Theta1 Orionis D (θ1 Orionis D) is a member of the Trapezium open cluster that lies within the Orion Nebula. It is a B class blue main sequence star with several faint companions.
 Theta1 Orionis D and companions in the Trapezium cluster | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Orion |
| Right ascension | 05h 35m 17.24645s[1] |
| Declination | −05° 23′ 16.5707″[1] |
| Apparent magnitude (V) | 6.70[2] |
| Characteristics | |
| Spectral type | B1.5 Vp[3] |
| U−B color index | −0.71[2] |
| B−V color index | +0.09[2] |
| Astrometry | |
| Radial velocity (Rv) | +32.4[4] km/s |
| Proper motion (μ) | RA: +1.822[1] mas/yr Dec.: _0.393[1] mas/yr |
| Parallax (π) | 2.2820 ± 0.0207 mas[1] |
| Distance | 1,430 ± 10 ly (438 ± 4 pc) |
| Absolute magnitude (MV) | −3.3[5] |
| Details | |
| Mass | 18±6[5] M☉ |
| Radius | 5.6±0.8[5] R☉ |
| Luminosity | 29,500[5] L☉ |
| Surface gravity (log g) | 4.2±0.1[5] cgs |
| Temperature | 32,000±1,000[5] K |
| Rotational velocity (v sin i) | 49.0±0.9[5] km/s |
| Age | 2.5±0.5[5] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
θ1 Orionis consists of multiple components, primarily the four stars of the Trapezium cluster (A, B, C, and D) all within one arc-minute of each other. θ2 Orionis is a more distant grouping of three main stars plus several fainter companions, 1-2 arc-minutes from θ1.
θ1 D itself has a faint optical companion 1.4" away and a spectroscopic companion in a 40-day orbit. Infrared Optical Telescope Array observations suggest another companion at 18.6 mas.[6]
References
edit- ^ a b c d e 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 Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237: 0. Bibcode:2002yCat.2237....0D.
- ^ Levenhagen, R. S.; Leister, N. V. (2006). "Spectroscopic analysis of southern B and Be stars". Monthly Notices of the Royal Astronomical Society. 371 (1): 252–262. arXiv:astro-ph/0606149. Bibcode:2006MNRAS.371..252L. doi:10.1111/j.1365-2966.2006.10655.x. S2CID 16492030.
- ^ Olivares, J.; Sánchez, L. J.; Ruelas-Mayorga, A.; Allen, C.; Costero, R.; Poveda, A. (2013). "Kinematics of the Orion Trapezium Based on Diffracto-Astrometry and Historical Data". The Astronomical Journal. 146 (5): 106. arXiv:1310.0769. Bibcode:2013AJ....146..106O. doi:10.1088/0004-6256/146/5/106. S2CID 119110490.
- ^ a b c d e f g h Simón-Díaz, S.; Herrero, A.; Esteban, C.; Najarro, F. (2006). "Detailed spectroscopic analysis of the Trapezium cluster stars inside the Orion nebula". Astronomy and Astrophysics. 448 (1): 351–366. arXiv:astro-ph/0510288. Bibcode:2006A&A...448..351S. doi:10.1051/0004-6361:20053066. ISSN 0004-6361. S2CID 16445304.
- ^ Grellmann, R.; Preibisch, T.; Ratzka, T.; Kraus, S.; Helminiak, K. G.; Zinnecker, H. (2013). "The multiplicity of massive stars in the Orion Nebula Cluster as seen with long-baseline interferometry". Astronomy & Astrophysics. 550: A82. arXiv:1301.3045. Bibcode:2013A&A...550A..82G. doi:10.1051/0004-6361/201220192. S2CID 6554786.