Helium enhanced cool bright stars
Scientists at Indian Institute of Astrophysics (IIA) which is an autonomous institute of Department of Science & Technology (DST), have studied stars of Omega Centauri globular cluster and found some Helium (He)-enhanced cool bright stars that are present among the metal-rich sample of the cluster. According to the Ministry of Science and Technology, this is the first time He abundance has been found in Omega Centauri and the work has been published in ‘The Astrophysical Journal’.
- It is to note that the globular clusters are stellar systems consisting of millions of stars that are formed from a gaseous cloud.
- This implies that stars present in this cluster are homogeneous in their chemical composition of elemental form. However, some clusters deviate from this norm. One of the examples is the largest and brightest globular cluster in the Milky Way is Omega Centauri.
- The government report stated that the different stars of Omega Centauri are not made of the same metal content which is also an indicator of its age.
- With the anomalous elemental abundances, the formation of these are at times different from normal. To be sure, the abundances are made on the back of an assumption that “He is one-tenth of the H-abundance.”
- Further, the ministry added that this is the first spectroscopic determination of He-abundance in Omega Centauri.
- According to the report, the study is important as it gives a clue for He-enhanced population origin. A team of scientists at IIA studied the spectrum by using a low-resolution spectra which had been obtained from the Optometric Medium Resolution Spectrograph (OMRS) installed with the Vainu Bappu Telescope, Vainu Bappu Observatory, Kavalur, India and identified the mild Helium and Helium enhanced stars.
- Moreover, in order to measure the amount of He that is present in the identified bright/ cool stars of Omega Centauri, the scientists used a high-resolution spectra that has been obtained from the Southern African Large Telescope (SALT).