Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Lyra |
Right ascension | 18h 53m 43.55924s [1] |
Declination | +36° 58′ 18.1891″ [1] |
Apparent magnitude (V) | 5.56 [2] |
Characteristics | |
Spectral type | B2.5V [3] [4] |
U−B color index | −0.67 [2] |
B−V color index | −0.15 [2] |
Astrometry | |
Radial velocity (Rv) | −25.8 [5] km/s |
Proper motion (μ) |
RA: +1.350
[1]
mas/
yr Dec.: −2.985 [1] mas/ yr |
Parallax (π) | 2.8072 ± 0.1334 mas [1] |
Distance | 1,160 ± 60
ly (360 ± 20 pc) |
Absolute magnitude (MV) | −1.55 [6] |
Orbit [7] | |
Period (P) | 88.352 days |
Semi-major axis (a) | ≥46.8 Gm (0.313 AU) |
Eccentricity (e) | 0.37±0.03 |
Periastron epoch (T) | 2428406.613±0.500 JD |
Argument of periastron (ω) (secondary) | 191.3±0.1° |
Semi-amplitude (K1) (primary) | 39.7±1.8 km/s |
Details | |
δ1 Lyr A | |
Mass | 7.9±0.1 M☉
[4] 7.75±0.50 M☉ [8] 6.6+0.68 −0.61 [9] M☉ |
Luminosity | 838 [6] L☉ |
Luminosity (bolometric) | 3,620 [8] L☉ |
Surface gravity (log g) | 3.764±0.032 (3.848 polar) [10] cgs |
Temperature | 20,350 [8] K |
Metallicity [Fe/H] | −0.05 [6] dex |
Rotational velocity (v sin i) | 86±10 [10] km/s |
Age | 21.1±2.2 Myr
[4] 9+9 −4 [9] Myr |
Other designations | |
Database references | |
SIMBAD | data |
Delta1 Lyrae, its name Latinized from δ1 Lyrae, is a binary star system in the northern constellation of Lyra. It is dimly visible to the naked eye at night with a combined apparent visual magnitude of 5.56. [2] The system is located at a distance of approximately 1,160 light years from the Sun based on parallax, [1] but is drifting closer with a radial velocity of −26 km/s. [5] O. J. Eggen originally included this as a candidate member of the proposed Delta Lyrae cluster. [12]
The variable radial velocity of this star was discovered from photographic plates taken at the Yerkes Observatory in 1904. [13] The first set of orbital elements was computed by Frank Craig Jordan in 1916. [14] It is a single-lined spectroscopic binary with an orbital period of 88.4 days and an eccentricity (ovalness) of 0.37. [7]
The visible component of the pair has a blue-white hue with a stellar classification of B2.5V, [3] [4] indicating that it is a B-type main-sequence star undergoing core hydrogen fusion. It is a few million years old with a relatively high rotation rate and around 7–8 times the mass of the Sun. The star is radiating about 3,620 [8] times the Sun's luminosity from its photosphere at an effective temperature of 20,350 K. [8]
There is a magnitude 9.93 visual companion at an angular separation of 175.30 arcseconds along a position angle of 20°, as of 2012. This component was discovered by William Herschel. [15] It is an evolved giant star with a class of K2III at a distance of around 1,760 light years. [16]
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Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Lyra |
Right ascension | 18h 53m 43.55924s [1] |
Declination | +36° 58′ 18.1891″ [1] |
Apparent magnitude (V) | 5.56 [2] |
Characteristics | |
Spectral type | B2.5V [3] [4] |
U−B color index | −0.67 [2] |
B−V color index | −0.15 [2] |
Astrometry | |
Radial velocity (Rv) | −25.8 [5] km/s |
Proper motion (μ) |
RA: +1.350
[1]
mas/
yr Dec.: −2.985 [1] mas/ yr |
Parallax (π) | 2.8072 ± 0.1334 mas [1] |
Distance | 1,160 ± 60
ly (360 ± 20 pc) |
Absolute magnitude (MV) | −1.55 [6] |
Orbit [7] | |
Period (P) | 88.352 days |
Semi-major axis (a) | ≥46.8 Gm (0.313 AU) |
Eccentricity (e) | 0.37±0.03 |
Periastron epoch (T) | 2428406.613±0.500 JD |
Argument of periastron (ω) (secondary) | 191.3±0.1° |
Semi-amplitude (K1) (primary) | 39.7±1.8 km/s |
Details | |
δ1 Lyr A | |
Mass | 7.9±0.1 M☉
[4] 7.75±0.50 M☉ [8] 6.6+0.68 −0.61 [9] M☉ |
Luminosity | 838 [6] L☉ |
Luminosity (bolometric) | 3,620 [8] L☉ |
Surface gravity (log g) | 3.764±0.032 (3.848 polar) [10] cgs |
Temperature | 20,350 [8] K |
Metallicity [Fe/H] | −0.05 [6] dex |
Rotational velocity (v sin i) | 86±10 [10] km/s |
Age | 21.1±2.2 Myr
[4] 9+9 −4 [9] Myr |
Other designations | |
Database references | |
SIMBAD | data |
Delta1 Lyrae, its name Latinized from δ1 Lyrae, is a binary star system in the northern constellation of Lyra. It is dimly visible to the naked eye at night with a combined apparent visual magnitude of 5.56. [2] The system is located at a distance of approximately 1,160 light years from the Sun based on parallax, [1] but is drifting closer with a radial velocity of −26 km/s. [5] O. J. Eggen originally included this as a candidate member of the proposed Delta Lyrae cluster. [12]
The variable radial velocity of this star was discovered from photographic plates taken at the Yerkes Observatory in 1904. [13] The first set of orbital elements was computed by Frank Craig Jordan in 1916. [14] It is a single-lined spectroscopic binary with an orbital period of 88.4 days and an eccentricity (ovalness) of 0.37. [7]
The visible component of the pair has a blue-white hue with a stellar classification of B2.5V, [3] [4] indicating that it is a B-type main-sequence star undergoing core hydrogen fusion. It is a few million years old with a relatively high rotation rate and around 7–8 times the mass of the Sun. The star is radiating about 3,620 [8] times the Sun's luminosity from its photosphere at an effective temperature of 20,350 K. [8]
There is a magnitude 9.93 visual companion at an angular separation of 175.30 arcseconds along a position angle of 20°, as of 2012. This component was discovered by William Herschel. [15] It is an evolved giant star with a class of K2III at a distance of around 1,760 light years. [16]
{{
cite web}}
: CS1 maint: postscript (
link)
{{
cite web}}
: CS1 maint: postscript (
link)