Pi2 Columbae (π² Columbae, Latinized from π² Columbae) is a multiple star system in the southern constellation of Columba, near the southern constellation border with Pictor. Its name is a Bayer designation, abbreviated Pi² Col or π² Col.
Observation Data
- Constellation: Columba
- Right ascension: 06ʰ 07ᵐ 52.860ˢ
- Declination: −42° 09′ 14.55″
- Apparent magnitude (V): 5.50
- Spectral type: A0 V + A
Characteristics
The system is white-hued and dimly visible to the naked eye with a combined apparent visual magnitude of 5.50. Based on an annual parallax shift of 12.76 mas as seen from Earth, it is located approximately 256 light-years (78 parsecs) from the Sun. The system is receding with a heliocentric radial velocity of +31 km/s.
The primary star is an A-type main-sequence star of spectral class A0 V, estimated to be 370 million years old and spinning rapidly with a projected rotational velocity of 274 km/s. It has 2.34 times the mass of the Sun and 2.23 times the Sun's radius. The star radiates 38.7 times the luminosity of the Sun from its photosphere at an effective temperature of 9,646 K.
X-ray Emission
The system is a source of X-ray emission with a luminosity of 184.3×10²⁰ W. This is considered unusual because A-type stars are not expected to display magnetic activity that would produce such emissions.
Companions
An A-class companion has been reported at an angular separation of 0.1 arc seconds, though its existence has been disputed by some authors. Additional possible companions include a 15th-magnitude star 6.6″ away and a 20th-magnitude star 103″ away. These share a common proper motion with the primary, though they are too distant for orbital motion to be detected. They are estimated to have masses of 0.48 M☉ and 0.12 M☉, respectively.
Other Designations
π² Col, CD−42°2351, GC 7816, HD 42303, HIP 29064, HR 2181, SAO 217730, WDS J06079-4209AB.
