irregular variables

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irregular variables

Stars, such as the majority of red giants, that are pulsating variables showing slow luminosity changes either with no periodicity or with a very slight periodicity. The latter can be grouped into slow irregular variables of spectral types F, G, K, M, C, and S that are usually giants, and slow irregular supergiants of spectral types M, C, and S.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006
References in periodicals archive ?
Alpha ([alpha]) Cassiopeiae is officially the constellation's brightest star at magnitude 2.24, although nearby Gamma ([gamma]) Cas is an eruptive, irregular variable star that sometimes outshines it.
Antares is a red supergiant thought to be approximately 900 times the size of the Sun, and is a slow irregular variable. Above Scorpio in the sky are the rather faint constellations of Ophiuchus and Serpens, the latter of which is divided into two distinct parts.
Within Pegasus is a nice variable star (betaPegasi).It is an irregular variable that varies from 2nd to 3rd magnitudes with no set period.
"But perhaps the most important potential impact on astronomy is that it may convince observers that useful information can be extracted from the observations of irregular variable stars and that these stars thus deserve more attention than they have been getting," the team adds.
Hind's Variable Nebula is usually visible as two or three faint arcs of nebulosity about 40" west or southwest of the irregular variable star, T Tauri, which varies erratically between magnitude 9 and 13.
In 1908 the programme consisted of 5 Algol, 9 short-period, 27 long-period and 9 irregular variable stars.
This carbon star is an irregular variable that slowly fluctuates between magnitude 4.8 and 5.2.
A slightly irregular variable, it's a classic runaway star, fleeing at 200 kilometers per second from Mu Columbae, its one-time mate, which now lies more than 70[degrees] to the south.
As with most such stars, Alpha Herculis is an irregular variable; its period is roughly 90 days.
A subtle cometlike patch of nebulosity, C68 is lit by the irregular variable star R Coronae Australis.
For instance, rarely are we reminded that Gemini offers an amazing three stars whose brightness variations can be studied with the naked eye: Zeta (|zeta~) Geminorum, a Cepheid that ranges from magnitude 3.7 to 4.2 and back again in just over 10 days; Eta (|eta~), a semiregular variable that meanders from 3.2 to 3.9 in 7 or 8 months; and Mu (|mu~), an irregular variable that slowly quivers between 2.8 and 3.0.
These included three series of annual reports on 'SS Cygni', on 'Long Period Variables' and on 'Three Irregular Variables', namely R CrB, U Gem, and U Sct (see Table 1 for a list of papers on these three groups of stars).