(ORDO NEWS) — Using the Ground-based Wide Angle Cameras (GWAC) scientific instrument at Xinglong Observatory, China, an international team of astronomers detected a new superflare from an ultracold star known as SDSS J013333.08 + 003223.7. Called GWAC 181229A, this event is one of the most powerful ultracold star flares on record to date.
Ultracold dwarfs are stellar or substellar objects of spectral type M, characterized by effective temperatures of less than 2700 Kelvin and masses of less than 0.3 solar masses. In general, they exhibit weak chromospheric emission and low brightness in the X-ray range, but sometimes they burst into rather powerful flares. The study of these flares plays an important role in understanding the interaction between the magnetic field and the surface of ultracold stars, as well as stars in general.
In a new scientific paper, a team of researchers led by Li-Ping Xin of the National Astronomical Observatories of the Chinese Academy of Sciences reports the discovery of a powerful flare on the star SDSS J013333.08 + 003223.7, an ultracold dwarf of spectral type M9, located at a distance of about 471 light years from us. The GWAC 181229A flare turned out to be much more powerful than flares usually observed from the side of ultracold dwarfs. It was characterized by a change in magnitude of 9.5 units and a magnetic field strength of 3.6-4.7 kilogauss. The total duration of the outbreak was approximately 14,465 seconds, the authors point out.
In conclusion, Xin and his colleagues note the great importance of the GWAC instrument for detecting flares from ultracold stellar objects.
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