Indian Astronomers Discover Actively Forming Blue Straggler Star
#GS-3 #Science & Technology #Space #Current Events #National #Blue Straggler Star #Indian Institute of Astrophysics
Why in News
- Indian astronomers from the **Indian Institute of Astrophysics (IIA)** and international collaborators discovered a **Blue Straggler Star (BSS)** actively forming in system **TIC 327546480**.
About Blue Straggler Stars
- A **Blue Straggler Star (BSS)** is an unusually hot, luminous, blue, and massive star found inside old star clusters.
- Standard theories of stellar evolution dictate that high-mass stars should become white dwarfs or red giants long ago, yet these stars appear much younger than surrounding cluster members.
Origin and Formation Mechanisms
- Astronomer **Allan Sandage** first observed these stars in **1953** inside globular cluster **M3**, where older stars gain extra hydrogen fuel to reset their nuclear clock.
- In binary mass transfer, an aging donor star expands beyond its gravitational limit known as its **Roche lobe**, leaking matter onto its companion star to make it hotter and bluer.
- In stellar collisions within dense cluster cores, two stars physically crash or merge together to fuse their mass into a single rejuvenated star.
Key Features of Blue Stragglers
- These stars defy normal stellar aging by appearing younger and hotter than companion stars formed at the same time in the same cluster.
- In the semi-detached binary system **TIC 327546480**, a smaller companion continuously transfers gas to the larger **BSS**, causing it to gain mass.
- Receiving gas from its companion transfers angular momentum to the **BSS**, making it spin significantly faster.
- Gas striking the star heats up substantially on impact, producing strong **X-rays** that confirm active mass transfer.
- Estimates indicate this mass transfer process started roughly **5.46 billion years ago** and continues today.
Significance
- This discovery provides direct observational proof that mass transfer can rejuvenate aging stars.
- The system helps astronomers refine models of binary star evolution, mass dynamics, and stellar life cycles across the universe.