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absolute magnitude 【天文學】絕對星等。

absolute majority

The first section is concerned with a brief description of the content and methods of evaluation . the second section is concerned with rifr evaluation of actual developing projects : ( 1 ) their absolute magnitudes and relative order of four risks based on sensitivity analysis of risk index ; and ( 2 ) the comprehensive risk grade evaluation of rifr through integrating fuzzy subordinate function with fuzzy integrative evaluation method 首先概要地介紹了衡量項目投融資區域風險的內容與方法,接著研究項目投融資風險評價:通過選取風險變量和評價指標,結合敏感度分析進行風險大小排序,再進一步結合模糊隸屬度函數和模糊評價法的運用進行項目投融資區域風險的風險等級判定。

We have to use some other methods to measure the luminosity or equivalently the absolute magnitude of the cepheid variable . since we can readily measure the apparent magnitude of a cepheid variable , to measure the luminosity means measuring the distance . we use some distance measurement methods , for example , parallax , to determine the relation 要弄清這個關系,我們要知道不同造父變星的光度和光變周期數據,量度光變周期當然不是問題,但要得知一顆恒星的光度,我們首先要得知它的距離,這時便須借助好像視差法等其他量度天體距離的方法。

The second part is concerned with the comprehensive evaluation of relations between risks , their absolute magnitude and relative order of risks . methods of point rating and fuzzy integrative evaluation methods are employed here 對于整體風險的評價,則包括各類風險之間的關系,整體風險大小以及風險的排序三方面內容,主要采用了主觀評分法和模糊綜合評價法。

A typical red supergiant could be about 100 times larger than the red giant . its surface temperature is low while the total luminosity remains high , with absolute magnitude up to - 10 comparing to 4 . 8 of our sun 典型的超紅巨星比普通紅巨星大上100倍,雖然表面溫度低,但整體光度仍然非常高,絕對星等可達- 10太陽的絕對星等只有4 . 8 。

The longer the period , the brighter the star is . thus , by measuring the period of a cepheid variable , we know its absolute magnitude , hence , we can tell how far it is away by comparing with its apparent magnitude 所以,只要知道某一造父變星的周期,我們便可得知它的絕對星等,只要和它的視星等作比較,便可以求得它和我們的距離。

Two stars have the same absolute magnitude . one is thousand times farther away than the other . what is the difference in apparent magnitudes ? which magnitude larger 兩顆星具有相同的絕對星等,其中的一顆比另一顆距離遠1000倍,它們的目視星等有何不同?哪一個的星等數值大?

The hertzsprung - russell diagram serves this purpose . it is a plot of absolute magnitude against surface temperature i . e . , spectral type of stars 簡單來說,赫羅圖把大量恒星的絕對星等和表面溫度或譜型關系以圖表方式顯示出來。

This greatly simplifies the various analyses , for example , their relative apparent magnitudes are equal to their relative absolute magnitudes 當然,成員星和地球的距離亦會差不多,因此大大簡化了對成員星的分析。

We know the luminosity is directly related to the absolute magnitude . so , in practice , we usually use absolute magnitudes instead 由于光度和絕對星等有直接的對應關系,所以很多時赫羅圖會選用絕對星等。

For example , the apparent magnitude of our sun is - 26 . 8 , but its absolute magnitude is just 4 . 8 . the absolute magnitude describes the 例如太陽的視星等為- 26 . 9等,但它的絕對星等只有4 . 8等。

We can also talk about the absolute magnitudes of objects like star clusters , galaxies , etc 絕對星等的概念可推廣至星團星系等。

Problems of urbanization are widely noted and studied, not only because of their absolute magnitude but also because of their visibility . 城市化的問題正在受到廣泛的注意和研究,不僅因為這些問題十分重要,而且非常突出。