论文标题
（3200）phaethon的围栏活性不是尘土飞扬的：立体声/cor2观察的证据
Perihelion Activity of (3200) Phaethon Is Not Dusty: Evidence from STEREO/COR2 Observations
论文作者
论文摘要
我们使用COR2摄像机在双人双太阳陆地关系天文台（立体声）航天器上进行了冠状摄像摄像机从2008年到2022年进行的冠状观测，对小行星（3200）phaethon进行了分析。尽管在单个图像中未被发现，但在同一近古观测的堆栈中可见，但仅在小（$ \ lyssim $ 30°）但不大（$ \ gtrsim $ 150°）相位的角度。这些观察结果与裸露的核的贡献一致，从而严重与基于HI-1观测值的解释相矛盾，HI-1观察结果将围盘活性归因于\微米大小的灰尘的弹射。我们获得了\微米大小的灰尘的有效横截面的上限为$ \ sillsim \！ 10^{5} $ M $^{2} $，至少基于HI-1数据的估计值小三个数量级。相反，COR2观察结果不能排除Phaethon周围MM大小或更大碎片的存在。但是，曾经检测到phaethon尚未检测到的后层碎屑尾巴这一事实表明，这种灰尘在周围活性中不重要。因此，我们得出的结论是，Phaethon的周围活性与灰尘的弹出极不可能。相反，我们推断活动与气体排放，可能是FE I和/或NA D线有关。为了验证我们的猜想并充分理解Phaethon的周围活性，需要更多的观察结果。我们汇编了一个观察窗户的列表，非常适合从地面望远镜中搜索小行星的气体排放。最好的机会将是在太阳日食期间。
We present an analysis of asteroid (3200) Phaethon using coronagraphic observations from 2008 to 2022 by the COR2 cameras onboard the twin Solar TErrestrial RElations Observatory (STEREO) spacecraft. Although undetected in individual images, Phaethon was visible in stacks combined from the same perihelion observations, yet only at small ($\lesssim$30°) but not large ($\gtrsim$150°) phase angles. The observations are in line with the contribution from a bare nucleus, thereby seriously contradicting the interpretation based on HI-1 observations that attributes the perihelion activity to the ejection of \micron-sized dust. We obtained an upper limit to the effective cross-section of \micron-sized dust to be $\lesssim \! 10^{5}$ m$^{2}$, at least three orders of magnitude smaller than earlier estimates based on HI-1 data. On the contrary, the COR2 observations cannot rule out the existence of mm-sized or larger debris around Phaethon. However, the fact that no postperihelion debris tail has ever been detected for Phaethon suggests the unimportance of such dust in the perihelion activity. We thus conclude that the perihelion activity of Phaethon is highly unlikely relevant to the ejection of dust. Rather, we deduce that the activity is associated with gas emissions, possibly Fe I and/or Na D lines. To verify our conjecture and to fully understand the perihelion activity of Phaethon, more observations at small heliocentric distances are desired. We compile a list of observing windows ideal for the search of gas emissions of the asteroid from ground telescopes. The best opportunities will be during total solar eclipses.
