Astronomy:Delta Trianguli

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Short description: Binary star in the constellation Triangulum
Delta Trianguli
Triangulum IAU.svg
Red circle.svg
Location of δ Trianguli (circled)
Observation data
Equinox J2000.0]] (ICRS)
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 + G9V to K4V[3]
U−B color index +0.02[4]
B−V color index +0.61[4]
Astrometry
Radial velocity (Rv)−5.70[5] 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
Distance35.2 ± 0.1 ly
(10.78 ± 0.05 pc)
Absolute magnitude (MV)4.69[2]
Orbit[6]
CompanionDelta Trianguli B
Period (P)10.02 days
Semi-major axis (a)9.80±0.06 mas
Eccentricity (e)0.020±0.005
Inclination (i)167±3°
Longitude of the node (Ω)15±9°
Details
A
Mass1.0[7] M☉
Radius0.98[8] R☉
Surface gravity (log g)4.5[9] cgs
Temperature6,215[3] K
Metallicity [Fe/H]−0.39[2] to −0.30[9] dex
Rotational velocity (v sin i)10.00[5] km/s
Age8.5[10] to 9.0[2] Gyr
B
Mass0.8[7] M☉
Temperature4,493[3] K
Other designations
δ Tri, Delta Tri, 8 Trianguli, BD+33° 395, HD 13974, HIP 10644, HR 660, SAO 55420, LHS 154, LTT 10770[11]
Database references
SIMBADdata

Delta Trianguli, Latinized from Delta Tri, 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. It has an apparent magnitude of +4.87 and forms an optical (line-of-sight) triple with Gamma Trianguli and 7 Trianguli.[7]

Stellar components

Delta Trianguli A is a main sequence star with a stellar classification of G0V and a mass similar to the Sun.[7] The spectral characteristics of the smaller companion Delta Trianguli B are not well determined since the close orbit makes observations difficult,[12] with estimates of the spectral class ranging from G9V to K4V.[3] The Delta Trianguli stars orbit their center of mass with an estimated separation of 0.106 AU;[7] it is certainly less than one AU.[3] The orbital period is 10.02 days and the eccentricity of the orbit is only 0.020. The orbit is inclined about 167° to the line of sight from Earth.[6]

A 2008 search for a tertiary companion to this system using an adaptive optics system on the VLT proved unsuccessful.[13] Examination of the system in infrared light at 70 μm shows no excess emission that would otherwise indicate the presence of a disk of orbiting dust.[3]

Naming

In Chinese, 天大將軍 (Tiān Dà Jiāng Jūn), meaning Heaven's Great General, refers to an asterism consisting of δ Trianguli γ Andromedae, φ Persei, 51 Andromedae, 49 Andromedae, χ Andromedae, υ Andromedae, τ Andromedae, 56 Andromedae, β Trianguli and γ Trianguli. Consequently, the Chinese name for δ Trianguli itself is 天大將軍十一 (Tiān Dà Jiāng Jūn shíyī, English: the Eleventh Star of Heaven's Great General.).[14]

See also

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V. 
  2. ↑ 2.0 2.1 2.2 2.3 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, doi:10.1051/0004-6361:20035959, Bibcode: 2004A&A...418..989N 
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 Kim, Jinyoung Serena et al. (October 2005), "Formation and Evolution of Planetary Systems: Cold Outer Disks Associated with Sun-like Stars", The Astrophysical Journal 632 (1): 659–669, doi:10.1086/432863, Bibcode: 2005ApJ...632..659K 
  4. ↑ 4.0 4.1 Johnson, H. L.; Iriarte, B.; Mitchell, R. I.; Wisniewskj, W. Z. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99): 99, Bibcode: 1966CoLPL...4...99J 
  5. ↑ 5.0 5.1 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, doi:10.1086/514336, Bibcode: 2007AJ....133.2524W 
  6. ↑ 6.0 6.1 "Sixth Catalog of Orbits of Visual Binary Stars", U.S. Naval Observatory, http://ad.usno.navy.mil/wds/orb6.html, retrieved 2008-06-22 
  7. ↑ 7.0 7.1 7.2 7.3 7.4 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 
  8. ↑ 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 (2): 5211–524, doi:10.1051/0004-6361:20000451, Bibcode: 2001A&A...367..521P 
  9. ↑ 9.0 9.1 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, doi:10.1093/mnras/181.1.1, Bibcode: 1977MNRAS.181....1C 
  10. ↑ 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, doi:10.1051/0004-6361/200811191, Bibcode: 2009A&A...501..941H 
  11. ↑ "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 
  12. ↑ Raghavan, Deepak et al. (September 2010), "A Survey of Stellar Families: Multiplicity of Solar-type Stars", The Astrophysical Journal Supplement 190 (1): 1–42, doi:10.1088/0067-0049/190/1/1, Bibcode: 2010ApJS..190....1R 
  13. ↑ Tokovinin, A. et al. (May 2006), "Tertiary companions to close spectroscopic binaries", Astronomy and Astrophysics 450 (2): 6811–693, doi:10.1051/0004-6361:20054427, Bibcode: 2006A&A...450..681T 
  14. ↑ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 10 日

External links



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