标题： ASASSN-24fw：主序星的候选原行星盘掩食 显示英文标题

标题： ASASSN-24fw: Candidate circumplanetary disk occultation of a main-sequence star

摘要： 在系外行星系统外围区域的行星周围的尘埃盘可以作为长期遮掩现象被探测到，前提是观测者接近行星的轨道平面。 在这里，我们报告了ASASSN-24fw（Gaia 07:05:18.97+06:12:19.4）的后续观测，这是一个持续8.5个月的主序星4等暗化事件。 使用KOSMOS（APO）、MagE（Magellan）和GHOST（Gemini-S）的光学光谱学，我们发现强烈的Na I D吸收，表明遮掩体富含气体。 我们检测到多个低电离金属发射线，其速度弥散小于10 km/s，并相对于系统蓝移27 km/s，这些线可能起源于遮掩体，以及蓝移且宽（200 km/s）的Halpha线，这可能起源于内部的原恒星盘。 我们确认了在历史数据中于1981年和1937年观测到的先前遮掩现象，得出遮掩体绕恒星轨道运动的半长轴为14 AU。 假设遮掩体是一个填充30-100%希尔半径的环行星盘，我们推导出行星的质量为0.5-19 MJupiter，以及环行星盘的质量为月球质量的1%。 鉴于恒星的年龄（超过2 Gyr），该盘不太可能是行星形成阶段的幸存者，更可能是行星碰撞的结果。 如果Na D吸收和金属发射线起源于环行星盘，那么这里的观测是首次发现由行星驱动的风或环绕次级盘旋转的证据。 显示英文摘要

摘要： Dusty disks around planets in outer reaches of exo-planetary systems can be detected as long-lasting occultations, provided the observer is close to the planet's orbital plane. Here we report follow-up observations of ASASSN-24fw (Gaia 07:05:18.97+06:12:19.4), a 4-magnitude dimming event of a main-sequence star which lasted 8.5 months. Using optical spectroscopy with KOSMOS (APO), MagE (Magellan) and GHOST (Gemini-S), we find strong Na I D absorption indicating that the occulter is gas rich. We detect multiple low-ionization metal emission lines with velocity dispersion <10 km/s blue-shifted by 27 km/s with respect to the system, which likely originate in the occulter, as well as blue-shifted and broad (200 km/s) Halpha line, which likely originates in the inner circumstellar disk. We confirm the previously reported occultations in 1981 and 1937 seen in historic data, yielding a semi-major axis of the occulter's orbital motion around the star of 14 AU. Assuming that the occulter is a circumplanetary disk filling 30-100% of the Hill radius, we derive the planet's mass of 0.5-19 MJupiter and a circumplanetary disk mass of 1% of the mass of the Moon. Given the age of the star (>2 Gyr), the disk is unlikely to be a survivor of the planet formation stage and is more likely to be a result of a planetary collision. If Na D absorption and metal emission lines originate in the circumplanetary disk, the observations presented here are the first discovery of a planet-driven wind or of circumsecondary disk rotation.