Astronomy:Theta1 Orionis E

From HandWiki
Short description: Star in the constellation Orion


θ1 Orionis E
TrapeziumStars.jpg
θ1 Orionis E and nearby stars in the Trapezium Cluster
Observation data
Equinox J2000.0]] (ICRS)
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 PMS[3]
Spectral type G2 IV[4]
Variable type Eclipsing[3]
Astrometry
Radial velocity (Rv)34.3[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[6] mas
Distance1,280 ± 30 ly
(391 ± 8 pc)
Absolute magnitude (MV)+1.43[7]
Orbit
Period (P)9.89520 ± 0.0007[4] days
Semi-major axis (a)34.430 ± 0.193[3] R
Eccentricity (e)< 0.001[4]
Inclination (i)73.7 ± 0.9[3]°
Semi-amplitude (K1)
(primary)
84.2 ± 1.2[4] km/s
Semi-amplitude (K2)
(secondary)
84.6 ± 1.3[4] km/s
Details
A
Mass2.807 ± 0.048[3] M
Radius7.1[7] R
Luminosity29[8] L
Temperature6,000[3] K
Rotational velocity (v sin i)37[8] km/s
B
Mass2.797 ± 0.048[3] M
Radius7.1[7] R
Luminosity29[8] L
Temperature6,000[3] K
Rotational velocity (v sin i)37[8] km/s
Age500[8] Myr
Other designations
41 Ori E, BD−05°1315E, COUP 732, 2MASS J05351577-0523100
Database references
SIMBADdata

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.

A near-infrared (4.5 micron) light curve for Theta1 Orionis E, adapted from Morales-Calderón et al. (2012)[3]

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 million 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

  1. 1.0 1.1 Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E. et al. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues 2246: II/246. Bibcode2003yCat.2246....0C. http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=II/246. 
  2. 2.0 2.1 2.2 Kukarkin, B. V.; Kholopov, P. N.; Artiukhina, N. M.; Fedorovich, V. P.; Frolov, M. S.; Goranskij, V. P.; Gorynya, N. A.; Karitskaya, E. A. et al. (1981). "Catalogue of suspected variable stars. Moscow, Acad. Of Sciences USSR Shternberg,1951 (1981)". Nachrichtenblatt der Vereinigung der Sternfreunde E.V. (1981). Bibcode1981NVS...C......0K. 
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 Morales-Calderón, M.; Stauffer, J. R.; Stassun, K. G.; Vrba, F. J.; Prato, L.; Hillenbrand, L. A.; Terebey, S.; Covey, K. R. et al. (2012). "YSOVAR: Six Pre-main-sequence Eclipsing Binaries in the Orion Nebula Cluster". The Astrophysical Journal 753 (2): 149. doi:10.1088/0004-637X/753/2/149. Bibcode2012ApJ...753..149M. 
  4. 4.0 4.1 4.2 4.3 4.4 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. Bibcode2008RMxAC..34..102C. 
  5. 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. doi:10.1088/0004-6256/146/5/106. Bibcode2013AJ....146..106O. 
  6. 6.0 6.1 6.2 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. doi:10.3847/1538-4357/834/2/142. Bibcode2017ApJ...834..142K. 
  7. 7.0 7.1 7.2 7.3 Herbig, G. H.; Griffin, R. F. (2006). "Θ1 Orionis E as a Spectroscopic Binary". The Astronomical Journal 132 (5): 1763. doi:10.1086/507769. Bibcode2006AJ....132.1763H. 
  8. 8.0 8.1 8.2 8.3 8.4 8.5 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. doi:10.1088/0004-637X/707/2/942. Bibcode2009ApJ...707..942H.