact binaries with additional components. III. The adaptive optics detections
• The short period end of the contact binary period distribution based on the All Sky Automated Survey (ASAS)
• Luminosity function of contact binaries based on the ASAS survey
• Period decrease in three SuperWASP eclipsing binary candidates near the short-period limit
• DE CVn: A bright, eclipsing red dwarf - white dwarf binary
• An evolved donor star in the long-period cataclysmic variable HS 0218+3229

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• CoBiToM Project -- I. Contact Binaries Towards Merging
• Contact Binaries as Viable Distance Indicators: New, Competitive (V)JHKs Period-Luminosity Relations
• Variability, periodicity and contact binaries in WISE
• CoBiToM Project -- II: Evolution of contact binary systems close to the orbital period cut-off
• Statistical Time-Resolved Spectroscopy: A higher fraction of short-period binaries for metal-rich F-type dwarfs in SDSS
• Case AD, AR, and AS binary evolution and their possible connections with W UMa binaries
• A New Stellar Outburst Associated with the Magnetic Activities of the K-type Dwarf in a White-dwarf Binary
• A Survey for High-Mass Eclipsing Binaries
• Three Ultra-short Period Contact Eclipsing Binary Systems Mined from Massive Astronomical Surveys
• YZ Phe: an active contact binary with variation of the O'Connell effect and orbital period change
• Photometric variability of candidate white dwarf binary systems from Palomar Transient Factory archival data
• Photometric analysis of three totally eclipsing W UMa stars with increasing periods: TYC 3700-1384-1, V1511 Her and V1179 Her