Friday 28 February 2025
A newly discovered binary star system has shed light on the mysteries of cataclysmic variables, a type of celestial body that is both fascinating and poorly understood. The system, known as LAMOST J101356.33+272410.7, consists of a white dwarf and a main-sequence star orbiting each other every 185 minutes.
The most striking feature of this binary pair is its location within the period gap, a region where cataclysmic variables are surprisingly rare. The period gap refers to the range of orbital periods between approximately 2-3 hours, during which these systems tend to be quiet and lack accretion activity. But why?
One possibility is that these systems have undergone a process called common envelope evolution (CEE), in which the white dwarf and main-sequence star interact closely, causing mass to be transferred from the latter to the former. This can lead to the formation of a detached binary system like LAMOST J101356.33+272410.7.
The researchers behind this discovery used data from several telescopes, including LAMOST (Large Sky Area Multi-Object Fiber Spectroscopic Telescope) and SDSS (Sloan Digital Sky Survey), to study the properties of both stars in the binary system. By analyzing their spectra, they were able to determine the stellar parameters and radial velocities of each component.
Further investigation revealed that the white dwarf has a mass of approximately 1.05 solar masses and a radius of about 0.009 solar radii, while the main-sequence star weighs around 0.299 solar masses with a radius of roughly 0.286 solar radii. These values are consistent with those expected for a binary system that has undergone CEE.
The emission lines observed in the spectra also indicate the presence of stellar magnetic activity in this system, which is not uncommon among cataclysmic variables. However, the relatively cool temperature of the white dwarf suggests that LAMOST J101356.33+272410.7 might be a post-common envelope binary (PCEB) that has not undergone mass transfer.
The researchers propose that this system could evolve into a cataclysmic variable and begin mass transfer in approximately 0.27 billion years, marking the beginning of its active phase. This discovery provides valuable insights into the complex dynamics of binary star systems and sheds light on the mysteries surrounding cataclysmic variables.
In summary, LAMOST J101356.
Cite this article: “Mysterious Binary Star System Sheds Light on Cataclysmic Variables”, The Science Archive, 2025.
Binary Star System, Cataclysmic Variables, White Dwarf, Main-Sequence Star, Period Gap, Common Envelope Evolution, Lamost, Sdss, Stellar Parameters, Radial Velocities
