Issue |
A&A
Volume 393, Number 3, October III 2002
|
|
---|---|---|
Page(s) | L85 - L88 | |
Section | Letters | |
DOI | https://doi.org/10.1051/0004-6361:20021251 | |
Published online | 01 October 2002 |
Letter to the Editor
Discovery of a very cool object with extraordinarily strong H
emission *
1
Laboratorio de Astrofísica Espacial y Física Fundamental, INTA, PO Box 50727, 28080 Madrid, Spain
2
Institute of Astronomy, University of Hawaii at Manoa. 2680 Woodlawn Drive, Honolulu, HI 96822, USA
3
Instituto de Astrofísica de Canarias, 38205 La Laguna, Tenerife, Spain
4
Consejo Superior de Investigaciones Científicas, CSIC, Spain
5
Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
Corresponding author: D. Barrado y Navascués, barrado@laeff.esa.es
Received:
22
July
2002
Accepted:
27
August
2002
We report on the finding of the strongest
Hα emission – pseudoequivalent width of 705 Å – known so
far in a young, late type dwarf. This object, named as S Ori 71, is a
substellar candidate member of the 1–8 Myr star cluster
σ Orionis. Due to its overluminous location in
color-magnitude diagrams, S Ori 71 might be younger than other
cluster members, or a binary of similar components. Its mass is in
the range 0.021–0.012 , depending on evolutionary models and
possible binarity. The broad Hα line of S Ori 71 appears
asymmetric, indicative of high velocity mass motions in the Hα
forming region. The origin of this emission is unclear at the present
time. We discuss three possible scenarios: accretion from a disk, mass
exchange between the components of a binary system, and emission from
a chromosphere.
Key words: open clusters and associations: individual: σ Orionis / stars: low-mass, brown dwarfs / stars: individual: S Ori 71 / stars: pre-main sequence
© ESO, 2002
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