[HN Gopher] A Circumplanetary Disk Around PDS70 C [pdf]
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A Circumplanetary Disk Around PDS70 C [pdf]
Author : leephillips
Score : 68 points
Date : 2021-08-19 12:53 UTC (10 hours ago)
(HTM) web link (www.eso.org)
(TXT) w3m dump (www.eso.org)
| baking wrote:
| https://www.almaobservatory.org/en/press-releases/astronomer...
| rendall wrote:
| Would someone who has knowledge in this domain be willing to
| explain the significance of this? To me, it just describes 2
| protoplanets in a dust disk, but I'm sure it has some importance
| to astronomers in order to hit front page of HN
| dcuthbertson wrote:
| From a layperson's perspective (I am not an astronomer at all),
| it sounds like they found 2 Saturn-like planets in the making.
| They're still forming from their dust disks. That in itself is
| cool.
| baking wrote:
| No expertise in the matter, but I assume the question is how
| our solar system formed with gas giants in the outer orbits and
| rocky planets in the habitable zone and how common this might
| be around other stars. The final paragraph of the conclusion
| has some hints.
|
| I am particularly interested in why we are on a planet that is
| so rich in phosphorus and the final phrase about "delivery of
| chemically enriched material to planetary atmospheres" is a
| real tease.
| svachalek wrote:
| The Bae et al paper linked in that paragraph
| (https://iopscience.iop.org/article/10.3847/2041-8213/ab46b0)
| (note Bae is cited second on OP paper) actually has quite a
| bit more to do with the way planets settle into orbits, based
| on study of this same system. As a fellow layman I haven't
| read it in detail but it looks fascinating, will check it out
| later.
|
| These are really interesting papers and full of pics and
| diagrams, although the math is beyond me.
| wthomp wrote:
| Many circumstellar disks have been detected, but this is the
| first unambiguous detection of a circumplanetary disk. This is
| believed to be material swirling around a protoplanet,
| accreting on to it, and perhaps, forming moons. The actual
| processes of how planets form out of protoplanetary disks are
| still not well understood, so observations like this will help
| narrow things down. Quite impressive that they were able to
| resolve it with ALMA.
| marcodiego wrote:
| My hardwired brain: an old disk from the 70's with an obscure c
| compiler was found!
| raducu wrote:
| I thought it was an (artificial) orbital ring.
| bregma wrote:
| It should be rewritten in Rust.
| willemojnr wrote:
| According to Wikipedia, "For the first time, we can conclusively
| see the tell-tale signs of a circumplanetary disk, which helps to
| support many of the current theories of planet formation."
|
| I'm confused though... doesn't our own Saturn have a
| circumplanetary disk?
| leephillips wrote:
| Do not read Wikipedia.
|
| What is new here is the clear observation of a circumplanetary
| disk around an exoplanet. Such disks are where moons are
| formed, so this is the first observation of a moon-forming
| process outside of our solar system.
| junon wrote:
| > so this is the first observation of a moon-forming process
| outside of our solar system
|
| Is that really true? We've never seen moons forming elsewhere
| in the universe?
| koheripbal wrote:
| Correct. The ability to infer this from observational data
| was only possible with the technique pioneered in this
| paper.
|
| Remember that we cannot even see exo-planets visually (with
| one or two very nearby exceptions).
| svachalek wrote:
| According to Wikipedia, there are not even any confirmed
| exomoons yet. So it's interesting that a disk was
| observed first, although given size/brightness that's
| probably not a surprising result.
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(page generated 2021-08-19 23:02 UTC)