Mayrit 1701117 (M1701117) is a proto-brown dwarf launching a large (0.8 light-years, 0.26 parsec) Herbig-Haro object, called HH 1165. Previously only small micro-jets (<=0.03 parsec) were known from young proto-brown dwarfs.

Mayrit 1701117 was discovered in 2008 in the Mayrit catalogue by J. A. Caballero. The Mayrit catalogue is a list of stars and high-mass brown dwarfs in the Sigma Orionis cluster. The catalogue uses DENIS and 2MASS data. Later, the source was detected in H-alpha with the ESO Schmidt telescope at La Silla and catalogued as ESO-HA 1736. The central object has a mass of around and will most likely evolve into a brown dwarf. The central object is surrounded by a H-alpha halo with a clumpy distribution, which could be due to wind-envelope interactions. The southeastern tail of the H-alpha emission is likely reflecting the light from the nearby star HR 1950. The mass of the central source was later estimated to be around and the system is 30,000-40,000 years old.

The disk and outflow

Observations at the Calar Alto 3.5-m telescope were used to measure an accretion rate of /year and an outflow rate of /year, similar to class I protostars. The researchers also obtained observations with the James Clerk Maxwell Telescope and find that the total envelope+disk mass is around 36 . VLT/UVES observations do show signs of strong accretion and outflow and the estimated outflow rate is higher than the previous estimate at /year. Observations with ALMA detected a pseudo-disk. According to core-collapse models, infalling material will form a flattened disk-like structure, which is called pseudo-disk. This pseudo-disk is rotating and surrounds the Keplerian disk. The pseudo-disk in Mayrit 1701117 has a size of and a mass of around . Emission by H₂CO likely traces the Keplerian disk and N₂D⁺ traces a clump close to this disk. Using ALMA the researchers determined the total mass of the circumstellar material as .

In 2017 a large Herbig-Haro object was discovered with SOAR narrow-band imaging. The Herbig-Haro object was named HH 1165 and the jet shows a bent C-shape, multiple knots and fragmented bow shocks at the end of the jets. The jet is mostly detected in sulfur [S II] emission, showing 8 knots in the northwestern direction. A fainter counter-jet in the southeastern direction shows only two knots. The multiple knots can be seen as individual ejection events. The H-alpha image shows a bright scattered emission next to the jet, likely tracing the outflow cavity. The northwest part resembles a classical jet running into a neutral medium, but the southern part resembles an externally irradiated jet.

References

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External links

* , press release by NOAO
* , press release by MPE

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