Theta Arae

Theta Arae
	The location of θ Arae (circled)
Observation data; Epoch J2000 Equinox J2000
Constellation	Ara
Right ascension	18h 06m 37.87129s
Declination	–50° 05′ 29.3125″
Apparent magnitude (V)	+3.67
Characteristics
Spectral type	B2 Ib
U−B color index	–0.870
B−V color index	–0.109
Astrometry
Radial velocity (Rv)	+3.4 km/s
Proper motion (μ)	RA: –8.27 mas/yr ; Dec.: –8.70 mas/yr
Parallax (π)	4.01 ± 0.15 mas
Distance	810 ± 30 ly ; (249 ± 9 pc)
Details
Mass	8.9 ± 0.1 M☉
Radius	20.1 R☉
Surface gravity (log g)	2.70 cgs
Temperature	17,231 ± 231 K
Rotational velocity (v sin i)	95 km/s
Age	28.2 ± 4.7 Myr
Other designations
	CD −50° 11720, FK5 1471, HD 165024, HIP 88714, HR 6743, SAO 245242.

Theta Arae (θ Ara, θ Arae) is the Bayer designation for a star in the constellation Ara. It has an apparent visual magnitude of +3.67,^[2] which is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 4.01 mas,^[1] Theta Arae is 810 light-years (250 parsecs) distant from the Earth.

This is a supergiant star with a stellar classification of B2 Ib.^[3] It has nearly nine^[5] times the mass of the Sun and is over 20^[6] times the Sun's radius. The outer atmosphere of this star has an effective temperature of 17,231 K;^[6] much hotter than the surface of the Sun. At this heat, the star shines with the characteristic blue-white hue of a B-type star.^[10]

References

^ ^a ^b ^c ^d ^e ^f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
^ ^a ^b ^c ^d Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968), "A photometric investigation of the Scorpio-Centaurus association", Astrophysical Journal Supplement, 15: 459, Bibcode:1968ApJS...15..459G, doi:10.1086/190168.
^ ^a ^b Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 2, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
^ Wielen, R.; et al. (1999), Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions, Astronomisches Rechen-Institut Heidelberg, Bibcode:1999VeARI..35....1W.
^ ^a ^b ^c Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x.
^ ^a ^b ^c ^d Underhill, A. B.; et al. (November 1979), "Effective temperatures, angular diameters, distances and linear radii for 160 O and B stars", Monthly Notices of the Royal Astronomical Society, 189: 601–605, Bibcode:1979MNRAS.189..601U, doi:10.1093/mnras/189.3.601.
^ Fraser, M.; et al. (May 2010), "Atmospheric parameters and rotational velocities for a sample of Galactic B-type supergiants", Monthly Notices of the Royal Astronomical Society, 404 (3): 1306–1320, arXiv:1001.3337, Bibcode:2010MNRAS.404.1306F, doi:10.1111/j.1365-2966.2010.16392.x.
^ Bernacca, P. L.; Perinotto, M. (1970), "A catalogue of stellar rotational velocities", Contributi Osservatorio Astronomico di Padova in Asiago, 239 (1), Bibcode:1970CoAsi.239....1B.
^ "tet Ara -- Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2010-07-30.
^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, retrieved 2012-01-16

External links

[aaa474_2_653-1] ^ ^a ^b ^c ^d ^e ^f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.

[apjs15_459-2] Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968), "A photometric investigation of the Scorpio-Centaurus association", Astrophysical Journal Supplement, 15: 459, Bibcode:1968ApJS...15..459G, doi:10.1086/190168.

[houk1978-3] Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 2, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.

[scfs-4] Wielen, R.; et al. (1999), Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions, Astronomisches Rechen-Institut Heidelberg, Bibcode:1999VeARI..35....1W.

[mnras410_1_190-5] Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x.

[mnras189_601-6] Underhill, A. B.; et al. (November 1979), "Effective temperatures, angular diameters, distances and linear radii for 160 O and B stars", Monthly Notices of the Royal Astronomical Society, 189: 601–605, Bibcode:1979MNRAS.189..601U, doi:10.1093/mnras/189.3.601.

[mnras404_3_1306-7] Fraser, M.; et al. (May 2010), "Atmospheric parameters and rotational velocities for a sample of Galactic B-type supergiants", Monthly Notices of the Royal Astronomical Society, 404 (3): 1306–1320, arXiv:1001.3337, Bibcode:2010MNRAS.404.1306F, doi:10.1111/j.1365-2966.2010.16392.x.

[coapa239_1-8] Bernacca, P. L.; Perinotto, M. (1970), "A catalogue of stellar rotational velocities", Contributi Osservatorio Astronomico di Padova in Asiago, 239 (1), Bibcode:1970CoAsi.239....1B.

[SIMBAD-9] "tet Ara -- Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2010-07-30.

[csiro-10] "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, retrieved 2012-01-16

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Observation data Epoch J2000 Equinox J2000
The location of θ Arae (circled)
Constellation	Ara
Right ascension	18^h 06^m 37.87129^s^[1]
Declination	–50° 05′ 29.3125″^[1]
Apparent magnitude (V)	+3.67^[2]
Characteristics
Spectral type	B2 Ib^[3]
U−B color index	–0.870^[2]
B−V color index	–0.109^[2]
Astrometry

Radial velocity (R_v)	+3.4^[4] km/s
Proper motion (μ)	RA: –8.27^[1] mas/yr Dec.: –8.70^[1] mas/yr
Parallax (π)	4.01 ± 0.15 mas^[1]
Distance	810 ± 30 ly (249 ± 9 pc)

Details

Mass	8.9 ± 0.1^[5] `M`_☉
Radius	20.1^[6] `R`_☉
Surface gravity (log g)	2.70^[7] cgs
Temperature	17,231 ± 231^[6] K
Rotational velocity (v sin i)	95^[8] km/s
Age	28.2 ± 4.7^[5] Myr

Other designations
CD −50° 11720, FK5 1471, HD 165024, HIP 88714, HR 6743, SAO 245242.^[9]