Journal
ASTROPHYSICAL JOURNAL
Volume 842, Issue 1, Pages -Publisher
IOP PUBLISHING LTD
DOI: 10.3847/1538-4357/aa71b4
Keywords
circumstellar matter; comets: general; molecular processes; planetary systems; stars: individual (Fomalhaut A); submillimeter: planetary systems
Categories
Funding
- Direct For Mathematical & Physical Scien
- Division Of Astronomical Sciences [1518332] Funding Source: National Science Foundation
- Science and Technology Facilities Council [ST/N000927/1] Funding Source: researchfish
Ask authors/readers for more resources
Recent Atacama Large Millimeter/submillimeter Array observations present mounting evidence for the presence of exocometary gas released within Kuiper Belt analogs around nearby main-sequence stars. This represents a unique opportunity to study their ice reservoir at the younger ages when volatile delivery to planets is most likely to occur. We here present the detection of CO J=2-1 emission colocated with dust emission from the cometary belt in the 440 Myr old Fomalhaut system. Through spectrospatial filtering, we achieve a 5.4s detection and determine that the ring's sky-projected rotation axis matches that of the star. The CO mass derived (0.65-42) x10(-7) M-circle plus is the lowest of any circumstellar disk detected to date and must be of exocometary origin. Using a steady-state model, we estimate the CO+ CO2 mass fraction of exocomets around Fomalhaut to be between 4.6% and 76%, consistent with solar system comets and the two other belts known to host exocometary gas. This is the first indication of a similarity in cometary compositions across planetary systems that may be linked to their formation scenario and is consistent with direct interstellar medium inheritance. In addition, we find tentative evidence that(49 +/- 27)% of the detected flux originates from a region near the eccentric belt's pericenter. If confirmed, the latter may be explained through a recent impact event or CO pericenter glow due to exocometary release within a steady-state collisional cascade. In the latter scenario, we show how the azimuthal dependence of the CO release rate leads to asymmetries in gas observations of eccentric exocometary belts.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available