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Binary star system in the constellation of Lyra
Delta1 Lyrae
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) 2428 406 .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
Delta1 Lyr ,
11 Lyrae ,
NSV 11504,
BD +36°3307 ,
GC 25934,
HD 175426,
HIP 92728,
HR 7131,
SAO 67537,
WDS J18537+3658A ,
GSC 02650-02146
[11]
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]
References
^
a
b
c
d
e
f
Brown, A. G. A. ; et al. (Gaia collaboration) (August 2018).
"Gaia Data Release 2: Summary of the contents and survey properties" .
Astronomy & Astrophysics . 616 . A1.
arXiv :
1804.09365 .
Bibcode :
2018A&A...616A...1G .
doi :
10.1051/0004-6361/201833051 .
Gaia DR2 record for this source at
VizieR .
^
a
b
c
d Guetter, H. H. (October 1974), "UBV photometry of 180 early-type stars", Publications of the Astronomical Society of the Pacific , 86 : 795–797,
Bibcode :
1974PASP...86..795G ,
doi :
10.1086/129675 .
^
a
b Guetter, Harry H. (April 1968), "Spectral classification of 239 early-type stars", Publications of the Astronomical Society of the Pacific , 80 (473): 197,
Bibcode :
1968PASP...80..197G ,
doi :
10.1086/128611 ,
S2CID
121565803 .
^
a
b
c
d Tetzlaff, N.; et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun",
Monthly Notices of the Royal Astronomical Society , 410 (1): 190–200,
arXiv :
1007.4883 ,
Bibcode :
2011MNRAS.410..190T ,
doi :
10.1111/j.1365-2966.2010.17434.x ,
S2CID
118629873 .
^
a
b Wilson, Ralph Elmer (1953), "General catalogue of stellar radial velocities", Carnegie Institute Washington D.C. Publication ,
Carnegie Institution of Washington ,
Bibcode :
1953GCRV..C......0W .
^
a
b
c Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters , 38 (5): 331,
arXiv :
1108.4971 ,
Bibcode :
2012AstL...38..331A ,
doi :
10.1134/S1063773712050015 ,
S2CID
119257644 .
^
a
b Richardson, E. H.; McKellar, A. (1957), "Redetermination of the spectrographic orbit of delta1 Lyrae", Publ. Dominion Astrophys. Obs. , 10 : 407–413,
Bibcode :
1958PDAO...10..407R . , p. 412
^
a
b
c
d
e Hohle, M. M.; et al. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten , 331 (4): 349,
arXiv :
1003.2335 ,
Bibcode :
2010AN....331..349H ,
doi :
10.1002/asna.200911355 ,
S2CID
111387483 .
^
a
b Gullikson, Kevin; et al. (July 26, 2016), "The Close Companion Mass-ratio Distribution of Intermediate-mass Stars", The Astronomical Journal , 152 (2): 40–53,
arXiv :
1604.06456 ,
Bibcode :
2016AJ....152...40G ,
doi :
10.3847/0004-6256/152/2/40 ,
S2CID
119179065 .
^
a
b Huang, W.; Gies, D. R. (August 2008), "Stellar Rotation in Field and Cluster B Stars", The Astrophysical Journal , 683 (2): 1045–1051,
arXiv :
0805.2133 ,
Bibcode :
2008ApJ...683.1045H ,
doi :
10.1086/590106 ,
S2CID
18926523 .
^
"del01 Lyr" .
SIMBAD .
Centre de données astronomiques de Strasbourg . Retrieved 2021-01-23 . {{
cite web }}
: CS1 maint: postscript (
link )
^ Eggen, O. J. (July 1983), "Concentrations in the Local Association- II. The northern concentrations including the alf Per, Pleiades, M 34 and del LYR clusters.", Monthly Notices of the Royal Astronomical Society , 204 : 391–403,
Bibcode :
1983MNRAS.204..391E ,
doi :
10.1093/mnras/204.2.391 .
^ Frost, E. B.; Adams, W. S. (1904), "Observations with the Bruce spectrograph", The Astrophysical Journal , 19 : 352,
Bibcode :
1904ApJ....19..350F ,
doi :
10.1086/141124 .
^ Jordan, Frank Craig (1916), "The orbit of [delta]1 Lyrae", Publications of the Allegheny Observatory of the University of Pittsburgh , 3 (14): 119–124,
Bibcode :
1916PAllO...3..119J .
^ Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal , 122 (6): 3466–3471,
Bibcode :
2001AJ....122.3466M ,
doi :
10.1086/323920 .
^
"BD+36 3308" .
SIMBAD .
Centre de données astronomiques de Strasbourg . Retrieved 2021-01-23 . {{
cite web }}
: CS1 maint: postscript (
link )