Object in inverse orbit in SOHO image

[Christopher Shriver]

I'm not used to reporting such things, but I seem to be looking at an object in orbit of the Sun, moving in the opposite orbital direction to the planets; a captured object, no doubt. The parallax suggests it is not an optical trick of Earth's movement around the Sun. This is just a still image highlighting the object in question, but it's clearly visible if viewing today's SOHO imagery: https://soho.nascom.nasa.gov/data/Theater/

If others are more savvy, please chime in. This could be already catalogued somewhere, but I'm running out of time to fart around on the internet for today. If this hasn't been officially discovered yet, go right ahead and discover it. (It's probably a distant star, but just in case)

https://sungrazer.nrl.navy.mil/

Edited March 31 by Christopher Shriver
Added link/mentioned it may just be a distant star

[Philalethes]

3 hours ago, Christopher Shriver said:

I'm not used to reporting such things, but I seem to be looking at an object in orbit of the Sun, moving in the opposite orbital direction to the planets; a captured object, no doubt. The parallax suggests it is not an optical trick of Earth's movement around the Sun. This is just a still image highlighting the object in question, but it's clearly visible if viewing today's SOHO imagery: https://soho.nascom.nasa.gov/data/Theater/

If others are more savvy, please chime in. This could be already catalogued somewhere, but I'm running out of time to fart around on the internet for today. If this hasn't been officially discovered yet, go right ahead and discover it. (It's probably a distant star, but just in case)

https://sungrazer.nrl.navy.mil/

Yep, that one's definitely a star as far as I can tell. It's easier to see when comparing the speed and direction it's moving at with all the other steadily moving points that can be seen here and there, which are also stars, even though they aren't as easy to spot as on C3 (but if you compare the distances it moves in the image relative to the Solar diameter marked by the white circle it's also apparent that it's moving at the same speed as the stars more easily visible in C3).

Here I've made a little overlay (which reminds me of when I foolishly tried to do the same from the perspective of Mars, heh) that makes it clear which stars are which relative to C3, where I've also added in C2:

I should probably have used your image with the star in question marked by the square from the beginning to make it even clearer, but I just double-checked, and the star is the same one, marked with the square here:

Checking with Stellarium it seems to be this star.

[Christopher Shriver]

Could you explain in a little detail how you investigated this? I'm far out of my depth and am not sure which catalogue to reference(or how). If you could distill your process down several steps, what should I do the next time I want to look up a star in the sky? What information should I possess going into the query?

I don't own a telescope, so all the skills/knowledge associated with what's in the sky has passed me by. I need to change that so I can validate these things myself, in the future. This was also an interesting demonstration of parallax, since that's what gave it away as a distant star - its visibility in C2 was, to me, worth the effort you made identifying it, but I can't ask you every time 😛

[Philalethes]

8 hours ago, Christopher Shriver said:

Could you explain in a little detail how you investigated this? I'm far out of my depth and am not sure which catalogue to reference(or how). If you could distill your process down several steps, what should I do the next time I want to look up a star in the sky? What information should I possess going into the query?

I can certainly share my method, although I'm sure there are others. To identify a star using tools that are freely available today (like catalogs and star maps) you'd essentially need one of two things as far as I can tell: either its coordinates or a visual on it relative to other easily identifiable stars. In this particular case we of course have a very easily identifiable star to go by, namely our very own Sol, which is always readily seen in star maps; so in this case I just took a screenshot centered on it (in this case I used the map of The Sky Live for it, although other good alternatives are In-The-Sky and Stellarium Web) and cropped out roughly an area around it corresponding to some of the star formations I could readily see on C3 (particularly those three notable stars in a line, where one is marked with the letter delta, δ, which turns out to be Delta Piscium).

Then I used an online tool to overlay the image with transparency (this one in this case, though I'm sure there are better ones, and you could use most image manipulation software for this) on the C2 and C3 imagery (which I had overlaid on top of each other to get the inner white circle representing the visible disc to match up, as I mentioned in the above post) and rotated and changed the size of the crop until I could get all the prominent stars in the image to match up. At this point one can already tell which star in the imagery you posted corresponds to which on the star map, and thus can look it up there, so the gif isn't ultimately necessary for that, it was just to show the matching stars; the method there was just to download an image from the above tool for each step of transparency and stitch them into a gif (with Ezgif).

So that's the general method if all you have to go by is a visual where you can identify one or more stars already and want to know what one of the other stars nearby it might be: crop from star map, match up stars, and then reference the star map again once you see which one it is.

If you don't have any reference objects to go by (which would have to be other imagery than Solar imagery like the coronagrams) it would be more difficult, since you'd have to cross-reference various rotations at various zooms throughout the entire night sky, which unless the stars in question were among the brightest and most notable could take a human ages. For that I would recommend Astrometry.net, which does that computationally; this is very useful if you e.g. take a photo of some portion of the night sky that you don't recognize and can't find in a star map yourself.

8 hours ago, Christopher Shriver said:

I don't own a telescope, so all the skills/knowledge associated with what's in the sky has passed me by. I need to change that so I can validate these things myself, in the future.

That's certainly very much in the spirit of science. Even without a telescope the above methods should be workable for imagery that you might come across or take with a camera otherwise, but I know that with a telescope on a computerized mount you can align the telescope and know which coordinates you're viewing at any given time. I don't own a telescope myself sadly, but there are certainly some decent options out there, like e.g. this one, which uses something called SkyAlign to align the telescope by simply pointing it at some bright objects (I don't know if this always works perfectly in practice though, and I'm sure viewing conditions matter quite a bit too).

8 hours ago, Christopher Shriver said:

This was also an interesting demonstration of parallax, since that's what gave it away as a distant star

Yep, the Solar movement across the ecliptic would definitely be the most conspicuous parallax of all.

Also interesting is the resulting movement of the planets that pop into view on the coronagrams every now and then; the superior planets will all always be moving in the same direction as the stars, albeit more slowly due to there being significantly less parallax (more easily visible the closer the planet is, i.e. most prominent for Mars), whereas the inferior planets on the other hand will move more quickly than the stars in the same direction when they pass in front and move in the opposite direction of the stars when they pass behind.

Edited April 3 by Philalethes
typo

[Christopher Shriver]

Awesome response; good links. I've eye'd such online tools before but haven't "vetted" any. I'll gladly take the help and will try to emulate this process. If I find anything useful in regards to that, I will share it. Thank you very much for your time!