标题： 形成首个行星系统：银河厚盘恒星周围的碎片 显示英文标题

标题： Forming the first planetary systems: debris around Galactic thick disc stars

摘要： 厚盘包含在银河系历史的前10亿年中形成的恒星，但对其行星系统知之甚少。斯皮策太空望远镜的MIPS仪器被用来搜索其中11颗最近的古老低金属恒星周围的星际碎片，作为至少与星子一样大的天体形成的标志。包括存档数据后，现在已经观测了总计22颗厚盘恒星，但在这些系统中没有发现尘埃。这些数据排除了早期银河系形成阶段的恒星系统中存在大量碎片的可能性。然而，这个非常古老的恒星群体中的一些恒星确实拥有巨型行星，其比例可能高于普通低金属太阳型恒星中的普遍比例。由于太阳系包含气态巨行星但几乎没有彗星尘埃，厚盘可能也包含类似系统，这些系统在太阳之前数十亿年就已经形成。 显示英文摘要

摘要： The thick disc contains stars formed within the first Gyr of Galactic history, and little is known about their planetary systems. The Spitzer MIPS instrument was used to search 11 of the closest of these old low-metal stars for circumstellar debris, as a signpost that bodies at least as large as planetesimals were formed. A total of 22 thick disc stars has now been observed, after including archival data, but dust is not found in any of the systems. The data rule out a high incidence of debris among star systems from early in the Galaxy's formation. However, some stars of this very old population do host giant planets, at possibly more than the general incidence among low-metal Sun-like stars. As the Solar System contains gas giants but little cometary dust, the thick disc could host analogue systems that formed many Gyr before the Sun.