{"title":"从恒星质量到行星质量对金牛座新成员的调查。","authors":"T L Esplin, K L Luhman","doi":"10.3847/1538-3881/ab2594","DOIUrl":null,"url":null,"abstract":"<p><p>We present a large sample of new members of the Taurus star-forming region that extend from stellar to planetary masses. To identify candidate members at substellar masses, we have used color-magnitude diagrams and proper motions measured with several wide-field optical and infrared (IR) surveys. At stellar masses, we have considered the candidate members that were found in a recent analysis of high-precision astrometry from the <i>Gaia</i> mission. Using new and archival spectra, we have measured spectral types and assessed membership for these 161 candidates, 79 of which are classified as new members. Our updated census of Taurus now contains 519 known members. According to <i>Gaia</i> data, this census should be nearly complete for spectral types earlier than M6-M7 at <i>A</i> <sub><i>J</i></sub> < 1. For a large field encompassing ~ 72% of the known members, the census should be complete for <i>K</i> < 15.7 at <i>A</i> <sub><i>J</i></sub> < 1.5, which corresponds to ~ 5-13 <i>M</i> <sub>Jup</sub> for ages of 1-10 Myr based on theoretical evolutionary models. Our survey has doubled the number of known members at ≥M9 and has uncovered the faintest known member in <i>M</i> <sub><i>K</i></sub> , which should have a mass of ~3-10 ~ <i>M</i> <sub>Jup</sub> for ages of 1-10 Myr. We have used mid-IR photometry from the <i>Spitzer Space Telescope</i> and the <i>Wide-field Infrared Survey Explorer</i> to determine whether the new members exhibit excess emission that would indicate the presence of circumstellar disks. 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At stellar masses, we have considered the candidate members that were found in a recent analysis of high-precision astrometry from the <i>Gaia</i> mission. Using new and archival spectra, we have measured spectral types and assessed membership for these 161 candidates, 79 of which are classified as new members. Our updated census of Taurus now contains 519 known members. According to <i>Gaia</i> data, this census should be nearly complete for spectral types earlier than M6-M7 at <i>A</i> <sub><i>J</i></sub> < 1. For a large field encompassing ~ 72% of the known members, the census should be complete for <i>K</i> < 15.7 at <i>A</i> <sub><i>J</i></sub> < 1.5, which corresponds to ~ 5-13 <i>M</i> <sub>Jup</sub> for ages of 1-10 Myr based on theoretical evolutionary models. Our survey has doubled the number of known members at ≥M9 and has uncovered the faintest known member in <i>M</i> <sub><i>K</i></sub> , which should have a mass of ~3-10 ~ <i>M</i> <sub>Jup</sub> for ages of 1-10 Myr. 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引用次数: 39
摘要
我们展示了一个从恒星质量延伸到行星质量的金牛座恒星形成区新成员的大样本。为了识别亚恒星质量的候选成员,我们使用了彩色星等图和通过几次宽场光学和红外(IR)测量的正确运动。在恒星质量方面,我们考虑了最近对盖亚任务高精度天体测量的分析中发现的候选成员。使用新的和存档的光谱,我们测量了这161个候选者的光谱类型并评估了其成员资格,其中79个被归类为新成员。我们最新的金牛座普查现在包含519名已知成员。根据Gaia的数据,对于早于M6-M7的光谱类型,在AJ<1时,这次普查应该几乎完成。对于一个包含约72%已知成员的大领域,根据理论进化模型,在AJ<1.5时,K<15.7的普查应该是完整的,这对应于1-10 Myr年龄的约5-13 M Jup。我们的调查将M9级以上的已知成员数量增加了一倍,并发现了MK中最微弱的已知成员,其质量应为~3-10~M Jup,年龄为1-10 Myr。我们使用了斯皮策太空望远镜和宽视场红外探测探测器的中红外光度法来确定新成员是否表现出过量发射,这表明存在星周盘。Taurus的更新磁盘分数在≤M3.5时约为0.7,在>M3.5时为0.4。
A SURVEY FOR NEW MEMBERS OF TAURUS FROM STELLAR TO PLANETARY MASSES.
We present a large sample of new members of the Taurus star-forming region that extend from stellar to planetary masses. To identify candidate members at substellar masses, we have used color-magnitude diagrams and proper motions measured with several wide-field optical and infrared (IR) surveys. At stellar masses, we have considered the candidate members that were found in a recent analysis of high-precision astrometry from the Gaia mission. Using new and archival spectra, we have measured spectral types and assessed membership for these 161 candidates, 79 of which are classified as new members. Our updated census of Taurus now contains 519 known members. According to Gaia data, this census should be nearly complete for spectral types earlier than M6-M7 at AJ < 1. For a large field encompassing ~ 72% of the known members, the census should be complete for K < 15.7 at AJ < 1.5, which corresponds to ~ 5-13 MJup for ages of 1-10 Myr based on theoretical evolutionary models. Our survey has doubled the number of known members at ≥M9 and has uncovered the faintest known member in MK , which should have a mass of ~3-10 ~ MJup for ages of 1-10 Myr. We have used mid-IR photometry from the Spitzer Space Telescope and the Wide-field Infrared Survey Explorer to determine whether the new members exhibit excess emission that would indicate the presence of circumstellar disks. The updated disk fraction for Taurus is ~0.7 at ≤M3.5 and ~0.4 at >M3.5.
期刊介绍:
The Astronomical Journal publishes original astronomical research, with an emphasis on significant scientific results derived from observations. Publications in AJ include descriptions of data capture, surveys, analysis techniques, astronomical interpretation, instrumentation, and software and computing.