Theta1 Orionis E
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Star in the constellation Orion
For other stars with this Bayer designation, see θ Orionis.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Orion |
| Right ascension | 05h 35m 15.773s[1] |
| Declination | −05° 23′ 10.02″[1] |
| Apparent magnitude (V) | 11.40 – 11.81[2] |
| Characteristics | |
| Evolutionary stage | Pre-main sequence [3] |
| Spectral type | G2 IV[4] |
| Variable type | Eclipsing [3] |
| Astrometry | |
| Radial velocity (Rv) | +29.7±0.2[5] km/s |
| Proper motion (μ) | RA: 1.45±0.03[6] mas/yr Dec.: 1.02±0.08[6] mas/yr |
| Parallax (π) | 2.557±0.051 mas [6] |
| Distance | 1,280 ± 30 ly (391 ± 8 pc) |
| Absolute magnitude (MV) | +1.43[7] |
| Orbit [5] | |
| Period (P) | 9.89522(3) days |
| Semi-major axis (a) | 34.22±0.18 R☉ (0.1589±0.0008 AU ) |
| Eccentricity (e) | 0 |
| Inclination (i) | 73.7±0.9° |
| Periastron epoch (T) | 3281.0455(94) HJD |
| Semi-amplitude (K1) (primary) | 83.36±0.29 km/s |
| Semi-amplitude (K2) (secondary) | 84.57±0.29 km/s |
| Details[5] | |
| A | |
| Mass | 2.755±0.043 M☉ |
| Radius | 6.26±0.31 R☉ |
| Luminosity | 24.8±4.6 L☉ |
| Surface gravity (log g) | 3.29±0.04 cgs |
| Temperature | 5,150±200 K |
| Rotational velocity (v sin i) | 30.7±2.1 km/s |
| Age | ≤0.1 Myr |
| B | |
| Mass | 2.720±0.043 M☉ |
| Radius | 6.25±0.30 R☉ |
| Luminosity | 24.7±4.5 L☉ |
| Surface gravity (log g) | 3.28±0.04 cgs |
| Temperature | 5,150±200 K |
| Rotational velocity (v sin i) | 30.7±2.1 km/s |
| Age | ≤0.1 Myr |
| Other designations | |
| 41 Ori E, BD−05°1315E, COUP 732, 2MASS J05351577-0523100 | |
| Database references | |
| SIMBAD | data |
θ1 Orionis E (Latinised as Theta1 Orionis E) is a double-lined spectroscopic binary located 4' north of θ1 Orionis A in the Trapezium Cluster. The two components are almost identical pre-main-sequence stars in a close circular orbit, and they show shallow eclipses that produce brightness variations of a few tenths of a magnitude.
Each component of the binary system is slightly under 3 M☉. Although they have a subgiant spectral classification, they are still contracting onto the main sequence and are estimated to be only about 500,000 years old.[8] It is estimated that they will reach the main sequence as smaller hotter late-B stars.[7]
The variability was first reported in 1954[2] and confirmed as an eclipsing binary in 2012. It has not been assigned a variable star designation but is listed in the New Catalogue of Suspected Variable Stars.[2]
References
[edit ]- ^ a b Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.
- ^ a b c Kukarkin, B. V.; Kholopov, P. N.; Artiukhina, N. M.; Fedorovich, V. P.; Frolov, M. S.; Goranskij, V. P.; Gorynya, N. A.; Karitskaya, E. A.; Kireeva, N. N.; Kukarkina, N. P.; Kurochkin, N. E.; Medvedeva, G. I.; Perova, N. B.; Ponomareva, G. A.; Samus, N. N.; Shugarov, S. Y. (1981). "Catalogue of suspected variable stars. Moscow, Acad. Of Sciences USSR Shternberg,1951 (1981)". Nachrichtenblatt der Vereinigung der Sternfreunde E.V. (1981). Bibcode:1981NVS...C......0K.
- ^ a b c Morales-Calderón, M.; Stauffer, J. R.; Stassun, K. G.; Vrba, F. J.; Prato, L.; Hillenbrand, L. A.; Terebey, S.; Covey, K. R.; Rebull, L. M.; Terndrup, D. M.; Gutermuth, R.; Song, I.; Plavchan, P.; Carpenter, J. M.; Marchis, F.; García, E. V.; Margheim, S.; Luhman, K. L.; Angione, J.; Irwin, J. M. (2012). "YSOVAR: Six Pre-main-sequence Eclipsing Binaries in the Orion Nebula Cluster". The Astrophysical Journal. 753 (2): 149. arXiv:1206.6350 . Bibcode:2012ApJ...753..149M. doi:10.1088/0004-637X/753/2/149. S2CID 44908832.
- ^ Costero, R.; Allen, C.; Echevarría, J.; Georgiev, L.; Poveda, A.; Richer, M. G. (2008). "The Escaping Spectroscopic Binary θ^1 Ori E". IV Reunión Sobre Astronomía Dinámica en Latino América (Eds. C. Allen. 34: 102. Bibcode:2008RMxAC..34..102C.
- ^ a b c Costero, Rafael; Echevarría, Juan; Yilen Gómez Maqueo Chew; Ruelas-Mayorga, Alex; Sánchez, Leonardo J. (2025). "Medium-resolution spectroscopic study of the intermediate-mass pre-main sequence binary $θ^1$ Ori E". arXiv:2511.03067 [astro-ph.SR].
- ^ a b c Kounkel, Marina; et al. (2017). "The Gould's Belt Distances Survey (GOBELINS) II. Distances and Structure toward the Orion Molecular Clouds". The Astrophysical Journal. 834 (2). 142. arXiv:1609.04041 . Bibcode:2017ApJ...834..142K. doi:10.3847/1538-4357/834/2/142 . S2CID 26439367.
- ^ a b Herbig, G. H.; Griffin, R. F. (2006). "Θ1 Orionis E as a Spectroscopic Binary". The Astronomical Journal. 132 (5): 1763. Bibcode:2006AJ....132.1763H. doi:10.1086/507769 .
- ^ Huenemoerder, David P.; Schulz, Norbert S.; Testa, Paola; Kesich, Anthony; Canizares, Claude R. (2009). "X-Ray Emission and Corona of the Young Intermediate-Mass Binary θ1 Ori E". The Astrophysical Journal. 707 (2): 942–953. arXiv:0911.0189 . Bibcode:2009ApJ...707..942H. doi:10.1088/0004-637X/707/2/942. S2CID 55747631.