为什么星团能帮我们估算恒星年龄？
Why do clusters help estimate stellar ages?
同一星团的恒星几乎同龄但质量不同，质量大的演化更快；看哪些质量的星已离开主序就能反推年龄。
Cluster stars share an age but differ in mass; since massive ones evolve faster, seeing which masses left the main sequence reveals the age.
难度 专业 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Carroll & Ostlie,《An Introduction to Modern Astrophysics》第2版,Cambridge University Press,2017
B. W. Carroll and D. A. Ostlie, An Introduction to Modern Astrophysics, 2nd ed., Cambridge University Press, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-1-108-42216-1 (2nd ed., Cambridge Univ. Press)
#主序 #恒星年龄
疏散星团和球状星团有什么不同？
How do open and globular clusters differ?
差别在数目、年龄和位置。疏散星团只有几百颗星，束缚松散、形状不规则，是近期由星际云坍缩而成，重元素偏多，多在银盘与旋臂上；球状星团有几十万到上百万颗，被自身引力压成致密球形，金属丰度低，年龄接近银河系本身，在银晕里。易混的是疏散星团终会瓦解：恒星逐个逃逸，加上与分子云擦肩的潮汐扰动，几亿年就散干净，所以太阳的出生星团早已不见；球状星团势阱深才撑到现在。
The differences lie in membership, age and location. An open cluster holds only a few hundred stars, loosely bound and irregular in shape; it condensed from interstellar gas relatively recently, is comparatively rich in heavy elements, and mostly sits in the galactic disk and spiral arms. A globular cluster may contain hundreds of thousands to over a million stars, compressed by its own gravity into a dense sphere, metal-poor and nearly as old as the Galaxy itself, orbiting in the halo. What gets mixed up is that open clusters are doomed to disperse: stars leak away one by one and tidal shocks from passing molecular clouds strip the rest, so a few hundred million years is enough to scatter them, which is why the Sun's birth cluster is long gone; globulars survive because their deeper potential wells hold on.
难度 进阶 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Carroll & Ostlie,《An Introduction to Modern Astrophysics》第2版,Cambridge University Press,2017
B. W. Carroll and D. A. Ostlie, An Introduction to Modern Astrophysics, 2nd ed., Cambridge University Press, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-1-108-42216-1 (2nd ed., Cambridge Univ. Press)
#疏散星团 #球状星团
天上成片的一群星叫什么？
What do we call a group of stars together in the sky?
叫星团，是同一时期诞生、彼此靠引力松散聚集的一群恒星，如昴星团（七姊妹星团）。
They're star clusters—groups of stars born together and loosely bound by gravity, like the Pleiades.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Carroll & Ostlie,《An Introduction to Modern Astrophysics》第2版,Cambridge University Press,2017
B. W. Carroll and D. A. Ostlie, An Introduction to Modern Astrophysics, 2nd ed., Cambridge University Press, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-1-108-42216-1 (2nd ed., Cambridge Univ. Press)
#星团 #昴星团