What Are W Ursae Majoris–Type Stars?

Astronomers have gained fresh insights into the evolution and fate of binary stars through a detailed study of W Ursae Majoris (W UMa)–type contact binaries. These are short-period, dumbbell-shaped stellar twins that orbit extremely close to each other, sharing a common outer atmosphere while revolving around a common centre.

Natural Laboratories for Stellar Physics
Because of their intimate configuration, W UMa systems act as natural laboratories for astrophysics. They allow precise determination of fundamental stellar parameters such as mass, radius and temperature, which are crucial for testing and refining theories of stellar evolution.

Indian Institutions Lead the Research
The study was conducted by astronomers from the Aryabhatta Research Institute of Observational Sciences (ARIES) and the Physical Research Laboratory (PRL), Ahmedabad.

Advanced Observational Tools Used
Researchers combined observations from:

• ARIES’s 1.3-metre Devasthal Fast Optical Telescope (DFOT), and
• NASA’s Transiting Exoplanet Survey Satellite (TESS)

Using these facilities, the team generated high-precision light curves of the binary systems.

Understanding Light Curves
Light curves track how the total brightness of a star system changes over time. In contact binaries, these variations provide key information about orbital motion, stellar interaction and energy transfer between the two stars.

Key Significance of the Study
The findings enhance understanding of:

• How close binary stars evolve over time,
• The mechanisms of mass and energy exchange between stellar companions, and
• The eventual fate of contact binary systems.

Source: PIB