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	V0637 Mon, 19 Mon, HR 2648, HD 52918, SAO 134106, BD -4 1788, FK5: 2547
constellation	Monoceros

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

position, motion, parallax:

position (J2000)	RA: 7h 2min 54.8sec	DEC: -4° 14' 21''
position (2000.72)	RA: 7h 2min 57sec	DEC: -4° 14' 25''
position (B1900)	RA: 6h 57min 56.8sec	DEC: -4° 5' 39''
proper motion (J2000)	RA: -0.003 arcsec/a	DEC: 0.003 arcsec/a
radial velocity	25 km/s note: suspected variable radial velocity
rotational velocity	336 km/s (uncertain) (variable)
galactic coordinates	longitude: 218.01°	latitude: 0.61°

note (category: radial and/or rotational velocities):

Rotational velocity vsini 336k/s.

magnitude

visual magnitude

4.99 (V on UBV Johnson system)

spectral / color information

spectral class	B1V
B-V-magnitude	-0.2
U-B-magnitude	-0.93
R-I-magnitude

note (category: spectra):

H alpha emission. uv indicates gB1.

variability information

variable star identification

V637 Mon

note (category: variability):

Beta C 4.96 - 5.01V, 0.19120d, secondary 0.19740d, beat period 6.09d.

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

position, motion, parallax:

position (J2000)	RA: 7h 2min 54.773sec	DEC: -4° 14' 21.23''	±0.22 arcsec	source: 15
position (2000.72)	RA: 7h 2min 57sec	DEC: -4° 14' 25''	JD: 2451809.24
proper motion (J2000)	RA: -0.0002 arcsec/a	DEC: 0.004 arcsec/a		source: 25
radial velocity	25 km/s			source: 25
galactic coord. (B1950)	longitude: 218.02°	latitude: 0.61°

magnitude:

visual	4.99 (observed)	source: 25
photovisual	4.9	source: 2
photographic	4.7	source: 2

spectral information:

spectral class	B3		source: 96
Morgan-Keenan	B1V		source: 25
B-magnitude	4.79 ±0.05	B-V-magnitude	-0.2
U-magnitude	3.86 ±0.05	U-B-magnitude	-0.93

variability information:

source of data: 30

variability type	140
var. amplitude	0.05
var. period	0.19
var. epoch	2443496 18. December 1977, 12:00:00 UT
next max light	2451809.26 21. September 2000, 18:14:24 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
15	FK5, FK5 Extension and FK5 Supplement
Fricke, W., H. Schwan and T. Lederle, "Fifth Fundamental Catalogue (FK5), Part I. The Basic Fundamental Stars," Veroff. Astronomisches Recheninstitut, No. 32, Heidelberg, Germany, 1988, and Fricke, W., H. Schwan, and T.E. Corbin, "Fifth Fundamental Catalogue (FK5), Part II. The FK5 Extension," Veröff. Astronomisches Recheninstitut, No. 33, Heidelberg, Germany, 1991
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
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: 7h 0min 25.747sec	DEC: -4° 9' 54.91''	±0.018 arcsec
position (2000.72)	RA: 7h 2min 57sec	DEC: -4° 14' 25''	JD: 2451809.24
position (J2000)	RA: 7h 2min 54.718sec	DEC: -4° 14' 21.29''
proper motion B1950 (FK4)	RA: -0.0011 arcsec/a	DEC: -0.001 arcsec/a	±0.003 arcsec/a in RA ±0.003 arcsec/a in DEC
proper motion J2000 (FK5)	RA: -0.0008 arcsec/a	DEC: 0.001 arcsec/a
source of proper motion data	Determined by source catalog

magnitude:

visual	4.9 (accuracy: 2 decimals)
source of visual magnitude data	Taken from Harvard or San Luis photometry.

spectral information:

spectral class	B3
source of spectral data	Taken from the Henry Draper Catalogue or no spectrum in source catalog.

catalogues

source catalogue	GC, catalogue number: 9293
Durchmusterung	BD-04 1788
Boss General Catalogue	9293
Henry Draper Catalogue	52918

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

position:

position (equinox 1950.0)

RA: 7h 0min 25.7sec

DEC: -4° 9' 55''

variability informations:

variability type	BCEP	pulsating variable star
magnitute at max. brightness	4.96
magnitute at min. brightness	5.01
photometric system	visual, photovisual or Johnson's V
epoch for maximum light [JD]	2443496.1169 18. December 1977, 14:48:20 UT
period [d]	0.1912
next maximum light [JD]	2451809.3017 21. September 2000, 19:14:27 UT

spectral information

spectral class

B1IV-Vea

references

to a study	Vol. I GCVS (see Kholopov et al. 1985-1988)
to a chart/photograph	no chart is avaible, but the star is contained in the 'Bonner Durchmusterung'

miscanellous

ID in the GCVS catalogue	55/637
constellation	Monoceros
notes on existence	The star is equivalent to '0550638 V0638'.
There are notes in published catalog.

variability type description

variability type

description

BCEP

Variables of the Beta Cephei type (Beta Cep, Beta CMa), which are pulsating O8-B6 I-V stars with periods of light and radial-velocity variations in the range of 0.1 - 0.6 days and light amplitudes from 0.01 to 0.3 mag in V. The light curves are similar in shape to average radial-velocity curves but lag in phase by a quarter of the period, so that maximum brightness corresponds to maximum contraction, i.e., to minimum stellar radius. The majority of these stars probably show radial pulsations, but some (V649 Per) display nonradial pulsations; multiperiodicity is characteristic of many of these stars.