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	e Eri, eps Eri, 18 Eri, HR 1084, HD 22049, SAO 130564, BD -9 697, FK5: 127, WDS 03330-0928
constellation	Eridanus

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

position, motion, parallax:

position (J2000)	RA: 3h 32min 55.8sec	DEC: -9° 27' 30''
position (2000.72)	RA: 3h 32min 58sec	DEC: -9° 27' 21''
position (B1900)	RA: 3h 28min 13.1sec	DEC: -9° 47' 48''
proper motion (J2000)	RA: -0.974 arcsec/a	DEC: 0.021 arcsec/a
radial velocity	15 km/s note: suspected variable radial velocity
rotational velocity	<17 km/s (uncertain) (variable)
trigonometric parallax	0.303 arcsec
galactic coordinates	longitude: 195.86°	latitude: -48.04°

magnitude

visual magnitude

3.73 (V on UBV Johnson system)

spectral / color information

spectral class	K2V
B-V-magnitude	0.88
U-B-magnitude	0.59
R-I-magnitude
IR-note	object is infrared source (NASA merged infrared catalogue, Schmitz et al., 1978)

double/multiple star system information

separation	2 arcsec
mag difference (of double or brightest multiple)	3
note	astrometric binary

note (category: double and multiple data):

Astrometric binary, 25y. Unresolved by speckle interferometry.

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

position, motion, parallax:

position (J2000)	RA: 3h 32min 55.846sec	DEC: -9° 27' 29.72''	±0.06 arcsec	source: 15
position (2000.72)	RA: 3h 32min 58sec	DEC: -9° 27' 21''	JD: 2451809.16
proper motion (J2000)	RA: -0.0658 arcsec/a	DEC: 0.021 arcsec/a		source: 25
radial velocity	15 km/s			source: 25
trigonometric parallax	0.303 arcsec		±0.03 arcsec	source: 25
galactic coord. (B1950)	longitude: 195.86°	latitude: -48.04°

magnitude:

visual	3.73 (observed)	source: 25
photovisual	3.8	source: 2
photographic	4.8	source: 2

spectral information:

spectral class	K0		source: 96
Morgan-Keenan	K2V		source: 25
B-magnitude	4.61 ±0.05	B-V-magnitude	0.88
U-magnitude	5.2 ±0.05	U-B-magnitude	0.59

double/multiple star system information:

source of data: 19

separation between brightest and second brightest component	0 arcsec
position angle	143 °

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
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
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: 3h 30min 34.355sec	DEC: -9° 37' 34.76''	±0.004 arcsec
position (2000.72)	RA: 3h 33min 1sec	DEC: -9° 27' 22''	JD: 2451809.16
position (J2000)	RA: 3h 32min 55.854sec	DEC: -9° 27' 29.65''
proper motion B1950 (FK4)	RA: -0.0662 arcsec/a	DEC: 0.019 arcsec/a	±0.001 arcsec/a in RA ±0.001 arcsec/a in DEC
proper motion J2000 (FK5)	RA: -0.0657 arcsec/a	DEC: 0.021 arcsec/a
source of proper motion data	Determined by source catalog

magnitude:

visual	3.8 (accuracy: 2 decimals)
source of visual magnitude data	Taken from the "Henry Draper Catalogue".

spectral information:

spectral class	K0
source of spectral data	Taken from the Henry Draper Catalogue or no spectrum in source catalog.

catalogues

source catalogue	FK4, catalogue number: 127
Durchmusterung	BD-09 697
Boss General Catalogue	4244
Henry Draper Catalogue	22049

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

position:

position (equinox 1950.0)

RA: 3h 30min 34.4sec

DEC: -9° 37' 35''

variability informations:

variability type	BY	rotating variable star
magnitute at max. brightness	3.73
magnitute amplitude	0.05
photometric system	visual, photovisual or Johnson's V

references

to a study	G.J.Frey, B.Grim, D.S.Hall, P.Mattingly, S.Robb, J.Wood, K.Zeigler, AJ 102, No.5, 1813, 1991.
to a chart/photograph	no chart is avaible, but the star is contained in the 'Bonner Durchmusterung'

miscanellous

ID in the GCVS catalogue	36/9005
constellation	Eridanus
notes on existence	The star is equivalent to '72012'.

variability type description

variability type

description

BY

BY Draconis-type variables, which are emission-line dwarfs of dKe-dMe spectral type showing quasiperiodic light changes with periods from a fraction of a day to 120 days and amplitudes from several hundredths to 0.5 mag in V. The light variability is caused by axial rotation of a star with a variable degree of nonuniformity of the surface brightness (spots) and chromospheric activity. Some of these stars also show flares similar to those of UV Cet stars, and in those cases they also belong to the latter type and are simultaneously considered eruptive variables.