A Search for Argon and O VI in Three Comets Using the Far Ultraviolet Spectroscopic Explorer
A Search for Argon and O VI in Three Comets Using the Far Ultraviolet Spectroscopic Explorer
复制标题
使用远紫外光谱探测器在三颗彗星中寻找氩和 O VI
DOI：
--
复制
发表时间：
2002
期刊：
影响因子：
--
通讯作者：
D. Shemansky
中科院分区：
文献类型：
--
作者：
H. Weaver;P. Feldman;M. Combi;V. Krasnopolsky;C. Lisse;D. Shemansky
我们对远紫外光谱探测器（FUSE）观测到的三颗长周期彗星的光谱中Ar I（λλ1048.22，1066.66）和O VI（λλ1031.93，1037.62）的共振线进行了灵敏的搜索。未从C/1999 T1（McNaught-Hartley）、C/2001 A2（LINEAR）或C/2000 WM 1（LINEAR）中检测到氩发射。与太阳值相比，[Ar/O]比在C/A2中至少减少10倍，在C/WM 1中至少减少13倍。C/T1的[Ar/O]上限基本上是太阳值，因为我们的测量在这种情况下灵敏度要低得多。在FUSE观测期间，我们还检测到CO，其挥发性与氩相似。C/T1为富CO（[CO/H2O] ≤ 13%），而C/A2和C/WM 1均为贫CO（[CO/H2O] ≤ 0.7%，C/A2和C/WM 1均≤ 0.4%）。C/A2和C/WM 1中的氩和CO贫化表明这两颗彗星的形成温度都在60 K左右。C/T1中高的CO丰度和Ar丰度上限表明其形成温度在40-50 K之间。彗星C/T1或C/A2没有检测到O VI发射，但在C/WM 1中检测到较强的线。
We conducted a sensitive search for the resonance lines of Ar I (λλ1048.22, 1066.66) and O VI (λλ1031.93, 1037.62) in the spectra of three long-period comets observed with the Far Ultraviolet Spectroscopic Explorer (FUSE). Argon emission was not detected from C/1999 T1 (McNaught-Hartley), C/2001 A2 (LINEAR), or C/2000 WM1 (LINEAR). Compared with the solar value, the [Ar/O] ratio is depleted in C/A2 by at least a factor of 10 and in C/WM1 by at least a factor of 13. The [Ar/O] upper limit for C/T1 is essentially the solar value, as our measurement was much less sensitive for that case. We also detected CO, which has a volatility similar to that of argon, during the FUSE observations. C/T1 was CO-rich ([CO/H2O] ≈ 13%), while both C/A2 and C/WM1 were CO-poor ([CO/H2O] ≈ 0.7% for C/A2 and ≈0.4% for C/WM1). The argon and CO depletions in C/A2 and C/WM1 suggest formation temperatures ≳60 K for both of these comets. The high CO abundance and upper limit on the argon abundance in C/T1 suggest that its formation temperature was in the range of ~40-50 K. No O VI emission was detected from comets C/T1 or C/A2, but the stronger line was marginally detected in C/WM1.