Yellow-white main-sequence star · Coma Berenices

Diadem

Also known as: α Comae Berenices (α Com), HIP 64241

mag 4.358 light-years

About

Diadem (α Comae Berenices) is a yellow-white main-sequence star of magnitude 4.3 in Coma Berenices, about 58 light-years away.

Diadem is in the constellation Coma Berenices.
Best evenings: around late May 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 62° 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	Diadem
Designation	α Comae Berenices (α Com)
Hipparcos number	HIP 64241
Type	Yellow-white main-sequence star
Spectral type	F5V
Colour	YellowB−V colour index 0.46
Magnitude	4.3The smaller the number, the brighter.
Distance	58 light-yearsThe light you see left it around 1968.
Proper motion	0.46″ per year across the sky
Constellation	Coma Berenices
Right ascension (J2000)	13h 09m 59.3s
Declination (J2000)	+17° 31′ 46″