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Created page with "{{Night Sky | image = | designation =Omicron Ceti<br/>Mira Ceti | rightascension =02<sup>h</sup> 19<sup>m</sup> 20.79210<sup>s</sup><ref name=simbad>[https://si..."
{{Night Sky
| image =
| designation =Omicron Ceti<br/>Mira Ceti
| rightascension =02<sup>h</sup> 19<sup>m</sup> 20.79210<sup>s</sup><ref name=simbad>[https://simbad.u-strasbg.fr/simbad/sim-id?Ident=mira&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id Mira] from the [http://simbad.u-strasbg.fr/simbad SIMBAD Astronomical Database]</ref>
| declination =-02° 58′ 39.4956″<ref name=simbad/>
| distance =350 ly
| constellation =Cetus
| type =Variable star
| dimensions =
| magnitude =Apparent Mag: +6.53<ref name=simbad/><br/>Absolute Mag: +1.38<ref>By direct calculation, using distance of 350 ly and an apparent magnitude of +6.53.</ref>
| redshift =
| radvelocity =63.50±0.6 km/s
| propmotion =RA: 9.33 mas/yr<ref name=simbad/><br/>Dec.: -237.5 mas/yr<ref name=simbad/>
| parallax =10.91±1.22 mas<ref name=simbad/>
}}
'''Mira''' (Omicron Ceti, Mira Ceti) is a well known [[variable star]] in the [[Constellation]] of [[Cetus]] and was the first variable star discovered that wasn't a [[supernova]].<ref name=britannica>{{cite web|url=https://www.britannica.com/place/Mira-Ceti|title=Mira Ceti|accessdate=2018-12-27}}</ref> It was discovered in 1596 by David Fabricius in 1596, a [[German]] [[astronomer]], though there is some evidence its variable nature may have been observed earlier by the [[Babylonian]]s.<ref name=constellation-guide>{{cite web|url=https://www.constellation-guide.com/constellation-list/cetus-constellation/|title=Cetus|accessdate=2018-12-27}}</ref> Another variable star, [[Algol]], was discovered earlier but its variable nature wasn't confirmed until 1667. Astronomers were amazed by the way the star's brightness changed and named it Mira, from the [[Latin]] for "miraculous" or "wonderful".
Being a [[variable star]], the star's [[star magnitude|magnitude]] (or brightness) varies over time with a period of roughly 330 days.<ref name=britannica/> The star's apparent magnitude peaks at approximately +3 and is at +9 at its lowest, 1,500 times fainter.<ref name=britannica/><ref name=earthsky>{{cite web|url=https://earthsky.org/brightest-stars/mira-quite-wonderful|title=Time to see Mira the Wonderful|accessdate=2018-12-27}}</ref> This means that depending where it is on its cycle, Mira may or may not be visible to the unaided eye.
==History==
The first definitive recorded observation of the star was by David Fabricus (1564-1617) of the [[Netherlands]].<ref name=Hoffleit>Hoffleit, D. (1997). History of the Discovery of Mira Stars. ''The Journal of the American Association of Variable Star Observers'', 25(2), pp.115-136. [https://adsabs.harvard.edu/abs/1997JAVSO..25..115H Bibcode:1997JAVSO..25..115H]</ref> He first saw the star in 1596 and originally believed it to be a nova. However later in 1609 he observed the star again and realised it therefore couldn't be a nova.<ref name=constellation-guide/> Meanwhile, in 1603 Johann Bayer catalogued the star as Omicron Ceti.<ref name=Hoffleit/> The star was then more or less forgotten until Johannes Holwarda, a [[Denmark|Dutch]] astronomer rediscovered the star and was the first to determine its period of roughly eleven months. The star was named Mira by Johannes Hevelius in 1662.<ref name=earthsky/>
==Properties and Structure==
Mira is in fact a [[Binary star|binary system]], where one smaller [[star]] orbits another.<ref name=constellation-guide/> These two stars are designated Mira A and Mira B. The larger star (Mira A) is a [[red giant]] with spectral type M7 IIIe. Mira A is an oscillating variable star, where the star periodically expands and contracts. As the surface area of the star changes, so does its [[luminosity]] and so apparent magnitude. Mira forms the prototype for this group of stars, of which there are around 6,000-7,000 known.<ref name=constellation-guide/> This class of variable stars are known as pulsating variables.[[File:Mira light curve.png|thumb|alt=The light curve of the variable star Mira|right|200px|The light curve of Mira showing how its brightness oscillates.]]
The companion star Mira B is a [[White dwarf]] and is thought to be accreting material from its neighbour, Mira A. Mira B completes one orbit around Mira A every 500 years.<ref name=nasa>{{cite web|url=https://www.nasa.gov/mission_pages/galex/20070815/c.html|title=Mira Soars Through the Sky|accessdate=2018-12-27}}</ref>
The system is though to be situated 350 [[light year]]s from [[Earth]], though some sources suggest it is higher at 420 ly.<ref name=britannica/><ref name=constellation-guide/> The system also appears to be racing round the [[Milky Way]] around 130&nsbp;km/s faster than other stars.<ref name=nasa/> [[Ultraviolet]] observations in 2006 by [[NASA]]'s Galaxy Evolution Explorer have shown Mira A is shedding vast quantities of material, which has formed a tail resembling that of a [[comet]].<ref name=nasa/>
==References==
{{reflist}}
{{Stars}}
[[Category:Astronomy]]
[[Category:Stars]]
| image =
| designation =Omicron Ceti<br/>Mira Ceti
| rightascension =02<sup>h</sup> 19<sup>m</sup> 20.79210<sup>s</sup><ref name=simbad>[https://simbad.u-strasbg.fr/simbad/sim-id?Ident=mira&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id Mira] from the [http://simbad.u-strasbg.fr/simbad SIMBAD Astronomical Database]</ref>
| declination =-02° 58′ 39.4956″<ref name=simbad/>
| distance =350 ly
| constellation =Cetus
| type =Variable star
| dimensions =
| magnitude =Apparent Mag: +6.53<ref name=simbad/><br/>Absolute Mag: +1.38<ref>By direct calculation, using distance of 350 ly and an apparent magnitude of +6.53.</ref>
| redshift =
| radvelocity =63.50±0.6 km/s
| propmotion =RA: 9.33 mas/yr<ref name=simbad/><br/>Dec.: -237.5 mas/yr<ref name=simbad/>
| parallax =10.91±1.22 mas<ref name=simbad/>
}}
'''Mira''' (Omicron Ceti, Mira Ceti) is a well known [[variable star]] in the [[Constellation]] of [[Cetus]] and was the first variable star discovered that wasn't a [[supernova]].<ref name=britannica>{{cite web|url=https://www.britannica.com/place/Mira-Ceti|title=Mira Ceti|accessdate=2018-12-27}}</ref> It was discovered in 1596 by David Fabricius in 1596, a [[German]] [[astronomer]], though there is some evidence its variable nature may have been observed earlier by the [[Babylonian]]s.<ref name=constellation-guide>{{cite web|url=https://www.constellation-guide.com/constellation-list/cetus-constellation/|title=Cetus|accessdate=2018-12-27}}</ref> Another variable star, [[Algol]], was discovered earlier but its variable nature wasn't confirmed until 1667. Astronomers were amazed by the way the star's brightness changed and named it Mira, from the [[Latin]] for "miraculous" or "wonderful".
Being a [[variable star]], the star's [[star magnitude|magnitude]] (or brightness) varies over time with a period of roughly 330 days.<ref name=britannica/> The star's apparent magnitude peaks at approximately +3 and is at +9 at its lowest, 1,500 times fainter.<ref name=britannica/><ref name=earthsky>{{cite web|url=https://earthsky.org/brightest-stars/mira-quite-wonderful|title=Time to see Mira the Wonderful|accessdate=2018-12-27}}</ref> This means that depending where it is on its cycle, Mira may or may not be visible to the unaided eye.
==History==
The first definitive recorded observation of the star was by David Fabricus (1564-1617) of the [[Netherlands]].<ref name=Hoffleit>Hoffleit, D. (1997). History of the Discovery of Mira Stars. ''The Journal of the American Association of Variable Star Observers'', 25(2), pp.115-136. [https://adsabs.harvard.edu/abs/1997JAVSO..25..115H Bibcode:1997JAVSO..25..115H]</ref> He first saw the star in 1596 and originally believed it to be a nova. However later in 1609 he observed the star again and realised it therefore couldn't be a nova.<ref name=constellation-guide/> Meanwhile, in 1603 Johann Bayer catalogued the star as Omicron Ceti.<ref name=Hoffleit/> The star was then more or less forgotten until Johannes Holwarda, a [[Denmark|Dutch]] astronomer rediscovered the star and was the first to determine its period of roughly eleven months. The star was named Mira by Johannes Hevelius in 1662.<ref name=earthsky/>
==Properties and Structure==
Mira is in fact a [[Binary star|binary system]], where one smaller [[star]] orbits another.<ref name=constellation-guide/> These two stars are designated Mira A and Mira B. The larger star (Mira A) is a [[red giant]] with spectral type M7 IIIe. Mira A is an oscillating variable star, where the star periodically expands and contracts. As the surface area of the star changes, so does its [[luminosity]] and so apparent magnitude. Mira forms the prototype for this group of stars, of which there are around 6,000-7,000 known.<ref name=constellation-guide/> This class of variable stars are known as pulsating variables.[[File:Mira light curve.png|thumb|alt=The light curve of the variable star Mira|right|200px|The light curve of Mira showing how its brightness oscillates.]]
The companion star Mira B is a [[White dwarf]] and is thought to be accreting material from its neighbour, Mira A. Mira B completes one orbit around Mira A every 500 years.<ref name=nasa>{{cite web|url=https://www.nasa.gov/mission_pages/galex/20070815/c.html|title=Mira Soars Through the Sky|accessdate=2018-12-27}}</ref>
The system is though to be situated 350 [[light year]]s from [[Earth]], though some sources suggest it is higher at 420 ly.<ref name=britannica/><ref name=constellation-guide/> The system also appears to be racing round the [[Milky Way]] around 130&nsbp;km/s faster than other stars.<ref name=nasa/> [[Ultraviolet]] observations in 2006 by [[NASA]]'s Galaxy Evolution Explorer have shown Mira A is shedding vast quantities of material, which has formed a tail resembling that of a [[comet]].<ref name=nasa/>
==References==
{{reflist}}
{{Stars}}
[[Category:Astronomy]]
[[Category:Stars]]