| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Scorpius |
| Right ascension | 17h 00m 48.884s[1] |
| Declination | −41° 39′ 21.46″[1] |
| Apparent magnitude (V) | >23[2] |
| Characteristics | |
| Spectral type | Ofpe/WN9[3] |
| Apparent magnitude (J) | 14.09[1] |
| Apparent magnitude (H) | 11.68[1] |
| Apparent magnitude (K) | 10.38[1] |
| Variable type | X-ray binary[3] |
| Astrometry | |
| Radial velocity (Rv) | 57.2±3[3] km/s |
| Distance | 7,100[2] pc |
| Orbit[3] | |
| Period (P) | 10.44812±0.00013 days |
| Semi-amplitude (K1) (primary) | 22.1±3.5 km/s |
| Details | |
| Ofpe/WN9 | |
| Mass | 14.3±0.8[3] M☉ |
| Radius | 24.8±1.5[3] R☉ |
| Luminosity | ~126,000[3] L☉ |
| Temperature | ~20,000[3] K |
| Compact object | |
| Mass | 1.42±0.26[3] M☉ |
| Other designations | |
AX J1700.7-4139, 2MASS J17004888-4139214 | |
| Database references | |
| SIMBAD | data |
OAO 1657-415 is a high-mass X-ray binary (HMXB) located in the constellation of Scorpius, over 20,000 light years away. It is believed to be composed of a compact object (likely a neutron star) and a highly evolved massive slash star, with Wolf–Rayet and O-type features in its spectrum, with a spectral type of Ofpe/WN9. OAO 1657-415 is special as it has the largest eccentricity and orbital period of any HMXB, and also because its donor star is much more evolved than many other HMXB donor stars.[3]
2mass was invoked but never defined (see the help page).jaisawal was invoked but never defined (see the help page).mason was invoked but never defined (see the help page).