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Expert: - 9/4/2008


Question
While doing a physics problem involving finding the rotational acceleration of a pulsar, I first calculated the rotational velocity by dividing the circumference of the pulsar by the time it takes to make one revolution.  My answer for velocity came out to be 2.85x10^9 m/s.  I know that nothing can travel faster than the speed of light, but is this something different and is this answer logical?

Answer
Hello,

I worked out the maximal rotational velocity for the x-ray pulsar Centaurus X-3 using the standard equation:

v = R (GM/R^3)^1/2

where R (Cen X-3) = 10^4 m and M (Cen X-3) = 1.4 S (solar masses)

and obtained v = 1.37 x 10^8 m/s

certainly less than c (3 x 10^8 m/s).

Thus, I suspect somewhere somehow you may have made an error in your units. Or perhaps used the wrong equation to find v.

If you can send the full data for the problem then I can look at it.  

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Volunteer

Philip A. Stahl

Expertise

I specialize in stellar and solar astrophysics. Can answer any questions pertaining to these areas, the spectroscopic analysis of stars – as well as the magneto-hydrodynamics of sunspots and solar flares. Sorry – No homework problems done or research projects! I will provide hints on solutions.

Experience

Have published papers on the relationship between sunspot morphology and solar flares; discovery of SID flares related to this, constructed computerized stellar models; MHD research.

Organizations
American Astronomical Society (Solar physics and Dynamical astronomy divisions), American Geophysical Union, American Mathematical Society, Intertel.

Publications
Solar Physics, Journal of the Royal Astronomical Society of Canada, Journal of the Barbados Astronomical Society, Meudon Solar Flare Proceedings (Meudon, France). Books: 'Selected Analyses in Solar Flare Plasma Dynamics', 'Physics Notes for Advanced Level'.

Education/Credentials
B.A. degree in Astronomy; M.Phil. degree in Physics - specializing in solar physics.

Awards and Honors
Postgraduate research award- Barbados government; Studentship Award in Solar Physics - American Astronomical Society

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