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A Methane Isolated Planetary Mass Object in Orion

M. R. Zapatero Osorio·V. J. S. Bejar·E. L. Martin·R. Rebolo·D. Barrado y Navascues·R. Mundt·J. Eisloeffel·J. A. Caballero
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Abstract

We report on the discovery of a free-floating methane dwarf toward the direction of the young star cluster sigma Orionis. Based on the object's far-red optical and near-infrared photometry and spectroscopy, we conclude that it is a possible member of this association. We have named it as S Ori J053810.1-023626 (S Ori 70 is the abridged name). If it is a true member of sigma Orionis, the comparison of the photometric and spectroscopic properties of S Ori 70 with state-of-the-art evolutionary models yields a mass of 3 (+5/-1) Jupiter mass for ages between 1 Myr and 8 Myr. The presence of such a low-mass object in our small search area (55.4 sq. arcmin) would indicate a rising substellar initial mass function in the sigma Orionis cluster even for planetary masses.

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M. R. Zapatero Osorio, V. J. S. Bejar, E. L. Martin, R. Rebolo, D. Barrado y Navascues, R. Mundt, J. Eisloeffel, J. A. Caballero. 2002-06-20. A Methane Isolated Planetary Mass Object in Orion. https://doi.org/10.1086/342474

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