Delta Trianguli

Delta Trianguli

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Triangulum
Right ascension	02h 17m 03.23016s[1]
Declination	+34° 13′ 27.2260″[1]
Apparent magnitude (V)	+4.865[2]
Characteristics
Spectral type	G0V / K3V[3]
U−B color index	0.02
B−V color index	0.60[4]
Astrometry
Radial velocity (Rv)	−5.70[4] km/s
Proper motion (μ)	RA: 1151.83[1] mas/yr Dec.: −246.89[1] mas/yr
Parallax (π)	92.73 ± 0.39[1] mas
Distance	35.2 ± 0.1 ly (10.78 ± 0.05 pc)
Absolute magnitude (MV)	4.69[2]
Details
Mass	1.09 M☉
Radius	0.98[5] R☉
Surface gravity (log g)	4.5[6]
Temperature	5,600[6] K
Metallicity	[Fe/H] = −0.39[2] to −0.30[6]
Rotational velocity (v sin i)	10.00[4] km/s
Age	8.5[7] to 9.0[2] Gyr
Orbit[8]
Companion	Delta Trianguli B
Period (P)	10.0200 days
Semimajor axis (a)	9.80 ± 0.06 mas
Eccentricity (e)	0.020 ± 0.005
Inclination (i)	167 ± 3°
Longitude of the node (Ω)	15 ± 9°
Other designations
8 Trianguli, BD+33°395, Gliese 92, HD 13974, HIP 10644, HR 660, LFT 198, LHS 154, LTT 10770, SAO 55420.[9]

Delta Trianguli (δ Tri, δ Trianguli) is a spectroscopic binary star system approximately 35 light-years (11 pc) away in the constellation of Triangulum. The primary star is a yellow dwarf, while the secondary star is thought to be an orange dwarf. The system is one part of a moving group of stars with Zeta Herculis.

Stellar components

Delta Trianguli A is a yellow dwarf star and with a mass higher than the Sun. The spectral characteristics of the smaller companion Delta Trianguli B are not well determined since the close orbit makes observations difficult, although it may be an orange dwarf of spectral type K3V.^[3] This system is part of the Zeta Herculis stellar moving group.

The Delta Trianguli stars orbit their center of mass. Star A orbits approximately 0.045 AU from the center and star B orbits approximately 0.065 AU from the center.^{[citation needed]} They orbit each other every 10.02 days in a nearly circular orbit; the eccentricity of the orbit is only 0.020. The orbit is inclined 167° to our line of sight.^[8]

A 2008 search for a tertiary companion to this system using an adaptive optics system on the VLT proved unsuccessful.^[10]

See also

• Alpha Centauri
• Binary star
• V4046 Sagitarii

References

1. ^ ^{a b c d e} van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. Bibcode 2007A&A...474..653V. doi:10.1051/0004-6361:20078357. 
2. ^ ^{a b c d} Nordström, B. et al. (May 2004), "The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ˜14 000 F and G dwarfs", Astronomy and Astrophysics 418: 989–1019, arXiv:astro-ph/0405198, Bibcode 2004A&A...418..989N, doi:10.1051/0004-6361:20035959 
3. ^ ^{a b} Raghavan, Deepak et al. (September 2010), "A Survey of Stellar Families: Multiplicity of Solar-type Stars", The Astrophysical Journal Supplement 190 (1): 1–42, Bibcode 2010ApJS..190....1R, doi:10.1088/0067-0049/190/1/1 
4. ^ ^{a b c} White, Russel J. et al. (June 2007), "High-Dispersion Optical Spectra of Nearby Stars Younger Than the Sun", The Astronomical Journal 133 (6): 2524–2536, Bibcode 2007AJ....133.2524W, doi:10.1086/514336 
5. ^ Pasinetti Fracassini, L. E. et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics", Astronomy and Astrophysics 367: 5211–524, arXiv:astro-ph/0012289, Bibcode 2001A&A...367..521P, doi:10.1051/0004-6361:20000451 
6. ^ ^{a b c} Clegg, R. E. S. (October 1977), "Carbon and nitrogen abundances in F- and G-type stars", Monthly Notices of the Royal Astronomical Society 181: 1–30, Bibcode 1977MNRAS.181....1C 
7. ^ Holmberg, J.; Nordström, B.; Andersen, J. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics 501 (3): 941–947, Bibcode 2009A&A...501..941H, doi:10.1051/0004-6361/200811191 
8. ^ ^{a b} "Sixth Catalog of Orbits of Visual Binary Stars", U.S. Naval Observatory, http://ad.usno.navy.mil/wds/orb6.html, retrieved 2008-06-22 
9. ^ "del Tri -- Spectroscopic binary", SIMBAD (Centre de Données astronomiques de Strasbourg), http://simbad.u-strasbg.fr/simbad/sim-id?Ident=%401580494, retrieved 2011-09-16 
10. ^ Tokovinin, A. et al. (May 2006), "Tertiary companions to close spectroscopic binaries", Astronomy and Astrophysics 450 (2): 6811–693, arXiv:astro-ph/0601518, Bibcode 2006A&A...450..681T, doi:10.1051/0004-6361:20054427 

External links

• "Delta Trianguli 2". SolStation. http://www.solstation.com/stars2/del-tri2.htm. Retrieved 2008-06-22. 
• Kaler, James. "Delta Tri". Stars: Portraits of Stars and their Constellations. University of Illinois. http://stars.astro.illinois.edu/sow/deltatri.html. Retrieved 2011-09-16.