All red giants are variable stars . the core keeps on contracting and heating up until it is hot enough for the 所有红巨星都是变星，当外壳不断膨胀，氦核心同时不断收缩加热，直至足以燃烧氦我们称之为
This makes space telescope invaluable for identifying a rare class of pulsating stars , called cepheid variable stars embedded within m100 ' s spiral arms 这对于从m100的旋臂中分辨出暗藏的造父变星有着莫大价值。
In 1784 , john gooddricke , a 19 - year old british astronomer discovered that delta cephei was a variable star with a period of 5 . 4 days . two years later , this dumb and deaf genius suddenly passed away 两年后，这位聋哑天才遽然逝世，但他的发现却把人类对天体距离的测度向前推展超过一亿光年！仙王座的
Astronomers made observations of cepheid variable stars [ pictured above ] ? pulsating stars used to measure vast distances ? in the virgo and other clusters to establish the expansion rate and the universe ' s age 天文学家用哈勃观测到仙女星座和其它星群中的造父变星(如图) ，以确定宇宙的膨胀速度和宇宙的年龄。
It analyses company of the value and controllable variable star according to the positive method , such as company of scale , velocity of share circulation , market shares and relevance of the trade value of goodwill , to test five hypothesizes on its value 其中商誉的交易价值大小表现为股票的流通股价格和产品交易价格超过它们各自符合假定市场公正平均价格的差额。
Sometimes , in a binary star system , one star will pass in front of the other producing what we call eclipsing binary . it can be treated as a special kind of visual binary . eclipsing binary systems are variable stars see below ：有些双星系统，其中一颗星会在另一颗星前经过，产生周期性的光度变化，我们称这种双星为食双星，基本上我们可以把食双星看成为目视双星的一种。
Based on the viewpoint of interaction between waves in plasmas , the partial differential equation that causes the spectral lines broadening has been deduced from radiation transfer equation of high - frequency electromagnetic waves in plasmas . the numerical solution has been obtained by using the fortran program we compiled . we concretely calculated the spectral lines widths of and fraunhoferx 3704 in corona , fj / a4923 . 9 in dwarf nova oy car and f . / a4934 in the variable star rr lyrae 本文从等离子体波与波相互作用观点出发，由高频电磁波辐射转移方程导出了引起谱线宽度变化的偏微分方程，编写fortran程序求解偏微分方程的数值解，具体计算了日冕绿线f _ exiv 5303和夫朗禾费线3704 、矮新星oycarf _ eii 4923 . 9 、天琴rr型变星f _ ei 4934的谱线加宽值，对以上各谱线加宽中的等离子体致宽效应作了初步计算。
