Mysterious Light Seen Around A Newly Forming Star; Here’s What Astronomers Think It Means
“In order to reproduce the signatures we see, the disk has to be practically edge-on to our line of sight. Which seems weird, because the main binary system that is CS Cha has a disk that’s inclined, somewhere between edge-on and face-on. This wouldn’t be the first time we’ve seen such a misalignment, as dusty, misaligned binary and trinary systems have been seen before. But it already marks the very first time we’ve detected a polarized companion outside of one of these protoplanetary disks! Because so much of the light is blocked by this dust disk, though, we have a hard time telling what the mass of this companion is. Is it a Jupiter-class planet? A super-Jupiter? Or, as the authors conjecture, is it a low-mass brown dwarf: a failed star?
With a dusty disk around the companion, there’s a near-certainty that whatever it is, it will be developing its own orbiting companions in the imminent future!”
600 light years away, in a small constellation in the southern skies, there’s a new binary star system that’s just in the process of forming: CS Cha. It’s only 2 or 3 million years old, a blip in a star’s lifetime. And all around it for billions of kilometers is a dusty, protoplanetary disk. But far outside that disk is a surprise: a companion object. Most companions will be either large planets or brown dwarfs, and that’s not a surprise. But when you look at the light, it should barely be polarized at all: 1% at most. Yet when we looked at the companion with SPHERE, a new instrument aboard the Very Large Telescope in Chile, we found that a whopping 14% of the light was polarized!
This was no mistake, but the implications are tremendous. After some very careful research, scientists think they know the answer to what’s going on: there’s a dusty disk around the companion object, too!