Astronomy:CEN 16
300px 2MASS image of CEN 16 | ||
| Observation data Equinox J2000.0]] (ICRS) | ||
|---|---|---|
| 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[1] mas | |
| 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 in March 1976 in a survey of stars in the Omega Nebula.[6]
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][lower-alpha 1]
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:
- .
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 "SIMBAD Results for CEN 16". https://simbad.u-strasbg.fr/simbad/sim-id?Ident=Cl*+NGC+6618+CEN+16&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id.
- ↑ 3.0 3.1 3.2 3.3 Ramírez-Tannus, M. C. (2017). "Massive pre-main-sequence stars in M17". Astronomy & Astrophysics 604: A78. doi:10.1051/0004-6361/201629503. Bibcode: 2017A&A...604A..78R. https://ui.adsabs.harvard.edu/abs/2017A%26A...604A..78R/abstract. Retrieved 2026-01-27.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 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. doi:10.1051/0004-6361/202450494. Bibcode: 2024A&A...690A.113B. https://ui.adsabs.harvard.edu/abs/2024A%26A...690A.113B/abstract. Retrieved 2026-01-27.
- ↑ 5.0 5.1 5.2 5.3 5.4 Patten, Nikhil (2025). "Fundamental Parameters for Central Stars of 103 Infrared Bow Shock Nebulae". The Astrophysical Journal 988 (2): 183. doi:10.3847/1538-4357/ade22f. Bibcode: 2025ApJ...988..183P.
- ↑ 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. doi:10.1093/pasj/28.1.35. Bibcode: 1976PASJ...28...35O. https://ui.adsabs.harvard.edu/abs/1976PASJ...28...35O/abstract. Retrieved 2026-01-27.
- ↑ 7.0 7.1 7.2 7.3 Pauwels, Tinne (2024). "Low-mass Stellar and Substellar Candidate Companions around Massive Stars in Sco OB1 and M17". The Astronomical Journal 168 (5): 209. doi:10.3847/1538-3881/ad6f06. Bibcode: 2024AJ....168..209P.
- ↑ 8.0 8.1 8.2 8.3 "EPE Results for CEN 16 b". https://exoplanet.eu/catalog/cen_16_b--10769/.
- ↑ Veras, Dimitri (2020). "Constraining planet formation around 6-8 M⊙ stars". Monthly Notices of the Royal Astronomical Society 493 (1): 765. doi:10.1093/mnras/staa241. Bibcode: 2020MNRAS.493..765V.
- ↑ "EPE Catalog". 1995. https://exoplanet.eu/home/.
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