A Gap in the Lower Main Sequence Revealed by Gaia Data Release 2
A Gap in the Lower Main Sequence Revealed by Gaia Data Release 2
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DOI：
10.3847/2041-8213/aacdf6
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发表时间：
2018-07-01
影响因子：
7.9
通讯作者：
Hambly, Nigel C.
中科院分区：
文献类型：
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作者：
Jao, Wei-Chun;Henry, Todd J.;Hambly, Nigel C.
我们根据盖亚数据版本 2 (DR2) 中提供的测量结果，在赫罗图 (HRD) 的主序列中发现了 M-G 附近大约为 10 的间隙。使用 HRD 的观测形式，其中 MG 代表光度，G(BP) - G(RP) 代表温度，间隙呈现出对角线特征，在较红的颜色处向较低的光度倾斜。在从不同距离的 DR2 中提取的样本中可以看到这种间隙，这并不是 Gaia 光度测定所独有的，在使用近红外 (NIR) 光度测定（J - K-s 与 M-Ks）时也会出现这种间隙。该间隙非常窄（类似于 0.05 星等），并且接近 M 矮星从部分对流过渡到完全对流的光度-温度范围，即近光谱类型 M3.0V。这个间隙提供了 HRD 的一个新特征，暗示了潜在的天体物理原因，我们认为它与 M 矮星中完全对流的开始有关。
We present the discovery of a gap near M-G approximate to 10 in the main sequence on the Hertzsprung-Russell Diagram (HRD) based on measurements presented in Gaia Data Release 2 (DR2). Using an observational form of the HRD with MG representing luminosity and G(BP) - G(RP) representing temperature, the gap presents a diagonal feature that dips toward lower luminosities at redder colors. The gap is seen in samples extracted from DR2 with various distances, and is not unique to the Gaia photometry-it also appears when using near-IR (NIR) photometry (J - K-s versus M-Ks). The gap is very narrow (similar to 0.05 mag) and is near the luminosity-temperature regime where M dwarf stars transition from partially to fully convective, i.e., near spectral type M3.0V. This gap provides a new feature in the HRD that hints at an underlying astrophysical cause, and we propose that it is linked to the onset of full convection in M dwarfs.