| DC 欄位 |
值 |
語言 |
| DC.contributor | 天文研究所 | zh_TW |
| DC.creator | 李建德 | zh_TW |
| DC.creator | Chien-De Lee | en_US |
| dc.date.accessioned | 2009-6-23T07:39:07Z | |
| dc.date.available | 2009-6-23T07:39:07Z | |
| dc.date.issued | 2009 | |
| dc.identifier.uri | http://ir.lib.ncu.edu.tw:88/thesis/view_etd.asp?URN=952209009 | |
| dc.contributor.department | 天文研究所 | zh_TW |
| DC.description | 國立中央大學 | zh_TW |
| DC.description | National Central University | en_US |
| dc.description.abstract | Classical Be星為演化至主序末期且自轉快速(300km/s)的星球，它們的觀測特徵為光譜中的發射線以及超過光球的紅外輻射。其紅外超量源於離子氣體的自由態間發射。然而，少數J-H及H-K皆大於0.6星等者，則是Classical Be星沿赤道表面的氣體拋出後，凝華為塵埃。這些塵埃吸收星光後，產生明顯的紅外超量。本文計算電漿的自由態間發射，貢獻在紅外超量所達到的極限。並且針對六顆具有高度紅外超量Be星球探討其演化的狀態。
| zh_TW |
| dc.description.abstract | Classical Be stars are B-type main sequence stars with one or more Balmer lines in emission, characterized by their rotational velocity (up to 300 km s−1), and circumstellar gas distributed in shell-, disk- or ring like configuration. Classical Be stars also are associated with infrared excess attibuted to free-free emission from ionized gas. A few with exceptionally large infrared excess, namely with J-H, and H-K both greater than 0.6 mag, however, must be accounted for by thermal emission from circumstellar dust which is condensed out in the flattened, expanding envelope as these fast-rotating stars evolve to the giant phase. This thesis calculates the extent plasma free-free emission can contribute to the near-infrared excess observed in the JHK color-color diagram and in the spectral energy distribution seen in the classical Be stars. We made detailed studies of 6 Be stars that show large JHK excess, and clarify their status of being classical Be stars, as opposed to Herbig Ae/Be stars, which are intermediate-mass pre-main sequence stars, whose infrared excess arise from surplus star forming circumstellar dust.
| en_US |
| DC.subject | 恆星 | zh_TW |
| DC.subject | 紅外超量 | zh_TW |
| DC.subject | color-color diagram | en_US |
| DC.subject | spectral energy distribution | en_US |
| DC.subject | IR excess | en_US |
| DC.subject | Herbig Ae/Be stars | en_US |
| DC.subject | Classical Be stars | en_US |
| DC.title | Classical Be 星球的紅外超量輻射 | zh_TW |
| dc.language.iso | zh-TW | zh-TW |
| DC.title | Near Infrared Excess of Classical Be star | en_US |
| DC.type | 博碩士論文 | zh_TW |
| DC.type | thesis | en_US |
| DC.publisher | National Central University | en_US |