Talk:HD 209458 b

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HD 209458 b has been listed as a good article under the good-article criteria. If you can improve it further, please do. If it no longer meets these criteria, you can delist it, or ask for a review.

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Contents 1 Removed from article 2 Fate 3 Article location 4 WP:RM 5 Transit discoverers 6 Atmosphere 7 GA Re-Review and In-line citations

[edit] Removed from article

removed:

Do we have permission to use this? And if so, I'm sure the artist would like to get credit. --mav

This is public domain. Sennheiser checked the "i affirm that i have permission..." box when he uploaded. Sennheiser! 16:34, 8 Feb 2004 (UTC)

I can't find the source of the image anyway. (I should have pasted the address of the source, but I was newer than I am now) I found another image media:heic0403a.jpg from the ESA/hubblesite which is copyright free, and is a good illustration. We can replace the other one with this one. Sennheiser! 16:39, 8 Feb 2004 (UTC)

Wait, I found it!! http://www.spacetelescope.org/bin/news.pl?string=heic0303 --Sennheiser! 16:42, 8 Feb 2004 (UTC)

Very cool. Thanks! :) --mav

[edit] Fate

I think an estimate of when Osiris becomes a Cthonian planet would be in order. A statement of some astronomer would be best, but if that can't be found, we can do a simple calculation based on the rate of loss and the size of the atmosphere. I tried doing it, but my result is about 4 trillion years (either I am too stupid to do simple math, or Osiris is relatively safe), ignoring that helium (BTW, there must be some helium, why it's not mentioned in the article), oxygen, carbon would have a different loss rate, ignoring the possibility of an orbit change and assuming the rate of atmosphere loss remains constant. 81.211.110.171 18:39, 27 Nov 2004 (UTC)

Your calculation is correct, "10,000 tonnes of hydrogen per second" is far too low (!) to cause any appreciable loss of hydrogen, even after billions of years (4 thousand billion years to lose all its mass, or ~300 universe lifetimes, or a mere 150 lifetimes, if only half is hydrogen). Hence I question either the 10,000 or the implication of a Cthonian fate here. -Wikibob | Talk 04:20, 2005 Apr 2 (UTC)

I found a conference paper which appears to be the only reference to Chthonian planets in the astronomical literature - [1] - they give the evaporation rate as 100,000 to 500,000 tonnes/s, so it looks like a 0 may have got dropped at some point. At this rate they reckon the planet will have lost 1-7% of its mass over a lifetime of 5 billion years. So, not negligible, but not in danger of losing all of its atmosphere, it would seem. I'll add some info to the article. Worldtraveller 11:14, 2 Apr 2005 (UTC)

A paper published later in 2004 May 18, Numerical simulations of hydrodynamic evaporation of short periodic giant exoplanets in the light of Roche lobe effects, describes a model that gives "a maximum rate of 6 × 10^10 g s-1" for hydrogen loss. This is 6 1 E 7 kg, or 60000 tonnes, per second. This would only cause a loss of around a half a percent of its mass over 5 billion years. However I have not added this ref to the article for now. -Wikibob 17:57, 24 December 2005 (UTC)

Replying to myself, searching the Notes for HD 209458, there are several papers discussing how certain exoplanets may suffer large losses due to evaporation, and one that points out it is incorrect to simply extrapolate a loss rate:

• H. Lammer et al (2003-11-13). Atmospheric Loss of Exoplanets Resulting from Stellar X-Ray and Extreme-Ultraviolet Heating. The Astrophysical Journal. Retrieved on December 24, 2005. 10^12 g s-1 and may evaporate down to their core sizes
• G.F. Jaritz et al (2005). Roche lobe effects on expanded upper atmospheres of short-periodic giant exoplanets. A&A 439, 771-775 (2005). Retrieved on December 24, 2005. OGLE-TR-56 b ... subject to geometrical blow-off ... 2x10^11 g s-1 ... However, ... HD 209458 b, OGLE-TR-10 b and OGLE-TR-111 b ... may experience classical hydrodynamic blow-off ... can result in higher mass loss rates
• I. Baraffe et al (2004 April 4). The effect of evaporation on the evolution of close-in giant planets. A&A 419, L13-L16 (2004). Retrieved on December 24, 2005. evaporation leads to a rapid expansion ... HD 209458b might be in such a dramatic phase, although with an extremely small probability

After reading these (and this one) I wonder if we are making estimates too soon, and should wait for more conclusive research results. -Wikibob 20:10, 24 December 2005 (UTC)

[edit] Article location

As 'Osiris' is just an unofficial nickname, I think this article would be better placed at HD209458 B, its official designation. Any objections to a move? Worldtraveller 16:11, 8 Feb 2005 (UTC)

I'd object, though not strenuously. According to Wikipedia:Naming conventions (common names), it's best to use the most common name for something. True, it suggests using the most common name that doesn't conflict with something (in this case there are several Osirises), but it also says "When choosing a name for a page ask yourself: What word would the average user of the Wikipedia put into the search engine?" I suspect most people wouldn't do a search for "HD 209458b" :) If you want to go ahead with the move anyway I won't raise a ruckus, though. Bryan 16:22, 8 Feb 2005 (UTC)

I'm inclined to support Bryan, albeit not very strenuously either. After looking at Category:Extrasolar planets and reading around the subject a bit, change to neutral / unqualified to opine. But pending a decision, I made HD209458 B a redirect. –Hajor 16:30, 8 Feb 2005 (UTC)

I take the point that the official name is not what people would be searching for! I'm just uncomfortable with an unofficial nickname being used as an article title. It's probably not a very good comparison, but for example the article on Prozac can be found at Fluoxetine, rather than Prozac which redirects, although it would be by far the better known name. If this one were moved, then searching for Osiris would still lead people to the article via the redirect.

In a similar case to this I had already moved Bellerophon (planet) to 51 Pegasi B having proposed it on that talk page a couple of weeks ago with no objections (no comment at all, in fact), but happy to leave this one alone if objections remain. Worldtraveller 19:23, 8 Feb 2005 (UTC)

I think there should be an exception made in this case, because if was the first time these measurements have been made this particular planet may need a more applicable name. I'm all for having the name of the article show the planets true designation, the less common (but perhaps more well known) name could be the redirect. Wikipedia is after all a site for clarifying information, even when there is little information to go by. Just my oppinion :PMonat 0715, 27 Nov 2006 (EST)

[edit] WP:RM

[edit] Transit discoverers

The HD 209458 article says that teams led by Greg Henry and David Charbonneau first detected the transit of HD209458 b, this article mentions only David Charbonneau and Timothy Brown. According to the NASA press release [3], Greg Henry's group alone found the transit. It could be that NASA didn't know that Charbonneau too had detected the transit. Either way, these articles conflict with each other.--Jyril 10:29, 24 December 2005 (UTC)

According to IAUC 7307: HD 209458; SAX J1752.3-3138 dated 12th November 1999, Henry et al reported a transit ingress on Nov. 8.

Now David Charbonneau's paper Detection of Planetary Transits Across a Sun-like Star, dated November 19th, cited Henry's circular 7307, but state full transit observations were made on September 9 and 16. So it looks like David saw the transit first but published after Henry had published his later observation (and this would explain NASA not knowing about on November 14, 1999, the date of their press release -added by Wikibob 20:25 24 Dec 2005).

Accordingly I've added Henry's team to the article, and included these refs. -Wikibob 17:04, 24 December 2005 (UTC)

[edit] Atmosphere

Should we add the atmospheric information like planets in our solar system just without percentages?

[edit] GA Re-Review and In-line citations

Note: This article has a small number of in-line citations for an article of its size and currently would not pass criteria 2b.
Members of the Wikipedia:WikiProject Good articles are in the process of doing a re-review of current Good Article listings to ensure compliance with the standards of the Good Article Criteria. (Discussion of the changes and re-review can be found here). A significant change to the GA criteria is the mandatory use of some sort of in-line citation (In accordance to WP:CITE) to be used in order for an article to pass the verification and reference criteria. It is recommended that the article's editors take a look at the inclusion of in-line citations as well as how the article stacks up against the rest of the Good Article criteria. GA reviewers will give you at least a week's time from the date of this notice to work on the in-line citations before doing a full re-review and deciding if the article still merits being considered a Good Article or would need to be de-listed. If you have any questions, please don't hesitate to contact us on the Good Article project talk page or you may contact me personally. On behalf of the Good Articles Project, I want to thank you for all the time and effort that you have put into working on this article and improving the overall quality of the Wikipedia project. Agne 00:47, 26 September 2006 (UTC)