Astronomers have conducted photometric and spectroscopic observations of TIC 60040774, a binary system. The observational campaign’s findings shed more light on the system’s properties, revealing that it is an eclipsing post-common-envelope binary. The study was published on arXiv.org on August 5.
A binary star system is contained within a common envelope (CE). Observations show that once the more massive star in a binary exits the main sequence, dynamically unstable mass transfer or a tidal instability may force the system into the CE phase, depending on the initial conditions.
The CE evolution generates a sizable population of close-but-disconnected white-dwarf/main-sequence (WDMS) binaries. A quarter of WDMS are close enough that they must be post-common-envelope binaries (PCEBs), and about 10% of these systems exhibit eclipses. PCEB research could help us understand the formation and evolution of close compact binary stars.
That is why, led by RhoromPriyatikanto of the National Research and Innovation Agency in Bandung, Indonesia, an astronomical team investigated TIC 60040774, one of the close binaries with a low-mass secondary star located 437 light years away. Previous research has suggested that it could be a PCEB.
“We present the discovery and characterization of a bright new eclipsing PCEB in this paper. The system, TIC 60040774, is a high-property-motion object that is close to the WD sequence in the color-magnitude diagram and is relatively close to Earth “The researchers wrote about it.
The researchers examined TIC 60040774’s light curve obtained from the Transiting Exoplanet Survey Satellite (TESS), multi-band photometry obtained from the Virtual Observatory SED Analyzer (VOSA), and spectroscopic data obtained from the Southern African Large Telescope (SALT). They discovered that the system is made up of a young white dwarf and a M dwarf companion.
The white dwarf in TIC 60040774 has a mass of nearly 0.6 solar masses and an effective temperature of 14,050 K, according to the study. The companion dwarf star was discovered to be of spectral type M6.5, with a mass of about 0.11 solar masses and an effective temperature of 2,759 K.
The system’s orbital period was estimated to be 9.71 hours, which is relatively long when compared to other known PCEBs. The system’s total age was calculated to be approximately 1.024 billion years, with the researchers assuming that the common-envelope stage occurred approximately 243 million years ago.
The astronomers concluded that TIC 60040774 most likely began as a binary with a late B primary star with a mass of around 2.5 solar masses and an initial separation of about 2.4 AU. However, they added that more precise high-cadence photometry is required to better understand the system’s history and nature.