Red giant · Gemini

Propus

Also known as: η Geminorum (η Gem), HIP 29655

mag 3.3390 light-years

About

Propus (η Geminorum) is a red giant of magnitude 3.3 in Gemini, about 390 light-years away.

Propus is in the constellation Gemini.
Best evenings: around early February it is highest at about 9 pm (10 pm in summer time); a month earlier, two hours later.
Where on Earth: it is seen well, at least 10° up, from north of 57° S.

When it rises and sets tonight, how high it climbs and how much the Moon gets in the way are worked out in your browser for your place.

EyesVisible from the suburbs on a clear night, but lost in bright city skies.
Binoculars (10×50)A sharp point; binoculars bring out its colour and the fainter stars around it.
Telescope (6–8 inch)Still a point of light at any magnification — stars are too far away to show a disc. Low in the sky, bright stars twinkle and flash colours.

Stars look the same in any instrument: brighter and sharper, but never bigger.

Proper name	Propus
Designation	η Geminorum (η Gem)
Hipparcos number	HIP 29655
Type	Red giant
Spectral type	M3III
Colour	Orange-redB−V colour index 1.60
Magnitude	3.3The smaller the number, the brighter.
Distance	390 light-yearsThe light you see left it around 1640.
Proper motion	0.063″ per year across the sky
Constellation	Gemini
Right ascension (J2000)	06h 14m 52.7s
Declination (J2000)	+22° 30′ 24″