HD 93129
 HD 93129 surrounded by the lesser stars of Trumpler 14 Credit: NASA & ESA, Jesús Maíz Apellániz (Instituto de Astrofisica de Andalucia) |
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| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Carina |
| Right ascension | 10h 43m 57.5s |
| Declination | −59° 32′ 51.3″ |
| Apparent magnitude (V) | 6.90(7.310 + 8.84) |
| Characteristics | |
| A | |
| Spectral type | O2If* (O2If+O3.5V) |
| U−B color index | −0.81 |
| B−V color index | +0.25 |
| B | |
| Evolutionary stage | main sequence |
| Spectral type | O3.5 V((f))z |
| U−B color index | −0.79 |
| B−V color index | +0.23 |
| Astrometry | |
| Radial velocity (Rv) | −0.4 ± 7.4 km/s |
| Proper motion (μ) |
RA: -5.0 mas/yr Dec.: 17.0 mas/yr |
| Distance | 2,300pc |
| Absolute magnitude (MV) |
(A): −6.5 (−6.1 + −5.2) (B): −4.9 |
| Details | |
| Aa | |
| Mass | 110 M☉ |
| Radius | 22.5 R☉ |
| Luminosity | 1,480,000 L☉ |
| Surface gravity (log g) | 3.71 cgs |
| Temperature | 42,500 K |
| Rotational velocity (v sin i) | 130 km/s |
| Age |
0.9+0.2 −0.4 Myr |
| Ab | |
| Mass | 70 M☉ |
| Radius | 13.1 R☉ |
| Luminosity | 575,000 L☉ |
| Temperature | 44,000 K |
| B | |
| Luminosity | 575,000 L☉ |
| Temperature | 52,000 K |
| Rotational velocity (v sin i) | 112 km/s |
| Other designations | |
| A: TYC 8626-2805-1, ALS 15862, LS 1820 | |
| B: ALS 19309 | |
| Database references | |
| SIMBAD | HD 93129 data |
| SIMBAD | HD 93129 A data |
| SIMBAD | HD 93129 B data |
HD 93129 is a triple star system in the Carina Nebula, with all three components being hot O class stars amongst the most luminous stars in the Milky Way. It is the dominant member of the Trumpler 14 star cluster, a young star cluster within the Carina OB1 stellar association that harbors other super luminous stars, like Eta Carinae and WR 25.
HD 93129 is found at the centre of the massive Trumpler 14 open cluster in the Carina Nebula star forming region. It is too far away for its distance to have been accurately determined using the annual parallax method, but accurate distances for η Carinae and the Homunculus Nebula, modelling of clusters, and astrophysical data about other stars assumed to be within the same region, all lead to a distance around 2,300 parsecs. HD 93129 Aa is the closet O2 supergiant to Earth.
That area of the sky is home to many other massive and luminous stars. HD 93128, yet another O3.5 main sequence star, is only 24' away within Trumpler 14, and HD 93250 and HD 93205 are two more O3.5 stars in the larger Trumpler 16 cluster around η Carinae. There are also three Wolf-Rayet stars, an O4 supergiant, many other class O stars, and the unique η Carinae itself.
HD 93129 consists of two clearly resolved components, HD 93129 A and HD 93129 B, and HD 93129 A itself is made up of two much closer stars.
HD 93129 A has been resolved into two components. The spectrum is dominated by the brighter component, although the secondary is only 0.9 magnitudes fainter. HD 93129 Aa is an O2 supergiant and Ab is an O3.5 main sequence star. Their separation has decreased from 55 mas in 2004 to only 27 mas in 2013, but an accurate orbit is not available.
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