Images reveal exocomets around nearby stars

araes

It's a neat result, its maybe a bit to specify sizes. At least with the images provided in the article, they're getting maybe:

10 pixels, across across objects of >1 astronomic unit (149,597,870 km). If those rings are like our own Kuiper belt objects, then those are more like 25-50 AU. If they're like the asteroid belt in the inner solar system, then maybe 2-5 AU.

If those are images from the nearest 74 solar systems, then those are somewhere from 4 ly to 20 ly away (~4e13 km to 2e14 km away). [1][2] They're probably further away.

Based on the stated resolution, ALMA is supposed to get ~10 milliarcseconds (10−7 radians) resolution. [3] With the small angle approx. that means it can resolve:

  (~4e13 km to 2e14 km) * 10^-7
   = 4e6 km to 2e7 km
   = 0.025 AU to 0.125 AU

It's cool though, as it at least implies disc path clearing, orbital harmonics resulting in ring formation, and probably a lot of other implications. Likely gives excellent regions to try looking for further planets, planetoids, or planetesimals. Provides some idea of how likely it is for the conditions in our own solar system to cause similar formations in further away solar systems. Mostly a lot of single rings, not that many double ring groups. Quite a few that end up looking more like bloby clouds.

[1] 100 Nearest Star Systems, http://www.recons.org/TOP100.posted.htm

[2] GJ 1005 (#74), https://en.wikipedia.org/wiki/GJ_1005

[3] Atacama Large Millimeter Array, https://en.wikipedia.org/wiki/Atacama_Large_Millimeter_Array

divbzero

I always thought that comets come from the Oort cloud, but apparently short-period comets come from the Kuiper belt or its associated scattered disk—similar to the exocometary belts in these images.

AtlasBarfed

Doesn't that practically guarantee Exoplanets in those systems?

tantalor

The article says we already knew that:

> astronomers knew disks of debris leftover from planet formation were common around newborn stars

The new result allows much more insight:

> only a few have been resolved in sufficient detail to study their internal structure. “This is the first time we can make a statistical analysis of what’s going on in these disks,

HN

Images reveal exocomets around nearby stars

Images reveal exocomets around nearby stars