Capella, two giant stars in one point of light

Capella is the brightest star in Auriga, the Charioteer, and the first-magnitude star nearest the north celestial pole. What looks like one yellowish star is two giant stars circling each other every 104 days.

Where is it from where I am?

How to spot it: Yellowish and brilliant: the first-magnitude star nearest the north celestial pole. Source (opens in a new tab)

Two giants

Jim Kaler (opens in a new tab) explains that Capella is a pair of similar giant stars, classes G8 and G0, so close together that separating them took interferometry and the Hubble Space Telescope. They orbit each other in 104 days, 0.72 astronomical units apart. ESA's list (opens in a new tab) ranks the combined light sixth and gives the distance as 42 light-years.

The She-Goat and her Kids

The name means "the She-Goat" (opens in a new tab), from Roman times. Just south of Capella a thin triangle of fainter stars is an asterism called the Kids.

How to find it

On early winter evenings at mid-northern latitudes, Capella shines almost overhead (opens in a new tab). Kaler groups it with Arcturus of spring and Vega of summer as the three bright stars spread around the northern sky: Arcturus orange, Vega white and Capella yellow-white between them.

Where on Earth, and when

It rises from anywhere north of about 44°S.

North of about 44°N, it never sets.

It climbs at least 20° high, the finder's threshold for a suggestion, from anywhere north of about 24°S.

It is highest in the evening sky, at about 9 p.m. local time, in mid-January, from either hemisphere, wherever it rises. With daylight saving time, that is nearer 10 p.m. on the clock.

Worked out by this site from the Bright Star Catalogue, for a flat, clear horizon. Hills, buildings, haze and city light all cut into this; the air also lifts objects near the horizon by about half a degree. For your own place and night, use the sky finder.