Resolving the terrestrial planet-forming region of HD 172555 with ALMA: I. Post-impact dust distribution

Fuente: arXiv
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Autores principales: Roumeliotis, Zoe, Matrà, Luca, Kennedy, Grant M., Marino, Sebastian, Su, Kate Y. L., Wilner, David J., Wyatt, Mark C., Jackson, Alan P.
Formato: Preprint
Publicado: 2025
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author Roumeliotis, Zoe
Matrà, Luca
Kennedy, Grant M.
Marino, Sebastian
Su, Kate Y. L.
Wilner, David J.
Wyatt, Mark C.
Jackson, Alan P.
author_facet Roumeliotis, Zoe
Matrà, Luca
Kennedy, Grant M.
Marino, Sebastian
Su, Kate Y. L.
Wilner, David J.
Wyatt, Mark C.
Jackson, Alan P.
contents Giant impacts between planetary embryos are a natural step in the terrestrial planet formation process and are expected to create disks of warm debris in the terrestrial regions of their stars. Understanding the gas and dust debris produced in giant impacts is vital for comprehending and constraining models of planetary collisions. We reveal the distribution of millimeter grains in the giant impact debris disk of HD 172555 for the first time, using new ALMA 0.87 mm observations at $\sim$80 mas (2.3 au) resolution. We modeled the interferometric visibilities to obtain basic spatial properties of the disk, and compared it to the disk's dust and gas distributions at other wavelengths. We detect the star and dust emission from an inclined disk out to $\sim$9 au and down to 2.3 au (on-sky) from the central star, with no significant asymmetry in the dust distribution. Radiative transfer modeling of the visibilities indicates the disk surface density distribution of millimeter grains most likely peaks around $\sim$5 au, while the width inferred remains model-dependent at the S/N of the data. We highlight an outward radial offset of the small grains traced by scattered light observations compared to the millimeter grains, which could be explained by the combined effect of gas drag and radiation pressure in the presence of large enough gas densities. Furthermore, SED modeling implies a size distribution slope for the millimeter grains consistent with the expectation of collisional evolution and flatter than inferred for the micron-sized grains, implying a break in the grain size distribution and confirming an overabundance of small grains.
format Preprint
id arxiv_https___arxiv_org_abs_2512_04154
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Resolving the terrestrial planet-forming region of HD 172555 with ALMA: I. Post-impact dust distribution
Roumeliotis, Zoe
Matrà, Luca
Kennedy, Grant M.
Marino, Sebastian
Su, Kate Y. L.
Wilner, David J.
Wyatt, Mark C.
Jackson, Alan P.
Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
Giant impacts between planetary embryos are a natural step in the terrestrial planet formation process and are expected to create disks of warm debris in the terrestrial regions of their stars. Understanding the gas and dust debris produced in giant impacts is vital for comprehending and constraining models of planetary collisions. We reveal the distribution of millimeter grains in the giant impact debris disk of HD 172555 for the first time, using new ALMA 0.87 mm observations at $\sim$80 mas (2.3 au) resolution. We modeled the interferometric visibilities to obtain basic spatial properties of the disk, and compared it to the disk's dust and gas distributions at other wavelengths. We detect the star and dust emission from an inclined disk out to $\sim$9 au and down to 2.3 au (on-sky) from the central star, with no significant asymmetry in the dust distribution. Radiative transfer modeling of the visibilities indicates the disk surface density distribution of millimeter grains most likely peaks around $\sim$5 au, while the width inferred remains model-dependent at the S/N of the data. We highlight an outward radial offset of the small grains traced by scattered light observations compared to the millimeter grains, which could be explained by the combined effect of gas drag and radiation pressure in the presence of large enough gas densities. Furthermore, SED modeling implies a size distribution slope for the millimeter grains consistent with the expectation of collisional evolution and flatter than inferred for the micron-sized grains, implying a break in the grain size distribution and confirming an overabundance of small grains.
title Resolving the terrestrial planet-forming region of HD 172555 with ALMA: I. Post-impact dust distribution
topic Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2512.04154