Eta Scorpii, a white subgiant star in Scorpius
Eta Scorpii is a white subgiant star in the constellation Scorpius. At 73 light years away, it is the 239th brightest star in the Earth's sky, where it shines at an apparent visual magnitude of 3.32.
Eta Scorpii (HIP 84143)
Eta Scorpii is a white subgiant star in the constellation Scorpius. At 73 light years away, it is the 239th brightest star in the Earth's sky, where it shines at an apparent visual magnitude of 3.32. The star's age is estimated to be 1.1 billion years but is certainly no less than 1 billion years and no greater than 1.2 billion years. The iron abundance of Eta Scorpii is +0.13 (134.9% of the Sun). It is moving through the Galaxy at a speed of 41 km/s relative to the Sun. Its projected Galactic orbit carries it between 21,900 and 26,300 light years from the center of the Galaxy. It will come closest to the Sun 353,000 years from now when it will brighten to magnitude 2.70 from a distance of 55 light years.
Sky position: RA 17h 12.2m, Dec -43° 14.4'
Common designations: Eta Scorpii, HIP 84143, HD 155203, HR 6380, Gliese 657
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Brightest stars in Scorpius:
(list all)
| Rank | Mag. | Star |
| 6 | 2.39 | Kappa Scorpii |
| 7 | 2.56 | Graffias |
| 8 | 2.70 | Lesath |
| 9 | 2.82 | Alniyat |
| 10 | 2.89 | Pi Scorpii |
| 11 | 2.90 | Alniyat |
| 12 | 2.99 | Iota-1 Scorpii |
| 13 | 3.00 | Mu-1 Scorpii |
| 14 | 3.19 | G Scorpii |
15
| 3.32
) Eta Scorpii
| Rank | Mag. | Star |
| 16 | 3.56 | Mu-2 Scorpii |
| 17 | 3.62 | Grafias |
| 18 | 3.87 | Rho Scorpii |
| 19 | 3.93 | Omega-1 Scorpii |
| 20 | 4.00 | Jabbah |
| 21 | 4.18 | H Scorpii |
| 22 | 4.24 | N Scorpii |
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Galactic Orbit of Eta Scorpii
(compared to the Sun)
E
ccentricity: 9.1% vs. 16.0%Angle φ : -94.1°vs. 26.0°
Semi-major axis : 7,391 pc vs. 8,686 pc
Semi-minor axis: 7,361 pc vs. 8,574 pc
Focus-to-center
: 670 pcvs. 1,388 pcSemilatus rectum : 7,330 pc vs. 8,464 pc
Perigalacticon: 6,721 pc vs. 7,297 pc
Apogalacticon
: 8,061 pcvs. 10,074 pcSome Tabulated XHIP Data for Eta Scorpii
(see also: SIMBAD)
Astrometry
2007A&A...474..653V
| Position | Proper Motion | |
| Right Ascension: | 258.03823358° ±0.14 mas | 21.20 ±0.70 mas/yr. |
| Declination: | -43.23849048° ±0.08 mas | -288.50 ±0.70 mas/yr. |
| Galactic Longitude: | 344.36501125° | -220.75 mas/yr. |
| Galactic Latitude: | -2.30332349° | -186.95 mas/yr. |
Parallax: 44.39 ± 0.16 mas
Spectrography
Spectral Type: F5IV 2006AJ....132..161G.
Radial Velocity: -27.00 ±2.60 km/s [A rating] 2006AstL...32..759G.
Iron Abundance [Fe/H]:
0.13 ±0.15 dex
2009A&A...501..941H.
Photometry
| band | magnitude | Abs. Mag. |
| U | ||
| B | 3.76 | 2.00 |
| V | 3.32 | 1.56 |
| R | ||
| I | 2.90 | 1.13 |
| J | 2.40 | 0.63 |
| H | 2.30 | 0.53 |
| K | 2.26 | 0.49 |
B-V: +0.44 V-I: +0.42
Derivations
Heliocentric distance: 22.53 pc (0.4% margin of error)
Galactocentric distance: 7,378 pc
Transverse velocity: 30.9 km/s
3D heliocentric position and motion:
|
toward: |
Galactic center | Galactic rotation | North Galactic Pole |
| Position ( X, Y, Z) | 21.7 pc | -6.1 pc | -0.9 pc |
| Velocity (U, V, W) | -33.1 km/s | -15.2 km/s | -18.9 km/s |