d2Lyrae
| 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)
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 | |
magnitude
| 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 | |
magnitude:
| 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:
| variability type | 192 |
| var. amplitude | 0,11 |
double/multiple star system information:
| separation between brightest and second brightest component | 86,2 arcsec |
| magnitude difference between brightest and second brightest component | 6,9 |
| position angle | 349 ° |
sources:
| 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 | |
| 17 | ACRS |
| 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 | ||
magnitude:
| 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) |
catalogues
| 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. | - |
notes:
| note | Delta (2) Lyr. A is an unclassified variable. |
data from Combined General Catalogue of Variable Stars (Vol. I-III) (Kholopov+ 1998)
position:
| 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 |
references
| to a chart/photograph | no chart is avaible, but the star is contained in the 'Bonner Durchmusterung' |
miscanellous
| 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). SRA 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; SRB 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; SRC 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; SRD 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). |