Talk:Stellar rotation

Good article

This article read well, was well structured, had a good lead, and was broad in scope. It meets all of the GA criteria... Johnfos 10:00, 31 August 2007 (UTC)

Thank you! — RJH (talk) 18:32, 1 September 2007 (UTC)

Rotational Speed of the sun

According to my calculation, the rotational speed (at the equator) of the sun is (((4 379 000km / 25 days) / 24) / 60) / 60 = 2.03 km/sec. But the table in this article quotes a G0 star as rotating at 12 km/sec. (the sun is G2). Is the sun so unusual??? Geoffrey.landis (talk) 17:21, 28 November 2008 (UTC)

12 km/s matches the value in the reference (#16). So I would say... possibly.—RJH (talk) 23:06, 28 November 2008 (UTC)

Microturbulence

Microturbulence in a star? What is this? Coronellian (talk) 19:58, 11 October 2009 (UTC)

I believe it is small scale turbulence on the photosphere. You might want to take a look at the "microturbulence" article.—RJH (talk) 14:54, 12 October 2009 (UTC)

Rotational braking confusion

Under rotational braking it says "As the expected life span of a star decreases with increasing mass, this can be explained as a decline in rotational velocity with age." This seems to be confusing association with cause. The expected life of a star decreases with larger mass due to faster rate of fusion. Better to just delete the whole sentence from this section ? - Rod57 (talk) 09:44, 14 July 2014 (UTC)

But... why do they rotate

Why do stars rotate? think this very pertinent question goes unanswered in the article. Did I miss something? Jyg (talk) 04:51, 6 January 2015 (UTC)

Good point - we should say: Mostly they are formed rotating from the conserved angular momentum of the gas cloud that collapsed. But hot stars slow down from magnetic effects [need ref], and it seems brown dwarfs can speed up as they cool and contract.[1] - Rod57 (talk) 12:33, 9 April 2021 (UTC)

Planets

Does stellar rotation ever correlate with planetary orbits? Kortoso (talk) 23:20, 6 January 2016 (UTC)

2018 results - unexpected high latitudinal shear

[2] reports on Asteroseismic detection of latitudinal differential rotation in 13 Sun-like stars quote "We report the measurement using asteroseismology of latitudinal differential rotation in the convection zones of 40 Sun-like stars. For the most significant detections, the stars’ equators rotate approximately twice as fast as their midlatitudes. The latitudinal shear inferred from asteroseismology is much larger than predictions from numerical simulations." - Rod57 (talk) 13:22, 30 September 2018 (UTC)

Which telescopes and instruments have been used.

Which telescopes and instruments have been used. Spitzer (before retirement) could measure brown dwarf rotation (by doppler?).[3] What others telescopes have been used ? - Rod57 (talk) 20:04, 8 April 2021 (UTC)

may be made clearer?

I have doubts on

The magnetic field of a star interacts with the stellar wind. As the wind moves away from the star its rate of angular velocity slows. The magnetic field of the star interacts with the wind, which applies a drag to the stellar rotation. As a result, angular momentum is transferred from the star to the wind, and over time this gradually slows the star's rate of rotation.

1) rate of angular velocity?

2) the cause-effect relationship is left to the reader's immagination. the angular velocity slows as a result of what follows or what follows is caused by this decrease? or the transfer is due to an effect not related to this change? I have tried to image the Lorentz force, but proved superior to my forces.

3) I would feel clearer a statement like "the magnetic field acts on the stellar wind, increasing its angular momentun and thus ...", but this may be caused by the fact that my native language is italian.

thanks. pietro 151.29.59.56 (talk) 07:36, 24 May 2022 (UTC)

Black hole rotation rate

Current edition says:

The rotation rate of a black hole has been measured as high as 98.7% of the speed of light.

The source isn't accessible, likely dead.

An article https://phys.org/news/2007-05-supermassive-black-holes.html says that "Their analysis indicates that this black hole is spinning very fast indeed, at least 98.7 percent of the maximum possible spin rate allowed by Einstein's Theory of General Relativity."

I will remove the above sentence from the article, assuming that introducing "maximum possible spin rate allowed by Einstein's Theory of General Relativity" would only confuse readers. Dobrichev (talk) 11:40, 5 November 2024 (UTC)