Located relatively close at 36.7 light-years from the Sun, Arcturus is a red giant of spectral type K1.5III—an aging star around 7.1 billion years old that has used up its core hydrogen and evolved off the main sequence.

Arcturus, also known as Alpha Boötis, is one of the brightest stars in the northern hemisphere. In fact, it is the third brightest individual star in the entire night sky behind Sirius and Canopus. At times, it is referred to as the fourth brightest star in the night sky, behind Alpha Centauri, when binary stars are included.

2022年2月11日 · Arcturus is a red giant star in the Northern Hemisphere of Earth 's sky and the brightest star in the constellation Boötes (the herdsman). Arcturus is also among the brightest...

2020年10月13日 · Arcturus is a fine example of a red giant star — impressively large, accordingly rarefied, brilliantly bright, and surprisingly cool. Arcturus possesses only slightly more mass than the Sun, but expands that material into a radius about 25 times larger.

Arcturus is the brightest star in the constellation Boötes and the fourth-brightest star in the night sky. It is a red giant star approximately 36.7 light-years away from Earth. With an apparent magnitude of -0.05, Arcturus is one of the most luminous stars in the Sun's neighborhood and is often used in celestial navigation.

2023年6月9日 · Arcturus, Alpha Boötis (α Boo), is a red giant star located 36.7 light-years away in the northern constellation Boötes. With an apparent magnitude of -0.05, it is the brightest star in Boötes and the 4th brightest star in the sky.

2023年11月30日 · If you're curious to learn about Arcturus, one of the brightest stars in the night sky, read on for interesting facts on how it can be spotted with the naked eye, fascinating discoveries, and more interesting facts about Arcturus star.

The star Arcturus, also known as Alpha Boötis, is a star in the Boötes constellation in the northern sky. It is the brightest star in Boötes and the fourth brightest star in the night sky, with an apparent magnitude of -0.05.

2025年2月19日 · Arcturus, the fourth brightest star in the night sky, and the brightest star in the northern constellation Boötes, with an apparent visual magnitude of −0.05. It is an orange-coloured giant star 36.7 light-years from Earth.

2024年6月28日 · Arcturus is the brightest star in the northern sky, easily visible without a star chart. This brilliant orange-red star, found in the constellation Boötes (boh- OH -teez) the Herdsman, is around 36.7 light-years from Earth. Arcturus’ distinctive reddish hue reflects its …