太阳（Sun）是一颗普通的恒星，目前在赫-罗图上度过了主序生涯的一半左右。它是一个质量为1989.1亿亿亿吨(约为地球质量的33万倍)、直径139.2万km（约为地球直径的109倍）的热气体（严格说是等离子体）球。其平均密度为水的1.4倍，但这一平均密度隐含着很宽的密度范围，从超高密的核心到稀薄的外层。

The sun is an ordinary star, which has spent about half of its main sequence career on the H-R diagram. It is a hot gas (plasma) sphere with a mass of 19.91 billion tons (about 330000 times the mass of the earth) and a diameter of 1.392 million km (about 109 times the diameter of the earth). Its average density is 1.4 times that of water, but it implies a wide range of density, from the ultra-high density core to the thin outer layer.

太阳知识手抄报

作为一颗恒星太阳，其总体外观性质是，光度为383亿亿亿瓦，绝对星等为4.8，他是一颗黄色G2型矮星，有效温度等于开氏5800度。太阳与在轨道上绕它公转的地球的平均距离为149597870km（499.005光秒或1天文单位）。按质量计，它的物质构成是71%的氢、26%的氦和少量重元素。太阳圆面在天空的角直径为32角分，与从地球所见的月球的角直径很接近，是一个奇妙的巧合（太阳直径约为月球的400倍而离我们的距离恰是地月距离的400倍），使日食看起来特别壮观。

As a star, the overall appearance of the sun is 38.3 billion watts in luminosity and 4.8 in absolute magnitude. It is a yellow G2 dwarf with an effective temperature equal to 5800 degrees Kelvin. The average distance between the sun and the earth in orbit is 149597870km (499.005 light seconds or 1 astronomical unit). By mass, it consists of 71% hydrogen, 26% helium and a small amount of heavy elements. The angular diameter of the solar circle in the sky is 32 minutes, which is very close to the angular diameter of the moon seen from the earth. It is a wonderful coincidence (the diameter of the sun is about 400 times the diameter of the moon and the distance from us is just 400 times the distance between the earth and the moon), which makes the solar eclipse look particularly spectacular.

由于太阳比其他恒星离我们近得多，其视星等达到-26.8，成为地球上看到最明亮的天体。太阳每25.4天自转一周（平均周期；赤道比高纬度自转得快），每2亿年绕银河系中心公转一周。太阳因自转而呈轻微扁平状，与完美球形相差0.001%,相当于赤道半径与极半径相差6km（地球这一差值为21km，月球为9km，木星9000km，土星5500km）。

As the sun is much closer to us than other stars, its apparent magnitude reaches - 26.8, making it the brightest object on earth. The sun rotates once every 25.4 days (average period; the equator rotates faster than high latitude), and once every 200 million years around the center of the galaxy. The sun is slightly flat due to rotation, 0.001% different from the perfect sphere, which is equivalent to 6km difference between the equatorial radius and the polar radius (the difference is 21km for the earth, 9km for the moon, 9000km for Jupiter and 5500km for Saturn).