David's Astronomy Pages (Projects)
|
Short Period Pulsating |
Variable Stars |
Home Page |
Rotating Variables |
Long Period Pulsating Variable Stars Example / Project Stars L Slow irregular variables (Type L) M Mira stars (Type M) | U And | W And | S Cyg | SS Her | U Her | EZ And | RV RV Tauri stars (Type RV) | U Mon | SR Semiregular variables (Type SR) | CV CMi | Other Pulsating Variable Star Types
can be found on a separate page:
Short Period Pulsating Variable Stars
Stars whose surface layer periodically expand and contract. The pulsations may be radial or non-radial. A radially pulsating star remains spherical in shape. In the case of non-radial pulsations, the star's shape periodically deviates from a sphere and even neighbouring zones of its surface may have opposite pulsation phases.
Grouped roughly into Short Period and Long Period variables for convenience.
(This web page is for Long Period types.
Short Period pulsating variables
are placed on a separate page)
Slow irregular variables. The light variations of these stars show no evidence
of periodicity, or any periodicity present is very poorly defined and appears only
occasionally. Like for the type I, stars are often attributed to this type because
of being insufficiently studied. Many type L variables are really semiregulars or
belong to other types.
LB
Slow irregular variables
of late spectral types (K, M, C, S); as a rule, they are giants (CO Cyg). This type
is also ascribed, in the GCVS, to slow red irregular variables in the case of unknown
spectral types and luminosities.
LC
Irregular variable
supergiants of late spectral types having amplitudes of about 1 mag in V (TZ Cas).
Back to Top
Mira stars, sometimes called long period variables. Giant stars with visual light amplitudes of 2.5 - 11 mag. and a well pronounced periodicity, and periods in the range 80 to 1000 days. Infrared amplitudes are smaller, for usually don't exceed 0.9 mag. If the amplitude is greater than 1 - 1.5 mag, but it is not certain that it exceeds 2.5 mag. , the type may be given as M. or alternatively the star may be tentatively classed as a semi-regular variable (SR).
U And |
||||||||||||||
U And is a mira variable with catalog period of 346.55
days and magnitude range of +8.9 to +15.0. |
||||||||||||||
U And (Andromeda), |
||||||||||||||
|
||||||||||||||
Annotated CCD Image |
||||||||||||||
|
||||||||||||||
|
||||||||||||||
|
||||||||||||||
|
||||||||||||||
|
||||||||||||||
U And Magnitude and Colour Variation (2006-2007) |
||||||||||||||
|
||||||||||||||
|
||||||||||||||
|
||||||||||||||
U And B-V Colour (2006-2007) |
||||||||||||||
|
||||||||||||||
|
||||||||||||||
Check graphs (only V band check graphs shown here) | ||||||||||||||
|
||||||||||||||
|
||||||||||||||
The deep red colour of U And (top right)
is indicated by very noticeable differences |
||||||||||||||
|
||||||||||||||
Composite CCD Image (2x2 binning) |
||||||||||||||
60s exposure, B Filter (#132225) |
30s exposure, Filter (#132226) |
|||||||||||||
|
Back to Top
W And (Andromeda) |
||||||||||||||||||||||||||
W And is a Mira variable with catalog period of 395.93
days |
||||||||||||||||||||||||||
W And (Andromeda), |
||||||||||||||||||||||||||
|
||||||||||||||||||||||||||
Annotated CCD Image |
||||||||||||||||||||||||||
|
||||||||||||||||||||||||||
|
||||||||||||||||||||||||||
|
||||||||||||||||||||||||||
|
||||||||||||||||||||||||||
|
||||||||||||||||||||||||||
|
||||||||||||||||||||||||||
|
||||||||||||||||||||||||||
Check Graphs |
||||||||||||||||||||||||||
|
||||||||||||||||||||||||||
|
||||||||||||||||||||||||||
|
||||||||||||||||||||||||||
|
||||||||||||||||||||||||||
|
||||||||||||||||||||||||||
|
||||||||||||||||||||||||||
Minor periodic variation noted in control (check)
star magnitude |
||||||||||||||||||||||||||
|
||||||||||||||||||||||||||
|
||||||||||||||||||||||||||
The comparative brightness of W And in the
Infrared band is |
||||||||||||||||||||||||||
V (Visual) Band |
I (Infrared) Band |
|||||||||||||||||||||||||
|
||||||||||||||||||||||||||
Annotated CCD Image 10s exposure, 2x2 binning, V Filter 2006-08-06 22:36 hUT (#132241) |
Annotated CCD Image 10s exposure, 2x2 binning, I Filter 2006-08-06 22:36 hUT (#132241) |
|||||||||||||||||||||||||
|
||||||||||||||||||||||||||
|
Back to Top
S Cyg (Cygnus) |
||||||||||||||||
S Cyg is a mira variable with catalog period of 322.93
days and magnitude range of +9.3 to +16.0. |
||||||||||||||||
|
||||||||||||||||
Annotated CCD Image |
||||||||||||||||
|
||||||||||||||||
S Cyg - Reference Stars Used |
||||||||||||||||
|
||||||||||||||||
Annotated CCD Image |
||||||||||||||||
|
||||||||||||||||
|
||||||||||||||||
S Cyg Magnitude and Colour Variation (2007) |
||||||||||||||||
|
||||||||||||||||
|
Back to Top
SS Her (Hercules) |
||||||||||||
Baseline image of SS Her recorded in CBVRI filters |
||||||||||||
|
||||||||||||
Annotated CCD Image |
||||||||||||
|
||||||||||||
SS Her - Reference Stars |
||||||||||||
|
||||||||||||
Annotated CCD Image |
||||||||||||
|
||||||||||||
|
||||||||||||
|
||||||||||||
SS Her Magnitude and Colour Variation (2007-2008) |
||||||||||||
|
||||||||||||
|
||||||||||||
|
Back to Top
U Her (Hercules) |
||||||||||||||
U Her is a mira variable with catalog period of 406.1
days and magnitude range of +6.4 to +13.4.
|
||||||||||||||
U Her (Hercules), |
||||||||||||||
|
||||||||||||||
Annotated CCD Image |
||||||||||||||
|
||||||||||||||
|
||||||||||||||
|
||||||||||||||
|
||||||||||||||
|
||||||||||||||
|
||||||||||||||
|
||||||||||||||
|
||||||||||||||
|
||||||||||||||
Check Graphs |
||||||||||||||
|
||||||||||||||
|
||||||||||||||
|
||||||||||||||
The comparative brightness of U Her in Infrared
band is |
||||||||||||||
|
||||||||||||||
CCD Images (cropped) |
Back to Top
EZ And (Andromeda) |
EZ And is a mira variable with catalog period of 275 days |
Annotated CCD Image 20s exposure, 2x2 binning, C Filter 2006-08-06 01:36 hUT (#132245) |
Back to Top
Variables of the RV Tauri type. These are radially pulsating supergiants having spectral types F-G at maximum light and K-M at minimum. The light curves are characterized by the presence of double waves with alternating primary and secondary minima that can vary in depth so that primary minima may become secondary and vice versa. The complete light amplitude may reach 3-4 mag in V. Periods between two adjacent primary minima (usually called formal periods) lie in the range 30-150 days (these are the periods appearing in the Catalogue).
Two subtypes, RVA and RVB, are recognized:
RVA RV Tauri
variables that do not vary in mean magnitude (AC Her);
RVB RV Tauri
variables that periodically (with periods from 600 to 1500 days and amplitudes up
to 2 mag in V) vary in mean magnitude (DF Cyg, RV Tau).
U Mon (Monoceros) |
|
CCD Image 20s exposure, 2x2 binning, C filter, 2007-02-04 21:24h UT (#174230) |
U Mon - reference stars |
CCD Image 10s exposure, 2x2 binning, V filter, 2007-02-04 21:22h UT (#174224) |
U Mon Variation |
U Mon Variation (Dec 2007-Mar 2008) |
Back to Top
Semiregular variables, which are giants or supergiants of intermediate
and late spectral types showing noticeable periodicity in their light changes, accompanied
or sometimes interrupted by various irregularities. Periods lie in the range from
20 to >2000 days, while the shapes of the light curves are rather different and
variable, and the amplitudes may be from several hundredths to several magnitudes
(usually 1-2 mag in V).
SRA
Semiregular late-type (M,
C, S or Me, Ce, Se) giants displaying persistent periodicity and usually small (<2.5
mag in V) light amplitudes (Z Aqr). Amplitudes and light-curve shapes generally
vary and periods are in the range of 35-1200 days. Many of these stars differ from
Miras only by showing smaller light amplitudes;
SRB
Semiregular late-type (M, C, S or Me, Ce, Se)
giants with poorly defined periodicity (mean cycles in the range of 20 to 2300 days)
or with alternating intervals of periodic and slow irregular changes, and even with
light constancy intervals (RR CrB, AF Cyg). Every star of this type may usually
be assigned a certain mean period (cycle), which is the value given in the Catalogue.
In a number of cases, the simultaneous presence of two or more periods of light
variation is observed;
SRC
Semiregular late-type (M, C, S or Me, Ce, Se) supergiants
(Mu Cep) with amplitudes of about 1 mag and periods of light variation from 30 days
to several thousand days;
SRD
Semiregular variable giants
and supergiants of F, G, or K spectral types, sometimes with emission lines in their
spectra. Amplitudes of light variation are in the range from 0.1 to 4 mag, and the
range of periods is from 30 to 1100 days (SX Her, SV UMa).
Back to Top
CV CMi (Canis Minor) |
Annotated CCD Image 3 x 90s exposure (average combine), 2x2 binning, V Filter 2008-02-15 23:07h UT (#264077-83) |
|
CV CMi - reference stars |
Annotated CCD Image Image details as above. |
CV CMi - Variation |
Back to Top
This Web Page: | Pulsating Variable Stars - Long Period |
Last Updated : | 2015-05-15 |
Site Owner : | David Richards |
Home Page : | David's Astronomy Web Site |