Is there a theoretical size limit for a planet?

[Feynstein100]

I'm not sure what it would do. The Silicon burning process in stars seems to skip Manganese, instead adding an alpha particle to Chromium-48 to make Iron-52.

Wait then where does manganese come from?

 

[PAllen]

Wait then where does manganese come from?

Google helps:

https://www.aanda.org/articles/aa/full_html/2013/11/aa22599-13/aa22599-13.html

 

[swampwiz]

Just speculating, but wouldn't it be possible to find large concentrations of iron, up to whatever the size limit before gravitational collapse. near the centers of galaxies, where the ejecta from multiple supernovae might find its way into a stable orbit around another star or black hole? the farthest explanets found are around 17K LY, about 2/3rds the distance to the center of the Milky Way, so we have no idea what weird cold objects may be floating around there?

My understanding is that once a star runs its course to end up with an iron core, it becomes a black hole in less than an hour. An astronomer would have better luck looking for an Aricebo-type message from ET.

 

[swampwiz]

Hopefully, some of Webb's time is devoted to scanning the sky for brown dwarfs, which emit most of their energy in the IR band. (Can Webb even do such a scan?)

 

[Drakkith]

Hopefully, some of Webb's time is devoted to scanning the sky for brown dwarfs, which emit most of their energy in the IR band. (Can Webb even do such a scan?)

Depends on what you mean by 'scan'. It can take a series of images in a session, move over, and start a new series, but I'm not sure it can do 'drift scanning' like some telescopes on Earth do.