The Sun's almost perfectly round shape baffles scientists!
Discussion
Found this at lunch that has thrown a question to he astroscientist.
http://phys.org/news/2012-08-sun-perfectly-baffles...
As one comment "And in 2003, astronomers discovered the equatorial diameter of the blue B3 main sequence star Achernar is 56% greater than its polar diameter, making it flattest star known." Its not a normal sun for sure!
http://phys.org/news/2012-08-sun-perfectly-baffles...
As one comment "And in 2003, astronomers discovered the equatorial diameter of the blue B3 main sequence star Achernar is 56% greater than its polar diameter, making it flattest star known." Its not a normal sun for sure!
Eric Mc said:
I must be spinning rapidly.
This would be the 'simple' conclusion, but surely they can detect the rotation period? Presumably the rotation period is normal? I would imagine that if the rotation isn't abnormally fast, (pulsars do not bulge like that, do they?), then somebody very clever will have to spend a lot of time studying it. Magnetic fields can affect the shape, as they can attract, and repulse by varying degrees, I think. This can happen with some stars, I believe. Edited by TheHeretic on Saturday 18th August 23:43
It's hard to measure the spin rate of a distant star unless we gave some indicator from that star that allows the spin to be observed in some way. With the sun, we can look at how fast surface features move across the disc. We can also measure the magnetic field as it rotates.
With an extreeme object like a pulsar, the spin can be measured by counting the pulses of radio eneregy emitted.
If a star does not show a disc, then observing the surface is impossible - and for a more normal star, the magnetic fiedl will be two weak to be measured from a few light yeas away.
Pulsars are so dense, and have such a strong gravitaional field, that, despite the fact they are spinning rapidly, the centrifugal force at the equator is not strong enough to overcome the gravitational pull and an equatorial bulge will not develop
With an extreeme object like a pulsar, the spin can be measured by counting the pulses of radio eneregy emitted.
If a star does not show a disc, then observing the surface is impossible - and for a more normal star, the magnetic fiedl will be two weak to be measured from a few light yeas away.
Pulsars are so dense, and have such a strong gravitaional field, that, despite the fact they are spinning rapidly, the centrifugal force at the equator is not strong enough to overcome the gravitational pull and an equatorial bulge will not develop
I'm surprised anyone would be surprised!
Stars can and do occasionally have both a magnetic North and a South Pole, they don't have to spin at all to flatten.
Our Sun is a long way from transforming to a Magnetar (which it can't in fact do), a Flattened star is simply one is accommodating huge magnetic polar forces.
Magnetars are thought by many to be fat discs as far as its mass is concerned, not round objects as so often portrayed in artists impressions. The roundness is more the effect of the magnetic field 'rounding it up'.
Stars can and do occasionally have both a magnetic North and a South Pole, they don't have to spin at all to flatten.
Our Sun is a long way from transforming to a Magnetar (which it can't in fact do), a Flattened star is simply one is accommodating huge magnetic polar forces.
Magnetars are thought by many to be fat discs as far as its mass is concerned, not round objects as so often portrayed in artists impressions. The roundness is more the effect of the magnetic field 'rounding it up'.
Gassing Station | Science! | Top of Page | What's New | My Stuff