Astronomers recorded Eclipse of a rare brown dwarf

Astronomers have registered a rare Eclipse is a brown dwarf in the Pleiades, which may indicate the presence of subsistence object companion. If the assumption is confirmed, then Roque 12 will be one of the few known binary systems where both components are brown dwarfs. Preprint available on the website arXiv.org.

Diffuse Pleiades cluster in the constellation Taurus is one of the nearest to Earth of star clusters, which are clearly visible even to the naked eye, but modern telescopes are distinguished in this more than 800 luminaries. In addition, due to the relative youth and the brightness of the clusters, and small distance to it (it is about 400 light years), astronomers were able to detect it tens of brown dwarfs — objects intermediate between giant planets and stars. Their mass greater than the mass of Jupiter at least 13 times, but not enough to sustain thermonuclear “burning” hydrogen.

One of the brown dwarfs was Roque 12, which was discovered by Leif Festina (Leif Festin) in 1998. Subsidy object belongs to the spectral class M7,5 and has a mass of 63 times larger than the mass of Jupiter. In the past researchers did not find his gravitational related partners, but it now appears that Roque 12 may be part of a binary system.

Alex Scholz (Aleks Scholz) from St. Andrews University, along with colleagues analyzed archival observations performed in 2002, using the telescopes of the Observatory Kalar Alto. It was found that the instruments registered the Eclipse Roque 12, which lasted 1.3 hours. During the event, the apparent magnitude of a celestial body is increased by 0.6 (the higher the magnitude, the dimmer the object) — it means that the past in front of the brown dwarf object was closed almost half of the heavenly bodies. In this case, scientists have not detected a measurable change color Roque 12.

The authors believe that the observed Eclipse can best be explained by the presence of a companion which revolves around Roque 12 in an elongated orbit. According to their calculations, its mass is 10 to 42 Jupiter masses — that is, it is either a planet-giant, or, more likely, a brown dwarf. The analysis of observations conducted with a telescope “Kepler” in 2015, for 70 days, did not reveal a repeated Eclipse. This may be due to either a large orbital period of the companion, or the fact that astronomers actually recorded not a brown dwarf, a cloud of gas and dust prior to subsidy (however, the researchers did not find the characteristic features).

If scientists will be able to confirm the existence of a companion then Roque 12 will be one of the few known double brown dwarfs. In the past a similar system failed to detect the American scholar, however, the distance between components is 341 astronomical unit.

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