arXivDaily arXiv每日学术速递 周一至周五更新
北美退伍军人节（Veterans Day），12 日无更新
arXiv 0810.2714astro-ph
收藏

海王星外天体两种不同偏振行为的发现

Discovery of two distinct polarimetric behaviours of trans-Neptunian objects

S. Bagnulo, I. Belskaya, K. Muinonen, G. P. Tozzi, M. A. Barucci, L. Kolokolova, S. Fornasier

备注：
accepted for publication in A&A Letters
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

海王星外天体（TNO）包含太阳系早期吸积阶段最原始和热处理最少的材料。它们使我们能够研究各种小天体之间的相互关系，它们的起源和演化。使用ESO VLT的FORS 1，我们已经在Bessell R滤波器中获得了五个TNO在其相位角的不同值（即，太阳、物体和地球之间的角度）。由于目标的大距离（> 30 AU），所观察到的相位角的范围被限制在约0-2度。我们已经分析了我们的新观察的五个TNOs，和其他四个TNOs在以前的作品中获得的，并发现存在两类对象，表现出不同的极化行为。直径> 1000 km的物体，例如，冥王星和厄里斯在散射平面上显示出一个小的偏振（~0.5%），在观测到的相位角范围内缓慢变化。在较小的物体中，例如，Ixion和Varuna，线偏振随相位角迅速变化，并在相位角1度时达到~ 1%（在散射平面内）。较大的物体比较小的物体具有更高的吸收度，并且具有保留诸如CO、N2和CH 4的挥发物的能力。这两个事实都与它们与较小物体相比的不同偏振行为有关。尽管可观测相位角的范围非常有限，但地面极化观测是识别TNO表面不同性质的有力工具。我们建议，一个单一的偏振观测相位角~1度允许一个确定目标的偏振度是低还是高。

英文摘要：

Trans-Neptunian objects (TNOs) contain the most primitive and thermally least-processed materials from the early accretional phase of the solar system. They allow us to study interrelations between various classes of small bodies, their origin and evolution. Using FORS1 of the ESO VLT, we have obtained linear-polarization measurements in the Bessell R filter for five TNOs at different values of their phase angle (i.e., the angle between the Sun, the object, and the Earth). Due to the large distance of the targets (> 30 AU), the observed range of phase angles is limited to about 0-2 deg. We have analyzed our new observations of five TNOs, and those of another four TNOs obtained in previous works, and discovered that there exist two classes of objects that exhibit different polarimetric behaviour. Objects with a diameter > 1000 km, such as, e.g., Pluto and Eris, show a small polarization in the scattering plane (~0.5%) which slowly changes in the observed phase angle range. In smaller objects such as, e.g., Ixion and Varuna, linear polarization changes rapidly with the phase angle, and reaches ~ 1% (in the scattering plane) at phase angle 1 deg. The larger objects have a higher albedo than the smaller ones, and have the capability of retaining volatiles such as CO, N2 and CH4. Both of these facts can be linked to their different polarimetric behaviour compared to smaller objects. In spite of the very limited range of observable phase angles, ground-based polarimetric observations are a powerful tool to identify different properties of the surfaces of TNOs. We suggest that a single polarimetric observation at phase angle ~1 deg allows one to determine whether the target albedo is low or high.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑