Scientists discover Saturn-sized star, smallest ever measured
The newly-measured star, called EBLM J0555-57Ab, was identified as it passed in front of its much larger companion, a method which is usually used to detect planets.world Updated: Jul 12, 2017 16:40 IST
A team of astronomers based in universities in the United Kingdom have discovered a star about the size of Saturn – the smallest ever measured – located about 600 light years away.
The gravitational pull at the star’s stellar surface is about 300 times stronger than what humans feel on Earth, a release by the University of Cambridge said on Wednesday. Astronomers from the universities of Keele, Warwick, Leicester and St Andrews were part of the team.
“The star is likely as small as stars can possibly become, as it has just enough mass to enable the fusion of hydrogen nuclei into helium. If it were any smaller, the pressure at the centre of the star would no longer be sufficient to enable this process to take place,” the release said.
“Hydrogen fusion is also what powers the Sun, and scientists are attempting to replicate it as a powerful energy source here on Earth.”
The newly-discovered star, called EBLM J0555-57Ab, was identified as it passed in front of its much larger companion, a method which is usually used to detect planets. Details are to be published in the journal Astronomy & Astrophysics.
“Our discovery reveals how small stars can be,” said Alexander von Boetticher, the Cambridge-based lead author of the study. “Had this star formed with only a slightly lower mass, the fusion reaction of hydrogen in its core could not be sustained, and the star would instead have transformed into a brown dwarf.”
The star was detected when it passed in front of, or transited, its larger parent star, forming what is called an eclipsing stellar binary system. The parent star became dimmer in a periodic fashion, the signature of an orbiting object.
“This star is smaller, and likely colder than many of the gas giant exoplanets that have so far been identified,” said von Boetticher. “While a fascinating feature of stellar physics, it is often harder to measure the size of such dim low-mass stars than for many of the larger planets.”