Optical spectroscopy of isolated planetary mass objects in the σ Orionis cluster

Barrado y Navascués, D. and Zapatero Osorio, M. R. and Béjar, V. J. S. and Rebolo, R. and Martín, E. L. and Mundt, R. and Bailer-Jones, C. A. L. (2001) Optical spectroscopy of isolated planetary mass objects in the σ Orionis cluster. Astronomy & Astrophysics, 377 (2). L9-L13. ISSN 0004-6361. https://resolver.caltech.edu/CaltechAUTHORS:20180307-084140419

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Abstract

We have obtained low resolution optical spectra of 15 isolated planetary mass objects (IPMOs) in the σ Orionis cluster, and derived spectral types by comparison with nearby M and L dwarfs. The spectral types are in the range late M -mid L, in agreement with our expectations based on colors and magnitudes for bona fide members. Therefore, most of these objects have masses below the deuterium burning limit. About 2/3 show Hα in emission at our spectral resolution. From our spectroscopic and photometric data, we infer that three IPMOs in this sample may be binaries with components of similar masses. These results confirm that the substellar mass function of the σ Orionis cluster, in the form dN/dM, keeps rising in the planetary domain.

Item Type:

Article

Related URLs:

URL	URL Type	Description
https://doi.org/10.1051/0004-6361:20011152	DOI	Article
https://www.aanda.org/articles/aa/abs/2001/38/aade291/aade291.html	Publisher	Article
https://arxiv.org/abs/astro-ph/0108249	arXiv	Discussion Paper

Alternate Title:

Optical spectroscopy of isolated planetary mass objects in the sigma Orionis cluster

Additional Information:

© 2001 ESO. Received: 29 May 2001. Accepted: 15 August 2001. We thanks the ESO staff at Paranal Observatory. The referee, G. Chabrier, has helped to improve the original version with his comments and suggestions. Partial financial support was provided by the Spanish DGES project PB98-0531-C02-02 and CICYT grant ESP98-1339-CO2.

Funders:

Funding Agency	Grant Number
Direcção-Geral do Ensino Superior (DGES)	PB98-0531-C02-02
Comisión Interministerial de Ciencia y Tecnología (CICYT)	ESP98-1339-CO2

Subject Keywords:

stars: planetary systems: formation - open clusters and associations: individual: σ Orionis - stars: low mass, brown dwarfs

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Record Number:

CaltechAUTHORS:20180307-084140419

Persistent URL:

https://resolver.caltech.edu/CaltechAUTHORS:20180307-084140419

Official Citation:

Optical spectroscopy of isolated planetary mass objects in the Formula Orionis cluster D. Barrado y Navascués, M. R. Zapatero Osorio, V. J. S. Béjar, R. Rebolo, E. L. Martín, R. Mundt and C. A. L. Bailer-Jones A&A, 377 2 (2001) L9-L13 DOI: https://doi.org/10.1051/0004-6361:20011152

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ID Code:

85167

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CaltechAUTHORS

Deposited By:

Ruth Sustaita

Deposited On:

07 Mar 2018 17:14

Last Modified:

03 Oct 2019 19:27

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