来自“后院世界：行星九号”公民科学项目的新极端T型亚矮星候选体
太阳与恒星天体物理
2022-07-06 v1 地球与行星天体物理
摘要
Schneider等人(2020)报道了WISEA J041451.67-585456.7和WISEA J181006.18-101000.5的发现，它们似乎是极端T型亚矮星(esdT；金属丰度≤-1 dex，T_eff≤1400 K)的首批例子。在此，我们展示了对三个T型亚矮星候选体的新发现与后续观测，旨在扩充这类具有极低金属丰度和极高运动学特征的样本，这些性质暗示其属于银河系晕族。对由“后院世界：行星九号”公民科学项目发现的高速运动天体WISEA J155349.96+693355.2进行的Keck/NIRES近红外光谱观测确认它是一颗中T型亚矮星。WISEA J155349.96+693355.2的H_W2=22.3 mag，在所有经光谱确认的L型和T型亚矮星中具有最大的W2约化自行，表明它可能在运动学上极为极端。然而，我们对WISEA J155349.96+693355.2近红外光谱的建模表明其金属丰度仅略低于太阳。在分析J155349.96+693355.2光谱时，我们给出了一套新的低温、低金属丰度模型大气光谱网格。我们还基于其大自行以及与两个已知esdT天体相似的颜色，报道了两个新esdT候选体CWISE J073844.52-664334.6和CWISE J221706.28-145437.6的发现。发现更多esdT例子是描绘这一新确认星族的谱序与观测性质的关键一步。
引用
@article{arxiv.2106.01387,
title = {New Candidate Extreme T Subdwarfs from the Backyard Worlds: Planet 9 Citizen Science Project},
author = {Aaron M. Meisner and Adam C. Schneider and Adam J. Burgasser and Federico Marocco and Michael R. Line and Jacqueline K. Faherty and J. Davy Kirkpatrick and Dan Caselden and Marc J. Kuchner and Christopher R. Gelino and Jonathan Gagne and Christopher Theissen and Roman Gerasimov and Christian Aganze and Chih-Chun Hsu and John P. Wisniewski and Sarah L. Casewell and Daniella C. Bardalez Gagliuffi and Sarah E. Logsdon and Peter R. M. Eisenhardt and Katelyn Allers and John H. Debes and Michaela B. Allen and Nikolaj Stevnbak Andersen and Sam Goodman and Leopold Gramaize and David W. Martin and Arttu Sainio and Michael C. Cushing and The Backyard Worlds and : and Planet 9 Collaboration},
journal= {arXiv preprint arXiv:2106.01387},
year = {2022}
}
备注
accepted for publication in ApJ; models available at https://doi.org/10.7910/DVN/SJRXUO