Discovery of a very cool object with extraordinarily strong Hα emission

被引：36

作者：

Navascués, DBY

Osorio, MRZ

Martín, EL

Béjar, VJS

Rebolo, R

Mundt, R

机构：

[1] INTA, Lab Astrofis Espacial & Fis Fundamental, Madrid 28080, Spain

[2] Univ Hawaii Manoa, Inst Astron, Honolulu, HI 96822 USA

[3] Inst Astrofis Canarias, Tenerife 38205, Spain

[4] CSIC, Madrid, Spain

[5] Max Planck Inst Astron, D-69117 Heidelberg, Germany

来源：

ASTRONOMY & ASTROPHYSICS | 2002年 / 393卷 / 03期

关键词：

open clusters and associations : individual : sigma Orionis; stars; low-mass; brown dwarfs; stars : individual : S Ori 71; stars : pre-main sequence;

D O I：

10.1051/0004-6361:20021251

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We report on the finding of the strongest Halpha emission - pseudoequivalent width of 705 Angstrom - 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 sigma 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 M-., depending on evolutionary models and possible binarity. The broad H line of S Ori 71 appears asymmetric, indicative of high velocity mass motions in the Halpha 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.

引用

页码：L85 / L88

页数：4

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