Pulsars:Pulsars:Astronomical Clocks Astronomical Clocks

In The SkyIn The Sky

Team J:Team J:Ashley RandallAshley RandallAshton ButtsAshton Butts

Priscilla GarciaPriscilla GarciaJessica WilkinsonJessica WilkinsonOlivia ArringtonOlivia Arrington

IntroductionIntroduction Pulsars are rapidly rotating neutron Pulsars are rapidly rotating neutron

stars stars

A neutron star is only ten kilometers A neutron star is only ten kilometers in sizein size

They are created in a supernova They are created in a supernova explosion near the end of a star’s lifeexplosion near the end of a star’s life

Pulsars spin at quick speeds ranging Pulsars spin at quick speeds ranging from milliseconds to secondsfrom milliseconds to seconds

Single pulsars spin about once every Single pulsars spin about once every second, and pulsars in binary systems second, and pulsars in binary systems spin thousands of times every secondspin thousands of times every second

PurposePurpose To learn how to calculate the rotation period of a pulsarTo learn how to calculate the rotation period of a pulsar

To calculate the size of the pulsar’s orbitTo calculate the size of the pulsar’s orbit

To calculate the luminosity of the pulsarTo calculate the luminosity of the pulsar

MethodsMethods

Used NASA observations collected with the Chandra Used NASA observations collected with the Chandra X-ray telescopeX-ray telescope

Used the ds9 computer program to analyze the Used the ds9 computer program to analyze the observations observations

MaterialsMaterials DS9 computer program written by NASA DS9 computer program written by NASA

DS9 instruction handbook DS9 instruction handbook

Textbook: Textbook: HorizonsHorizons: : Exploring the UniverseExploring the Universe by Michael A. Seeds by Michael A. Seeds

Lecture Notes: Dr. M. Richards Lecture Notes: Dr. M. Richards

Chandra Chandra X-rayX-ray Telescope archives: http://chandra.harvard.eduTelescope archives: http://chandra.harvard.edu//

NASA Chandra Education webpage NASA Chandra Education webpage http://chandra-ed.harvard.edu/activities.htmlhttp://chandra-ed.harvard.edu/activities.html

ProceduresProcedures Load the light curve data from the Chandra archives Load the light curve data from the Chandra archives

We measured the period directly from the light curve We measured the period directly from the light curve – Calculated the average period and standard deviation for the Calculated the average period and standard deviation for the

group.group.

Light CurveLight Curve: how light from the pulsar changes with : how light from the pulsar changes with time time

ProceduresProcedures The power spectrum finds any patterns in the light curve The power spectrum finds any patterns in the light curve

– We calculated the period from the frequency: We calculated the period from the frequency: Period = Period = 1 . 1 .

FrequencyFrequency

ResultsResults Objects studied: Cen X-3, GK Per, Vela pulsarObjects studied: Cen X-3, GK Per, Vela pulsar

GK PerCen X-3

Star size = 6000 kmRotation period = 350.87 sec

Star size = 10 kmRotation period = 4.807 sec

ResultsResults When we expand the power spectrum for Cen X-3, the peak When we expand the power spectrum for Cen X-3, the peak

looks broad looks broad

The light from the pulsar is blue-shifted and red-shifted The light from the pulsar is blue-shifted and red-shifted because the pulsar is moving around another objectbecause the pulsar is moving around another object

Measure the spin period and orbital period of Cen X-3Measure the spin period and orbital period of Cen X-3

Pulsar moving away from us

Pulsar moving towards us

ResultsResults

Luminosity = 4 distance2 x flux

Cen X-3 PulsarCen X-3 Pulsar Vela PulsarVela Pulsar

Size of star (km)Size of star (km) 10 10 1010

Distance (light years)Distance (light years) 2600026000 800800

Rotation Period (sec)Rotation Period (sec) 4.809 sec4.809 sec 0.089 sec0.089 sec

Size of orbit Size of orbit 1.387 x 101.387 x 107 7 kmkm ——

Flux or brightness (counts/sec)Flux or brightness (counts/sec) 66.8 66.8 1.1 1.1 12.6 12.6 1.1 1.1

Luminosity (ergs/sec)Luminosity (ergs/sec) 7.55 x 107.55 x 103636 9.07 x 109.07 x 103232

Luminosity compared to the SunLuminosity compared to the Sun 1970 x L1970 x Lsunsun 0.24 x L0.24 x Lsunsun

Conclusions/ Further Conclusions/ Further ResearchResearch

Astronomical clocks are found in many places in the Astronomical clocks are found in many places in the sky.sky.

We studied the light curves of three astronomical We studied the light curves of three astronomical clocks and measured their properties.clocks and measured their properties.

We calculated spin periods and confirmed that We calculated spin periods and confirmed that pulsars spin at very high speeds. They have periods pulsars spin at very high speeds. They have periods from seconds to milliseconds. from seconds to milliseconds.

Future work:Future work:

AcknowledgementsAcknowledgements……

Eberly College Of Science Eberly College Of Science Dr. Daniel Larson, Dean of Eberly College of Science Dr. Daniel Larson, Dean of Eberly College of Science Dr. Mercedes RichardsDr. Mercedes Richards Ms. Jody MarkleyMs. Jody Markley Mrs. Annie Holmes Mrs. Annie Holmes Mr. Craig KeiserMr. Craig Keiser Ms. Joanne Nash Ms. Joanne Nash UBMS Staff UBMS Staff

Any Questions??Any Questions??