行星狀星雲

出自維基百科,自由嘅百科全書
貓眼星雲,行星狀星雲之一

行星狀星雲係一種天體,係低質量恆星(質量係0.1至1個太陽質量)死嗰陣嘅一種狀態,外圍有由等離子構成嘅發光氣體外殼,中心就係裸露嘅核心(白矮星)。佢哋實際同行星無關係,只係因為通過光學望遠鏡睇落好似例如木星咁嘅巨型氣體行星,所以有呢個名。

概論[編輯]

內文:發射星雲

行星狀星雲係發射星雲嘅一種,呢類星雲係低質量恆星(例如係太陽)生命終結嘅產物:喺一粒噉嘅恆星生命就嚟要結束,即係內部嘅氫燃料就快用完嗰陣,佢會演變成一粒紅巨星(red giant),並且將佢最外部嘅物料射向四周圍嘅太空,令到佢周圍嘅太空有咗一浸氣體喺度;而當佢喪失質量喪失到咁上下嗰時,佢會變成一粒白矮星(white dwarf)-佢溫度會上升,而且會開始射出大量嘅紫外線,啲紫外線會令到佢周圍嗰啲之前射咗出去嘅氣體離子化,跟手呢啲離子化嘅物料就會發光,形成一笪電離氫區(所以一嚿行星狀星雲實係本身識發光嘅)。呢啲機制喺行星狀星雲嘅外觀嗰度會睇到-行星狀星雲嘅一個大特徵係中心會有一粒星喺度發光。行星狀星雲通常頂櫳都只係會維持幾千年左右,以天文現象嚟講短暫得好交關[1][2]

根據天文物理學家嘅計算,太陽估計會喺 120 億年老嗰時變成行星狀星雲[3]

[編輯]

  1. They are created after the red giant phase, when most of the outer layers of the star have been expelled by strong stellar winds Frew & Parker 2010, pp. 129–148.
  2. Aller, Lawrence H.; Hyung, Siek (2003), "Historical Remarks on the Spectroscopic Analysis of Planetary Nebulae (invited review)", in Kwok, Sun; Dopita, Michael; Sutherland, Ralph (eds.), Planetary Nebulae: Their Evolution and Role in the Universe, Proceedings of the 209th Symposium of the International Astronomical Union held at Canberra, Australia, 19-23 November, 2001, 209, Astronomical Society of the Pacific.
  3. Chaisson, E.; McMillan, S. (1995). Astronomy: a beginner's guide to the universe (2nd ed.). Upper Saddle River, New Jersey: Prentice-Hall.