Exploring the planetary-mass population in the Upper Scorpius association
Exploring the planetary-mass population in the Upper Scorpius association
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DOI：
10.1093/mnras/stab401
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发表时间：
2021-02
影响因子：
4.8
通讯作者：
N. Lodieu;N. Hambly;N. J. G. C. Iac;Tenerife;Spain.;Ull;Roe;Edinburgh;Scotland
中科院分区：
文献类型：
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作者：
N. Lodieu;N. Hambly;N. J. G. C. Iac;Tenerife;Spain.;Ull;Roe;Edinburgh;Scotland
我们的目标是确定非常低质量的孤立行星质量的成员候选人在最近的OB协会太阳，上天蝎座（USCO）（145 pc; 5-10百万年），约束的形式和形状的光度函数和质谱在这个制度。我们进行了深多波段（Y = 21.2，J = 20.5，Z = 22.0等）光度测量6 deg 2的中心区域的USCO。我们延长目前的序列的天体测量和光谱成员约两个大小的Y和一个大小的J，达到潜在的T型自由浮动的成员在与预测的质量低于5木星质量，以及到行星质量制度。我们在该地区提取了57个候选者的样本，并展示了红外光谱，确认其中两个是年轻的L型成员，具有10万年历史的褐矮星的特征光谱特征。在57个候选者中，我们突出了10个新的候选者，比以前光谱确认的最酷的成员要暗。我们没有看到该星协的质量谱有任何明显的下降迹象，这表明星星过程可以形成质量低至4-5木星质量的亚恒星天体。
We aim at identifying very low-mass isolated planetary-mass member candidates in the nearest OB association to the Sun, Upper Scorpius (USco) (145 pc; 5–10 Myr), to constrain the form and shape of the luminosity function and mass spectrum in this regime. We conducted a deep multiband (Y = 21.2, J = 20.5, Z = 22.0 mag) photometric survey of 6 deg2 in the central region of USco. We extend the current sequence of astrometric and spectroscopic members by about two magnitudes in Y and one magnitude in J, reaching potentially T-type free-floating members in the association with predicted masses below 5 Jupiter masses, well into the planetary-mass regime. We extracted a sample of 57 candidates in this area and present infrared spectroscopy confirming two of them as young L-type members with characteristic spectral features of 10-Myr-old brown dwarfs. Among the 57 candidates, we highlight 10 new candidates fainter than the coolest members previously confirmed spectroscopically. We do not see any obvious sign of decrease in the mass spectrum of the association, suggesting that star processes can form substellar objects with masses down to 4–5 Jupiter masses.