Science. 1979 Feb 23;203(4382):770-2. doi: 10.1126/science.203.4382.770.
Measurements in situ of the neutral composition and temperature of the thermosphere of Venus are being made with a quadrupole mass spectrometer on the Pioneer Venus orbiter. The presence of many gases, incluiding the major constituents CO(2), CO, N(2), O, and He has been confirmed. Carbon dioxide is the most abundant constituent at altitudes below about 155 kilometers in the terminator region. Above this altitude atomic oxygen is the major constituent, with O/CO(2) ratios in the upper atmosphere being greater than was commonly expected. Isotope ratios of O and C are close to terrestrial values. The temperature inferred from scale heights above 180 kilometers is about 400 K on the dayside near the evening terminator at a solar zenith angle of about 69 degrees . It decreases to about 230 K when the solar zenith angle is about 90 degrees .
金星热层中性成分和温度的原位测量正在先驱者金星轨道飞行器上的四极质谱仪进行。已经证实存在许多气体，包括主要成分 CO(2)、CO、N(2)、O 和 He。在日界线地区，低于约 155 公里的高度，二氧化碳是最丰富的成分。在这个高度以上，原子氧是主要成分，高层大气中的 O/CO(2)比值大于通常预期的值。O 和 C 的同位素比值接近地球的值。从 180 公里以上的标高推断出的温度，在日侧，靠近傍晚日界线，太阳天顶角约为 69 度时约为 400 K。当太阳天顶角约为 90 度时，温度下降到约 230 K。
