The first spectroscopically identified L dwarf in Praesepe

作者：Boudreault S^*; Lodieu N

来源：Monthly Notices of the Royal Astronomical Society, 2013, 434(1): 142-147.

DOI：10.1093/mnras/stt1009

• techniques: spectroscopic
• brown dwarfs
• stars: fundamental parameters
• stars: low-mass
• open clusters and associations: individual: Praesepe

We have obtained a low-resolution optical spectrum for one of the faintest cluster member candidates in Praesepe with the Optical System for Imaging and low Resolution Integrated Spectroscopy mounted on the 10.4 m Gran Telescopio de Canarias. We confirm spectroscopically the first L dwarf member in Praesepe, UGCS J084510.66+214817.1. We derived an optical spectral type of L0.3 +/- 0.4 and estimated its effective temperature to T-eff = 2279 +/- 371 K and a mass of 71.1 +/- 23.0 M-Jup, according to state-of-the-art models, placing it at the hydrogen-burning boundary. We measured the equivalent width of the gravity-sensitive sodium doublet at 8182/8194 A, which adds credit to the membership of this new L dwarf to Praesepe. We also derived a probability of similar to 20.5 per cent that our candidate would be a field L0 dwarf. We conclude that this object is likely to be a true member of Praesepe, with evidence of being a binary system.

• 出版日期2013-9