Epsilon¹ Arae

Epsilon¹ Arae
	The location of ε1 Arae (circled)
Observation data; Epoch J2000.0 Equinox J2000.0
Constellation	Ara
Right ascension	16h 59m 35.04880s
Declination	–53° 09′ 37.5713″
Apparent magnitude (V)	+4.068
Characteristics
Spectral type	K3 III
U−B color index	+1.71
B−V color index	+1.45
Astrometry
Radial velocity (Rv)	+23.1 km/s
Proper motion (μ)	RA: +2.16 mas/yr ; Dec.: +22.04 mas/yr
Parallax (π)	9.04 ± 0.27 mas
Distance	360 ± 10 ly ; (111 ± 3 pc)
Absolute magnitude (MV)	–0.79 ± 0.16
Details
Mass	1.74 ± 0.24 M☉
Radius	33.7 ± 3.4 R☉
Surface gravity (log g)	1.80 cgs
Temperature	4,176 K
Metallicity [Fe/H]	0.08 ± 0.05 dex
Age	1.70 ± 0.57 Gyr
Other designations
	CPD–52° 10372, FK5 632, HD 152980, HIP 83153, HR 6295, SAO 244331.
Database references
SIMBAD	data

Epsilon¹ Arae (ε¹ Ara, ε¹ Arae) is the Bayer designation for a star in the constellation Ara, the Altar. It is visible to the naked eye with an apparent visual magnitude of +4.1^[2] Based upon an annual parallax shift of 9.04 mas,^[1] this star is around 360 light-years (110 parsecs) distant from the Earth.

ε¹ Arae is an evolved giant star^[7] with a stellar classification of K3 III.^[3] It is around 74% more massive than the Sun. At an age of about 1.7 billion years, the outer envelope of the star has expanded to almost 34 times the Sun's radius.^[7] It is radiating energy into space at an effective temperature of 4,176 K,^[2] giving it the orange-hued glow of a K-type star.^[9]

ε¹ Arae was known as 龜一(spelled as "Guī yī", meaning: "the 1st (star) of Guī") in traditional Chinese astronomy.^[10]^[11] Allen erroneously called it Tso Kang (左更).^[12] He probably confused the constellation "Ara" with "Ari", as Tso Kang is actually in Aries.^[10]^[11]

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, S2CID 18759600.
^ ^a ^b ^c ^d ^e ^f Soubiran, C.; Le Campion, J.-F.; Cayrel de Strobel, G.; Caillo, A. (June 2010), "The PASTEL catalogue of stellar parameters", Astronomy and Astrophysics, 515: A111, arXiv:1004.1069, Bibcode:2010A&A...515A.111S, doi:10.1051/0004-6361/201014247, S2CID 118362423.
^ ^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.
^ ^a ^b Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
^ Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg, 35 (35), Astronomisches Rechen-Institut Heidelberg: 1, Bibcode:1999VeARI..35....1W.
^ Setiawan, J.; et al. (July 2004), "Precise radial velocity measurements of G and K giants. Multiple systems and variability trend along the Red Giant Branch", Astronomy and Astrophysics, 421: 241–254, Bibcode:2004A&A...421..241S, doi:10.1051/0004-6361:20041042-1.
^ ^a ^b ^c ^d ^e da Silva, L.; et al. (November 2006), "Basic physical parameters of a selected sample of evolved stars", Astronomy and Astrophysics, 458 (2): 609–623, arXiv:astro-ph/0608160, Bibcode:2006A&A...458..609D, doi:10.1051/0004-6361:20065105, S2CID 9341088.
^ "eps01 Ara". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-07-28.{{cite web}}: CS1 maint: postscript (link)
^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on 2012-03-18, retrieved 2012-07-21.
^ ^a ^b Chevalier, S., and Tsuchihashi, P., (1911): "Catalogue d'Étoiles fixes, observés a Pekin sous l'Empereur Kien Long (Qianlong (Chien-Lung)), XVIII^e siecle", Annales de l'Observatoire Astronomique de Zô-Sé.
^ ^a ^b 伊世同 (Yi Shi Tong) (1981): 『中西対照恒星図表』科学出版社.(in Chinese)
^ Allen, R. H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York, NY: Dover Publications Inc., p. 64, ISBN 0-486-21079-0.

External links

Simbad Epsilon¹ Arae
Image Epsilon¹ Arae
AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 1 日 Archived 2011-09-28 at the Wayback Machine(in Chinese)

[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, S2CID 18759600.

[aaa515_A11-2] ^ ^a ^b ^c ^d ^e ^f Soubiran, C.; Le Campion, J.-F.; Cayrel de Strobel, G.; Caillo, A. (June 2010), "The PASTEL catalogue of stellar parameters", Astronomy and Astrophysics, 515: A111, arXiv:1004.1069, Bibcode:2010A&A...515A.111S, doi:10.1051/0004-6361/201014247, S2CID 118362423.

[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.

[clpl4_99-4] Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.

[scfs-5] Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg, 35 (35), Astronomisches Rechen-Institut Heidelberg: 1, Bibcode:1999VeARI..35....1W.

[Setaiwan2004-6] Setiawan, J.; et al. (July 2004), "Precise radial velocity measurements of G and K giants. Multiple systems and variability trend along the Red Giant Branch", Astronomy and Astrophysics, 421: 241–254, Bibcode:2004A&A...421..241S, doi:10.1051/0004-6361:20041042-1.

[aaa458_2_609-7] ^ ^a ^b ^c ^d ^e da Silva, L.; et al. (November 2006), "Basic physical parameters of a selected sample of evolved stars", Astronomy and Astrophysics, 458 (2): 609–623, arXiv:astro-ph/0608160, Bibcode:2006A&A...458..609D, doi:10.1051/0004-6361:20065105, S2CID 9341088.

[SIMBAD-8] "eps01 Ara". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-07-28.{{cite web}}: CS1 maint: postscript (link)

[csiro-9] "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on 2012-03-18, retrieved 2012-07-21.

[ChT-10] Chevalier, S., and Tsuchihashi, P., (1911): "Catalogue d'Étoiles fixes, observés a Pekin sous l'Empereur Kien Long (Qianlong (Chien-Lung)), XVIII^e siecle", Annales de l'Observatoire Astronomique de Zô-Sé.

[YST-11] 伊世同 (Yi Shi Tong) (1981): 『中西対照恒星図表』科学出版社.(in Chinese)

[allen-12] Allen, R. H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York, NY: Dover Publications Inc., p. 64, ISBN 0-486-21079-0.

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Observation data Epoch J2000.0 Equinox J2000.0
The location of ε¹ Arae (circled)
Constellation	Ara
Right ascension	16^h 59^m 35.04880^s^[1]
Declination	–53° 09′ 37.5713″^[1]
Apparent magnitude (V)	+4.068^[2]
Characteristics
Spectral type	K3 III^[3]
U−B color index	+1.71^[4]
B−V color index	+1.45^[4]
Astrometry

Radial velocity (R_v)	+23.1^[5] km/s
Proper motion (μ)	RA: +2.16^[1] mas/yr Dec.: +22.04^[1] mas/yr
Parallax (π)	9.04 ± 0.27 mas^[1]
Distance	360 ± 10 ly (111 ± 3 pc)
Absolute magnitude (M_V)	–0.79 ± 0.16^[6]

Details

Mass	1.74 ± 0.24^[7] `M`_☉
Radius	33.7 ± 3.4^[7] `R`_☉
Surface gravity (log g)	1.80^[2] cgs
Temperature	4,176^[2] K
Metallicity [Fe/H]	0.08 ± 0.05^[2] dex
Age	1.70 ± 0.57^[7] Gyr

Other designations
CPD–52° 10372, FK5 632, HD 152980, HIP 83153, HR 6295, SAO 244331.^[8]
Database references
SIMBAD	data

References

Further reading

External links