I want a list of objects with a semi-major axis between 0.95 AU and 1.05 AU that are probably larger than 1 km in diameter. For this, the JPL Small-Body Database Search Engine seems to be the best option.
Here is an example search query:
- a >= 0.95 (AU) (Semi-major axis)
- a <= 1.05 (AU)
This gives 403 objects. Estimated diameter is only given for 6. Largest is 2.48 km. 3753 Cruithne has a diameter of about 5 km and orbits at a=0.998 AU. It's even in those search results, but it just doesn't have a diameter listed.
As far as I know, diameter estimates are made roughly from magnitude information. Obviously albedo factors into this, but let's say I'm happy with the uncertainty of using a standard albedo and standard density. I have absolute magnitude, H, as a parameter for all objects, but the problem is I don't know how far away it was when the measurement was taken. It seems obvious to me that you couldn't get orbital parameters without at least having a distance estimate at the time of when you recorded magnitude. In other words, there absolutely must be enough information taken to estimate the object's diameter, but it's not obvious how to do it.
There is another database tool for Near Earth Objects that NASA has online for candidates for an asteroid mission. However, the objects in this database are already restricted by some criteria that excludes larger objects I'm trying to tabulate.
Using the output fields available from the JPL database, how can I calculate an estimate of object diameter?