CHARACTERIZATION OF MOLECULAR OUTFLOWS IN THE SUBSTELLAR DOMAIN
CHARACTERIZATION OF MOLECULAR OUTFLOWS IN THE SUBSTELLAR DOMAIN
复制标题
DOI：
10.1088/0004-637x/795/1/70
复制
发表时间：
2014-08
期刊：
影响因子：
--
通讯作者：
N. Phan-Bao;Chin-Fei Lee;P. Ho;C. Dang-Duc;Di Li
中科院分区：
文献类型：
--
作者：
N. Phan-Bao;Chin-Fei Lee;P. Ho;C. Dang-Duc;Di Li
我们在这里报告了我们对附近恒星形成区域年轻棕矮星和极低质量恒星分子流出的最新搜索。我们使用亚毫米波阵列和毫米波天文学研究组合阵列在 230 GHz 频率下观测了金牛座的三个源，以寻找 CO J = 2 → 1 外流。我们在 GM Tau 源头处初步检测到红移且延伸的气体瓣，GM Tau 是金牛座的一颗年轻褐矮星，估计质量为 73 MJ，正好低于氢燃烧极限。没有检测到褐矮星位置周围的蓝移发射。向东北方向拉长的红移气瓣表明可能存在来自源头的双极流出，位置角约为 36°。假设红移发射是 GM Tau 的流出发射，然后我们估计分子流出质量在 1.9 × 10−6 M☉ 到 2.9 × 10−5 M☉ 范围内，流出质量损失率从 2.7 × 10−9 M☉ yr−1 到 4.1 × 10−8 M☉ yr−1 范围内。这些值与我们在蛇夫座 ρ 中 60 MJ 的年轻褐矮星 ISO-Oph 102 和金牛座中 90 MJ 的极低质量恒星 MHO 5 中观察到的值相当。我们的研究结果表明，极低质量天体的流出过程是间歇性的，持续时间长达几千年，并且活跃事件的流出速率在极低质量天体形成过程的不同阶段没有显着变化。这可能为我们提供澄清褐矮星形成过程的重要意义。
We report here our latest search for molecular outflows from young brown dwarfs and very low-mass stars in nearby star-forming regions. We have observed three sources in Taurus with the Submillimeter Array and the Combined Array for Research in Millimeter-wave Astronomy at 230 GHz frequency to search for CO J = 2 → 1 outflows. We obtain a tentative detection of a redshifted and extended gas lobe at about 10 arcsec from the source GM Tau, a young brown dwarf in Taurus with an estimated mass of 73 MJ, which is right below the hydrogen-burning limit. No blueshifted emission around the brown dwarf position is detected. The redshifted gas lobe that is elongated in the northeast direction suggests a possible bipolar outflow from the source with a position angle of about 36°. Assuming that the redshifted emission is outflow emission from GM Tau, we then estimate a molecular outflow mass in the range from 1.9 × 10−6 M☉ to 2.9 × 10−5 M☉ and an outflow mass-loss rate from 2.7 × 10−9 M☉ yr−1 to 4.1 × 10−8 M☉ yr−1. These values are comparable to those we have observed in the young brown dwarf ISO-Oph 102 of 60 MJ in ρ Ophiuchi and the very low-mass star MHO 5 of 90 MJ in Taurus. Our results suggest that the outflow process in very low-mass objects is episodic with a duration of a few thousand years and the outflow rate of active episodes does not significantly change for different stages of the formation process of very low-mass objects. This may provide us with important implications that clarify the formation process of brown dwarfs.