English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We present follow-up observations and analysis of the recently discoveredshort period low-mass eclipsing binary, SDSS J001641-000925. With an orbitalperiod of 0.19856 days, this system has one of the shortest known periods foran M dwarf binary system. Medium-resolution spectroscopy and multi-bandphotometry for the system are presented. Markov chain Monte Carlo modeling ofthe light curves and radial velocities yields estimated masses for the stars ofM1 = 0.54 +/- 0.07 Msun and M2 = 0.34 +/- 0.04 Msun, and radii of R1 = 0.68 +/-0.03 Rsun and R2 = 0.58 +/- 0.03 Rsun respectively. This solution places bothcomponents above the critical Roche overfill limit, providing strong evidencethat SDSS J001641-000925 is the first verified M-dwarf contact binary system.Within the follow-up spectroscopy we find signatures of non-solid body rotationvelocities, which we interpret as evidence for mass transfer or loss within thesystem. In addition, our photometry samples the system over 9 years, and wefind strong evidence for period decay at the rate of dP/dt ~8 s/yr. Both ofthese signatures raise the intriguing possibility that the system is inover-contact, and actively losing angular momentum, likely through mass loss.This places SDSS J001641-000925 as not just the first M-dwarf over-contactbinary, but one of the few systems of any spectral type known to be activelyundergoing coalescence. Further study SDSS J001641-000925 is on-going to verifythe nature of the system, which may prove to be a unique astrophysicallaboratory.

The Very Short Period M Dwarf Binary SDSS J001641-000925