The disk instability model attributes the outbursts of dwarf novae to a thermal-viscous instability of their accretion disk, an instability to which nova-like stars are not subject. We aim to test the fundamental prediction of the disk instability model: the separation of cataclysmic variables (CVs) into nova-likes and dwarf novae depending on orbital period and mass transfer rate from the companion. We analyse the lightcurves from a sample of ~130 CVs with a parallax distance in the Gaia DR2 catalogue to derive their average mass transfer rate. The method for converting optical magnitude to mass accretion rate is validated against theoretical lightcurves of dwarf novae. Dwarf novae (resp. nova-likes) are consistently placed in the unstable (resp. stable) region of the orbital period - mass transfer rate plane predicted by the disk instability model. None of the analyzed systems present a challenge to the model. These results are robust against the possible sources of error and bias that we investigated. Lightcurves from Kepler or, in the future, the LSST or Plato surveys, could alleviate a major source of uncertainty, the irregular sampling rate of the lightcurves, assuming good constraints can be set on the orbital parameters of the CVs that they happen to target. The disk instability model remains the solid base on which to construct the understanding of accretion processes in cataclysmic variables.
Properties of Cataclysmic Variables in Globular Clusters
星团的研究在我们对宇宙的理解中起着重要的作用，因为这些系统是测试恒星动力学和演化理论的天然实验室。特别是，球状星团（GCs）是研究奇异系统的形成和物理性质的最重要的对象之一，这反过来又提供了基本的信息和工具，可以帮助我们了解星团本身，星系和一般的年轻宇宙的形成和演化过程。GC中最有趣的天体是激变变星（CV），它们是相互作用的双星，其中包含一颗从低质量伴星吸积而来的白矮星。由于GC密度足够高，涉及双星的动力学遭遇应该是常见的，CV祖先预计会在早期阶段以某种方式受到动力学的影响。本文综述了GC中CV的形成途径以及动力学对CV群体的影响。特别是，我们回顾了最近的进展，数值模拟。此外，我们还讨论了GC中CV的观测特性以及用于识别和研究它们的技术。我们集中讨论的多波长观测进行了与HST和钱德拉上研究最好的GC NGC 6397，NGC 6752，47 Tuccenda和欧米茄半人马座;最近的光谱研究结果与MUSE，并更新有关的数量之间的相关性微弱的X射线源和集群恒星相遇率。最后，我们讨论了一些可能有助于未来研究的观测前景。
IPHAS J190812.63+045728.1: A deeply eclipsing, X-ray bright cataclysmic variable with frequent outbursts
Universidade Federal de Sergipe（塞尔希培联邦大学）；Observatório Nacional（国家天文台）；Laboratório Nacional de Astrofísica（国家天体物理实验室）；NASA/GSFC（美国宇航局戈达德太空飞行中心）；University of Maryland, Baltimore County（马里兰大学巴尔的摩县分校）；Instituto Nacional de Pesquisas Espaciais（国家空间研究所）
A study of transients from ground-based surveys reveals new ultra-compact accreting white dwarf binaries
University of Texas Rio Grande Valley（德克萨斯大学里奥格兰德河谷分校）；South Texas Space Science Institute, University of Texas Rio Grande Valley（德克萨斯大学里奥格兰德河谷分校南德克萨斯空间科学研究所）；Texas Tech University（德克萨斯理工大学）；Universidad Nacional Autónoma de México, Instituto de Astronomía（墨西哥国立自治大学天文学研究所）；University of Michigan（密歇根大学）；Institute of Science and Technology Austria（奥地利科学技术研究所）
Time-dependent Accretion Disks in Tidal Disruption Events: Long-term Light Curves
National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；School of Astronomy and Space Science, University of Chinese Academy of Sciences（中国科学院大学天文与空间科学学院）
