h an H-beam steel H形鋼條。 an H-Post H形電桿。 drop one's h's 不發h音〔如倫敦方言中把 hat 讀作'at 〕。 H hour 【軍事】發起攻擊的時間;特定軍事行動開始的時刻。 = 【電學】 henry; 【化學】 hydrogen; 【物理學】磁場密度 (intensity of magnetic field), 地磁水平分量 (the horizontal component of terrestrial magnetism); 〔表示鉛筆芯硬度的符號〕= hard(ness); 〔俚語〕heroin. H1 = 【化學】protium. H1+ = 【物理學】proton. H2 = 【化學】deuterium. H3 = 【化學】tritium.
In the h - r diagram below , our sun is now in the main sequence 在以下的赫羅圖中,太陽正位于主序上。
From the two h - r diagrams below , we can also tell which cluster is older and which is younger 由以下兩幅赫羅圖中,我們可斷言右圖表示的星團比較年老。
Before the interstellar cloud contracts , it was very cold and dim . thus , the cloud is represented by a point at the right in the h - r diagram 在星際云收縮之前,它非常冰冷,所以在這個階段,星際云會位于赫羅圖上一個極右的位置。
Upon contraction under its own gravity , the interstellar cloud heats up , and thus moving to the left in the diagram . note that the position of a star in the h - r diagram shows its physical properties , not its position in the sky 當星際云收縮,它會變得越來越熱,而它在赫羅圖上的位置亦會向左移動注意:恒星在赫羅圖上的位置顯示了它們的物理特性,而非其在天空的位置。
We expect stars with short life span are already dead . when we plot the stars of a cluster in the h - r diagram , we see the more massive stars , which are stars in the upper left , have already evolved off the main sequence 換句話說,星團內壽命短的星應該已經死去,當我們把星團內的星以赫羅圖的形式繪畫出來時,我們發覺位于圖中左上角的大質量恒星果然已經步入死亡階段,離開了主序星的行列。