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arXiv · 1412.2736

Low-resolution optical spectra of ultracool dwarfs with OSIRIS/GTC

Yanina Metodieva·Antoaneta Antonova·Valeri Golev·Dinko Dimitrov·David García-Álvarez·John Gerard Doyle
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Abstract

We present the results of low-resolution optical spectroscopy with OSIRIS/GTC (Optical System for Imaging and Low Resolution Integrated Spectroscopy / Gran Telescopio Canarias) for a sample of ultracool dwarfs. For a subsample of seven objects, based on 2MASS NIR photometric colours, a 'photometric' spectral type is determined and compared to the results of the optical spectroscopy. For the stars, showing H$α$ line in emission, equivalent widths were measured, and the ratio of H$α$ to bolometric luminosity were calculated. We find that two dwarfs show the presence of magnetic activity over long periods, LP 326-21 -- quasi-constant-like, and 2MASS J17071830+6439331 -- variable.

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Yanina Metodieva, Antoaneta Antonova, Valeri Golev, Dinko Dimitrov, David García-Álvarez, John Gerard Doyle. 2014-12-08. Low-resolution optical spectra of ultracool dwarfs with OSIRIS/GTC. https://doi.org/10.1093/mnras%2Fstu2370

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