2025年10月10日
距离飞马座51大约50光年
影像提供与版权: José Rodrigues
说明: 距离地球仅有50光年的51 Pegasi是一颗引人注目的恒星。这颗恒星的位置在2025年8月的一个夜晚被拍摄下来，当时法国上普罗旺斯天文台的圆顶上方可见大多数较亮的星星。三十年前，在1995年10月，天文学家米歇尔·马约尔和迪迪埃·奎洛兹在该天文台宣布了一项重大的发现。他们使用精密的光谱仪发现了一颗围绕51 Peg运行的行星，这是首颗已知围绕类太阳恒星运行的系外行星。马约尔和奎洛兹使用光谱仪测量了恒星径向速度的变化，径向速度是由于行星引力牵引而造成的规律性摆动。这颗行星被命名为51 Pegasi b，其质量至少是木星质量的一半，轨道周期为4.2天。这使得该系外行星与其母恒星的距离比水星与太阳的距离还要近得多。他们的发现迅速得到证实，马约尔和奎洛兹最终在2019年获得了诺贝尔物理学奖。现在，51 Pegasi b被认为是被亲切称为「热木星」的系外行星类型之原型，并于2015年正式命名为Dimidium，拉丁语意为「一半」。自从30年前被发现以来，已有超过6,000颗系外行星被发现。
明日的图片: light-weekend
Due to the lapse in federal government funding, NASA is not updating APOD website. We sincerely regret this inconvenience.
由于美国联邦政府资金中断，NASA目前暂停更新APOD网站。对此带来的不便，我们深感抱歉。
英文原文:
Explanation: It’s only 50 light-years to 51 Pegasi. That star’s position is indicated in this snapshot from August 2025, taken on a night with mostly brighter stars visible above the dome at Observatoire de Haute-Provence in France. Thirty years ago , in October of 1995, astronomers Michel Mayor and Didier Queloz announced a profound discovery made at the observatory. Using a precise spectrograph they had detected a planet orbiting 51 Peg, the first known exoplanet orbiting a sun-like star. Mayor and Queloz had used the spectrograph to measure changes in the star’s radial velocity , a regular wobble caused by the gravitational tug of the orbiting planet. Designated 51 Pegasi b , the planet was determined to have a mass at least half of Jupiter’s mass and an orbital period of 4.2 days. That made the exoplanet much closer to its parent star than Mercury is to the Sun. Their discovery was quickly confirmed and Mayor and Queloz were ultimately awarded the Nobel Prize in physics in 2019. Now recognized as the prototype for the class of exoplanets fondly known as hot Jupiters , 51 Pegasi b was formally named Dimidium , Latin for half, in 2015. Since its discovery 30 years ago, over 6,000 exoplanets have been found.
