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TY Pup is a well-known bright eclipsing binary in southern hemisphere 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 from January to February 2015 and from March to April 2017. By analyzing those photometric data with the W-D method, it is found that TY Pup is a low-mass-ratio ($q sim$ 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 $mathrm{d}P/mathrm{d}t = 5.57(pm 0.08)times10^{-8}$ d $textrm{yr}^{-1}$. The period increase can be explained by mass transfer from the less massive component ($M_2 sim 0.3 M_{odot}$) to the more massive one ($M_1 sim 1.65 M_{odot}$) and the mass ratio of the binary system will become more smaller. In this way, the binary will be merging when it meets the criterion that the orbital angular momentum is less than 3 times the total spin angular momentum, i.e., $J_{orb} < 3J_{rot}$. 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 (LITE) via the presence of an additional companion.
We present extensive datasets for a class of intermediate-luminosity optical transients known as luminous red novae (LRNe). They show double-peaked light curves, with an initial rapid luminosity rise to a blue peak (at -13 to -15 mag), which is follo
Luminous Red Novae (LRNe) are astrophysical transients associated with the partial ejection of a binary systems common envelope (CE) shortly before its merger. Here we present the results of our photometric and spectroscopic follow-up campaign of AT2
Measurements of sulphur isotopes in presolar grains can help to identify the astrophysical sites in which these grains were formed. A more precise thermonuclear rate of the 33S(p,gamma)34Cl reaction is required, however, to assess the diagnostic abil
Both high precision CCD photometric and H$alpha$ line studies are presented for an overcontact binary ASAS J082243+1927.0. The light curve exhibits a total eclipse at secondary minima along with an OConnell effect. The light curve was modeled using t
In this study, we present photometric and spectroscopic variations of the extremely small mass ratio ($qsimeq 0.1$) late-type contact binary system astrobj{V1191 Cyg}. The parameters for the hot and cooler companions have been determined as $M_textrm