The Milky Way is home to a disk of much younger stars that were not known to the astronomers as a result of being hidden among older stars. A team of astronomers have found those young stars using data acquired by the VISTA Telescope at the European Southern Observatory between the years 2010 and 2014. All these newly spotted stars were hidden behind thick dust clouds covering the central bulge of the Milky Way.
The study’s lead author Istvan Dekany, an astronomer from the Pontificia Universidad Católica de Chile, said that Milky Way’s central bulge is believed to be home to millions of old stars. The astronomer added that the data gathered by VISTA revealed fresh information; the stars spotted by the telescope are significantly young by the astronomical standards.
When studying the data, astronomers came to know about as many as 655 variable stars referred to as Cepheids, which contract and expand periodically. They take between a few days to months for completing a cycle and during this period their brightness keeps on changing notably.ESO/Microsoft WorldWide Telescope
The brightness of a Cepheid pulses quite predictably and this gives astronomers the opportunity of using Cepheids for calculating distances from other galaxies. For those who don’t know: this is possible as observed brightness tend to drop by the square of the distance.
Among the 655 Cepheids spotted at Milky Way’s heart, 35 were identified to be “classical Cepheids”. Here, the term “classical Cepheids” refer to stars that are typically young.
According to information provided by Universidad Andrés Bello’s Dante Minniti, one of the coauthors of the paper published in Astrophysical Journal Letters, each of these 35 classical Cepheids were formed less than 100 million years back. He added the youngest of them all might just be nearly 25 million years old. According to Minniti, the astronomers can also not exclude the possibility of the presence of even brighter and younger Cepheids.
There’s a strong connection between the period of Cepheid star and its brightness. The brighter Cepheids boast a slower and longer pulse compared to that of the dimmer ones. This connection was first identified in 1998 by Henrietta Swan Leavitt, an American astronomer.
Spotting of young stars at the center of the Milky Way stands as the testimony of the constant supply of freshly formed stars during at least the past 100 million years.