ALMA Discovery of Dust Belts around Proxima Centauri
ALMA Discovery of Dust Belts around Proxima Centauri
复制标题
DOI：
10.3847/2041-8213/aa978b
复制
发表时间：
2017-11-20
影响因子：
7.9
通讯作者：
Rodriguez, Eloy
中科院分区：
文献类型：
--
作者：
Anglada, Guillem;Amado, Pedro J.;Rodriguez, Eloy
半人马座比邻星是离太阳最近的恒星，已知在温带轨道上至少有一颗类地行星。在这里，我们报告了阿塔卡马大型毫米/亚毫米阵列（ALMA）在1.3毫米波长下探测到这颗恒星，并在大约1到4 au的距离上发现了环绕它的尘埃带。考虑到比邻星的低亮度，我们估计这颗尘埃的特征温度约为40 K，这可能构成了太阳系柯伊伯带的小规模模拟物的尘埃成分。估计的总质量，包括尘埃和大小不超过50公里的天体，大约是地球质量的0.01倍，这与太阳柯伊伯带的质量相似。我们的数据还显示，在离恒星更近的地方有一些温暖的尘埃。我们还发现了可能与比邻星系统有关的两个额外特征的迹象，这些特征仍需要进一步的观测来证实：在大约30天文单位的恒星周围有一个极冷（约10 K）的外部带，其轨道平面相对于天空平面倾斜约45度；此外，我们在距离恒星约1.2弧秒的投影距离处探测到一个紧凑的1.3毫米发射源，其性质尚不清楚。
Proxima Centauri, the star closest to our Sun, is known to host at least one terrestrial planet candidate in a temperate orbit. Here we report the Atacama Large Millimeter/submillimeter Array (ALMA) detection of the star at 1.3 mm wavelength and the discovery of a belt of dust orbiting around it at distances ranging between 1 and 4 au, approximately. Given the low luminosity of the Proxima Centauri star, we estimate a characteristic temperature of about 40 K for this dust, which might constitute the dust component of a small-scale analog to our solar system's Kuiper Belt. The estimated total mass, including dust and bodies up to 50 km in size, is of the order of 0.01 Earth masses, which is similar to that of the solar Kuiper Belt. Our data also show a hint of warmer dust closer to the star. We also find signs of two additional features that might be associated with the Proxima Centauri system that still require further observations to be confirmed: an outer extremely cold (about 10 K) belt around the star at about 30 au, with an orbital plane that is tilted about 45 degrees with respect to the plane of the sky; additionally, we marginally detect a compact 1.3 mm emission source at a projected distance of about 1.2 arcsec from the star, the nature of which is still unknown.