CEN 16
O-type dwarf star in the Omega Nebula
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CEN 16, also known as ALS 19608, is a O-type main sequence star in the constellation of Sagittarius.[2] The star is located in the center of the Omega Nebula, roughly 4600±100 light years (or 1420±50 parsecs) away.[2] The star has an apparent visual magnitude of 13.69.[2] The star was discovered in March 1976 in a survey of stars in the Omega Nebula.[6]
2MASS image of CEN 16 | ||
| Observation data Epoch J2000.0 Equinox J2000.0 | ||
|---|---|---|
| Constellation | Sagittarius | |
| Right ascension | 18h 20m 22.70s[1] | |
| Declination | −16° 08′ 34.17″[1] | |
| Apparent magnitude (V) | 13.69[2] | |
| Characteristics | ||
| Evolutionary stage | Main sequence[3] | |
| Spectral type | O8.5V[3] | |
| Apparent magnitude (G) | 12.61[1] | |
| Apparent magnitude (K) | 8.884[3] | |
| Astrometry | ||
| Proper motion (μ) | RA: 0.339±0.022[1] mas/yr Dec.: −1.599±0.015[1] mas/yr | |
| Parallax (π) | 0.7051±0.0226 mas[1] | |
| Distance | 4,600 ± 100 ly (1,420 ± 50 pc) | |
| Details | ||
| Mass | 20.4+7.9 −7.3[4] M☉ | |
| Radius | 10.9[5] R☉ | |
| Luminosity | 125000±37000[5] L☉ | |
| Surface gravity (log g) | 4.24+0.16 −0.22[4] cgs | |
| Temperature | 34000±1000[5] K | |
| Rotational velocity (v sin i) | 30+15 −25[4] km/s | |
| Age | 4[4] Myr | |
| Other designations | ||
| NGC 6618 258, ALS 19608, B311, SLS 165, Gaia DR2 4098003291268883584, Gaia DR3 4098003291268883584 | ||
| Database references | ||
| SIMBAD | data | |
Characteristics
CEN 16 is a massive, young late O-type main sequence star in the Omega Nebula.[2] The star has a spectral type of O8.5V found using data from the Very Large Telescope, meaning it is still in the main-sequence phase.[3] The star is also believed to very massive with a spectroscopic-derived stellar mass of 20.4+7.9
−7.3 M☉.[4] The star has a rotational velocity of 30+15
−25 km/s.[4] The star is predicted to be extremely young with an age of only four million years.[4] The star has an estimated radius of 10.9 R☉.[5] The diameter was found using a stellar luminosity of 125000±37000 L☉, and an effective temperature of 34000±1000 K.[5][a]
Substellar Companion
In November 2024, it was discovered that a potential brown dwarf companion may orbit CEN 16.[7] The unconfirmed brown dwarf companion has a radius of 7.5 RJ and a mass of 70 MJ.[7][8] The candidate brown dwarf companion has a calculated temperature of 2,884 K, and a luminosity of 0.033 L☉.[7][8] CEN 16 B has a semi-major axis of 883.5 astronomical units.[8] CEN 16 B is notable because substellar objects orbiting O-type main sequence stars are exceptionally rare.[9] According to the Extrasolar Planets Encyclopaedia, CEN 16 B is the only substellar object found around a O-type main sequence star.[10]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (years) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| B | 70 MJ | 883.5 | — | — | — | 7.5 RJ |
Notes
- Applying the Stefan–Boltzmann law with a nominal solar effective temperature of 5,772 K:
- .
