On an unusual active dwarf star, new flares

A team of astronomers led by Karolina Baskowska (Karolina BÄ…kowska) from the Astronomical Center. Nicholas Copernicus, based in Warsaw, Poland, opened several new outbreaks on an unusual, dwarfish new, known as MN Dragon.

The Dragon Star MN is an active dwarf of the new SU Ursae Majoris type, SU UMa. This poorly studied star differs in that it demonstrates quasi-periodic oscillations, called “superhumps” (superhumps).

The superhump are observed on the light curves in the optical range of systems of the SU UMa type during superflashes. Often you can observe positive superhumbs – oscillations with periods of several percent longer, compared with the orbital periods of the system. However, in the case of the MN Dragon system negative super-humps were observed, that is, oscillations with periods of several percent shorter, compared with the orbital periods of the system.

Stars like SU UMa, similar to the MN Dragon system, are characterized by short orbital periods (shorter than 2.5 hours) and so-called superflashes, which occur relatively rarely, but their brightness is one magnitude larger than the brightness of conventional flares. Outbreaks on MN Dragon were first seen in 2002-2003. These observations found that the super cycle of flares on a star is about 60 days – which is one of the shortest supercycles for stars of the SU UMa type. In her work, Bakovska and her colleagues present the results of an extensive observational campaign aimed at studying the properties of this unusual dwarfish new one.

New observations have shown that the new cycle of this new one is about 74 + -0.5 days and increases at a rate of 3.3 * 10 ^ (-3) during the last 12 years.

The increase in the duration of the super-cycle observed for this star can be of great importance for understanding the evolution of dwarfish new ones, the authors of the study note.

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