NSVS 2569022: a peculiar binary among W UMa stars with extremely small mass ratios
Abstract
Photometric observations of the W UMa binary NSVS 2569022 are presented. The light curve solution reveals that both components are of F spectral type (temperatures T _{1} = T _{2} = 6100 K). NSVS 2569022 undergoes a total eclipse of W subtype and the mass ratio is welldetermined. Its extremely small value of only 0.077 implies that the target will probably experience instability and a possible merger. This value ranks NSVS 2569022 in sixth place among binaries with the smallest mass ratio. Based on an empirical relation of “period  total mass” for low massratio binaries, we estimate the global parameters of NSVS 2569022: masses M _{1} = 1.17 M _{⊙} and M _{2} = 0.09 M _{⊙} radii R _{1} = 1.19 R _{⊙} and R _{2} = 0.38 R _{⊙} luminosities L _{1} = 1.73 L _{⊙} and L _{2} = 0.17 L _{⊙}. An analysis of the characteristics of binaries with extremely lowmass ratios is made. NSVS 2569022 turns out to be a peculiar binary among W UMa stars with extremely small mass ratios due to its unexpectedly small fillout factor of only 0.014 (slightly overcontact configuration).
 Publication:

Research in Astronomy and Astrophysics
 Pub Date:
 October 2018
 DOI:
 10.1088/16744527/18/10/129
 arXiv:
 arXiv:1806.02086
 Bibcode:
 2018RAA....18..129K
 Keywords:

 Astrophysics  Solar and Stellar Astrophysics
 EPrint:
 Accept