Mira
catalogues and names | Mira, o Cet, omi Cet, 68 Cet, HR 681, HD 14386, SAO 129825, WDS 02193-0259Aa |
constellation | Cetus |
data from The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version) (Hoffleit+, 1991)
note (category: star names): | MIRA. |
position, motion, parallax:
position (J2000) | RA: 2h 19min 20,7sec | DEC: -2° 58' 39'' |
position (J1900) | RA: 2h 14min 17,6sec | DEC: -3° 25' 54'' |
proper motion (J2000) | RA: -0,008 arcsec/a | DEC: -0,237 arcsec/a |
radial velocity | 64 km/s note: variable radial velocity |
|
trigonometric parallax | 0,024 arcsec |
note (category: dynamical parallaxes): | 0.0058". Masses A 15.7, P 4.0 solar. |
magnitude
visual magnitude | 3,04 (V on UBV Johnson system) |
spectral / color information
spectral class | M7IIIe+Bep |
B-V-magnitude | 1,42 |
U-B-magnitude | 1,09 |
R-I-magnitude | 1,9 |
note (category: spectra): | Stratoscope II observations indicate infrared H2O bands. SiO maser source. Technetium found in spectrum. Also classified M5e-M9e. |
note (category: colors): | The tabulated magnitude and colors refer to a time near maximum. Another determination at 6.99V gives B-V +1.56, U-B +0.12, R-I +3.08. |
variability information
variable star identification | Omi Cet |
note (category: variability): | Two variables: Mira and VZ Cet. Mira, ADS 1778A, M 2.0 - 10.1v, 331.96d; var. CO emission from circumstellar envelope. Speckle interferometry indicates large abrupt variation of diameter as a function of wavelength. Hydrogen lines vary on time scale of 1-2 days. Mira was discovered to be variable by Fabricius in 1596, the first such variable discovered. ADS 1778P, Ne "Novoides" class, VZ Cet, 9.5 - 12.0v, dBe. |
double/multiple star system information
number of components of multiple star system | 4 |
separation | 118,7 arcsec |
mag difference (of double or brightest multiple) | 7,3 |
component ID | AC |
note (category: double and multiple data): | AP var. M7IIIe, var. dBe, 400y, a = 0.85". The faint companion was first predicted in 1920 by Joy on the basis of a slightly displaced blue secondary spectrum. First seen by Aitken in 1923. Visible only when Mira is faint. Light variations on scale of hours superimposed by variations of 10-15 min. and rare flares of 2 min. duration. Components B, 13v at 73" and C, optical. |
miscellaneous information
note (category: polarization): | Polarization possibly due to circumstellar dust scattering. |
data from SKY2000 - Master Star Catalog (Myers+ 1997)
position, motion, parallax:
position (J2000) | RA: 2h 19min 20,787sec | DEC: -2° 58' 39,68'' | ±0,35 arcsec | source: 17 |
proper motion (J2000) | RA: 0,0001 arcsec/a | DEC: -0,24 arcsec/a | source: 25 | |
radial velocity | 64 km/s | source: 25 | ||
trigonometric parallax | 0,024 | ±0,002 arcsec | source: 25 | |
galactic coord. (B1950) | longitude: 167,76° | latitude: -57,98° | ||
GCI unit vector (J2000) | X: 0,819676 | Y: 0,570467 | Z: -0,051947 |
magnitude:
visual | 3,04 (observed) | source: 25 |
spectral information:
spectral class | M0 | source: 96 | |
Morgan-Keenan | M5.5-9IIIe+Bep | source: 25 | |
B-magnitude | 4,46 ±0,2 | B-V-magnitude | 1,42 |
U-magnitude | 5,55 ±0,2 | U-B-magnitude | 1,09 |
variability information:
variability type | 180 |
var. amplitude | 8,1 |
var. period | 331,96 |
var. epoch | 2444839 22. August 1981, 12:00:00 UT |
next max light | 2451810,16 22. September 2000, 15:50:24 UT |
double/multiple star system information:
separation between brightest and second brightest component | 0,5 arcsec |
position angle | 116 ° |
component | magnitude | spectral class | catalogue(s)/name(s) |
A | 3,04 | M0 | Mira, o Ceti, 68 Cet, HR 681, HD 14386, SAO 129825 |
B | 9,33 | M0 |
sources:
17 | ACRS |
Corbin, T.E., and S.E. Urban, Astrographic Catalog Reference Stars, United States Naval Observatory, 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 | |
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 (J1950) | RA: 2h 16min 49,045sec | DEC: -3° 12' 13,39'' | ±0,009 arcsec |
position (J2000) | RA: 2h 19min 20,729sec | DEC: -2° 58' 39,42'' | |
proper motion J1950 (FK4) | RA: -0,0008 arcsec/a | DEC: -0,233 arcsec/a | ±0,002 arcsec/a in RA ±0,002 arcsec/a in DEC |
proper motion J2000 (FK5) | RA: -0,0005 arcsec/a | DEC: -0,237 arcsec/a | |
source of proper motion data | Determined by source catalog |
magnitude:
visual | 2 (accuracy: 1 decimal) |
source of visual magnitude data | Source cited in source catalog introduction. |
spectral information:
spectral class | M5e |
source of spectral data | Taken from the Henry Draper Catalogue or no spectrum in source catalog. |
remarks for duplicity and variability
Variable star in visual magnitude in source catalog |
catalogues
source catalogue | GC, catalogue number: 2796 |
Durchmusterung | BD-03 353 |
Boss General Catalogue | 2796 |
Henry Draper Catalogue | 14386 |
data from The Washington Visual Double Star Catalog, 1996.0 (Worley+, 1996)
position and proper motion:
position (J2000) | RA: 2h 19,3min | DEC: -2° 59' |
proper motion (J2000) | RA: 0,002 arcsec/a | DEC: -0,24 arcsec/a |
double/multiple star system information:
component | year | number of measures | position angle | angular separation | magnitude of 1st component | magnitude of 2nd component | spectral class(es) | discoverer code |
Aa | 1923 | 62 | 132° | 0,9'' | - | 9,6 | M7IIIe | JOY 1 |
1993 | 116° | 0,5'' | ||||||
Aa-B | 1878 | - | 90° | 74,7'' | - | 13 | - | BU 1371 |
1911 | 85° | 73,1'' | ||||||
Aa-C | 1782 | 18 | 92° | 114,6'' | - | 9,3 | - | H 1 |
1925 | 78° | 118,7'' | ||||||
Aa-D | 1921 | 2 | 318° | 148,3'' | - | 9,3 | - | STG 1 |
BC | 1911 | 1 | 69° | 45,5'' | 13 | 9,3 | - | H 1 |
discoverer information:
discoverer code | discoverer | reference |
JOY 1 | - | - |
BU 1371 | Burnham, S.W. | - |
H 1 | Herschel, W. | (Mem. R. Astron. Soc. 35, 21; 1867.) |
STG 1 | Struve, G. | - |
notes:
note | Omicron Ceti. Prototype of the Mira-type variables. "Orbits" have been computed for the visual pair, but are most likely false. All distant companions are optical. B is a Cepheid, VZ Cet. H VI 1. C is BD-03@355. |
data from Combined General Catalogue of Variable Stars (Vol. I-III) (Kholopov+ 1998)
position:
position (J1950) | RA: 2h 16min 49sec | DEC: -3° 12' 13'' |
variability informations:
variability type | M | pulsating variable star |
magnitute at max. brightness | 2 | |
magnitute at min. brightness | 10,1 | |
photometric system | visual, photovisual or Johnson's V | |
epoch for maximum light [JD] | 2444839 22. August 1981, 12:00:00 UT |
|
period [d] | 331,96 | |
next maximum light [JD] | 2451810,16 22. September 2000, 15:50:24 UT |
|
rising time | 38 % of period |
spectral information
spectral class | M5e-M9e |
references
to a study | the main characteristics of the star was determined by the authors themselves |
to a chart/photograph | Vol. I GCVS (see Kholopov et al. 1985-1988) |
miscanellous
ID in the GCVS catalogue | 21/9015 |
constellation | Cetus |
notes on existence | The star is equivalent to '0220001 R'. |
There are notes in published catalog. |
variability type description
variability type | description |
M | Mira (Omicron) Ceti-type variables. These are long-period variable giants with characteristic late-type emission spectra (Me, Ce, Se) and light amplitudes from 2.5 to 11 mag in V. Their periodicity is well pronounced, and the periods lie in the range between 80 and 1000 days. Infrared amplitudes are usually less than in the visible and may be <2.5 mag. For example, in the K band they usually do not exceed 0.9 mag. If the amplitudes exceed 1 - 1.5 mag , but it is not certain that the true light amplitude exceeds 2.5 mag, the symbol "M" is followed by a colon, or the star is attributed to the semiregular class with a colon following the symbol for that type (SR). |