标题： 赫歇尔/PACS对10 Myr老的T Tauri盘TW Hya的观测：限制盘气质量 显示英文标题

标题： Herschel-PACS observation of the 10 Myr old T Tauri disk TW Hya: Constraining the disk gas mass

摘要： 行星形成于年轻恒星周围的盘状结构中。 年龄约为10 Myr的TW Hya是仍然被相对大质量盘环绕的最邻近的T Tauri星之一。 此外，在TW Hya盘中发现了大量的分子，使得TW Hya成为利用赫歇尔空间天文台的PACS仪器进行的大规模盘调查中的理想测试案例，以直接研究它们的气态成分。 我们旨在限制围绕TW Hya的原恒星盘的气体和尘埃质量。 作为开放时间大型计划GASPS的一部分，我们观测了[OI]和[CII]的精细结构线。 我们补充了连续谱数据以及基于地面的12CO 3-2和13CO 3-2观测。 我们同时使用三维蒙特卡洛代码MCFOST和热化学代码ProDiMo来模拟连续谱和线光谱，以推导气体和尘埃的质量。 我们在63微米处检测到了[OI]线。 所观测到的其他谱线，145微米处的[OI]线和157微米处的[CII]线未被检测到。 未发现扩展发射。 初步建模假设[12CO]/[13CO]=69，表明半径小于1毫米的尘埃质量约为1.9乘以10^-4太阳质量（总固态质量为3乘以10^-3太阳质量），气体质量为(0.5--5)乘以10^-3太阳质量。 气体与尘埃的质量比可能低于星际标准值100。 显示英文摘要

摘要： Planets are formed in disks around young stars. With an age of ~10 Myr, TW Hya is one of the nearest T Tauri stars that is still surrounded by a relatively massive disk. In addition a large number of molecules has been found in the TW Hya disk, making TW Hya the perfect test case in a large survey of disks with Herschel-PACS to directly study their gaseous component. We aim to constrain the gas and dust mass of the circumstellar disk around TW Hya. We observed the fine-structure lines of [OI] and [CII] as part of the Open-time large program GASPS. We complement this with continuum data and ground-based 12CO 3-2 and 13CO 3-2 observations. We simultaneously model the continuum and the line fluxes with the 3D Monte-Carlo code MCFOST and the thermo-chemical code ProDiMo to derive the gas and dust masses. We detect the [OI] line at 63 micron. The other lines that were observed, [OI] at 145 micron and [CII] at 157 micron, are not detected. No extended emission has been found. Preliminary modeling of the photometric and line data assuming [12CO]/[13CO]=69 suggests a dust mass for grains with radius < 1 mm of ~1.9 times 10^-4 Msun (total solid mass of 3 times 10^-3 Msun) and a gas mass of (0.5--5) times 10^-3 Msun. The gas-to-dust mass may be lower than the standard interstellar value of 100.