Post on 11-May-2015
Group Presentation
Study and Compare the Light Curve of 5 different Variable
Stars
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)
What Is Variable Star ?
Variable Star Light Curve
As you can see, chi Cyg is an example of a Variable Star with a period around one year.
Selection of TargetsTools
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
Variable Star eps CrA
Variable Star V460 Vir
Variable Star V1159 Ori
Variable Star DY her
Variable Star PX And
Our Targets
eps CrA
Light Curve of V*eps CrA
-19.500
-19.000
-18.500
-18.000
-17.500
-17.000
-16.500
Lightcurve of V*eps CrA
MJD
V M
agnit
ude
W Ursae Majoris-type eclipsing variables(extrinsic)
Around 0.3 MJD a periodRelatively balanced periodThe V Magnitude varies between -19 to -17.5
Characteristics of the Light Curve
V460 Vri
Light Curve of V*V460
12.700
12.800
12.900
13.000
13.100
13.200
13.300
Lightcurve of V* V460
MJD
V M
agnit
ude
RR Lyrae variables (intrinsic)Around 0.07 MJD a periodRapid increase and gradual decrease(shark
fin like)V Magnitude varies between 12.81 and 13.25
Characteristics of the Light Curve
V1159 Ori
Light Curve of V*V1159 Ori
15.75
15.8
15.85
15.9
15.95
Lightcurve of V*V1159
MJD
V M
agnit
ude
UGSU dwarf novae(intrinsic)Around 0.4 MJD a periodA more complicated variation which has a
small increase on the down slopeV Magnitude varies between 15.85 to 15.9
Characteristics of the Light Curve
DY Her
Light Curve of V*DY Her
-15.400-15.300-15.200-15.100-15.000-14.900-14.800-14.700-14.600-14.500
Lightcurve of DY Her
MJD
V M
ag
nit
ud
e
δ Scuti type Variables(Intrinsic)Around 0.1 MJD a periodSteeper increasing slope and a gentler down
slope(shark fin like)V Magnitude varies between -18.3 to -14.8
Characteristics of the Light Curve
Px And
Light Curve of V*PX And
12.200
12.400
12.600
12.800
13.000
13.200
13.400
13.600
Lightcurve of PX And
MJD
V M
agnit
ude
Eclipsing binary systems(ext.) and Nova like Star(int.)
Around 0.1 MJD a periodFluctuated(generally with rapid increase and
gradual decrease, shape like a shark fin)V Magnitude varies between 12.7 and 13.4
Characteristics of the Light Curve
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
Comparison