catalogues and names

The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version)

SKY2000 - Master Star Catalog

Smithsonian Astrophysical Observatory Star Catalog

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

catalogues and names

catalogues and names

DT Cyg, HR 8084, HD 201078, SAO 70917, BD +30 4318, FK5: 3687

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

position, motion, parallax:

position (J2000)	RA: 21h 6min 30.3sec	DEC: +31° 11' 5''
position (B1900)	RA: 21h 2min 18.4sec	DEC: +30° 47' 1''
proper motion (J2000)	RA: 0.007 arcsec/a	DEC: -0.004 arcsec/a
radial velocity	0 km/s note: variable radial velocity
rotational velocity	9 km/s (uncertain) (variable)
galactic coordinates	longitude: 76.55°	latitude: -10.78°

magnitude

visual magnitude

5.82 (V on UBV Johnson system)

spectral / color information

spectral class	F7.5Ib-II
B-V-magnitude	0.56
R-I-magnitude
IR-note	object is infrared source (NASA merged infrared catalogue, Schmitz et al., 1978)

note (category: spectra):

Also classified F5.5-F7Ib-II.

variability information

variable star identification

DT Cyg

note (category: variability):

CDelta 5.57 - 5.96V, 2.499215d. Period varies.

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

position, motion, parallax:

position (J2000)	RA: 21h 6min 30.236sec	DEC: +31° 11' 4.82''	±0.2 arcsec	source: 52
proper motion (J2000)	RA: -0.0001 arcsec/a	DEC: -0.004 arcsec/a		source: 25
radial velocity	0 km/s			source: 25
galactic coord. (B1950)	longitude: 76.56°	latitude: -10.78°

magnitude:

visual	5.6 (observed)	source: 31
photovisual	5.9	source: 2
photographic	6.3	source: 16

spectral information:

spectral class	F5		source: 96
Morgan-Keenan	F7.5Ib-II		source: 25
B-magnitude	6.3 ±0.3	B-V-magnitude	0.53
U-magnitude	6.62 ±0.3	U-B-magnitude	0.32

variability information:

source of data: 30

variability type	115
var. amplitude	0.39
var. period	2.5
var. epoch	2444047 22. June 1979, 12:00:00 UT
next max light	2452219.5 6. November 2001, 00:00:00 UT

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
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
52	PPMN-HP subset
PPMN Star Catalogue (Reference 16) High-Precision Subset (Code H)
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 (B1950)	RA: 21h 4min 24.223sec	DEC: +30° 58' 59.79''	±0.02 arcsec
position (J2000)	RA: 21h 6min 30.205sec	DEC: +31° 11' 4.9''
proper motion B1950 (FK4)	RA: -0.0002 arcsec/a	DEC: 0 arcsec/a	±0.004 arcsec/a in RA ±0.005 arcsec/a in DEC
proper motion J2000 (FK5)	RA: -0.0001 arcsec/a	DEC: -0.003 arcsec/a
source of proper motion data	Determined by source catalog

magnitude:

visual	5.7 (accuracy: 1 decimal)
source of visual magnitude data	Source cited in source catalog introduction.

spectral information:

spectral class	F5
source of spectral data	Taken from the Henry Draper Catalogue or no spectrum in source catalog.

remarks for duplicity and variability

Variable star in visual magnitude in source catalog

catalogues

source catalogue	GC, catalogue number: 29502
Durchmusterung	BD+30 4318
Boss General Catalogue	29502
Henry Draper Catalogue	201078

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

position:

position (equinox 1950.0)

RA: 21h 4min 24.2sec

DEC: +30° 59' 0''

variability informations:

variability type	DCEPS	pulsating variable star
magnitute at max. brightness	5.57
magnitute at min. brightness	5.96
photometric system	visual, photovisual or Johnson's V
epoch for maximum light [JD]	2444046.969 22. June 1979, 11:15:22 UT
period [d]	2.499215
next maximum light [JD]	2452219.40205 5. November 2001, 21:38:57 UT
rising time	48 % of period

spectral information

spectral class

F5.5-F7Ib-II

references

to a study	the main characteristics of the star was determined by the authors themselves
to a chart/photograph	Vol. I GCVS (see Kholopov et al. 1985-1988)

miscanellous

ID in the GCVS catalogue	31/142
constellation	Cygnus
notes on existence	The star is equivalent to '0310143 DU'.
There are notes in published catalog.

variability type description

variability type	description
DCEPS	These are Delta Cep variables having light amplitudes <0.5 mag in V (<0.7 mag in B) and almost symmetrical light curves (M-m approx. 0.4 - 0.5 periods); as a rule, their periods do not exceed 7 days. They are probably first-overtone pulsators and/or are in the first transition across the instability strip after leaving the main sequence (SU Cas).