The smallest star ever discovered. This has been the finding of a team of astronomers from the University of Cambridge (United Kingdom) has discovered the smallest star measured so far. Located about 600 light years distant from Earth, EBLM J0555-57Ab is part of a binary system and its tiny size suggests that it is the smallest thing a star can be.
Thus, with a size slightly larger than Saturn, the star was identified by passing in front of the other star of the binary system, which is much larger, with the same system that experts use to detect planets.
“ Our discovery reveals how small stars can be ,” explains Alexander Boetticher, co-author of the work published in the journal Astronomy & Astrophysics.
“If this star was formed with a slightly lower mass, the hydrogen fusion reaction in its core could not be sustained, and the star would have transformed into a brown dwarf ,” he clarifies.
However, with miniature proportions, EBLM J0555-57Ab maintains sufficient mass to allow hydrogen fusion to helium at its core . But of course, it is extremely faint, some 2,000 to 3,000 times dimmer than our own Sun.
Combined with its proximity to its much brighter and larger parent star – finding the star was a challenge. “It’s like trying to look at a candle next to a lighthouse,” says Amaury Triaud, a co-author of the study.
Analysis by researchers involved in the Wide Angle Search for Planets (WASP) experiment showed that the tiny star has a mass comparable to the estimated mass of the already known TRAPPIST-1 discovered earlier in the year, but with a radius of around 30%. smaller and a gravitational pull on its surface about 300 times stronger than on Earth.
Stars like this, small, dark and cooler than many of the gaseous exoplanets discovered in recent times, are considered optimal candidates to give light to worlds that can host life , as this quality of the stars could increase the probability of finding planets that retain liquid water on their surface.
Although these tiny stars with less than 20% of the mass of the Sun are not really the most common in the Universe, there is still much that we do not know about them, in large part because of how difficult it is to find them.
Breaking records
When we refer to small stars, we are talking about celestial objects with small but sufficient dimensions to give the right pressure and temperature conditions for the nuclear fusion of hydrogen into helium.
The star that until now held the record for one of the smallest stars in the known universe, 2MASS J05233822-1403022 , has a mass equal to 0.08 times that of our Sun. Now, the tiny EBLM J0555-57Ab, is in the top of this ranking and it will be difficult for them to surpass it.
Referencia: The EBLM project. III. A Saturn-size low-mass star at the hydrogen-burning limit. A. von Boetticher, A. H. M. J. Triaud, D. Queloz, S. Gill, M. Lendl, L. Delrez, D. R. Anderson, A. C. Cameron, F. Faedi, M. Gillon, Y. Gomez Maqueo Chew, L. Hebb, C. Hellier, E. Jehin, P. F. L. Maxted, D. V. Martin, F. Pepe, D. Pollacco, et al. Astronomy & Astrophysics.doi.org/10.1051/0004-6361/201731107
