4

This video talks about how by sending a spacecraft to around 600 AU and beyond, we would could use the Sun as a gravitational lens and take clear detailed images of exoplanets light-years away.

What it doesn't say however is the exact resolution. An exoplanet 4 light-years away would obviously appear bigger and more detailed than one 100 light years away. But by how much?

Is there a direct formula showing the resolution for an exoplanet at x light-years? As in kilometers/pixel?

screenshot from "Using the Sun to Image Alien Planets"

uhoh
  • 31,151
  • 9
  • 89
  • 293
user177107
  • 2,689
  • 10
  • 30
  • Possible duplicate of https://astronomy.stackexchange.com/questions/3644/using-the-sun-as-a-gravitational-lens? – WarpPrime Jan 23 '21 at 20:25
  • @fasterthanlight No. I want to know the resolution of a planet at a certain distance by using the Sun's gravitational lensing. As in km/pixel. Not necessarily those units, but you know. Just how clear would the image be? – user177107 Jan 23 '21 at 21:13
  • @fasterthanlight where are you seeing anything about "...a direct formula showing the resolution for an exoplanet at x light-years?" I don't find the word "resolution" anywhere on that page. This is a different question needing a different answer. – uhoh Jan 23 '21 at 23:38
  • @user177107 and uhoh: it does answer it someway : there is no way on earth, but you'd need to go to the kuiper belt or oort cloud to start using it as a lens to focus the light of a single source – planetmaker Jan 24 '21 at 04:21
  • The calculation you want is done here. https://astronomy.stackexchange.com/questions/33498/what-is-the-gravitational-lensing-focal-distance-of-a-white-dwarf-star – ProfRob Jan 24 '21 at 09:58
  • @ProfRob you've worked out a substantial fraction of the necessary calculation there and it is disheartening that the sun is actually too strong to conveniently image an exoplanet without building something at least a little bit like this as a focal plane, but I'm thinking that resolution may have other factors as well. – uhoh Jan 24 '21 at 23:18
  • @ProfRob In oder to obtain an image with a non-lens like this (i.e. $\theta \sim 1/r$ vs thin lens $\theta \sim r$) one needs some kind of annular restriction in angle to see the Einstein ring for a given feature on the exoplanet's surface. Does that restriction somehow also restrict resolution (e.g. diffraction)? See also the currently insufficiently answered Space SE question What might the first deep space telescope using the Sun or Jupiter as a gravitational lens be like? – uhoh Jan 24 '21 at 23:24
  • The article here https://www.centauri-dreams.org/2020/12/16/jpl-work-on-a-gravitational-lensing-mission/ suggests a resolution of 10 to 25km, is that the sort of thing you're looking for? – Dave Gremlin Jun 20 '21 at 23:36

0 Answers0