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矮行星Makemake的阿尔贝多和大气约束来自恒星遮蔽
J L Ortiz1, B Sicardy, F Braga-Ribas
1Instituto de Astrofísica de Andalucía, CSIC, Apartado 3004, 18080 Granada, Spain. ortiz@iaa.es
Nature
|November 23, 2012
概括
冰的矮行星马凯马克 (Makemake) 使用恒星隐蔽进行了研究. 研究人员确定了它的尺寸,光度和密度,发现它没有像冥王星这样的全球大气层,但可能有局部的大气口袋.
科学领域:
- 跨海王星的物体
- 矮行星的特征描述
- 行星大气层的行星大气层
背景情况:
- 冥王星和埃里斯是冰的矮行星,具有相似的特征,但不同的大气状态.
- 另一个矮行星马克马克位于冥王星和爱丽丝之间的中间位置,密度和大气特性不明.
- 之前的研究表明了马基马基的大小和白色,但缺乏对其密度和大气存在的限制.
研究的目的:
- 为了确定马基马基的物理特性,包括它的尺寸,光度,密度和大气条件.
- 为了比较马基马基的特征与冥王星和爱丽丝的特征.
- 为了调查Makamake上可能存在类似冥王星的大气层.
主要方法:
- 2011年4月23日观测到的恒星遮蔽事件.
- 对隐蔽和弦的分析,以确定马基马基的预测轴和几何色度.
- 从恒星隐蔽的光曲线推断密度和大气压力.
主要成果:
- 马卡梅克的预测轴被确定为1,430 ± 9公里和1,502 ± 45公里.
- V波段的几何色度被计算为p(V) = 0.77 ± 0.03,高于冥王星,但低于爱里斯.
- 确定没有全球大气层,表面压力的上限为4-12纳米巴尔;局部大气层仍然是可能的.
- 据推断,它的密度为1.7 ± 0.3 g cm(-3).
结论:
- 马克马克是一个密集的,高度反射的矮行星,缺乏全球大气层.
- 它的物理特性表明与冥王星和爱丽丝相比,它有一个不同的进化路径.
- 需要进一步的观测来确认局部大气现象的存在.
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