Astron. J., 156, 199-199 (2018/November-0)
TY Pup: a low-mass-ratio and deep contact binary as a progenitor candidate of luminous red novae.
SAROTSAKULCHAI T., QIAN S.-B., SOONTHORNTHUM B., ZHOU X., ZHANG J., REICHART D.E., HAISLIP J.B., KOUPRIANOV V.V. and POSHYACHINDA S.
Abstract (from CDS):
TY Pup is a well-known bright eclipsing binary with an orbital period of 0.8192 days. New light curves in B, V, (RI)C bands were obtained with the 0.61 m reflector robotic telescope (PROMPT-8) at CTIO in Chile during 2015 and 2017. By analyzing those photometric data with the W-D method, it is found that TY Pup is a low-mass-ratio (q ∼ 0.184) and deep-contact binary with a high fill-out factor (84.3%). An investigation of all available times of minimum light including three new ones obtained with the 60 cm and the 1.0 m telescopes at Yunnan Observatories in China indicates that the period change of TY Pup is complex. An upward parabolic variation in the O - C diagram is detected to be superimposed on a cyclic oscillation. The upward parabolic change reveals a long-term continuous increase in the orbital period at a rate of dP/dt = 5.57(±0.08) x 10–8 days yr–1. The period increase can be explained by mass transfer from the less massive component (M2 ∼ 0.3 M☉) to the more massive one (M1 ∼ 1.65 M☉). The binary will be merging when it meets the criterion that the orbital angular momentum is less than three times the total spin angular momentum, i.e., Jorb < 3Jrot. This suggests that the system will finally merge into a rapid-rotating single star and may produce a luminous red nova. The cyclic oscillation in the O - C diagram can be interpreted by the light-travel time effect via the presence of a third body.
© 2018. The American Astronomical Society. All rights reserved.
binaries: close - binaries: eclipsing - stars: evolution - stars: individual: TY Pup
VizieR on-line data:
<Available at CDS (J/AJ/156/199): table2.dat table3.dat>
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