Measuring White Dwarf Variability from Sparsely Sampled Gaia DR3 Multi-Epoch Photometry
Maya Steen, J. J. Hermes, Joseph A. Guidry, Annabelle Paiva, Jay Farihi, Tyler M. Heintz, Brison B. Ewing, Nathanial Berry
备注：
22 pages, 8 figures, 3 tables, accepted for publication in ApJ; updated headers in table 3 to reflect correct units of amplitude; updated formatting for readability
White dwarf stars are ubiquitous in the Galaxy, and are essential to understanding stellar evolution. While most white dwarfs are photometrically stable and reliable flux standards, some can be highly variable, which can reveal unique details about the endpoints of low-mass stellar evolution. In this study we characterize a sample of high-confidence white dwarfs with multi-epoch photometry from Gaia Data Release 3. We compare these Gaia light curves with light curves from the Zwicky Transiting Facility and the Transiting Exoplanet Survey Satellite to see when Gaia data independently can accurately measure periods of variability. From this sample, 105 objects have variability periods measured from the Gaia light curves independently, with periods as long as roughly 9.5 d and as short as 256.2 s (roughly 4 min), including seven systems with periods shorter than 1000 s. We discover 86 new objects from the 105 target sample, including pulsating, spotted, and binary white dwarfs, and even a new 68.4 min eclipsing cataclysmic variable. The median amplitude of the absolute photometric variability we confirm from Gaia independently is 1.4%, demonstrating that Gaia epoch photometry is capable of measuring short-term periods even when observations are sparse.
Identification of RR Lyrae stars in multiband, sparsely-sampled data from the Dark Energy Survey using template fitting and Random Forest classification
GAIA卫星可以通过微透镜效应精确测量附近褐矮星和低主序星的质量。如果地面望远镜也能跟踪微透镜事件，提供密集采样的测光，科学产量将最大化。有两种可能的策略。首先，正在发生的事件可以由GAIA的光度或天体测量警报触发。第二，可以用已知的高自行星作为透镜来预测事件。这很容易，因为可以预测事件的位置和时间。使用GAIA源密度，我们估计，高自行（$>300$ mas yr $^{-1}$）棕矮星的样本大小需要提供可预测的事件在5年的任务寿命是令人惊讶的小，只有100的顺序。这与UKIDSS大面积巡天和全天空WISE卫星已经知道的高自行棕矮星的数量相当。如果透镜的相对视差和爱因斯坦半径角可以从天体测量数据中恢复，那么透镜的质量就可以找到。微透镜提供了测量单个物体质量的唯一方法，而不管它们的光度如何。因此，用GAIA进行微透镜是在褐矮星区域进行质量清点的最佳方法。
Gaia DR3 high radial velocity stars: Genuine fast-moving objects or outliers?
Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CY Cergy Paris Université, CNRS（巴黎天文台，巴黎文理研究大学，索邦大学，巴黎西岱大学，塞吉-蓬图瓦兹大学，法国国家科学研究中心）；UNIDIA, Observatoire de Paris, Université PSL, CNRS（UNIDIA，巴黎天文台，巴黎文理研究大学，法国国家科学研究中心）；Laboratoire d’astrophysique de Bordeaux, Université de Bordeaux, CNRS（波尔多天体物理实验室，波尔多大学，法国国家科学研究中心）
StarCLR: Contrastive Learning Representation for Astronomical Light Curves
Tibet University（西藏大学）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；Zhejiang Laboratory（之江实验室）；University of the Chinese Academy of Sciences（中国科学院大学）；Beijing Normal University（北京师范大学）
