Talk:HD 80606 b

Orbital speed

The average orbital speed of this planet is 44.4 km/s, compared to Earth's 29.8 km/s. I calculated by using 2πa/P*1737.33 where a is the semimajor axis and P is orbital period in days. So 2π0.453 = 2.846 → 2.846 ÷ 111.436 = 0.02554 → 0.02554 × 1737.33 = 44.37 which rounds it to 44.4 since semimajor axis has only 3 significant figures. Well Icalanise, you used ellipse perimeter formula based on Gauss-Kummer series and you calculated as 31.7 km/s, so how did you get that value? BlueEarth (talk | contribs) 22:08, 22 March 2010 (UTC)

You seem to be assuming that the perimeter of an ellipse with semimajor axis a is the same as the circumference of a circle with radius r=a. This is not the case. Take a look at [1] which gives several ways to calculate the perimeter of the ellipse, including the method based on the Gauss-Kummer series I mentioned in my tag:

$p=\pi \left(a+b\right)\left(1+{\frac {1}{4}}h^{2}+{\frac {1}{64}}h^{4}+{\frac {1}{256}}h^{6}+\ldots \right)$ where $h={\frac {a-b}{a+b}}$ and b is the semiminor axis.

The term in h⁶ is already less than 10^-4, so I don't take any terms beyond there. I get the perimeter of the orbit as 2.04 AU (as opposed to the circle formula you are using which gives 2.85 AU, which shows that your value for the speed is too large), then dividing this by the orbital period gives an average speed of 31.7 km/s. Icalanise (talk) 18:00, 23 March 2010 (UTC)

Invalid thumbnail parameters

Might wanna check it out. Syntheticalconnections (talk) 23:22, 9 April 2010 (UTC)

External links modified

Hello fellow Wikipedians,

I have just modified one external link on HD 80606 b. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:

• Added archive https://web.archive.org/web/20111025043742/http://www.sciencefriday.com/program/archives/200901303 to http://www.sciencefriday.com/program/archives/200901303

When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.

This message was posted before February 2018. After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than regular verification using the archive tool instructions below. Editors have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the RfC before doing mass systematic removals. This message is updated dynamically through the template {{source check}} (last update: 18 January 2022).

• If you have discovered URLs which were erroneously considered dead by the bot, you can report them with this tool.
• If you found an error with any archives or the URLs themselves, you can fix them with this tool.

Cheers.—InternetArchiveBot (Report bug) 06:20, 27 October 2017 (UTC)