31 Orionis
31 Orionis is a binary star system in the equatorial constellation of Orion, located near the bright star Mintaka. It is visible to the naked eye as a faint, orange-hued point of light with a baseline apparent visual magnitude of 4.71. The distance to this system is approximately 490 light years away based on parallax, and it is drifting further away with a mean radial velocity of +6 km/s.

As of 2008, the pair had an angular separation of . The brighter member, designated component A, is an aging giant star with a stellar classification of K5III. It is reported as a semi-regular variable with magnitude ranging from 4.68 to 4.72 over 141 days, although the General Catalogue of Variable Stars describes this as unconfirmed by subsequent observations. It has the variable star designation CI Orionis, while "31 Orionis" is the Flamsteed designation. The magnitude 10.2 companion star, component B, is an F-type main-sequence star with a class of F7V.
Q50053
binary star
Concept
Q187646
equatorial
Concept
Q8928
constellation
Concept
Q8860
Orion
Concept
Q680341
Mintaka
CEL
Q124313
apparent visual magnitude
Concept
Q531
light year
Concept
Q906561
parallax
Concept
Q240105
radial velocity
Concept
Q1357788
angular separation
Concept
Q5875
giant star
Concept
Q25377588
stellar classification
Concept
Q593448
variable star designation
Concept
Q111116
Flamsteed designation
Concept
Q1353952
F-type main-sequence star
Concept
Q3598853
31 Orionis
CEL
Q3598853
31 Orionis
CEL
2008-01-01T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
2008
DATE
+31^^http://www.w3.org/2001/XMLSchema#decimal
31
NUMBER
+4.71^^http://www.w3.org/2001/XMLSchema#decimal
4.71
NUMBER
++6^^http://www.w3.org/2001/XMLSchema#decimal
+6
NUMBER
+5^^http://www.w3.org/2001/XMLSchema#decimal
5
NUMBER
+4.68^^http://www.w3.org/2001/XMLSchema#decimal
4.68
NUMBER
+4.72^^http://www.w3.org/2001/XMLSchema#decimal
4.72
NUMBER
+31^^http://www.w3.org/2001/XMLSchema#decimal
31
NUMBER
+10.2^^http://www.w3.org/2001/XMLSchema#decimal
10.2
NUMBER
+7^^http://www.w3.org/2001/XMLSchema#decimal
7
NUMBER
constellation
apparent magnitude
instance of
constellation