Abstract
Context. The protoplanetary disk around the star HD 100546 displays prominent substructures in the form of two concentric rings. Recent observations with the Atacama Large Millimeter/sub-millimeter Array (ALMA) have revealed these features with high angular resolution and have resolved the faint outer ring well. This allows us to study the nature of the system further. Aims. Our aim is to constrain some of the properties of potential planets embedded in the disk, assuming that they induce the observed rings and gaps. Methods. We present the self-calibrated 0.9 mm ALMA observations of the dust continuum emission from the circumstellar disk around HD 100546. These observations reveal substructures in the disk that are consistent with two rings, the outer ring being much fainter than the inner one. We reproduced this appearance closely with a numerical model that assumes two embedded planets. We varied planet and disk parameters in the framework of the planet-disk interaction code FARGO3D and used the outputs for the gas and dust distribution to generate synthetic observations with the code RADMC-3D. Results. From this comparison, we find that an inner planet located at r1 = 13 au with a mass M1 = 8 MJup and an outer planet located at r2 = 143 au with a mass M2 = 3 MJup leads to the best agreement between synthetic and ALMA observations (deviation less than 3σ for the normalized radial profiles). To match the very low brightness of the outer structure relative to the inner ring, the initial disk gas surface density profile needs to follow an exponentially tapered power law (self-similar solution), rather than a simple power-law profile.
Highlights
The formation of planets in protoplanetary disks is one of the main subjects of study in modern astrophysics
A very intriguing part of this topic is how newborn planets interact and actively shape the disk they are embedded in. This idea of planetinduced substructures is currently driven by recent observations with advanced telescopes, which have revealed that circumstellar disks can exhibit various prominent substructures, such as rings, gaps, asymmetries, or spirals (e.g., Atacama Large Millimeter/sub-millimeter Array (ALMA) Partnership 2015; Long et al 2018; Andrews et al 2018; Andrews 2020; Cieza et al 2021)
We present the corresponding synthetic observation and the combined ALMA image, both normalized to their respective maximum, and using the same color map
Summary
The formation of planets in protoplanetary disks is one of the main subjects of study in modern astrophysics. A very intriguing part of this topic is how newborn planets interact and actively shape the disk they are embedded in This idea of planetinduced substructures is currently driven by recent observations with advanced telescopes, which have revealed that circumstellar disks can exhibit various prominent substructures, such as rings, gaps, asymmetries, or spirals (e.g., ALMA Partnership 2015; Long et al 2018; Andrews et al 2018; Andrews 2020; Cieza et al 2021). The following substructures were revealed: a ring of emission with a radius of 27 au (Hubble Telescope, Ardila et al 2007), and a second very faint ring at 200 au (Atacama Large Millimeter/sub-millimeter Array (ALMA), Walsh et al 2014)
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