Observations of Sodium in the Lunar Atmosphere during International Lunar Atmosphere Week, 1995
Observations of Sodium in the Lunar Atmosphere during International Lunar Atmosphere Week, 1995
复制标题
1995 年国际月球大气周期间月球大气中钠的观测
DOI：
10.1006/icar.1997.5848
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发表时间：
1998
期刊：
影响因子：
3.2
通讯作者：
R. Morris
中科院分区：
文献类型：
--
作者：
A. Sprague;D. Hunten;R. Kozlowski;F. A. Grosse;R. Hill;R. Morris
摘要：我们报告了五个观测小组同时观测月球大气中钠的部分结果。国际月球大气周为1995年9月15日至22日这一周。在这七个晚上中，我们有四个晚上的观景条件很好。我们使用了莱蒙山月球日冕仪（MLLC）和dark光谱仪。两者都是专门为从月球表面延伸到大约1个月球半径高度或约1700公里（860公里地球势高度）的月球大气测量而设计的。在相对较大的相位角（96°~ 129°）下，Na的发射率与先前报道的发射率一致，D2和D1的平均发射率为6.9 kRayleigh。仅在9月17日晚上观测到热成分，当时太阳在边缘的天顶角只有6°。9月18日，我们观察到北极的列丰度比阳光照射的赤道翼高约2倍，而9月19日，赤道明亮翼的列丰度比北极高约5倍。视位势尺度高度在279 ~ 435 km之间变化，表明大气扩展。如果刻度高度由温度表示，则值为985至1470k。数据集似乎支持这一观点，即这一时期的主要来源是陨石撞击挥发。
Abstract We report results of a part of an organized effort of five observing groups to simultaneously observe sodium in the lunar atmosphere. International Lunar Atmosphere Week spanned the week of September 15–22, 1995. Of the seven nights, we experienced four nights with good viewing conditions. We used the Mt. Lemmon Lunar Coronagraph (MLLC) and DARRK spectrograph. Both are especially designed for lunar atmospheric measurements from the surface extending to an altitude of approximately 1 lunar radius or ∼1700 km (860 km geopotential height). Emission rates for Na were compatible with those previously reported for relatively large phase angles (96° to 129°) with the average total of D2 and D1 emission rate ∼6.9 kRayleigh. A thermal component was observed only on the night of September 17, when the solar zenith angle at the limb was only 6°. We observed a factor of ∼2 greater column abundances over the north pole than over the sunlit equatorial limb on September 18 while on September 19, the equatorial bright limb column abundance was a factor of ∼5 higher than the north polar. Apparent geopotential scale heights varied from 279 to 435 km, indicating an extended atmosphere. If the scale heights are represented by a temperature, values are 985 to 1470 K. The data set appears to support the idea that the dominant source during this period was meteoritic impact volatilization.