Variable star Mira (omicron Ceti - ο Ceti) is now close to peak magnitude and for the next couple of months will be visible to the naked eye. This popular variable star, also known as "the Wonderful", is located in the constellation of Cetus. It can be seen as soon as it's dark enough, towards the south from northern locations or towards the north from southern locations, and remains visible until around midnight.
Mira's peak magnitude is expected to be about +3.4. The star climbs very quickly from minimum to maximum brightness over a period of about a month and then takes a quieter route on the downward slope, requiring 6 months to reach minimum. The minimum magnitude is usually of the order of +9, when at least a pair of binoculars and dark skies will be required to spot it.
Mira is the prototype of the pulsating red giant stars that vary by at least one magnitude over a period ranging from 80 to more than 1,000 days. These stars have a mass of less than two solar masses, and are coming to the end of their lives. There are at 6,000 known Mira type stars and all will eventually form planetary nebulae with a white dwarf at the centre.
There are not many bright stars in Cetus, but locating Mira is not difficult. The star chart below shows the correct region of sky, together with apparent magnitudes of surrounding stars for comparative purposes. Magnitude measurements may be submitted to the British Astronomical Association's Variable Star Section or the American Association of Variable Stars.
Mira Data Table
|Names||Mira, Omicron Ceti, Wonderful Star|
|RA (J2000)||02h 19m 20.8s|
|DEC (J2000)||-02d 58m 39.5s|
|Spectral type||M7 IIIe|