Achernar

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

note (category: star names):

ACHERNAR.

position, motion, parallax:

position (J2000)	RA: 1h 37min 42.9sec	DEC: -57° 14' 12''
position (B1900)	RA: 1h 33min 59.4sec	DEC: -57° 44' 41''
proper motion (J2000)	RA: 0.095 arcsec/a	DEC: -0.035 arcsec/a
radial velocity	16 km/s note: variable radial velocity
rotational velocity	251 km/s (uncertain) (variable)
trigonometric parallax	0.026 arcsec
galactic coordinates	longitude: 290.84°	latitude: -58.79°

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

Period in RV and light (1.26d) seems best explained by rotation. Weak but significant variations in strength of MgII 4481. RV of H gamma and HeI 4471 consistent with period, amp. 30k/s. Variable light amp. 0.02V.

magnitude

visual magnitude

0.46
(V on UBV Johnson system)

spectral / color information

spectral class	B3Vpe
B-V-magnitude	-0.16
U-B-magnitude	-0.66
R-I-magnitude

note (category: spectra):

Lyman alpha and Lyman beta observed from COPERNICUS. H alpha and H beta var. emission and possible high-velocity mass loss. Expanding circumstellar shell.

variability information

variable star identification

Var

note (category: variability):

EB or Ell, amp. 0.02V. H alpha var. emission and possible high-velocity mass loss. Expanding circumstellar shell.

miscellaneous information

note (category: group membership):

Member of Pleiades group.

note (category: stellar radii or diameters):

Diam. = 0.00185 - 0.00192".

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

position, motion, parallax:

position (J2000)	RA: 1h 37min 42.852sec	DEC: -57° 14' 12.18''	±0.06 arcsec	source: 15
proper motion (J2000)	RA: 0.0117 arcsec/a	DEC: -0.035 arcsec/a		source: 25
radial velocity	16 km/s			source: 25
trigonometric parallax	0.026 arcsec		±0.003 arcsec	source: 25
galactic coord. (B1950)	longitude: 290.84°	latitude: -58.79°

magnitude:

visual	0.46 (observed)	source: 25
photovisual	0.6	source: 2
photographic	0.5	source: 2

spectral information:

spectral class	B5		source: 96
Morgan-Keenan	B3Vnp(shell)		source: 25
B-magnitude	0.3 ±0.05	B-V-magnitude	-0.16
U-magnitude	-0.36 ±0.05	U-B-magnitude	-0.66

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
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: 1h 35min 51.307sec	DEC: -57° 29' 24.93''	±0.008 arcsec
position (J2000)	RA: 1h 37min 42.925sec	DEC: -57° 14' 12.13''
proper motion B1950 (FK4)	RA: 0.0129 arcsec/a	DEC: -0.028 arcsec/a	±0.001 arcsec/a in RA ±0.002 arcsec/a in DEC
proper motion J2000 (FK5)	RA: 0.0127 arcsec/a	DEC: -0.034 arcsec/a
source of proper motion data	Determined by source catalog

magnitude:

visual	0.6 (accuracy: 2 decimals)
source of visual magnitude data	Taken from the "Henry Draper Catalogue".

spectral information:

spectral class	B5
source of spectral data	Taken from the Henry Draper Catalogue or no spectrum in source catalog.

catalogues

source catalogue	FK4, catalogue number: 54
Durchmusterung	CP-57 334
Boss General Catalogue	1979
Henry Draper Catalogue	10144

catalogues and names	Achernar, a Eri, NSV 15353, HR 472, HD 10144, SAO 232481, CP -57 334, FK5: 54
constellation	Eridanus