Omicron Sagittarii
Template:Location mark Location of ο Sagittarii (circled) | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | Template:RA[1] |
| Declination | Template:DEC[1] |
| Apparent magnitude (V) | +3.771[2] |
| Characteristics | |
| Evolutionary stage | horizontal branch[3] |
| Spectral type | G9IIIb[4] |
| B−V Template:Engvar | Script error: No such module "val".[5] |
| Astrometry | |
| Radial velocity (Rv) | Script error: No such module "val".[5] km/s |
| Proper motion (μ) | RA: Script error: No such module "val".[1] mas/yr Dec.: Script error: No such module "val".[1] mas/yr |
| Parallax (π) | 22.96±0.24 mas[1] |
| Distance | Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc) |
| Absolute magnitude (MV) | 0.625[2] |
| Details | |
| Mass | 1.80[6] Template:Solar mass |
| Radius | Script error: No such module "val".[7] Template:Solar radius |
| Luminosity | Script error: No such module "val".[7] Template:Solar luminosity |
| Surface gravity (log g) | 2.66[2] cgs |
| Temperature | Script error: No such module "val". K |
| Metallicity [Fe/H] | −0.04[2] dex |
| Age | 2.39[6] Gyr |
| Metallicity [Fe/H] | {{{metal_fe2}}} dex |
| Other designations | |
| Template:Odlist[8] | |
| Database references | |
| SIMBAD | data |
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ο Sagittarii, Latinized as Omicron Sagittarii, is a single[9] star in the constellation Sagittarius. It is yellow in hue and visible to the naked eye with an apparent visual magnitude of +3.77.[2] The distance to this star is approximately 142 light years based on parallax.[1] It is drifting further away from the Sun with a radial velocity of +26 km/s, having come to within Script error: No such module "convert". around a million years ago.[5]
This object is position 0.86 degrees north of the ecliptic, so ο Sagittarii can be occulted by the Moon and very rarely by planets. The last occultation by a planet took place on 24 December 1937, when it was occulted by Mercury.Script error: No such module "Unsubst". It was almost eclipsed by the sun, which occupies a mean, rounded, half of one degree of the sky, on 5 January.[10] Thus the star can be viewed the whole night, crossing the sky, in early July.
This is an aging giant star with a stellar classification of G9IIIb.[4] It is classified as a red clump giant, suggesting it is on the horizontal branch undergoing core helium fusion.[3] The star is 2.39 billion years old[6] with 1.80 times the mass of the Sun.[6] It has expanded to 12 times the radius of the Sun and is radiating 67 times the Sun's luminosity from its swollen photosphere at an effective temperature of 4,744 K.[7]
It has a faint, magnitude 13.8 companion, designated component B and positioned Script error: No such module "val". away along a position angle of 252°, as of 2010.[11]
Name and etymology
- In Chinese, Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Establishment, refers to an asterism consisting of ο Sagittarii ξ² Sagittarii, π Sagittarii, 43 Sagittarii, ρ¹ Sagittarii and υ Sagittarii. Consequently, the Chinese name for ο Sagittarii itself is Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx.)[12]
References
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- ↑ a b c d e f Script error: No such module "citation/CS1".
- ↑ a b c d e Script error: No such module "citation/CS1".
- ↑ a b Script error: No such module "citation/CS1".
- ↑ a b Script error: No such module "citation/CS1".
- ↑ a b c Script error: No such module "citation/CS1".
- ↑ a b c d Script error: No such module "citation/CS1".
- ↑ a b c Template:Cite DR2
- ↑ Template:Cite simbad
- ↑ Script error: No such module "citation/CS1".
- ↑ In the Sky Earth astronomy reference utility showing the ecliptic and relevant date as at J2000 - present
- ↑ Script error: No such module "citation/CS1".
- ↑ Template:In lang AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 11 日 Template:Webarchive
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