Gienah (Gamma Corvi)
Gienah (Gamma Corvi) is a star in the constellation Corvus, magnitude 2.6.
The Crow’s brightest star — whose calm atmosphere is unusually rich in mercury.
Gienah’s atmosphere is sorting itself out. In this calm, hot star the elements slowly separate — some sinking, others drifting upwards — and the surface ends up with far more mercury and manganese than normal. Astronomers call it a mercury-manganese star.
It is a blue-white giant of about four times the Sun’s mass and width, with a surface near 12,000 K, twice as hot as the Sun’s. A much smaller, cooler star of about 0.8 solar masses circles it, perhaps once every 158 years.
The name comes from an Arabic phrase in Ulugh Beg’s star catalogue meaning “the right wing of the crow” — though on modern charts it marks the left wing. Epsilon Cygni was also called Gienah, so the IAU gave the name to this star in 2016, and the Swan’s star became Aljanah.
Gienah (Gamma Corvi) is 150 light-years away: the light we see from it set off around 1875, around the time Edison lit his first practical light bulb — the start of light pollution.
Did you know?
- The Chariot. In Chinese astronomy Gienah is the first star of Zhěn, the Chariot — a group formed by the four bright stars of Corvus.
- Dextra ala Corvi. The Calendarium of Al Achsasi al Mouakket listed it as Djenah al Ghyrab al Eymen, translated into Latin as Dextra ala Corvi — the Crow’s right wing.
A blue-white star of magnitude 2.6 at the north-western corner of Corvus, the Crow’s lopsided four-sided figure. Find bright Spica, then look west for the Crow. Its 10th-magnitude companion, about an arcsecond away, is beyond most backyard telescopes.
When and where to see it
It is best placed in the evening sky around April, when it crosses the meridian at about 10 pm local time (around midnight in March). It can be seen from everywhere south of 72°N and never sets south of 72°S.
At its highest it stands 22° up from 50°N, 37° up from 35°N, 72° up from the equator, 73° up from 35°S.
Facts
- Type
- Star
- Constellation
- Corvus
- Designations
- Gamma Corvi, γ Crv, 4 Crv, HR 4662, HD 106625, HIP 59803
- Magnitude
- 2.6
- Position
- RA 12h 15.8m, Dec −17° 33′ (J2000)
- Spectral type
- B8III
- Colour
- blue-white (B−V -0.11)
- Distance
- 150 light-years
- Discovered
- Known since antiquity
Open AstroPilot to see when Gienah (Gamma Corvi) is highest tonight from your location, how easy it is with your telescope or binoculars, and an eyepiece view.