Astronomers Target Chemically Peculiar Star HD 72968

In an exciting venture, astronomers have harnessed the power of NASA's Transiting Exoplanet Survey Satellite (TESS) alongside the mighty Very Large Telescope (VLT) to delve deep into the mysteries of a remarkable star known as HD 72968. Their findings, which hit the pre-print stage on May 9, promise to unlock key secrets about this chemically peculiar celestial body.

What Makes HD 72968 Stand Out?

Chemically peculiar (CP) stars, like HD 72968, are fascinating because of their abnormal metal compositions, leading to either extraordinarily strong or weak spectral lines for certain elements. A subset of these, known as magnetic chemically peculiar stars (mCPs), are often characterized by powerful magnetic fields. Yet, precisely defining their fundamental characteristics poses a challenge, especially due to their unique atmospheric chemistry.

A Star 350.5 Light Years Away

Located about 350.5 light years from Earth, HD 72968 belongs to a category known as Alpha2 Canum Venaticorum variables—fascinating stars that naturally fluctuate in brightness. Over a cycle of 11.3 days, the star's brightness dances between 5.72 and 5.74 magnitudes.

Peering into the Heart of HD 72968

Under the expert guidance of Milton Macías Laz and his team from the Valencian International University, astronomers utilized TESS and the VLT's UVES to perform an in-depth photometric and spectroscopic analysis of HD 72968. Their meticulous observations revealed a precise orbital period of 11.307 days, coupled with a mysterious sub-period of 2.7 days, likely linked to the star's pulsations.

Light Curve Mysteries

The observational data unveiled intriguing variations in HD 72968’s light curve, marked by sudden brightness drops. These fluctuations might be caused by material ejections during pulsation events, potentially shedding light on the star's inner workings. Notably, after significant drops, a persistent disturbance in the light curve suggests residual effects from either a second eclipse or additional ejections.

Chemistry of the Cosmos

The team didn’t stop there; they ventured into a chemical abundance analysis, detecting spectral lines from elements like chromium and strontium in HD 72968's spectrum. Such data enrich our understanding of the star's composition and its place in cosmic evolution.

Parameters That Define a Star

Key parameters emerged from the study: HD 72968 boasts an effective temperature of around 10,500 K, a rotational velocity of 8 km/s, and an impressive radius estimated at 2.5 times that of our Sun. Remarkably, the calculated distance to this star aligns closely at approximately 350.55 light years.

A Call for Further Exploration

As the research concludes, the authors advocate for continued spectral investigations into HD 72968. Each new study could add another piece to the cosmic puzzle of this remarkable star, intriguing astronomers and stargazers alike.