Evidence for Color Dichotomy in the Primordial Neptunian Trojan Population
Hsing Wen Lin, David W. Gerdes, Stephanie J. Hamilton, Fred C. Adams, Gary M. Bernstein, Masao Sako, Pedro Bernadinelli, Douglas Tucker, Sahar Allam, Juliette C… 展开作者
Hsing Wen Lin, David W. Gerdes, Stephanie J. Hamilton, Fred C. Adams, Gary M. Bernstein, Masao Sako, Pedro Bernadinelli, Douglas Tucker, Sahar Allam, Juliette C. Becker, Tali Khain, Larissa Markwardt, Kyle Franson, T. M. C. Abbott, J. Annis, S. Avila, D. Brooks, A. Carnero Rosell, M. Carrasco Kind, C. E. Cunha, C. B. D'Andrea, L. N. da Costa, J. De Vicente, P. Doel, T. F. Eifler, B. Flaugher, J. Garcia-Bellido, D. L. Hollowood, Klaus Honscheid, D. J. James, K. Kuehn, N. Kuropatkin, M. A. G. Maia, J. L. Marshall, R. Miquel, A. A. Plazas, A. K. Romer, E. Sanchez, V. Scarpine, I. Sevilla-Noarbe, M. Smith, R. C. Smith, M. Soares-Santos, F. Sobreira, E. Suchyta, G. Tarle, A. R. Walker, W. Wester
In the current model of early Solar System evolution, the stable members of the Jovian and Neptunian Trojan populations were captured into resonance from the leftover reservoir of planetesimals during the outward migration of the giant planets. As a result, both Jovian and Neptunian Trojans share a common origin with the primordial disk population, whose other surviving members constitute today's trans-Neptunian object (TNO) populations. The cold classical TNOs are ultra-red, while the dynamically excited "hot" population of TNOs contains a mixture of ultra-red and blue objects. In contrast, Jovian and Neptunian Trojans are observed to be blue. While the absence of ultra-red Jovian Trojans can be readily explained by the sublimation of volatile material from their surfaces due to the high flux of solar radiation at 5AU, the lack of ultra-red Neptunian Trojans presents both a puzzle and a challenge to formation models. In this work we report the discovery by the Dark Energy Survey (DES) of two new dynamically stable L4 Neptunian Trojans,2013 VX30 and 2014 UU240, both with inclinations i >30 degrees, making them the highest-inclination known stable Neptunian Trojans. We have measured the colors of these and three other dynamically stable Neptunian Trojans previously observed by DES, and find that 2013 VX30 is ultra-red, the first such Neptunian Trojan in its class. As such, 2013 VX30 may be a "missing link" between the Trojan and TNO populations. Using a simulation of the DES TNO detection efficiency, we find that there are 162 +/- 73 Trojans with Hr < 10 at the L4 Lagrange point of Neptune. Moreover, the blue-to-red Neptunian Trojan population ratio should be higher than 17:1. Based on this result, we discuss the possible origin of the ultra-red Neptunian Trojan population and its implications for the formation history of Neptunian Trojans.
Predictions of the LSST Solar System Yield: Neptune Trojans
Queen's University Belfast（贝尔法斯特女王大学）；University of Washington（华盛顿大学）；University of Michigan（密歇根大学）；University of Illinois at Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校）；University of Turku（图尔库大学）；University of Helsinki（赫尔辛基大学）；Asteroid Institute（小行星研究所）；Carnegie Mellon University（卡内基梅隆大学）；Northern Arizona University（北亚利桑那大学）
Optical Colors as Compressed Spectral Information for Trans-Neptunian Objects
University of Michigan（密歇根大学）；Michigan Institute for Data and AI in Society, University of Michigan（密歇根大学数据与人工智能社会研究所）；Case Western Reserve University（凯斯西储大学）；University of Auckland（奥克兰大学）；The University of Arizona（亚利桑那大学）
OSSOS II: A Sharp Transition in the Absolute Magnitude Distribution of the Kuiper Belt's Scattering Population
我们测量的绝对星等，$H$，分布，$dN(H) \propto 10^{αH}$的散射海王星外天体（TNOs）作为其大小频率分布的代理。我们发现，散射TNOs的H-分布是不一致的单斜率分布，但必须过渡到$H_g \sim 9$周围的膝关节与浅斜率或diligent，这是一个微分下降其次是第二指数分布。我们的分析是基于一个样本的22个散射TNO从三个不同的TNO调查，加拿大-法国黄道面调查（CFEPS，Petit et al. 2011），Alexandersen et al.（2014），and the Outer Solar System Origins Survey（OSSOS，Bannister等人，2016），所有这些都提供了良好表征的检测阈值，结合宇宙起源模型的散射TNO人口的形成。我们测量的绝对星等分布结果与天体演化模型的选择无关。根据我们的分析，我们估计散射TNO的数量为（2.4-8.3）$\times 10^5$为$H_r < 12$。在各种地层情况下都可以看到一个弥散的$H$分布，它可以解释柯伊伯带科学中的几个难题。我们发现，一个diferous $H$分布同时解释了观察到的散射TNO，海王星特洛伊，冥王星，半人马座$H$分布，同时预测一个足够大的散射TNO人口作为唯一的供应的彗星家族。
