EK Eridani
catalogues and names
| catalogues and names | EK Eri, HR 1362, HD 27536, SAO 131129, BD -6 875 |
data from The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version) (Hoffleit+, 1991)
position, motion, parallax:
| position (J2000) | RA: 4h 20min 38.7sec | DEC: -6° 14' 44'' | ||
| position (2000.72) | RA: 4h 20min 41sec | DEC: -6° 14' 38'' | ||
| position (B1900) | RA: 4h 15min 44.1sec | DEC: -6° 29' 2'' | ||
| proper motion (J2000) | RA: 0.103 arcsec/a | DEC: -0.044 arcsec/a | ||
| radial velocity | 8 km/s | |||
| galactic coordinates | longitude: 200.02° | latitude: -36.2° | ||
magnitude
| visual magnitude | 6.27 (V on UBV Johnson system) |
spectral / color information
| spectral class | G8IV: |
| B-V-magnitude | 0.91 |
| U-B-magnitude | 0.56 |
variability information
| variable star identification | EK Eri |
| note (category: variability): | BY, amp. 0.12V, 154d. |
data from SKY2000 - Master Star Catalog (Myers+ 1997)
position, motion, parallax:
| position (J2000) | RA: 4h 20min 38.635sec | DEC: -6° 14' 45.56'' | ±0.19 arcsec | source: 16 |
| position (2000.72) | RA: 4h 20min 41sec | DEC: -6° 14' 40'' | JD: 2451809.16 | |
| proper motion (J2000) | RA: 0.0061 arcsec/a | DEC: -0.055 arcsec/a | source: 25 | |
| radial velocity | 8 km/s | source: 25 | ||
| galactic coord. (B1950) | longitude: 200.02° | latitude: -36.2° | ||
magnitude:
| visual | 6.27 (observed) | source: 25 |
| photovisual | 6.5 | source: 16 |
| photographic | 7.1 | source: 2 |
spectral information:
| spectral class | G5 | source: 96 | |
| Morgan-Keenan | G8IV: | source: 25 | |
| B-magnitude | 7.18 ±0.05 | B-V-magnitude | 0.91 |
| U-magnitude | 7.74 ±0.05 | U-B-magnitude | 0.56 |
variability information:
| variability type | 440 |
| var. amplitude | 0.1 |
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 | |
| 27 | Catalog of Red Magnitudes (CRM) |
| 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: 4h 18min 11.313sec | DEC: -6° 21' 48.22'' | ±0.055 arcsec |
| position (2000.72) | RA: 4h 20min 40sec | DEC: -6° 14' 36'' | JD: 2451809.16 |
| position (J2000) | RA: 4h 20min 38.721sec | DEC: -6° 14' 44.45'' | |
| proper motion B1950 (FK4) | RA: 0.0065 arcsec/a | DEC: -0.042 arcsec/a | ±0.01 arcsec/a in RA ±0.009 arcsec/a in DEC |
| proper motion J2000 (FK5) | RA: 0.0069 arcsec/a | DEC: -0.044 arcsec/a | |
| source of proper motion data | Determined by source catalog | ||
magnitude:
| visual | 6.3 (accuracy: 2 decimals) |
| source of visual magnitude data | Taken from Harvard or San Luis photometry. |
spectral information:
| spectral class | G5 |
| source of spectral data | Taken from the Henry Draper Catalogue or no spectrum in source catalog. |
catalogues
| source catalogue | GC, catalogue number: 5264 |
| Durchmusterung | BD-06 875 |
| Boss General Catalogue | 5264 |
| Henry Draper Catalogue | 27536 |
data from Combined General Catalogue of Variable Stars (Vol. I-III) (Kholopov+ 1998)
position:
| position (equinox 1950.0) | RA: 4h 18min 11.3sec | DEC: -6° 21' 48'' |
variability informations:
| variability type | BY | rotating variable star |
| magnitute at max. brightness | 6.24 | |
| magnitute amplitude | 0.12 | |
| photometric system | visual, photovisual or Johnson's V |
references
| to a study | L.J.Boyd, R.M.Genet, D.S.Hall, W.S.Barksdale, R.E.Fried, G.W.Henry, J.E.Pearsall, N.F.Wasson, IBVS No.2696,1985. |
| to a chart/photograph | no chart is avaible, but the star is contained in the 'Bonner Durchmusterung' |
miscanellous
| ID in the GCVS catalogue | 36/154 |
| constellation | Eridanus |
| notes on existence | The star is equivalent to '68105'. |
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. |