Washington, District of Columbia 2021-08-05 09:45:16 –
August 5, 2021
Astronomers have long suspected that superflares, extreme radiation bursts from stars, can cause permanent damage to the atmosphere and thus habitability. Exoplanet..New research Release The Royal Astronomical Society’s monthly report, August 5, reports that they pose only limited danger to the planetary system.
“We know these are big flares that are much larger than we see in our own sun,” the co-author said. James Davenport, Associate Professor of Astronomy at the University of Washington. “Now we can see that superflares are occurring at high latitudes near the” poles “of the stars. This means that the burst of radiation is not directed to the orbiting exoplanet’s path. “
Flare is a magnetic explosion on the surface of a star that emits powerful electromagnetic radiation into space. Large flares, such as superflares, emit a cascade of energy particles that can collide with extrasolar planets orbiting flare stars, changing or evaporating the planet’s atmosphere in the process.
Using optical observations from the Transiting Exoplanet Exploration Satellite (TESS), a team led by astronomers at the Potsdam Institute for Astronomers studied a large superflare of red dwarfs. My sun.
Many exoplanets have been discovered around these types of stars. The long-standing question in the study of exoplanets was whether these exoplanets were habitable, as red dwarfs are more active than our Sun and flare much more frequently and violently.
The team has developed a way to determine the location of flared stars on the surface. The team achieved this by analyzing the so-called “white light flare” of fast-rotating red dwarfs. These types of flares last long enough that their brightness changes as they rotate and appear or disappear on the surface of the star, as observed by TESS.
“Because we can’t see the surface of these stars, determining latitudes such as hot flares and cool spots has traditionally been between difficult and impossible!” Data-intensive research in astrophysics and cosmology Said Davenport, who is also the deputy director of DiRAC — Institute at the University of Washington. “This work combines clever data modeling with unique and accurate data from missions like TESS, and finds something worth noting.”
The team discovered a rotating flare by processing the light curve of over 3,000 red dwarfs with TESS. Among these stars, they found four with flares large enough for the new method. The team estimated the latitude of the flare region using the exact shape of each star’s light curve and found that all four flares occurred above a latitude of about 55 degrees. This is much closer than the flares and spots on the surface of the sun. , Usually occurs at latitudes less than 30 degrees. The team also showed that their detection method was not biased towards the latitude of a particular star.
These findings are important even if there are only four flares. If the flares are evenly distributed over the surface of the star, the chances of finding four flares in a row at such high latitudes are about one-thousandth.
This affects the models of the star’s magnetic fields and the habitability of the exoplanets that orbit them.
Lead author Ekaterina Irin, a Leibniz PhD student, said: “Therefore, like our own planets in our solar system, extrasolar planets that orbit the same plane as the equator of a star are directed upwards or downwards from the extrasolar planets, so most of them are from such superflares. It can protect. This improves the habitability prospects of exoplanets around small host stars, which are far more endangered by flare-related high-energy radiation and particles compared to planets in the solar system. There is a possibility. “
The detection of these flares is further evidence that a strong and dynamic concentration of stellar magnetic fields, which can appear as dark spots or flares, is formed near the rotating poles of fast-rotating stars. The existence of such “poles” has long been suspected by indirect reconstruction techniques such as Doppler imaging of stellar surfaces, but has not been directly detected so far.
“Nature teaches us what is important about how these small, typically young stars generate a much stronger magnetic field than our Sun,” says Davenport. I did. “It has a big impact on how we think about the planets that orbit them.”
The co-authors are Katja Poppenhaeger, Sarah Schmidt, Silva Järvinen, Julián Alvarado-Gómez and Ilya Ilyin of the Potsdam Institute for Astrophysics in Leibniz. Elizabeth Newton of Dartmouth College. Sebastian Pineda at the University of Colorado at Boulder. Mahmoudreza Oshagh of the Institute of Astrophysics of the Canary Islands and the University of La Laguna, Spain. Ilin and Poppenhaeger have also been appointed to the University of Potsdam. This study was funded by NASA, the German National Scholarship Fund, the Leibniz Association, and UW.
Contact Davenport for more information. email@example.com..
Adapted from Press release According to the Potsdam Institute for Astrophysics.
Superflares may be less harmful to exoplanets than previously thought, study shows Source link Superflares may be less harmful to exoplanets than previously thought, study shows