在非常低的恒星质量和年轻时,对质量-亮度关系的动态校准
Laird M Close1, Rainer Lenzen, Jose C Guirado
1Steward Observatory, University of Arizona, Tucson, Arizona 85721, USA. lclose@as.arizona.edu
Nature
|January 22, 2005
概括
天文学家准确地测量了一个年轻的,低质量伴星的质量. 这一发现表明,标准质量-亮度关系高估了这些物体的近红外亮度,影响了棕矮星的频率估计.
科学领域:
- 天文学和天体物理学
- 恒星进化 恒星进化
- 太阳系外行星研究
背景情况:
- 恒星质量是基本的,但很难直接测量.
- 目前的质量估计依赖于质量-亮度关系,对于年轻的低质量恒星和棕色矮星来说,这些关系的校准不佳.
- 理论模型通常用于限制这些物体的质量.
研究的目的:
- 为了动态确定一个年轻的,低质量恒星伴侣 (AB Dor C) 的质量.
- 对年轻的低质量物体重新评估标准质量-亮度关系的准确性.
- 评估这些发现对棕矮星和行星质量物体频率估计的影响.
主要方法:
- 利用一种新的高对比度自适应光学相机来发现和解析伴星.
- 采用动态方法来精确确定伴侣的质量.
- 测量了伴侣的近红外 (1-2微米) 亮度.
主要成果:
- 动态确定了低质量伴侣AB Dor C的质量为0.090 +/- 0.005太阳质量.
- 发现标准质量-亮度关系高估了年轻的低质量物体的近红外亮度,大约是2.5.
- 表明以前估计的年轻,凉爽物体的质量可能被低估了两倍.
结论:
- 质量-亮度关系需要对年轻的低质量恒星和棕矮星进行重大修订.
- 棕矮星和行星质量物体在年轻恒星星团中的频率可能被高估了.
- 直接的动态质量测量对于准确校准恒星和亚恒星质量-亮度关系至关重要.
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