👁 Image 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 |
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 on 25 March 1976 in a survey of stars in the Omega Nebula.[6]
Characteristics
[edit]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
[edit]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
[edit]- ^ Applying the Stefan–Boltzmann law with a nominal solar effective temperature of 5,772 K:
References
[edit]- ^ a b c d e f Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c d e "SIMBAD Results for CEN 16". SIMBAD. Retrieved 2026-01-27.
- ^ a b c d Ramírez-Tannus, M. C. (2017). "Massive pre-main-sequence stars in M17". Astronomy & Astrophysics. 604: A78. arXiv:1704.08216. Bibcode:2017A&A...604A..78R. doi:10.1051/0004-6361/201629503. Retrieved 2026-01-27.
- ^ a b c d e f g Backs, F. (2024). "Properties of intermediate- to high-mass stars in the young cluster M17: Characterizing the (pre-)zero-age main sequence". Astronomy and Astrophysics. 690. arXiv:2408.11713. Bibcode:2024A&A...690A.113B. doi:10.1051/0004-6361/202450494. Retrieved 2026-01-27.
- ^ a b c d e Patten, Nikhil (2025). "Fundamental Parameters for Central Stars of 103 Infrared Bow Shock Nebulae". The Astrophysical Journal. 988 (2): 183. arXiv:2506.07904. Bibcode:2025ApJ...988..183P. doi:10.3847/1538-4357/ade22f.
- ^ Ogura, K. (1976). "UBV Photometry of the Stars in the Fields of Emission Nebulae. II. M 17". Publications of the Astronomical Society of Japan. 28 (1): 35. Bibcode:1976PASJ...28...35O. doi:10.1093/pasj/28.1.35. Retrieved 2026-01-27.
- ^ a b c d Pauwels, Tinne (2024). "Low-mass Stellar and Substellar Candidate Companions around Massive Stars in Sco OB1 and M17". The Astronomical Journal. 168 (5): 209. arXiv:2409.16212. Bibcode:2024AJ....168..209P. doi:10.3847/1538-3881/ad6f06.
- ^ a b c d "EPE Results for CEN 16 b". Extrasolar Planets Encyclopaedia. Retrieved 2026-01-27.
- ^ Veras, Dimitri (2020). "Constraining planet formation around 6-8 M⊙ stars". Monthly Notices of the Royal Astronomical Society. 493 (1): 765. arXiv:2001.08757. Bibcode:2020MNRAS.493..765V. doi:10.1093/mnras/staa241.
- ^ "EPE Catalog". Extrasolar Planets Encyclopaedia. 1995. Retrieved 2026-01-27.
