The ALMA-FAUST revolution: Hunting large-grains factories in protostellar outflow cavities

Giovanni, Sabatini

doi:10.5281/zenodo.17108825

The ALMA-FAUST revolution: Hunting large-grains factories in protostellar outflow cavities

Giovanni, Sabatini

Publisher: Zenodo
DOI: 10.5281/zenodo.17108825
Repository: zenodo.org
Language: en

Abstract

Planet formation models still face a crucial challenge: millimeter-sized dust grains in protoplanetary discs migrate rapidly inwards, hindering their growth into planetesimals – the building blocks of planets. However, recent high-resolution ALMA observations, taken as part of the FAUST Large Programme, suggest an alternative scenario. We have discovered dust-rich cavity walls associated with the protostellar objects IRS7B and L1551, located in the Corona Australis (CrA) and in the Taurus star-forming regions, respectively. The sub-mm spectral index (α) derived from Band 3 and Band 6 observations indicates possible grain growth in the outflow cavities. In this talk I will present new results from other young protostellar systems observed in ALMA-FAUST. I will discuss the implications of dust growth in outflow cavities and how this mechanism could overcome the radial drift barrier and potentially revolutionize our understanding of planet formation. I will also look at the impact of these dusty structures on the chemical evolution of protoplanetary systems.

Full text

Collaborators : Bianchi E. (INAF-OAA), Chandler C. J. (NRAO), Cacciapuoti L. (ESO), Podio L. (INAF-OAA), Maureira M. J. (MPE-CAS), Codella C. (INAF-OAA), Ceccarelli C. (UGA), Testi L. (UniBo), Sakai N. (RIKEN), Yamamoto S. (SOKENDAI) & the FAUST Team Osservatorio Astrofisico di Arcetri (INAF-OAA) The ALMA-FAUST revolution: Hunting large-grains factories in protostellar outflow cavities Giovanni Sabatini (INAF-OAA) Towards new frontiers: the astrochemical journey from young stellar nurseries to exoplanets ESO Garching, 10-14 March 2025 Molecular cloud Protostellar system Protoplanetary disk Planetary system Context: Star & Planet formation Inheritance scenario Reshaping/Reset scenario G. Sabatini - New Frontiers 2025 - 11 Mar. 2025 [01] Dust growth Image credit: Bill Saxton (NSF/AUI/NRAO) Turbulent & sub-Keplerian disks Several interacting processes play a role in the coagulation/growth of dust grains (e.g. Testi et al. 2014, Drazkowska et al. 2023, Miotello et al. 2023, Birnstiel 2024) G. Sabatini - New Frontiers 2025 - 11 Mar. 2025 [02] Road to planets (Galametz et al. 2019) (Windmark et al. 2012) Bouncing Mass transfer Erosion Fragmentation Sticking Sticking-bouncing Both processes concur in the metre-size barrier Radial-drift Outcomes of particles collision (e.g. Ormel et al. 2009; Bate 2022, Lebreuilly et al. 2023) How can we explain all these results? (Weidenschilling 1977) ❏dust growth (~mm-size) could begin in collapsing inner protostellar envelope ❏… but models show limited dust growth (up to ~µm) in diffuse molecular clouds. (e.g. Kwon et al. 2009; Miotello et al. 2014; Galametz et al. 2019) G. Sabatini - New Frontiers 2025 - 11 Mar. 2025 [03] Key problem: growth barrier βISM ~ 1.6 (>25 papers accepted) Setup & Tracers FAUST: Fifty AU Study of the chemistry in the disk/envelope system of Solar-like protostars Yamamoto S., Ceccarelli C., Chandler C., Codella C., Sakai, N. Band 6 Band 3 L1551 IRS5 (Podio et al 2024) Accretion streamer (Bianchi et al 2020) Hot-corino chemistry (Codella et al 2024) Disc winds (De Simone et al 2024) Chemical-rich disc (Codella et al 2021) IRS 63 L1551 VLA 1623-2417 NGC 1333 IRAS 4A2 G. Sabatini - New Frontiers 2025 - 11 Mar. 2025 [04] FAUST ALMA Large Program H2CO Sabatini et al. (2024) Sabatini et al. (2024) Dust-rich cavity walls associated with the outflow driven by IRS7B alternative scenario to explain large grains in protostellar envelopes (e.g. Cacciapuoti et al 2024 and Giacalone et al. 2019, Tsukamoto et al. 2021, Bhandare et al. 2024) Bipolar radio-jets @ 3.5, 6 and 20 cm + CH3OH and SiO: signature of the jet impact. (Miettinen et al. 2008, Hariu et al. 2001, Choi & Tatematsu 2004) G. Sabatini - New Frontiers 2025 - 11 Mar. 2025 [05] Dusty cavities in CrA @mm IRS7B (Corona Australis) New large-grains factories (?) IRS7B (Corona Australis) CH3OH (42,3-31,2) E Slope of the dust sub-mmSED Dust opacity index (Rayleigh-Jeans approximation + optically thin emission) (Sabatini et al 2024) ●We found αmm> 1.4: grain growth in the envelope ?! @ Tdust = 30 K 〈Mwalls〉~ 9 ✕ 10-3 M☉ (e.g. Draine 2006, Testi et al 2014, Guidi et al 2016, Ricci et al. 2018, Carrasco-González et al. 2019, Ysard et al. 2019) G. Sabatini - New Frontiers 2025 - 11 Mar. 2025 [06] Testi et al (2014) L1551-IRS5 (Taurus) Sabatini et al. (2024) From CrA and beyond!!! (Sabatini et al in prep ) ❏Prototypical Class-I ❏distance of 141 ± 7 pc ❏Lbol ~ 30 L⊙ ❏FU Ori-like object ❏Mass-loss ~ 1-5 ☓ 10-5 M⊙ yr-1 (e.g. Adams, Lada & Shu 1987, Connelley & Reipurth 2018, Zucker et al. 2019) 1” Bianchi et al. 2020 FAUST I (Sabatini et al in prep ) 3σ 6σ 10σ G. Sabatini - New Frontiers 2025 - 11 Mar. 2025 [07] Physical prop. of the cavity wall (Sabatini et al in prep ) (Bianchi et al. 2020) 0.4” (e.g. Ceccarelli et al. 2000, Motte & André 2001, Jorgensen et al 2002) ❏Rayleigh-Jeans approximation ❏Optically thin emission @ Tdust = 30 K 〈Mdust〉~ 58 M⊕ 〈n(H2)〉> 2 ✕ 105 cm-3 G. Sabatini - New Frontiers 2025 - 11 Mar. 2025 [08] (Sabatini et al in prep )