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Glossary term: 双星

Description: 双星是由两颗恒星组成的系统,它们在引力的作用下围绕共同的质心运行。它们的轨道遵循开普勒运动定律,呈椭圆形(形状像一个压扁的圆)或圆形。

银河系中一半以上的恒星要么属于双星系统,要么是有一颗以上伴星的系统(称为高阶多星系统)的一部分。由于与地球距离遥远,大多数双星和高阶多星系统在观测者看来都是单颗恒星。

根据发现双星所用的观测方法,双星可以分为如下几类,它们可能同时属于多个类别:

目视双星是直接观测即可分辨的两颗靠近的独立恒星。并不是所有看起来在天空中离得很近的两颗恒星都是受引力约束的双星,有些可能只是出于巧合在天空中看起来很近,但并不受引力约束。不受引力约束的双星可能相距数百光年。

光谱双星是由于恒星围绕它们共同的质心运行时,恒星光谱中的谱线发生了多普勒频移而被发现的。

食双星是其中一颗恒星从它的伴星和观测者之间穿过时,挡了住来自伴星的部分光线,使系统的组合光线看起来短暂变暗而被探测到的。

天体测量双星是指只能观测到一个恒星图像的系统——可能是由于其中一颗恒星太暗而无法观测到,也可能是由于两颗恒星的图像被混合在一起——但双星系统中恒星的轨道运动会导致恒星图像中最亮的点在天空中的位置发生周期性变化。

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Term and definition status: The original definition of this term in English have been approved by a research astronomer and a teacher
The translation of this term and its definition is still awaiting approval

The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".

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Related Diagrams


Carina appears as the hull of a line drawing of a ship which faces left (east). Canopus is on its right (west) edge

Carina Constellation Map

Caption: The constellation Carina along with its bright stars and surrounding constellations. Carina is surrounded by (going clockwise from the top): Vela, Puppis, Pictor, Volans, Chamaeleon, Musca and Centaurus. Carina is notable for Canopus, the second brightest star in the night sky and for the famous variable star Eta Carinae. This latter object is a binary star system of two young very massive stars. Its brightness has varied greatly over the past few centuries. At one point it outshone Canopus before dimming by a factor of four thousand to become invisible to the naked eye. In recent years it has brightened enough to again be visible without the aid of a telescope. Carina is a southern constellation and thus the whole constellation is visible at some point in the year to the entire southern hemisphere. The whole constellation is also visible from equatorial regions of the northern hemisphere with parts of the constellation visible from northern temperate regions. The open clusters NGC 2516, NGC 3532 and IC 2602 lie in Carina. These are marked here by yellow circles. The Carina Nebula, also known as NGC 3372, lies in the constellation. This large nebula contains many massive young stars, including Eta Carinae. This diagram maps an area around the south celestial pole. Here lines of constant right ascension converge. The right ascension values of these lines are marked on the x-axis above and below the diagram. Some of the lines of constant declination are marked on the y-axis. The sizes of the stars marked here relate to the star's apparent magnitude, a measure of its apparent brightness. The larger dots represent brighter stars. The Greek letters mark the brightest stars in the constellation. These are ranked by brightness with the brightest star being labeled alpha, the second brightest beta, etc., although this ordering is not always followed exactly. Carina was previously part of the larger Argo Navis constellation along with Vela and Puppis. As the letter designations for stars were created before this division took place, Greek letter designations are now divided between the three constellations with Carina having stars designated alpha and beta but no gamma or delta. The dotted boundary lines mark the IAU's boundaries of the constellations and the solid green lines mark one of the common forms used to represent the figures of the constellations. Neither the constellation boundaries, nor the lines joining the stars appear on the sky.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by the IAU and Sky & Telescope

License: CC-BY-4.0 Creative Commons 署名 4.0 国际 (CC BY 4.0) icons