Hi, the limb darkening calculator referenced in Dennis Conti’s guide to exoplanet observations (http://astroutils.astronomy.ohio-state.edu/exofast/limbdark.shtml) is not working. Error 404: File Not Found
I discovered another calculator here: ExoPlanet Characterization Tool Kit
but unfortunately that didn’t work either for my target / filter (Johnson V)
Any advice on a suitable calculator or news on the one referenced by Dennis?
Thanks, Les
The author of that page, Jason Eastman, indicates that the school no longer host the page. He has suggested alternates here: Astro Utils Update
I found a selection for Johnson.V
Was there another reason it didn’t work for you?
Thanks Epsori! I didn’t see that message. The site I tried didn’t report anything for the WASP-92b.
Your screenshot is giving the min and max wavelengths for which to calculate the coefficients. When I clicked on calculate coefficients below that nothing came back.
I’ll try one of the other sites your link references
regards, Les
If the site does not resolve for your target you can still enter details of the star in the boxes beneath. Note that the name is optional.
Specify the stellar parameters using the GAIA DR3 catalog values for your star. And of course the other parameters further down.
Hope this helps.
It does resolve the target (WASP 92b) but on clicking calculate (with Johnson V selected) no coefficients are returned
@dennis-conti Would you be able to update the URL to the limb arkening tool the next time you revise the Guide to Exoplanet Observations?
Yep, will do that.
Dennis
Hi Dennis, do you have a particular calculator in mind you can share here? I’ve tried the one at ExoPlanet Characterization Tool Kit.
However for WASP-92b for a Johnson V bandpass it fails to return any values. As a test if I use one of the JWST NIR filters in the bandpass drop-down values are returned but for a range of specific wavelengths. So even if it did work for my Johnson V filter it’s unclear which of the many values would be used within AIJ
Thanks for looking into this
Les
Les: I agree. New table of results are not helpful?
Dennis:
I have been using Google Gemini AI. I identify parameters of host star;
Teff; Fe/H; log g (from Exoplanet Archive) and filter name (e.g., Johnson V or Clear).
I ask Gemini: "Calculate the Limb Darkening Coefficients for a star with the following reported parameters: Teff=5773; Fe/H=0.278; log g=4.174 (from Exoplanet Archive) and filter name (e.g., Johnson V or Clear).
Yields quadratic coeffs u1; u2 that seem to agree with my old site requests.
Thoughts? New site does not give a simple result but a long table with different wavelengths that don’t make a lot of sense to me??
Ken
PS: The specific stellar parameters are based on actual data, not what I stated above. Then I usually select Kepler rather than Tess system alternatives for my Clear filter bandpass?
The SCO-LDC app is available but I would advise holding off on using it for production work until full testing is complete. Thanks!
We need to be careful with Gemini. I spent much of yesterday afternoon working with Gemini to determine optimally-placed transits to capture from my observatory location in UT for TFOP submission. It appeared to correctly accessed the TESS TFOP Transit Finder but then returned incorrect starting and ending times for the observation. I haven’t had time yet to look into this further.
