心宿增四星云的年轻恒星

2019 November 17

Young Stars in the Rho Ophiuchi Cloud
Image Credit: NASA, JPL-Caltech, WISE

Explanation: How do stars form? To help find out, astronomers created this tantalizing false-color composition of dust clouds and embedded newborn stars in infrared wavelengths with WISE, the Wide-field Infrared Survey Explorer. The cosmic canvas features one of the closest star forming regions, part of the Rho Ophiuchi cloud complex some 400 light-years distant near the southern edge of the pronounceable constellation Ophiuchus. After forming along a large cloud of cold molecular hydrogen gas, young stars heat the surrounding dust to produce the infrared glow. Stars in the process of formation, called young stellar objects or YSOs, are embedded in the compact pinkish nebulae seen here, but are otherwise hidden from the prying eyes of optical telescopes. An exploration of the region in penetrating infrared light has detected emerging and newly formed stars whose average age is estimated to be a mere 300,000 years. That’s extremely young compared to the Sun’s age of 5 billion years. The prominent reddish nebula at the lower right surrounding the star Sigma Scorpii is a reflection nebula produced by dust scattering starlight. This view from WISE, released in 2012, spans almost 2 degrees and covers about 14 light-years at the estimated distance of the Rho Ophiuchi cloud.

心宿增四星云的年轻恒星
影像提供: NASA, JPL-Caltech, WISE

说明: 恒星是如何诞生的？为找出答案提供助力，天文学家用广角红外光巡天相机(WISE)的红外光影像数据，建构出这幅迷人的尘埃云与其内的新诞生恒星之假色组合影像。这幅宇宙画，呈现离我们约只有400光年远，位在读音独特的蛇夫座南缘之心宿增四星云复合体，一个最邻近我们的恒星形成区。当恒星诞生于庞大冰冷的氢分子云内之后，年轻的恒星会加热周遭的尘埃，并激发它们发出明亮的红外辉光。尚处在诞生过程称为年轻星体 (YSOs)的恒星，位在上面影像的粉红小亮斑内，不过可见光望远镜还看不见这种天体。只有在高透视的红外光波段探索这个区域，才得以发现许多年龄估计约只有30万年的新形成恒星。和50亿年的太阳高龄比起来，它们真的非常年轻。影像右下方的鲜明红色星云，是环拱在心宿一周围的云气，由于它内部的尘埃会散射星光，因此其分类为反射星云。这幅发布于2012年的广角红外光巡天相机影像，跨幅将近2度，以心宿增四星云所在的距离来估算，相当于14光年的区域。(译注：在这张假色照片里，反射星云的著色未选用蓝色。)