arXiv subjects

Elena M. Viscardi

Publications and source records attributed to Elena M. Viscardi.

2 recordsLinked to original sources

arXiv2026

Dust characterization of halos: The extended emission in protoplanetary disks

Extended low surface brightness emission has been identified in a number of protoplanetary disks, in tension with predictions of radial drift theory. We aim to investigate the nature and origin of faint, extended dust emission in the outer regions of protoplanetary disks, which we define as the "Halo", using multiwavelength (sub)millimeter continuum observations of three systems: Elias 2-24, IM Lup, and DM Tau. We utilized Atacama Large Millimeter Array (ALMA) observations of our targets to perform spectral energy distribution (SED) fitting with four dust compositions and derived radial profiles of their dust properties. The halos identified in our sources account for 20 - 30% of the total flux density at (sub)millimeter wavelengths. In Elias 2-24, IM Lup, and DM Tau, we infer maximum grain sizes of 2 cm, $<$ 4 mm, and $<$ 9 mm, with the data best reproduced by porous amorphous carbon, compact amorphous carbon, and compact organic carbon compositions, respectively. Their total dust masses are $125^{+34}_{-23}$, $301^{+139}_{-101}$, and $829^{+761}_{-378}$ M$_{\oplus}$, with corresponding halo masses of $33^{+12}_{-6}$, $103^{+25}_{-17}$, and $316^{+202}_{-117}$ M$_{\oplus}$. The halos of IM Lup and DM Tau are dust rich with gas-to-dust mass ratios of 64 and 18, respectively. In all three disks, the dust drift and growth timescales are shorter than the disk ages, implying that the smooth outer disks should not exist. The halos in our sources hold relevant fractions of the total dust reservoir, demonstrating that they play an important role in alleviating the mass-budget problem. While the persistence of halos in IM Lup and DM Tau could be explained by late infall, the presence of centimeter-sized grains in Elias 2-24's halo suggests that unresolved dust traps also play a role.

astro-ph.EP↗

arXiv2025

Dust characterization of protoplanetary disks: a guide to multi-wavelength analyses and accurate dust mass measurements

Multi-wavelength dust continuum observations of protoplanetary disks are essential for accurately measuring two key ingredients of planets formation theories: the dust mass and grain size. Unfortunately, they are also extremely time-expensive. We aim to investigate the most economic way of performing this analysis. We benchmark the dust characterization analysis on multi-wavelength observations of two disk models. We test three different combinations of bands (in the 0.45 mm $\to$ 7.46 mm range) to see how optically thick and thin observations aid the reconstruction of the dust properties for different morphologies and in three different dust mass regimes. We also test different spatial resolutions. Dust properties are robustly measured in a multi-band analysis if optically thin observations are included. For typical disks, this requires wavelengths longer than 3 mm. High-resolution (< 0.03"-0.05") is fundamental to resolve the changes in dust content of substructures. However, lower-resolution results still provide an accurate measurement of the total dust mass and of the level of grain growth of rings. Additionally, we propose a new approach that successfully combines lower and higher resolution observations in the multi-wavelength analysis without losing spatial information. We also test individually enhancing the resolution of each radial intensity profile with Frank but we note the presence of artifacts. Finally, we discuss on the total dust mass that we derive from the SED analyses and compare it with the traditional method of deriving dust masses from millimeter fluxes. Accurate dust mass measurements from the SED analysis can be derived by including optically thin tracers. On the other hand, single-wavelength flux-based masses are always underestimated by even more than one order of magnitude.

astro-ph.EP↗