# Matar (Eta Pegasi)

Matar (Eta Pegasi) is a star in the constellation Pegasus, magnitude 3.0.

**‘The lucky star of rain’: a yellow giant in Pegasus that has slowed its spin to a crawl.**

Matar’s name promised rain. It comes from the Arabic Sa‘d al-Maṭar, ‘the lucky star of rain’, and the US Navy later named a cargo ship, USS Matar, after it.

It is really [two stars](https://astropilot.space/glossary/double-star). The brighter is a yellow giant of about three and a half solar masses that has swollen to more than 24 times the Sun’s radius and shines about 331 times as brightly. A smaller, hotter main-sequence partner circles it every 813 days on a slightly stretched orbit.

As the giant expanded, its spin slowed, the way a twirling skater slows by spreading her arms. It now turns only about once every 818 days — close to the time its partner takes to go round it.

Matar (Eta Pegasi) is 210 light-years away: the light we see from it set off around 1815, 30 years before Neptune was discovered.

## Did you know?

- **The Resting Palace.** Chinese astronomers grouped Matar with five other stars of Pegasus as Lì Gōng, the Resting Palace. Matar is its fourth star.
- **More family, perhaps.** Two more yellow G-type stars lie farther out from the main pair. Nobody yet knows whether they really belong to the system.

A yellow 3rd-magnitude giant about five degrees west-north-west of Scheat, the north-west corner of the Great Square of Pegasus, marking one of the horse’s forelegs. Compare its yellow with Scheat’s deeper orange.

## When and where to see it

It is best placed in the evening sky around October, when it crosses the meridian at about 10 pm local time (around midnight in September). It can be seen from everywhere north of 60°S and never sets north of 60°N.

At its highest it stands 70° up from 50°N, 85° up from 35°N, 60° up from the equator, 25° up from 35°S.

## Facts

- Type: Star
- Constellation: Pegasus
- Designations: Eta Pegasi, η Peg, 44 Peg, HR 8650, HD 215182, HIP 112158
- Magnitude: 3.0
- Position: RA 22h 43.0m, Dec +30° 13′ (J2000)
- Spectral type: G8II+F0V
- Colour: orange (B−V 0.86)
- Distance: 210 light-years
- Discovered: Known since antiquity

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