Location of δ Trianguli (circled) |
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Observation data Epoch J2000.0 Equinox J2000.0 |
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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 |
Distance | 35.2 ± 0.1 ly (10.78 ± 0.05 pc) |
Absolute magnitude (MV) | 4.69[2] |
Details | |
Mass | 1.0/0.8[6] M☉ |
Radius | 0.98[7] R☉ |
Surface gravity (log g) | 4.5[8] |
Temperature | 6,215/4,493[3] K |
Metallicity [Fe/H] | −0.39[2] to −0.30[8] dex |
Rotational velocity (v sin i) | 10.00[5] km/s |
Age | 8.5[9] to 9.0[2] Gyr |
Orbit[10] | |
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 | |
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. It has an apparent magnitude of +4.87 and forms an optical (line-of-sight) triple with Gamma Trianguli and 7 Trianguli.[6]
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Delta Trianguli A is a main sequence star with a stellar classification of G0V and a mass similar to the Sun.[6] 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;[6] 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 our line of sight.[10]
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]
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