Star profile
Sigma Ophiuchi
Highly luminous starWhat is Sigma Ophiuchi
Sigma Ophiuchi is a luminous K-type giant about 901 light-years away, half-hidden in the broad body of the Serpent-Bearer. Its orange ember owes more to true luminosity than to apparent brightness: what reaches Earth is only a faint share of the light it pours into space. Distance dissolves its splendour into a modest spark, yet its spectrum betrays a deep atmosphere bright enough to illuminate whole stretches of the molecular cloud in which it ages, well away from the bustle of the galactic core.
Where it is and when to see it
Sigma Ophiuchi lies in the northern celestial hemisphere. It is visible to the naked eye under a dark sky. Its best month of the year is June, when it culminates around midnight.
- From London it culminates about 43° above the horizon.
- From New York it culminates about 53° above the horizon.
- From Sydney it culminates about 52° above the horizon.
It can be seen from anywhere north of 86° S.
It ranks no. 21 in brightness among the 88 stars of Ophiuchus in our catalogue. To find it, start from Rasalhague, the brightest: it lies about 9° away (a fist at arm's length covers about 10°).
The light you see today left it about 900 years ago.
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Astronomical data for Sigma Ophiuchi
- Constellation
- Ophiuchus
- Apparent magnitude
- 4.34
- Distance
- 901.1 light years
- Coordinates (J2000)
- RA 261.629° · Dec 4.140°
- Catalogue
- HIP 85355 · HD 157999
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Other stars in Ophiuchus
Ophiuchus has 88 stars in Stelvia's catalogue. Here are a few of them.
- RasalhagueAlpha Ophiuchi2.08
- SabikEta Ophiuchi2.43
- Zeta Ophiuchi2.54
- 45 Ophiuchi4.28
- Phi Ophiuchi4.29
- Guniibuu4.33
- Iota Ophiuchi4.39
- Xi Ophiuchi4.39