Smallest-ever star discovered by astronomers
The smallest but equal star was discovered by a team of astronomers led by the University of Cambridge. With a size of only more ribbons than Saturn, the force of gravity on its stellar surface is approximately 300 times stronger than the experience of humans on Earth.
The star is probably as small as stars can become as it has enough mass to allow hydrogen to melt in helium nuclei.
If it was smaller, the pressure in the center of the star would not be enough for this process to occur. Hydrogen fusion is also forcing the sun, and scientists try to reproduce it as a powerful source of energy on Earth.
These stars are very small and tender also the best possible candidates for detecting Earth-sized planets that may have liquid water on their surface, such as TRAPENSE-1, an ultra-cool dwarf surrounded by seven earth-tempered worlds.
The newly measured star, called EBLM J0555-57Ab, is about six hundred light-years away.
It is part of a binary system and has been identified as being overtaken by its much higher companion, a method generally used to detect planets, not stars. The details will be published in the journal Astronomy & Astrophysics.
“Our discovery reveals how small stars can be,” said Alexander Boetticher, lead author of the study and a master’s student at Cambridge’s Cavendish Laboratory and Institute of Astronomy.
“If this star only formed a slightly lower mass, the hydrogen fusion reactions at its core could not be sustained, and the star was transformed into brown dwarf.”
EBLM J0555-57Ab was identified by WASP, a research experiment carried out by the planet Universities of Keele, Warwick, Leicester and St. Andrews. EBLM J0555-57Ab was detected as it passed in front of or in transit, its parent’s largest star, forming what is called an eclipsed stellar binary system.
The mother became the most moderate star periodically, the signature of an object in orbit. With this special configuration, researchers can accurately measure the mass and size of all traveling companions in orbit, in this case, a small star. The mass of EBLM J0555-57Ab was done using the Doppler method, reeling, using data from the CORALIE spectrograph.
“This star is smaller and probably fresher than many of the giant gas exoplanets that have been identified so far,” said von Boetticher. “While it is fascinating for stellar physics, it is often difficult to measure the size of low-mass low stars over many large planets.
Fortunately, we can find these little stars with planets from the research team, when orbiting a larger mother star in a binary system. This may sound incredible, but finding a star can sometimes be harder than finding a planet. ”
This newly measured star has a mass comparable to the current estimate of TRAPENSE-1, but has a radius that is approximately 30% smaller. “The smaller stars provide the optimum conditions for the discovery of terrestrial planets and the remote exploration of their atmospheres,” said co-author Amaury Triaud, a researcher at the Cambridge Institute of Astronomy.
“However, before we can study the planets, it is absolutely necessary to understand their star is fundamental.”