Epsilon Trianguli

ε Trianguli
	Location of ε Trianguli (circled)
Observation data; Epoch J2000.0 Equinox J2000.0
Constellation	Triangulum
Right ascension	02h 02m 57.95579s
Declination	+33° 17′ 02.8813″
Apparent magnitude (V)	+5.50
Characteristics
Spectral type	A2 V
U−B color index	+0.06
B−V color index	+0.03
Astrometry
Radial velocity (Rv)	3.3 km/s
Proper motion (μ)	RA: –15.97 mas/yr ; Dec.: –7.22 mas/yr
Parallax (π)	8.33±0.34 mas
Distance	390 ± 20 ly ; (120 ± 5 pc)
Absolute magnitude (MV)	+0.11
Details
Mass	2.75±0.05 M☉
Radius	3.28 R☉
Luminosity	93 L☉
Surface gravity (log g)	3.76 cgs
Temperature	10,000 K
Rotational velocity (v sin i)	107 km/s
Age	600 Myr
Other designations
	ε Tri, 3 Tri, BD+32°369, HD 12471, HIP 9570, HR 599, SAO 55218
Database references
SIMBAD	data

Epsilon Trianguli, Latinized from ε Trianguli, is a binary star^[11] system in the northern constellation of Triangulum. Based upon measurement of its trigonometric parallax, it is approximately 390 light years from Earth.^[1]

The primary component is an A-type main sequence star with a stellar classification of A2 V,^[3] an apparent magnitude of +5.50 and an estimated age of 600 million years.^[7] It has 2.75^[6] times the mass of the Sun and is spinning with a projected rotational velocity of 107 km/s.^[9] The radius of this star is more than three times the radius of the Sun, and the photosphere has an effective temperature of about 10,000.^[7] The secondary component has an apparent magnitude of 11.4 and is separated from the primary by an angle of 3.9 arcseconds.^[12]

An excess emission of infrared radiation suggests the presence of a dusty disk in orbit about the primary. This disk has a mean radius of 105 AU, or 105 times the separation of the Earth from the Sun, and is radiating at a temperature of 85 K.^[7]

This star system is a probable member of the Ursa Major Moving Group of stars that share a common motion through space.^[8] The space velocity components of Epsilon Trianguli are [U, V, W] = [+11.8, +11.4, –3.8] km/s.^[13]

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 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
^ ^a ^b Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819
^ Wilson, Ralph Elmer (1953), "General catalogue of stellar radial velocities", Carnegie Institute Washington D.C. Publication, Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W
^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
^ ^a ^b ^c Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
^ ^a ^b ^c ^d ^e ^f Rhee, Joseph H.; et al. (May 2007), "Characterization of Dusty Debris Disks: The IRAS and Hipparcos Catalogs", The Astrophysical Journal, 660 (2): 1556–1571, arXiv:astro-ph/0609555, Bibcode:2007ApJ...660.1556R, doi:10.1086/509912, S2CID 11879505
^ ^a ^b Monier, R. (November 2005), "Abundances of a sample of A and F-type dwarf members of the Ursa Major Group", Astronomy and Astrophysics, 442 (2): 563–566, Bibcode:2005A&A...442..563M, doi:10.1051/0004-6361:20053222
^ ^a ^b Royer, F.; Zorec, J.; Gómez, A. E. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv:astro-ph/0610785, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224, S2CID 18475298
^ "eps Tri -- Variable Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2011-12-13
^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976
^ King, Jeremy R.; et al. (April 2003), "Stellar Kinematic Groups. II. A Reexamination of the Membership, Activity, and Age of the Ursa Major Group", The Astronomical Journal, 125 (4): 1980–2017, Bibcode:2003AJ....125.1980K, doi:10.1086/368241

[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.

[clpl4_99-2] 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

[aj74_375-3] Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819

[gcrv1953-4] Wilson, Ralph Elmer (1953), "General catalogue of stellar radial velocities", Carnegie Institute Washington D.C. Publication, Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W

[Anderson2012-5] Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.

[Zorec2012-6] Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.

[apj660_2_1556-7] ^ ^a ^b ^c ^d ^e ^f Rhee, Joseph H.; et al. (May 2007), "Characterization of Dusty Debris Disks: The IRAS and Hipparcos Catalogs", The Astrophysical Journal, 660 (2): 1556–1571, arXiv:astro-ph/0609555, Bibcode:2007ApJ...660.1556R, doi:10.1086/509912, S2CID 11879505

[aaa442_2_563-8] Monier, R. (November 2005), "Abundances of a sample of A and F-type dwarf members of the Ursa Major Group", Astronomy and Astrophysics, 442 (2): 563–566, Bibcode:2005A&A...442..563M, doi:10.1051/0004-6361:20053222

[aaa462_2_671-9] Royer, F.; Zorec, J.; Gómez, A. E. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv:astro-ph/0610785, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224, S2CID 18475298

[SIMBAD-10] "eps Tri -- Variable Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2011-12-13

[Eggleton2008-11] Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.

[mnras389_2_869-12] Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976

[aj125_4_1980-13] King, Jeremy R.; et al. (April 2003), "Stellar Kinematic Groups. II. A Reexamination of the Membership, Activity, and Age of the Ursa Major Group", The Astronomical Journal, 125 (4): 1980–2017, Bibcode:2003AJ....125.1980K, doi:10.1086/368241

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Epsilon Trianguli

References

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