Main-Sequence Stars with Circumstellar Solid Material - the VEGA Phenomenon
Main-Sequence Stars with Circumstellar Solid Material - the VEGA Phenomenon
复制标题
具有环星固体物质的主序星——织女星现象
DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
F. Paresce
中科院分区：
文献类型：
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作者：
D. Backman;F. Paresce
讨论了在 IRAS 任务早期围绕三颗附近的 A 主序星：天琴座阿尔法星（织女星）、南鱼座阿尔法星（北落师门）和绘架座β 周围的温度为 50 至 125 K 且分数测热光度在 10 exp -5 至 10 exp -3 范围内的固体颗粒的探测。发射的空间分辨率表明：颗粒比星际颗粒大，物质可能位于恒星赤道面的盘中，盘延伸到距恒星100到1000天文单位的距离，而中心恒星周围半径几十个天文单位的区域相对空旷。随后对 IRAS 数据的调查显示，所有光谱类别的 100 多颗主序星都具有未解决的过剩问题，其温度和分数光度与三个原型相似。一些过度恒星的年龄估计为 1 至 5 Gyr。因此，主序远红外过剩似乎很普遍，并且存在于足够古老的系统中，可能已经过了活跃行星形成阶段。
The detection of solid grains with temperatures of 50 to 125 K and fractional bolometric luminosities in the range 10 exp -5 to 10 exp -3 early in the IRAS mission around three nearby A main-sequence stars, Alpha Lyrae (Vega), Alpha Piscis Austrinus (Fomalhaut), and Beta Pictoris, is discussed. Spatial resolution of the emission indicates that: the grains are larger than interstellar grains, the material probably lies in disks in the stellar equatorial planes, the disks extend to distances of 100 to 1000 AU from the stars, and zones a few tens of AU in radius around the central stars are relatively empty. Subsequent surveys of IRAS data reveal more than 100 main-sequence stars of all spectral classes having unresolved excesses with similar temperatures and fractional luminosities to the three prototypes. Some stars with excesses have estimated ages of 1 to 5 Gyr. Thus, main-sequence FIR excesses appear to be widespread and are present in systems old enough to be probably past the stage of active planet formation.