The document discusses different types of variable stars, including intrinsic and extrinsic variables. It provides examples of five variable stars - eps CrA, V460 Vir, V1159 Ori, DY Her, and PX And. For each star, it analyzes their type of variability, periodicity, light curve shape, and amplitude of magnitude changes.

1. Group Presentation

2.  A Star fluctuating brightness as seen from Earth
 There are two kinds of Variable Stars
 Intrinsic Variables :
Actual changes on it’s luminosity (eg. change of mass
and size)
 Extrinsic Variables :
Apparent changes(due to the amount of light reaching
the earth varies, eg. Eclipse)

3.  As you can see, chi Cyg is an example of a Variable
Star with a period around one year.

4. Tools
 The International Variable
Star Index
 Simbad
 Skynet
 Wiki
Criteria
 Period < 1 day
 Dec” < -15
 At least 1 companion star
presents
 Visible from telescope for
at least 1 period

5.  Variable Star eps CrA
 Variable Star V460 Vir
 Variable Star V1159 Ori
 Variable Star DY her
 Variable Star PX And

7. -19.200
-19.000
-18.800
-18.600
-18.400
-18.200
-18.000
-17.800
-17.600
-17.400
-17.200
VMagnitude
MJD
Lightcurve of V*eps CrA

8.  W Ursae Majoris-type eclipsing variables(extrinsic)
 Around 0.3 MJD a period
 Relatively balanced period
 The V Magnitude varies between -19 to -17.5

10. 12.700
12.800
12.900
13.000
13.100
13.200
13.300
VMagnitude
MJD
Lightcurve of V* V460

11.  RR Lyrae variables (intrinsic)
 Around 0.07 MJD a period
 Rapid increase and gradual decrease(shark fin like)
 V Magnitude varies between 12.81 and 13.25

13. 15.75
15.8
15.85
15.9
15.95
VMagnitude
MJD
Lightcurve of V*V1159

14.  UGSU dwarf novae(intrinsic)
 Around 0.4 MJD a period
 A more complicated variation which has a small
increase on the down slope
 V Magnitude varies between 15.85 to 15.9

16. -15.300
-15.200
-15.100
-15.000
-14.900
-14.800
-14.700
VMagnitude
MJD
Lightcurve of DY Her

17.  δ Scuti type Variables(Intrinsic)
 Around 0.1 MJD a period
 Steeper increasing slope and a gentler down
slope(shark fin like)
 V Magnitude varies between -18.3 to -14.8

19. 12.600
12.700
12.800
12.900
13.000
13.100
13.200
13.300
13.400
13.500
VMagnitude
MJD
Lightcurve of PX And

20.  Eclipsing binary systems(ext.) and Nova like Star(int.)
 Around 0.1 MJD a period
 Fluctuated(generally with rapid increase and gradual
decrease, shape like a shark fin)
 V Magnitude varies between 12.7 and 13.4

21. Stars /
Description
eps CrA V460 Vir V1159 ORI PX And DY Her
Type of
Variables
(int./ext.)
Extrinsic Intrinsic Intrinsic Extrinsic
+
Intrinsic
Intrinsic
Symmetry of
the Light Curve
Symmetrical Asymmetrical Asymmetrical Asymmetrical Asymmetrical