# Sheratan (Beta Arietis)

Sheratan (Beta Arietis) is a star in the constellation Aries, magnitude 2.6.

**A hot white star in the Ram’s horn, with a faint partner much like our Sun.**

Sheratan’s faint companion is a near-match for the Sun. The two stars swing around each other every 107 days on a stretched orbit, too close to split in an ordinary telescope. The Mark III Stellar Interferometer at Mount Wilson resolved them, letting astronomers weigh both: the leader is a hot white A-type star, the follower a G2 dwarf — the same [type](https://astropilot.space/glossary/spectral-type) as our Sun.

The brighter star spins at least 73 kilometres per second, which smears out the lines in its spectrum, and it may have a mildly peculiar chemistry. As it ages and swells towards a red giant, it is expected to pour gas onto its Sun-like partner.

The name comes from the Arabic for “the two signs”. Several thousand years ago Sheratan and its neighbour Mesarthim, Gamma Arietis, marked the spring equinox, where the Sun crosses the celestial equator heading north.

Sheratan (Beta Arietis) is 59 light-years away: the light we see from it set off in 1967, around the time Apollo 11 landed on the Moon.

## Did you know?

- **The Bond.** Chinese astronomers grouped Sheratan with Hamal and Mesarthim as Lóu, the Bond. Sheratan is its first star.
- **No dust found.** The Spitzer Space Telescope searched for the infrared glow of a dusty disc around Sheratan, like those around Vega and Fomalhaut, but found none.

A white star of magnitude 2.6 in the short, bent line of three stars that marks the head of Aries, between orange Hamal and fainter Mesarthim. Mesarthim, just to its south, is a fine double star for a small telescope.

## When and where to see it

It is best placed in the evening sky around November, when it crosses the meridian at about 10 pm local time (around midnight in October). It can be seen from everywhere north of 69°S and never sets north of 69°N.

At its highest it stands 61° up from 50°N, 76° up from 35°N, 69° up from the equator, 34° up from 35°S.

## Facts

- Type: Star
- Constellation: Aries
- Designations: Beta Arietis, β Ari, 6 Ari, HR 553, HD 11636, HIP 8903
- Magnitude: 2.6
- Position: RA 1h 54.6m, Dec +20° 48′ (J2000)
- Spectral type: kA4hA5mA5Va
- Colour: white (B−V 0.13)
- Distance: 59 light-years
- Discovered: Known since antiquity

Open AstroPilot to see when Sheratan (Beta Arietis) is highest tonight from your location, how easy it is with your telescope or binoculars, and an eyepiece view. https://astropilot.space/object/sheratan