David's Astronomy - Pulsating Variable Stars, Long Period

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 (Type L)

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).

Mira stars (Type M)

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 - M variable

U And

U And is a mira variable with catalog period of 346.55 days and magnitude range of +8.9 to +15.0.

Images are being collected regularly in B, V, R & I filters. More than 1 year worth of data has now been acquired.
(Collection of data began in Aug 2007).

Two maximum brightness peaks have now been observed; on c. 2006-11-25 and c. 2007-10-27
indicating a measured period of c. 336 days
Observed Visual magnitude range is measured to be +9.6 to +13.8

U And (Andromeda),
Image showing U And with comparison and check stars

Annotated CCD Image
20s exposure, 2x2 binning, C Filter
2006-08-06 01:08 hUT (#132203)

		U And & Reference Star details
(V) :		U And (GSC 2804:1144)
(C) :		GSC 2804:661 / SAO 37066 (Bt: 9.68, Vt 8.50) Comparison star B,V,R & I magnitudes based on Arne Henden equations which provide BVRI estimates from Bt,Vt values
(K) :		GSC 2804:1787

[ Graph showing B-V uncertainty ]

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
in its apparent brightness in images taken in B, V, R and I Bands
( Notice how U And is almost invisible in B band (Blue), whilst
it is as bright as the check star in I band (Infrared). )
measured B-V index : 1.66
measured R-V index : 2.50

Composite CCD Image (2x2 binning)

60s exposure, B Filter (#132225)
30s exposure, R Filter (#132227)

30s exposure, Filter (#132226)
30s exposure, I Filter (#132228)

W And - M variable

W And (Andromeda)

W And is a Mira variable with catalog period of 395.93 days
and magnitude range of +6.7 to +14.6.

Images are being collected regularly in B, V, R & I filters.
More than 1 year worth of photometric data has now been acquired.
(Collection of data began in Aug 2007).

Visual magnitude range observed to date is +7.8 to +13.4

W And (Andromeda),
Image showing W And with comparison and check stars

Annotated CCD Image
3 x 20s exposure, 2x2 binning, C Filter
2006-07-23 22:36 hUT (#131027-29)

		W And & Reference Star details
(V) :		W And (GSC 2842:951 / HIP 10687)
(C) :		GSC 2842:1765 (Bt: 11.65, Vt 9.71) Comparison star B,V,R & I magnitudes based on Arne Henden equations which provide BVRI estimates from Bt,Vt values
(K) :		GSC 2842:739

[ Graph showing B-V uncertainty ]

Check Graphs

Minor periodic variation noted in control (check) star magnitude
indicating possible variability in either Comparison or Check Stars.
This will be investigated further, however in the meantime the variation is very
much less than the variation shown in W And star and thus does not effect the principal observations on W And

The comparative brightness of W And in the Infrared band is
shown in the following pair of images

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)

W And (Andromeda) CCD Images showing 6 magnitude brightening in W And between Jan 2008 and June 2008

W And - near minimum (2008-01-11 )		W And - near maximum (2008-06-26 )

Annotated CCD Image 90s exposure, 2x2 binning, CV Filter 2008-01-11 20:07hUT (#252117)		Annotated CCD Image 3 x 90s exposure (average combine), 2x2 binning, C Filter 2008-06-25 00:52hUT (#282106-12)

Light Curve for W And with above images shown by circles

S Cyg - M variable

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.

Images are too be collected regularly in B, V, R & I filters.
(Image collection began in Oct 2007)

Annotated CCD Image
3 x 20s exposure (average combine), 2x2 binning, C Filter
2007-10-19 21:15 hUT (#222147-49)

S Cyg - Reference Stars Used

Annotated CCD Image
30s exposure, 2x2 binning, V Filter
2007-10-19 21:20 hUT (#222153)

	S Cyg & Reference Star details
(V) :	S Cyg
(C) :	HD 239319	(Bt: 10.37, Vt 9.30) Comparison star B,V,R & I magnitudes based on Arne Henden equations which provide BVRI estimates from Bt,Vt values
(K) :	HD 239321	(Bt: 10.73, Vt 9.21)

S Cyg Magnitude and Colour Variation (2007)

SS Her - M Variable

SS Her (Hercules)

Baseline image of SS Her recorded in CBVRI filters
SS Her has a relatively short catalog period (107 days), and
a catalog magnitude variation of +8.5 to +13.5

Annotated CCD Image
30s exposure, 2x2 binning, C Filter
2008-01-12 06:28 hUT (#252740)

SS Her - Reference Stars
Image showing SS Her with comparison and check stars

Annotated CCD Image
30s exposure, 2x2 binning, V Filter
2008-01-12 06:31 hUT (#252742)

		SS Her & Reference Star details
(V) :		SS Her (GSC 394:943 / HIP 81026)
(C) :		GSC 394:1211 (Bt: 11.66, Vt 10.85)
(K) :		GSC 394:1291

SS Her Magnitude and Colour Variation (2007-2008)

U Her - M variable

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.
Images are being collected regularly in B, V, R & I filters. More than 1 year worth of data has now been acquired/
(Collection of BV data began in Jul 2007, whilst RI data collection began in Sep 2007).

U Her (Hercules),
Image showing U Her with comparison and check stars

Annotated CCD Image
3 x 20s exposure, 2x2 binning, C Filter
2006-07-23 22:36 hUT (#131027-29)

		U Her & Reference Star details
(V) :		U Her (SAO 102160)
(C) :		SAO 102156 (Bt: 11.44, Vt 9.53) Comparison star B,V,R & I magnitudes based on Arne Henden equations which provide BVRI estimates from Bt,Vt values
(K) :		GSC 1514:1226

[ Graph showing B-V uncertainty ]

Check Graphs

The comparative brightness of U Her in Infrared band is
shown in the following series of images (2006-07-23)

CCD Images (cropped)
5s sec exp, 2x2 binning,
2006-07-23
B: #131030, V: #131045, R: #131039, I: # 13143

EZ And - M variable

RV Tauri stars (Type RV)

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 - RVB variable

Semiregular variables (Type SR)

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).

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

This Web Page:	Pulsating Variable Stars - Long Period
Last Updated :	2009-06-21

David's Astronomy Pages (Projects)
Pulsating Variable Stars - Long Period

Pulsating Variables

Slow irregular variables (Type L)

Mira stars (Type M)

U And - M variable

W And - M variable

S Cyg - M variable

SS Her - M Variable

U Her - M variable

EZ And - M variable

RV Tauri stars (Type RV)

U Mon - RVB variable

Semiregular variables (Type SR)

CV CMi - variable star (Type: SR, semiregular variable)

David's Astronomy Pages (Projects) Pulsating Variable Stars - Long Period

Pulsating Variables

Slow irregular variables (Type L)

Mira stars (Type M)

U And - M variable

W And - M variable

S Cyg - M variable

SS Her - M Variable

U Her - M variable

EZ And - M variable

RV Tauri stars (Type RV)

U Mon - RVB variable

Semiregular variables (Type SR)

CV CMi - variable star (Type: SR, semiregular variable)

David's Astronomy Pages (Projects)
Pulsating Variable Stars - Long Period