论文标题
Lamost DR5的近30,000个晚期的后序列明星，年龄出色
Nearly 30,000 late-type main-sequence stars with stellar age from LAMOST DR5
论文作者
论文摘要
我们构建了一个近30,000个主要序列星的样本，其中4500K $ <t \ rm_ {eff} <$ 5000k和由色球活动$ - $ $年龄关系估算的恒星年龄。该样本用于确定银河系的$ R-Z $平面中的年龄分布，其中$ r $是磁盘中间平面中预计的galactacentric距离，$ z $是磁盘中平面上方的高度。随着$ | z | $的增加，旧星星的百分比变得更大。众所周知，随着$ r $的增加，银河磁盘的规模高度增加，这就是称为耀斑。从$ r $ $ \ sim $ 8.0到9.0 kpc的温和耀斑发现了出色的年龄分布。我们还发现，如先前研究所证实的那样，速度分散体随着年龄的增长而增加。最后，我们在$ z- \ upsilon_ {z} $相位空间中呈现螺旋形结构，三个恒星年龄箱。在[0，1] Gyr的年龄箱中清楚地看到了螺旋，这表明对磁盘的垂直扰动可能发生在最后$ \ sim $ 1.0 GYR之内。
We construct a sample of nearly 30,000 main-sequence stars with 4500K $<T\rm_{eff}<$ 5000K and stellar ages estimated by the chromospheric activity$-$age relation. This sample is used to determine the age distribution in the $R-Z$ plane of the Galaxy, where $R$ is the projected Galactocentric distance in the disk midplane and $Z$ is the height above the disk midplane. As $|Z|$ increases, the percentage of old stars becomes larger. It is known that scale-height of Galactic disk increases as $R$ increases, which is called flare. A mild flare from $R$ $\sim$ 8.0 to 9.0 kpc in stellar age distribution is found. We also find that the velocity dispersion increases with age as confirmed by previous studies. Finally we present spiral-shaped structures in $Z-\upsilon_{Z}$ phase space in three stellar age bins. The spiral is clearly seen in the age bin of [0, 1] Gyr, which suggests that a vertical perturbation to the disk probably took place within the last $\sim$ 1.0 Gyr.
