Spectroscopic anatomy of a meteor trail cross section with the European Southern Observatory Very Large Telescope
Spectroscopic anatomy of a meteor trail cross section with the European Southern Observatory Very Large Telescope
复制标题
使用欧洲南方天文台甚大望远镜对流星轨迹横截面进行光谱解剖
DOI：
10.1111/j.1945-5100.2004.tb00923.x
复制
发表时间：
2004
影响因子：
2.2
通讯作者：
I. Boyd
中科院分区：
文献类型：
--
作者：
P. Jenniskens;E. Jehin;R. Cabanac;C. Laux;I. Boyd
摘要--欧洲南方天文台(ESO)甚大望远镜(VLT)用FORS1在长缝光谱模式下进行长时间曝光，偶然记录到一种流星光谱。2002年5月12日，在正常服务模式下观测到一颗高z超新星时，−8级火球穿过了1？×7？狭缝。光谱覆盖了637-1050 nm的范围，在这个范围内，流星的大气等离子体辐射主要来自氮气、氮气和氧气。在900 nm以上相对未知的波长范围内没有探测到碳原子发射，但由于大气中二氧化碳的解离，观测到的上限仅比预期的低3西格玛。流星轨迹沿狭缝分辨，辐射服从正态分布，其维度为FWHM=7.0(±0.4)*SIN(α)*H(Km)/90m，其中α为流星路径与狭缝方向之间的未知角，H为流星假设高度，单位为Km。据我们所知，这是第一次观测到流星轨迹上的空间分辨光谱。与模型预测不同的是，根据原子和分子氮排放的比率，等离子体激发温度在整个试验过程中只在大约4300到4365 K之间变化。不幸的是，我们得出的结论是，这是因为这颗100公里高度的流星失去了焦距。
Abstract— A meteor spectrum was recorded serendipitously at the European Southern Obrervatory (ESO) Very Large Telescope (VLT) during a long exposure in long‐slit spectroscopic mode with FORS1. The −8 magnitude fireball crossed the narrow 1Î × 7î slit during the observation of a high z supernova in normal service mode operation on May 12, 2002. The spectrum covered the range of 637–1050 nm, where the meteor's air plasma emissions from N2, N, and O dominate. Carbon atom emission was not detected in the relatively unexplored wavelength range above 900 nm, but the observed upper limit was only 3 sigma less than expected from the dissociation of atmospheric CO2. The meteor trail was resolved along the slit, and the emission had a Gaussian distribution with a dimension of FWHM = 7.0 (±0.4) * sin(α) * H (km)/90 m, where α is the unknown angle between the orientation of the meteor path and slit and H the assumed altitude of the meteor in km. To our knowledge, this is the first observation of a spatially resolved spectrum across a meteor trail. Unlike model predictions, the plasma excitation temperature varied only from about 4,300 to 4,365 K across the trail, based on the ratio of atomic and molecular nitrogen emissions. Unfortunately, we conclude that this was because the meteor at 100 km altitude was out of focus.