Hot Jupiters

TVF, the link you provided says the solar wind is 88% hydrogen ions. The mass of the wind is not given.

On the T-Tauri stars, is Alpha Arae such a star at this time? In another recent article www.space.com/scienceastronomy/060925_mm_star_spin.html this star is said to be very close to its break-up speed. In this article they talk about a disk of material that may originate from the over-spin star. Would this 'disk' be something similar to the origin of new planets?

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Rudolf</i>
<br />On the T-Tauri stars, is Alpha Arae such a star at this time?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">No, the T-Tauri stage is mosty prior to completion of star formation. Alpha Arae is spectral type Be. But to some degree, most O, B, and A-type stars still have rapid spin and may still be forming planets. They would be in the late stages of such formation.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">they talk about a disk of material that may originate from the over-spin star. Would this 'disk' be something similar to the origin of new planets?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">A disk cannot produce a planet because accretion of nearby matter is dynamically excluded. Nearby matter tends to spread out to the maximum and to avoid collisions, not to accrete. Planets form when the star fissions an entire, intact mass (actually a pair of such masses).

The recent finds of very-low-density hot Jupiters suggests the prediction by the fission model that early-stage stars can have low density, low mass planets that have not yet lost their hydrogen and therefore not yet condensed into terrestrial planets. But because this stage does not last long on astronomical time scales, they will be rare. -|Tom|-

In this case what else can cause the star to spin up so rapidly? If this is an established star then there probably must be another source.

Then on the hot jupiters, do the stars they orbit still also show a rapid rotation? From the articles that I recall talking about these objects they never really mention the star rotation speed. Also, these hot jupiters - again from what I recall, are singular and not in pairs. Wouldn't that argue against a fission process forming twin planets at a time?

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Rudolf</i>
<br />In this case what else can cause the star to spin up so rapidly? If this is an established star then there probably must be another source.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Spin-up is a result of contraction, which can occur from either accretion or cooling.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Then on the hot jupiters, do the stars they orbit still also show a rapid rotation? From the articles that I recall talking about these objects they never really mention the star rotation speed.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">I likewise have seen no data on spin. But early stellar types have high spins on average, and later types tend to have low spins.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Also, these hot jupiters - again from what I recall, are singular and not in pairs. Wouldn't that argue against a fission process forming twin planets at a time?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">It is very difficult to tell whether it is one planet or two under some circumstances. For example, I've suggested that twin planets on circular orbits alternately pull in the same or opposite directions, which makes them appear like one planet on an eccentric orbit.

When we cannot see the planets but must infer them from data signals, there is room for more than one interpretation of the data. -|Tom|-