The object was found in the following catalogues:
  1. The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version)

  2. SKY2000 - Master Star Catalog

  3. Smithsonian Astrophysical Observatory Star Catalog

  4. The Washington Visual Double Star Catalog, 1996.0

  5. Combined General Catalogue of Variable Stars (Vol. I-III)

catalogues and names d2Lyr, del 2 Lyr, 12 Lyr, HR 7139, HD 175588, SAO 67559, WDS 18545+3654A
constellation Lyra

data from The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version) (Hoffleit+, 1991)

object is infrared source (NASA merged infrared catalogue, Schmitz et al., 1978)

position, motion, parallax:

position (J2000) RA: 18h 54min 30,2sec DEC: +36 53' 56''
position (J1900) RA: 18h 51min 0,3sec DEC: +36 46' 17''
proper motion (J2000) RA: -0,009 arcsec/a DEC: 0,01 arcsec/a
radial velocity -26 km/s
trigonometric parallax -0,001 arcsec


visual magnitude 4,3
(V on UBV Johnson system)

spectral / color information

spectral class M4II
B-V-magnitude 1,68
U-B-magnitude 1,65
R-I-magnitude 1,63

variability information

variable star identification Del2 Lyr
note (category: variability): SRc? 4.22 - 4.33V.

double/multiple star system information

number of components of multiple star system 3
separation 86,2 arcsec
mag difference (of double or brightest multiple) 7
component ID AB

miscellaneous information

note (category: group membership): In Delta Lyr cluster in the Pleiades group.

data from SKY2000 - Master Star Catalog (Myers+ 1997)

position, motion, parallax:

position (J2000) RA: 18h 54min 30,279sec DEC: +36 53' 54,76'' 0,35 arcsec source: 17
proper motion (J2000) RA: -0,0003 arcsec/a DEC: -0,004 arcsec/a source: 25
radial velocity -26 km/s source: 25
galactic coord. (B1950) longitude: 66,93 latitude: 15,32
GCI unit vector (J2000) X: 0,188398 Y: -0,777191 Z: 0,6004


visual 4,2 (observed) source: 31
photovisual 4,5 source: 2
photographic 5,9 source: 16

spectral information:

spectral class M0 source: 96
Morgan-Keenan M4II source: 25
B-magnitude 5,98 0,05 B-V-magnitude 1,68
U-magnitude 7,63 0,05 U-B-magnitude 1,65

variability information:

source of data: 30
variability type 192
var. amplitude 0,11

double/multiple star system information:

source of data: 19
separation between brightest and second brightest component 86,2 arcsec
magnitude difference between brightest and second brightest component 6,9
position angle 349


2 HD and HDE Catalogs
Cannon, A.J., and E.C. Pickering, Harvard Annals, Vols 91-99, 1918-24, Cambridge, Massachusetts: Harvard University; Cannon, A.J., Harvard Annals, Vol. 100, 1925-36, Cambridge, Massachusetts: Harvard University; and Cannon, A.J., and M. Walton Mayall, Harvard Annals, Vol. 112, 1949, Cambridge, Massachusetts: Harvard University
16 PPM North and PPM South Catalogs and PPM Supplement
Roser, S., and U. Bastian, "Catalogue of Positions and Proper Motions," A&AS, Vol. 74, p. 449, 1988, and Bastian, U., et al., "Catalogue of Positions and Proper Motions - South," 1993
Corbin, T.E., and S.E. Urban, Astrographic Catalog Reference Stars, United States Naval Observatory, 1991
19 WDS Catalog
Worley, C.E., and G.G. Douglass, Washington Catalog of Visual Double Stars 1996.0, United States Naval Observatory, 1996
25 Bright Star Catalogue, 5th edition
Hoffleit, D. and Warren, W.H. Jr., The Bright Star Catalogue, 5th Revised Edition, Version 2, 1994
30 GCVS, 4th edition
Kholopov, P.N., et al., General Catalogue of Variable Stars, fourth edition, Moscow: Nauka Publishing House, 1985-88
31 CRM' (non-GCVS variable data)
Warren, W.H. Jr., Northern Hemisphere Catalog of Red Magnitudes, 1994
96 SAO or HD/HDE Catalog
Reference from Value 1 or Reference from Value 2

data from Smithsonian Astrophysical Observatory Star Catalog (SAO Staff 1966; USNO, ADC 1990)

position and proper motion:

position (J1950) RA: 18h 52min 45,207sec DEC: +36 50' 2,93'' 0,024 arcsec
position (J2000) RA: 18h 54min 30,219sec DEC: +36 53' 55,83''
proper motion J1950 (FK4) RA: -0,0011 arcsec/a DEC: 0,01 arcsec/a 0,004 arcsec/a in RA
0,003 arcsec/a in DEC
proper motion J2000 (FK5) RA: -0,0008 arcsec/a DEC: 0,01 arcsec/a
source of proper motion data Determined by source catalog


visual 4,5 (accuracy: 2 decimals)
source of visual magnitude data Taken from Harvard or San Luis photometry.

spectral information:

spectral class Mb
source of spectral data Taken from the Henry Draper Catalogue or no spectrum in source catalog.

remarks for duplicity and variability

Double star in Aitken's Double Star Catalogue (Aitken 1932)


source catalogue GC, catalogue number: 25959
Durchmusterung BD+36 3319
Boss General Catalogue 25959
Henry Draper Catalogue 175588

data from The Washington Visual Double Star Catalog, 1996.0 (Worley+, 1996)

position and proper motion:

position (J2000) RA: 18h 54,5min DEC: +36 54'
proper motion (J2000) RA: -0,004 arcsec/a DEC: -0,004 arcsec/a

double/multiple star system information:

component year number of measures position angle angular separation magnitude of 1st component magnitude of 2nd component spectral class(es) discoverer code
AB 1923 2 349 86,2'' 4,3 11,2 M4II ES 2028
BC 1923 2 136 2,1'' 11,2 11,6 - ES 2028

discoverer information:

discoverer code discoverer reference
ES 2028 Espin, T.E. -


note Delta (2) Lyr. A is an unclassified variable.

data from Combined General Catalogue of Variable Stars (Vol. I-III) (Kholopov+ 1998)


position (J1950) RA: 18h 52min 45,2sec DEC: +36 50' 3''

variability informations:

variability type SRC: pulsating variable star
magnitute at max. brightness 4,22
magnitute at min. brightness 4,33
photometric system visual, photovisual or Johnson's V

spectral information

spectral class M4II


to a chart/photograph no chart is avaible, but the star is contained in the 'Bonner Durchmusterung'


ID in the GCVS catalogue 52/90042
constellation Lyra
notes on existence The star is equivalent to '0530001 R'.
There are notes in published catalog.

variability type description

variability type description
SRC Semiregular variables, which are giants or supergiants of intermediate and late spectral types showing noticeable periodicity in their light changes, accompanied or sometimes interrupted by various irregularities. Periods lie in the range from 20 to >2000 days, while the shapes of the light curves are rather different and variable, and the amplitudes may be from several hundredths to several magnitudes (usually 1-2 mag in V).

Semiregular late-type (M, C, S or Me, Ce, Se) giants displaying persistent periodicity and usually small (<2.5 mag in V) light amplitudes (Z Aqr). Amplitudes and light-curve shapes generally vary and periods are in the range of 35-1200 days. Many of these stars differ from Miras only by showing smaller light amplitudes;

Semiregular late-type (M, C, S or Me, Ce, Se) giants with poorly defined periodicity (mean cycles in the range of 20 to 2300 days) or with alternating intervals of periodic and slow irregular changes, and even with light constancy intervals (RR CrB, AF Cyg). Every star of this type may usually be assigned a certain mean period (cycle), which is the value given in the Catalogue. In a number of cases, the simultaneous presence of two or more periods of light variation is observed;

Semiregular late-type (M, C, S or Me, Ce, Se) supergiants (Mu Cep) with amplitudes of about 1 mag and periods of light variation from 30 days to several thousand days;

Semiregular variable giants and supergiants of F, G, or K spectral types, sometimes with emission lines in their spectra. Amplitudes of light variation are in the range from 0.1 to 4 mag, and the range of periods is from 30 to 1100 days (SX Her, SV UMa).