IRAS4A1: Multiwavelength continuum analysis of a very flared Class 0 disk

Astronomy and Astrophysics, vol. 681, pp. A82

Abstract

Context. Understanding the formation of substructures in protoplanetary disks is vital for gaining insights into dust growth and the process of planet formation. Studying these substructures in highly embedded Class 0 objects using the Atacama Large Millimeter-submillimeter Array (ALMA), however, poses significant challenges. Nonetheless, it is imperative to do so to unravel the mechanisms and timing behind the formation of these substructures. Aims. In this study, we present high-resolution ALMA data at Bands 6 and 4 of the NGC 1333 IRAS4A Class 0 protobinary system. This system consists of two components, A1 and A2, which are separated by 1.8″ and located in the Perseus molecular cloud at a distance of ~293 pc. Methods. To gain a comprehensive understanding of the dust properties and formation of substructures in the early stages, we conducted a multiwavelength analysis of IRAS4A1. Additionally, we sought to address whether the lack of observed substructures in very young disks could be attributed to factors such as high degrees of disk flaring and large scale heights. To explore this phenomenon, we employed radiative transfer models using RADMC-3D. We employed different approaches and compared the model outcomes with our observational data. This comparison allowed us to gain insights into the challenges in detecting substructures in nascent disks and shed light on the potential influence of the dust scale height on observations of protoplanetary disks. Results. The continuum data revealed the presence of two disks-envelopes around A1 and A2, along with structure connecting the two sources. Furthermore, spectral index measurements indicate lower optical depth within the A2 disk compared to the A1 disk. Our multiwavelength analysis of A1 discovered characteristics such as high dust surface density, substantial dust mass within the disk, and elevated dust temperatures. These findings suggest the presence of large dust grains compared to the ones in the interstellar medium (ISM), greater than 100 microns in size within the region. By employing RADMC-3D, we confirmed that increasing the scale height creates the appearance of an asymmetry in protoplanetary disks. Our findings indicate that a scale height of at least 0.3 (H/R) is necessary to produce this observed asymmetry. Furthermore, while there’s no direct detection of any substructure, our models indicate that some substructure, such as a small gap, must be present. However, reproducing the intensity profile along the major and minor axes necessitates considering other processes that may be occurring within the IRAS4A1 disk. Conclusions. The result implies that disk substructures may be masked or obscured by a large scale height in combination with a high degree of flaring in Class 0 disks.

Authors 10

1. Osmar M. Guerra-Alvarado Aachen Leiden Observatory

   Leiden University · Leiden Observatory

   Affiliation as printed

   Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands

2. Nienke van der Marel Aachen Leiden Observatory

   Leiden University · Leiden Observatory

   Affiliation as printed

   Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands

3. James Di Francesco

   Herzberg Institute of Astrophysics · National Research Council Canada

   Affiliation as printed

   National Research Council of Canada, Herzberg Astronomy and Astrophysics Research Centre, 5071 West Saanich Road, Victoria BC V9E 2E7, Canada

   National Research Council of Canada, Herzberg Astronomy and Astrophysics Research Centre, 5071 West Saanich Road, Victoria, BC V9E 2E7, Canada

4. Leslie W. Looney

   University of Illinois Urbana-Champaign

   Affiliation as printed

   Department of Astronomy, University of Illinois, 1002 West Green Street, Urbana, IL 61801, USA

5. John J. Tobin

   National Radio Astronomy Observatory

   Affiliation as printed

   National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA, USA

6. Erin G. Cox

   Northwestern University

   Affiliation as printed

   Center for Interdisciplinary Exploration and Research in Astronomy, Northwestern University, 1800 Sherman Rd., Evanston, IL 60202, USA

   Center for Interdisciplinary Exploration and Research in Astronomy, Northwestern University, 1800 Sherman Rd., Evanston, IL, 60202, USA

   NSF MPS-Fellow

7. Patrick Sheehan

   Northwestern University

   Affiliation as printed

   Center for Interdisciplinary Exploration and Research in Astronomy, Northwestern University, 1800 Sherman Rd., Evanston, IL 60202, USA

   Center for Interdisciplinary Exploration and Research in Astronomy, Northwestern University, 1800 Sherman Rd., Evanston, IL, 60202, USA

8. David J. Wilner

   Center for Astrophysics Harvard & Smithsonian

   Affiliation as printed

   Center for Astrophysics, Harvard & Smithsonian, Cambridge, MA 02138, USA

   Center for Astrophysics | Harvard & Smithsonian, Cambridge, MA 02138, USA

9. Enrique Macías

   European Southern Observatory

   Affiliation as printed

   ESO Garching, Karl-Schwarzschild-Str. 2, 85748 Garching bei Munchen, Germany

   ESO Garching, Karl-Schwarzschild-Str. 2, 85748, Garching bei Munchen, Germany

10. Carlos Carrasco‐González

    Universidad Nacional Autónoma de México

    Affiliation as printed

    Instituto de Radioastronomía y Astrofísica (IRyA), Universidad Nacional Autónoma de México (UNAM), Mexico

    Instituto de Radioastronomía y Astrofísica (IRyA), Universidad Nacional Autónoma de México (UNAM)