Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Puppis |
Right ascension | 07h 29m 13.83263s [1] |
Declination | −43° 18′ 05.1674″ [1] |
Apparent magnitude (V) | 3.25 [2] |
Characteristics | |
Spectral type | K5 III [3] |
U−B color index | +1.77 [2] |
B−V color index | +1.52 [2] |
Astrometry | |
Radial velocity (Rv) | +87.3 [4] km/s |
Proper motion (μ) |
RA: +199.39
mas/
yr
[1] Dec.: −61.828 mas/ yr [1] |
Parallax (π) | 17.0234 ± 0.5614 mas [1] |
Distance | 192 ± 6
ly (59 ± 2 pc) |
Absolute magnitude (MV) | −0.50 [5] |
Orbit [6] | |
Period (P) | 257.8 days |
Eccentricity (e) | 0.17 |
Periastron epoch (T) | 20418.6 |
Argument of periastron (ω) (secondary) | 349.3° |
Semi-amplitude (K1) (primary) | 18.6 km/s |
Details | |
σ Pup A | |
Mass | 1.65 [7] M☉ |
Radius | 43.7 [4] R☉ |
Luminosity | 344 [7] L☉ |
Surface gravity (log g) | 1.51 [7] cgs |
Temperature | 4,077±4 [7] K |
Rotational velocity (v sin i) | 3.0 [8] km/s |
Other designations | |
Database references | |
SIMBAD | data |
Sigma Puppis, Latinized from σ Puppis, is a binary star system in the southern constellation Puppis. It has an apparent visual magnitude of 3.25, [2] which is bright enough to be visible to the naked eye at night from the Southern Hemisphere. Through a telescope, it appears as a bright, orange-hued star with a nearby white companion. [10] Parallax measurements indicate this star is located at a distance of about 192 light-years (59 parsecs) from Earth. [1]
This is a spectroscopic binary system, [9] consisting of an orbiting pair of stars that have not been individually resolved with a telescope. Their orbital period is 257.8 days and the eccentricity is 0.17. [6] The pair form an eclipsing binary of the Beta Lyrae type and a period of 130.5 days, or one half of their orbital period. The eclipse of the primary component causes a decline of 0.04 of a magnitude, while the secondary eclipse reduces the magnitude by 0.03. [11] [12]
The combined stellar classification is K5 III, [3] which matches the spectrum of a giant star. The primary is 44 times larger than the Sun [4] and 340 times more luminous. Its surface has an effective temperature of 4,077 K, [7] giving it the orange hue of a K-type star. [13] It shows the behavior of a slow irregular variable. [11] [12]
In addition to its binary components, Sigma Puppis has a more distant companion that has a matching proper motion, suggesting that it may be gravitationally bound to the binary. This magnitude 8.5 [10] star is at an angular separation of 22.4 arcseconds with a position angle of 74° from Sigma Puppis, which is equivalent to a projected separation of 1,200 AU. [14] In 1970, American astronomer Olin J. Eggen suggested that Sigma Puppis belonged to a moving group of stars that share a similar motion through space, and thereby a common origin. It served as the eponym for this, the σ Puppis group. [15] The existence of this group was later brought into question. [16]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Puppis |
Right ascension | 07h 29m 13.83263s [1] |
Declination | −43° 18′ 05.1674″ [1] |
Apparent magnitude (V) | 3.25 [2] |
Characteristics | |
Spectral type | K5 III [3] |
U−B color index | +1.77 [2] |
B−V color index | +1.52 [2] |
Astrometry | |
Radial velocity (Rv) | +87.3 [4] km/s |
Proper motion (μ) |
RA: +199.39
mas/
yr
[1] Dec.: −61.828 mas/ yr [1] |
Parallax (π) | 17.0234 ± 0.5614 mas [1] |
Distance | 192 ± 6
ly (59 ± 2 pc) |
Absolute magnitude (MV) | −0.50 [5] |
Orbit [6] | |
Period (P) | 257.8 days |
Eccentricity (e) | 0.17 |
Periastron epoch (T) | 20418.6 |
Argument of periastron (ω) (secondary) | 349.3° |
Semi-amplitude (K1) (primary) | 18.6 km/s |
Details | |
σ Pup A | |
Mass | 1.65 [7] M☉ |
Radius | 43.7 [4] R☉ |
Luminosity | 344 [7] L☉ |
Surface gravity (log g) | 1.51 [7] cgs |
Temperature | 4,077±4 [7] K |
Rotational velocity (v sin i) | 3.0 [8] km/s |
Other designations | |
Database references | |
SIMBAD | data |
Sigma Puppis, Latinized from σ Puppis, is a binary star system in the southern constellation Puppis. It has an apparent visual magnitude of 3.25, [2] which is bright enough to be visible to the naked eye at night from the Southern Hemisphere. Through a telescope, it appears as a bright, orange-hued star with a nearby white companion. [10] Parallax measurements indicate this star is located at a distance of about 192 light-years (59 parsecs) from Earth. [1]
This is a spectroscopic binary system, [9] consisting of an orbiting pair of stars that have not been individually resolved with a telescope. Their orbital period is 257.8 days and the eccentricity is 0.17. [6] The pair form an eclipsing binary of the Beta Lyrae type and a period of 130.5 days, or one half of their orbital period. The eclipse of the primary component causes a decline of 0.04 of a magnitude, while the secondary eclipse reduces the magnitude by 0.03. [11] [12]
The combined stellar classification is K5 III, [3] which matches the spectrum of a giant star. The primary is 44 times larger than the Sun [4] and 340 times more luminous. Its surface has an effective temperature of 4,077 K, [7] giving it the orange hue of a K-type star. [13] It shows the behavior of a slow irregular variable. [11] [12]
In addition to its binary components, Sigma Puppis has a more distant companion that has a matching proper motion, suggesting that it may be gravitationally bound to the binary. This magnitude 8.5 [10] star is at an angular separation of 22.4 arcseconds with a position angle of 74° from Sigma Puppis, which is equivalent to a projected separation of 1,200 AU. [14] In 1970, American astronomer Olin J. Eggen suggested that Sigma Puppis belonged to a moving group of stars that share a similar motion through space, and thereby a common origin. It served as the eponym for this, the σ Puppis group. [15] The existence of this group was later brought into question. [16]