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