# Talk:Protostar

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## What is k

What is the k in the formula? —Sverdrup(talk) 12:24, 22 Feb 2004 (UTC)

It is ofcourse Boltzmanns constant. :-) —Sverdrup(talk)

## It's hard to keep up.

New data coming and it may well have something to say about the nature of Population III Stars:

http://www.nasa.gov/lb/vision/universe/starsgalaxies/xmm_magnetic_starbirth.html

http://arxiv.org/abs/astro-ph/0503029

X-ray telescopes are also revealing a higher-than-expected concentration of iron in the early universe.

And no talk about the jets and the effect on the surrounding medium! (http://arxiv.org/abs/astro-ph/0701022) —Preceding unsigned comment added by 206.248.178.184 (talk) 06:59, 21 June 2009 (UTC)

## Confusing statements

"Whatever the source of the disturbance, if it is sufficiently large it may cause the force due to gravity to become greater than the force due to thermal kinetic energy within a particular region of the cloud." - from paragraph 2, is confusing. Someone reword this please JustShin 02:11, 23 May 2007 (UTC)

JustShin: I just made an attempt at rewording and clarifying the sentence you mentioned. Hope this makes it clearer. MHD (talk) 11:06, 28 November 2007 (UTC)

The article states that kinetic energy is balanced by potential energy. It does not make sense. In fact according to virial theorem, for a bound state in equilibrium kinetic energy should be just half of the negative of potential energy. We may state that inward gravitational force is balanced by outward pressure.

In fact, the potential energy (that tries to contract the cloud) is counteracted not only by kinetic energy, but also by so-called turbulent pressure. I agree that a statement in the direction of 'gravitational force is balanced by outward pressure (kinetic energy + turbulent pressure)' would be better. I may try to rephrase this part later. MHD (talk) 11:11, 28 November 2007 (UTC)
Just did that part now. All I did was add a comment about other forces (besides thermal pressure) that can help to keep the cloud from collapsing: turbulence, magnetic pressure and rotation. And I added a reference. Hope that someone will check out whether it actually makes sense. MHD (talk) 12:50, 28 November 2007 (UTC)

## TAU Taurus stars?

In the "History" section, it says that protostars were discovered by observing "TAU Taurus" stars.

I'm pretty sure this should read "T Tauri", not TAU Taurus (T Tarui and Tau Tarui are two very different stars), but I don't know enough about the history of protostars to be confident in making an edit to this section. — Rogermw (talk) 18:41, 25 April 2011 (UTC)

I added Composition: "The protostellar Sun's composition was reconstructed as 71.1% hydrogen, 27.4% helium, and 1.5% heavier elements." - Sun 2601:589:4705:C7C0:CD39:BFB6:B7C2:56F0 (talk) 17:07, 23 October 2015 (UTC)

## Wrong definition of protostar?

Something doesn't look right in the lede.

The definition of a protostar has two major components: when it begins and when it ends. The definition of the end looks good, but the beginning seems wrong. "The phase begins when a molecular cloud first collapses under the force of self-gravity." I'm pretty sure that the generally accepted definition is when the second core forms. The first core forms earlier, when some sort of hydrostatic equilibrium is reached. Then the hydrogen molecules start to dissociate, triggering another collapse and the formation of the second core, which everyone says is the protostar.

here After the dissociation of molecular hydrogen triggers the second gravitational collapse at the center of the first core, a protostar is quickly formed and the first core gradually transforms into a circumstellar disk that eventually accretes onto the central protostar.

and here

Zyxwv99 (talk) 01:21, 22 March 2016 (UTC)

## Magnetism

I watched a show on magnetism, and apparently, the spinning disk creates magnetism, which slows down the disk, and eventually into the protostar. 32ieww (talk) 23:37, 28 January 2017 (UTC)

## Sub-optical wavelengths

Why can't we extend the star diagram to lower(like in protostars) and high wavelengths? That way, we can place the protostars on the star diagram. 32ieww (talk) 23:40, 28 January 2017 (UTC)