What powers the Heart Nebula? The large emission nebula dubbed IC 1805 looks, in whole, like a human heart. The nebula glows brightly in red light emitted by its most prominent element: hydrogen. The red glow and the larger shape are all created by a small group of stars near the nebula's center. A close up in high dynamic range (HDR) spanning about 30 light years contains many of these stars is shown above. This open cluster of stars contains a few bright stars nearly 50 times the mass of our Sun, many dim stars only a fraction of the mass of our Sun, and an absent microquasar that was expelled millions of years ago. The Heart Nebula is located about 7,500 light years away toward the constellation of Cassiopeia.

心形星云的成因何在?這團整個看起來就像人類的心臟的大發射星云被命名為IC 1805。心型星云明亮的紅光閃耀天際并發出最耀眼的氫元素。紅光和這樣的形狀都是由該星云中心附近一小群恒星所致。在封閉的高動態范圍(HDR)跨越大約30光年內包含圖中所示的這些恒星。這個疏散星團包含一些質量近我們的太陽近50倍的明亮恒星,許多微弱的星星只有太陽質量的一小部分并且缺席的微類星體在百萬年前就已經被排除。心型星云距離仙后星座約7500光年。