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	h Hya, eta Hya, 7 Hya, HR 3454, HD 74280, SAO 117050, BD +3 2039, FK5: 2687
constellation	Hydra

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

position, motion, parallax:

position (J2000)	RA: 8h 43min 13.5sec	DEC: +3° 23' 55''
position (2000.72)	RA: 8h 43min 16sec	DEC: +3° 23' 46''
position (B1900)	RA: 8h 37min 59.8sec	DEC: +3° 45' 28''
proper motion (J2000)	RA: -0.019 arcsec/a	DEC: -0.001 arcsec/a
radial velocity	17 km/s note: spectroscopic binaries
rotational velocity	128 km/s (uncertain) (variable)
galactic coordinates	longitude: 223.25°	latitude: 26.32°

magnitude

visual magnitude

4.3 (V on UBV Johnson system)

spectral / color information

spectral class	B3V
B-V-magnitude	-0.2
U-B-magnitude	-0.74
R-I-magnitude

variability information

variable star identification

Eta Hya

note (category: variability):

Beta C 4.27 - 4.33V, 0.17d.

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

position, motion, parallax:

position (J2000)	RA: 8h 43min 13.56sec	DEC: +3° 23' 53.74''	±0.43 arcsec	source: 16
position (2000.72)	RA: 8h 43min 16sec	DEC: +3° 23' 44''	JD: 2451809.23
proper motion (J2000)	RA: 0.0003 arcsec/a	DEC: -0.028 arcsec/a		source: 25
radial velocity	17 km/s			source: 25
galactic coord. (B1950)	longitude: 223.26°	latitude: 26.32°

magnitude:

visual	4.283 (observed)	source: 31
photovisual	4.3	source: 2
photographic	4	source: 16

spectral information:

spectral class	B3		source: 96
Morgan-Keenan	B3V		source: 25
B-magnitude	4.1 ±0.05	B-V-magnitude	-0.2
U-magnitude	3.36 ±0.05	U-B-magnitude	-0.74

variability information:

source of data: 30

variability type	140
var. amplitude	0.06
var. period	0.17

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
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: 8h 40min 36.696sec	DEC: +3° 34' 45.66''	±0.014 arcsec
position (2000.72)	RA: 8h 43min 16sec	DEC: +3° 23' 46''	JD: 2451809.23
position (J2000)	RA: 8h 43min 13.482sec	DEC: +3° 23' 54.94''
proper motion B1950 (FK4)	RA: -0.0013 arcsec/a	DEC: -0.005 arcsec/a	±0.003 arcsec/a in RA ±0.002 arcsec/a in DEC
proper motion J2000 (FK5)	RA: -0.0011 arcsec/a	DEC: -0.002 arcsec/a
source of proper motion data	Determined by source catalog

magnitude:

visual	4.3 (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: 11987
Durchmusterung	BD+03 2039
Boss General Catalogue	11987
Henry Draper Catalogue	74280

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

position:

position (equinox 1950.0)

RA: 8h 40min 36.7sec

DEC: +3° 34' 46''

variability informations:

variability type	BCEP	pulsating variable star
magnitute at max. brightness	4.27
magnitute at min. brightness	4.33
photometric system	visual, photovisual or Johnson's V
period [d]	0.17

spectral information

spectral class

B3V

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	42/9007
constellation	Hydra
notes on existence	The star is equivalent to '04290222khi 2'.

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.