- Delta¹ Lyrae
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Delta1 Lyrae[1][2] Observation data
Epoch J2000.0 Equinox J2000.0Constellation Lyra Right ascension 18 h 53 m 43.5596 s/18 h 5 3m 48.4506 s Declination +36° 58' 18.196"/+37° 01' 03.755" Apparent magnitude (V) 5.569/9.8 Characteristics Spectral type B2.5V/K2III U−B color index −0.67/+1.288 B−V color index −0.15/+1.224 Astrometry Radial velocity (Rv) −25.8/−49.0 km/s Proper motion (μ) RA: 1.49/3.70 mas/yr
Dec.: −2.60/10.20 mas/yrParallax (π) 3.02 ± 0.56 mas Distance approx. 1100 ly
(approx. 330 pc)Orbit[3], p. 412 Period (P) 88.352 days yr Eccentricity (e) 0.37±0.03 Argument of periastron (ω)
(secondary)204.5±7.7° Other designations Delta1 Lyrae (δ1 Lyr) is a binary star system in the constellation Lyra, approximately 1,100 light years away from Earth. The two stars complete an orbit around each other about once every 88 days. They are a spectroscopic binary, meaning the separation between the two is very small, and their orbital velocity is very high.[1][3]
The main star, IDS 18502+3650 A, is a bluish white star of the spectral type B2.5V, meaning it has a surface temperature of 11,000 to 25,000 kelvins. It is a dwarf star, like our Sun, but more than twice as hot in surface temperature and many times brighter.[1]
Its 10th magnitude companion, IDS 18502+3650 B, is an orange giant star with the spectral type K2III. It therefore possesses a surface temperature of 3,500 to 5,000 kelvins and is cooler than our Sun, yet larger and brighter.[2]
References
- ^ a b c "Simbad Query Result". Simbad. http://simbad.u-strasbg.fr/simbad/sim-id?protocol=html&Ident=11+Lyr&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id. Retrieved October 15, 2007.
- ^ a b "Simbad Query Result". Simbad. http://simbad.u-strasbg.fr/simbad/sim-id?mescat.ubv=on&Ident=%402900445&Name=BD%2B36++3308&submit=display+selected+measurements#lab_meas. Retrieved October 15, 2007.
- ^ a b Richardson, E. H. & McKellar, A.; Herbig (1957). "Redetermination of the spectrographic orbit of delta1 Lyrae". Publ. Dominion Astrophys. Obs. 10: 407–413. Bibcode 1991Obs...111..155G.
Bayer α (Vega) • β (Sheliak) • γ (Sulafat) • δ¹ • δ² • ε¹, ² (Double Double) • ζ¹ • ζ² • η (Aladfar) • θ • ι • κ • λ • μ (Alathfar) • ν¹ • ν²Flamsteed 1 (κ) • 2 (μ, Alathfar) • 3 (α, Vega) • 4 (ε¹, Double Double) • 5 (ε², Double Double) • 6 (ζ¹) • 7 (ζ²) • 8 (ν¹) • 9 (ν²) • 10 (β, Sheliak) • 11 (δ¹) • 12 (δ²) • 13 • 14 (γ, Sulafat) • 15 (λ) • 16 • 17 • 18 (ι) • 19 • 20 (η, Aladfar) • 21 (θ)Nearby 2MASS 1835+3259 • α (Vega) • GJ 4063 • Gliese 747 • WISE 1828+2650Categories:- Lyra constellation
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