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首页> 外文期刊>The Astrophysical journal >The Stellar Population of the M31 Spiral Arm around OB Association A24
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The Stellar Population of the M31 Spiral Arm around OB Association A24

机译:OB协会A24附近的M31螺旋臂的恒星种群

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A study of the stellar population of the M31 spiral arm around OB association A24 was carried out based on the photometric data obtained from deep V and JHK imaging. The luminosity function was obtained for -7 Mbol -3.5 by applying the extinction correction corresponding to AV = 1 and the bolometric correction BCK as an empirical function of (J - K)0. In comparing the observed color-luminosity diagrams with semitheoretical isochrones modified for the dust-shell effects, we found the young population of t 30 Myr with supergiants of Mbol -5, the bulk of the intermediate-age population of t ~ 0.2-2.5 Gyr with bright asymptotic giant branch (AGB) stars of -5 Mbol -4, and old populations of t 3 Gyr with AGB and red giant branch (RGB) stars of Mbol -4. The average star formation rate was estimated to be ~ 1.8 × 104 m☉ Myr-1 and ~ 0.7 × 104 m☉ Myr-1 per deprojected disk area of 1 kpc2 from the number density of B0 V stars around MV = -4.0 (age ~ 10 Myr) and the number density of bright AGB stars around Mbol = -4.3 (age ~ 1 Gyr), respectively. A study of the local variation in the V and the J and H luminosity functions revealed a kind of anticorrelation between the population of the young component and that of the intermediate-age component when subdomains of ~ 100 pc scales were concerned. This finding suggests that the disk domain around the A24 area experienced a series of star formation episodes alternatively among different subdomains with a timescale of several spiral passage periods. Brief discussions are given about the interstellar extinction and about the lifetimes of bright AGB stars and the highly red objects in the same area.
机译:基于从深V和JHK成像获得的光度数据,对OB关联A24附近的M31螺旋臂的恒星种群进行了研究。通过应用对应于AV = 1的消光校正和辐射热校正BCK作为(J-K)0的经验函数,可得到-7 Mbol -3.5的光度函数。通过比较观察到的颜色-光度图和针对尘壳效应而修改的半理论等时线,我们发现t 30 Myr的年轻种群与Mbol -5超级巨人,t〜0.2-2.5 Gyr的中年人口大部分具有-5 Mbol -4的明亮渐近巨型分支(AGB)星,以及具有AGB和Mbol -4的红色巨型分支(RGB)星的t 3 Gyr老种群。根据MV = -4.0(年龄)附近的B0 V星的数量密度,每1 kpc2的投影磁盘面积,平均恒星形成率估计为〜1.8×104m☉Myr-1和〜0.7×104m☉Myr-1 〜10 Myr)和Mbol附近的明亮AGB星的星密度= -4.3(年龄〜1 Gyr)。对V和J和H的光度函数的局部变化的研究表明,当涉及〜100 pc规模的子域时,年轻成分的种群与中间年龄成分的种群之间存在一种反相关。这一发现表明,A24区域周围的磁盘域经历了一系列的恒星形成事件,或者在不同的子域之间经历了几个螺旋通过周期的时间尺度。简要讨论了星际灭绝以及明亮的AGB恒星和同一区域中高度红色的物体的寿命。

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