Delta1 Lyrae
Template:Other stars by Bayer designation
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Lyra |
| Right ascension | Template:RA[1] |
| Declination | Template:DEC[1] |
| Apparent magnitude (V) | 5.56[2] |
| Characteristics | |
| Spectral type | B2.5V[3][4] |
| U−B Template:Engvar | −0.67[2] |
| B−V Template:Engvar | −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 | Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc) |
| Absolute magnitude (MV) | −1.55[6] |
| Orbit[7] | |
| Period (P) | 88.352 days |
| Semi-major axis (a) | ≥Script error: No such module "convert". |
| Eccentricity (e) | Script error: No such module "val". |
| Periastron epoch (T) | Script error: No such module "val". |
| Argument of periastron (ω) (secondary) | Script error: No such module "val".° |
| Semi-amplitude (K1) (primary) | Script error: No such module "val". km/s |
| Details | |
| δ1 Lyr A | |
| Mass | Script error: No such module "val".[4] Script error: No such module "val".[8] Script error: No such module "val".[9] Template:Solar mass |
| Luminosity | 838[6] Template:Solar luminosity |
| Luminosity (bolometric) | 3,620[8] Template:Solar luminosity |
| Surface gravity (log g) | Script error: No such module "val". (3.848 polar)[10] cgs |
| Temperature | 20,350[8] K |
| Metallicity [Fe/H] | −0.05[6] dex |
| Rotational velocity (v sin i) | Script error: No such module "val".[10] km/s |
| Age | Script error: No such module "val". Myr[4] Script error: No such module "val".[9] Myr |
| Metallicity [Fe/H] | {{{metal_fe2}}} dex |
| Other designations | |
| Template:Odlist[11] | |
| Database references | |
| SIMBAD | data |
Script error: No such module "Check for unknown parameters".
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 Script error: No such module "val". 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]
References
<templatestyles src="Reflist/styles.css" />
- ↑ a b c d e f Template:Cite Gaia DR2
- ↑ a b c d Script error: No such module "citation/CS1".
- ↑ a b Script error: No such module "citation/CS1".
- ↑ a b c d Script error: No such module "citation/CS1".
- ↑ a b Script error: No such module "citation/CS1".
- ↑ a b c Script error: No such module "citation/CS1".
- ↑ a b Script error: No such module "citation/CS1". , p. 412
- ↑ a b c d e Script error: No such module "citation/CS1".
- ↑ a b Script error: No such module "citation/CS1".
- ↑ a b Script error: No such module "citation/CS1".
- ↑ Template:Cite simbad
- ↑ Script error: No such module "citation/CS1".
- ↑ Script error: No such module "citation/CS1".
- ↑ Script error: No such module "citation/CS1".
- ↑ Script error: No such module "citation/CS1".
- ↑ Template:Cite simbad
Script error: No such module "Check for unknown parameters".