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ALMA observations of the narrow HR 4796A debris ring
- Publication Year :
- 2018
- Publisher :
- Oxford Academic, 2018.
-
Abstract
- The young A0V star HR 4796A is host to a bright and narrow ring of dust, thought to originate in collisions between planetesimals within a belt analogous to the Solar System's Edgeworth-Kuiper belt. Here we present high spatial resolution 880$\mu$m continuum images from the Atacama Large Millimeter Array. The 80au radius dust ring is resolved radially with a characteristic width of 10au, consistent with the narrow profile seen in scattered light. Our modelling consistently finds that the disk is also vertically resolved with a similar extent. However, this extent is less than the beam size, and a disk that is dynamically very cold (i.e. vertically thin) provides a better theoretical explanation for the narrow scattered light profile, so we remain cautious about this conclusion. We do not detect $^{12}$CO J=3-2 emission, concluding that unless the disk is dynamically cold the CO+CO$_2$ ice content of the planetesimals is of order a few percent or less. We consider the range of semi-major axes and masses of an interior planet supposed to cause the ring's eccentricity, finding that such a planet should be more massive than Neptune and orbit beyond 40au. Independent of our ALMA observations, we note a conflict between mid-IR pericenter-glow and scattered light imaging interpretations, concluding that models where the spatial dust density and grain size vary around the ring should be explored.<br />Comment: accepted to MNRAS
- Subjects :
- Planetesimal
Solar System
FOS: Physical sciences
Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
circumstellar matter
01 natural sciences
Neptune
Planet
0103 physical sciences
Galaxy formation and evolution
planetary systems
010303 astronomy & astrophysics
Astrophysics::Galaxy Astrophysics
QB
Physics
Earth and Planetary Astrophysics (astro-ph.EP)
010308 nuclear & particles physics
Astronomy and Astrophysics
submillimetre: planetary systems
planet-disc interactions
Planetary system
Atacama Large Millimeter Array
Debris
Galaxy: formation
13. Climate action
Space and Planetary Science
Astrophysics::Earth and Planetary Astrophysics
stars: individual: HR 4796A
Astrophysics - Earth and Planetary Astrophysics
Subjects
Details
- Language :
- English
- ISSN :
- 00358711 and 13652966
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....5ddfa2f70100dd5bbb590226d5c9107a