Pre-main sequence spectroscopic binaries suitable for VLTI observations ,
Pre-main sequence spectroscopic binaries suitable for VLTI observations ,
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适合 VLTI 观测的前主序谱双星，
DOI：
10.1051/0004-6361:20065686
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发表时间：
2007
影响因子：
6.5
通讯作者：
Stecklum
中科院分区：
文献类型：
--
作者：
Guenther;Esposito;Covino;Alcalá;Cusano;Stecklum
研究恒星形成的一个严重问题是，年轻恒星的质量几乎总是只根据演化轨迹来估计的。由于不同小组发表的轨道不同，通常只能对年轻恒星的质量给出一个粗略的估计。因此，测试和校准轨道是至关重要的。到目前为止，只能对轨道进行少量测试。然而，现在有了VLTI，通过精确地确定许多年轻双星的质量，可以在轨道上设置限制。为了有效地利用VLTI，第一步是找到合适的目标，这是本工作的目的。考虑到附近恒星形成区域的距离，合适的VLTI目标是轨道周期至少在50天到几年之间的双星。虽然已经进行了许多探测光谱双星的调查，但迄今为止发现的大多数双星的周期都太短了。方法对变色龙星、南冕星、狼座星、scoc -半人马座星和蛇夫座星形成区进行观测，寻找周期大于50天的适合VLTI观测的光谱双星。结果经过8年的研究，我们发现了8颗轨道周期超过50天的双星。在新发现的长周期双星中，CS Cha是为数不多的具有环双星盘的经典金牛座T星之一。该调查仅限于质量高于0.1至0.2的天体，持续时间为1至8年。结论轨道周期≤3000天的双星出现频率为20±5%。长周期和短周期主序前双星的光谱频率与太阳附近的恒星大致相同。现在已知总共有14个年轻的双星适合用VLTI进行质量测定。
ContextA severe problem for research in star-formation is that the masses of young stars are almost always estimated from evolutionary tracks alone. Since the tracks published by different groups differ, it is often only possible to give a rough estimate of the masses of young stars. It is thus crucial to test and calibrate the tracks. Up to now, only a few tests of the tracks could be carried out. However, it is now possible with the VLTI to set constrains on the tracks by determining the masses of many young binary stars precisely.AimsIn order to use the VLTI efficiently, a first step is to find suitable targets, which is the purpose of this work. Given the distance of nearby star-forming regions, suitable VLTI targets are binaries with orbital periods between at least 50 days and a few years. Although a number of surveys for detecting spectroscopic binaries have been carried out, most of the binaries found so far have periods that are too short.MethodsWe thus surveyed the Chamaeleon, Corona Australis, Lupus, Sco-Cen, andρOphiuci star-forming regions in order to search for spectroscopic binaries with periods longer than 50 days, which are suitable for the VLTI observations.ResultsAs a result of the 8 year campaign, we discovered 8 binaries with orbital periods longer than 50 days. Amongst the newly discovered long-period binaries is CS Cha, which is one of the few classical T Tauri stars with a circumbinary disk. The survey is limited to objects with masses higher than 0.1 to 0.2 for periods between 1 and 8 years.ConclusionsWe find that the frequency of binaries with orbital periods≤3000 days is of 20±5%. The frequency of long and short period pre-main sequence spectroscopic binaries is about the same as for stars in the solar neighbourhood. In total 14 young binaries are now known that are suitable for mass determination with the VLTI.
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到狼星恒星形成区的距离
DOI：
10.1086/116454
发表时间：
1993
期刊：
The Astronomical Journal
影响因子：
--
作者：
J. Hughes;P. Hartigan;L. Clampitt
通讯作者：
L. Clampitt
太阳附近T后金牛座恒星的新协会
DOI：
10.1086/301539
发表时间：
2000
期刊：
The Astronomical Journal
影响因子：
--
作者：
C. Torres;L. da Silva;G. Quast;R. de la Reza;E. Jilinski
通讯作者：
E. Jilinski
年轻的活跃双星 EK Draconis
影响因子：
6.5
作者：
B. Konig;E. Guenther;J. Woitas;A. Hatzes
通讯作者：
A. Hatzes
其他环球航空会员？
影响因子：
6.5
作者：
I. Song;M. Bessell;B. Zuckerman
通讯作者：
B. Zuckerman
DOI：
10.1086/341171
发表时间：
2002
期刊：
The Astronomical Journal
影响因子：
--
作者：
D. Paulson;S. Saar;W. Cochran;A. Hatzes
通讯作者：
A. Hatzes