Reflections on nebulae around young stars

Astronomy and Astrophysics, vol. 670, pp. L8

Abstract

Context. While it is generally assumed that Class II sources evolve largely in isolation from their environment, many still lie close to molecular clouds and may continue to interact with them. This may result in late accretion of material onto the disk that can significantly influence disk processes and planet formation. Aims. In order to systematically study late infall of gas onto disks, we identify candidate Class II sources in close vicinity to a reflection nebula (RN) that may be undergoing this process. Methods. First we targeted Class II sources with known kilo-au scale gas structures – possibly due to late infall of material – and we searched for RNe in their vicinity in optical and near-infrared images. Second, we compiled a catalogue of Class II sources associated with RNe and looked for the large-scale CO structures in archival ALMA data. Using the catalogues of protostars and RNe, we also estimated the probability of Class II sources interacting with surrounding material. Results. All of the sources with large-scale gas structures also exhibit some reflection nebulosity in their vicinity. Similarly, at least five Class II objects associated with a prominent RNe, and for which adequate ALMA observations are available, were found to have spirals or stream-like structures which may be due to late infall. We report the first detection of these structures around S CrA. Conclusions. Our results suggest that a non-negligible fraction of Class II disks in nearby star-forming regions may be associated with RNe and could therefore be undergoing late accretion of gas. Surveys of RNe and kilo-au scale gas structures around Class II sources will allow us to better understand the frequency and impact of late-infall phenomena.

Authors 13

1. Aashish Gupta

   European Southern Observatory

   Affiliation as printed

   European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany

2. Anna Miotello

   European Southern Observatory

   Affiliation as printed

   European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany

3. Carlo Felice Manara

   European Southern Observatory

   Affiliation as printed

   European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany

4. Jonathan P. Williams

   University of Hawaiʻi at Mānoa · University of Hawaii System

   Affiliation as printed

   Institute for Astronomy, University of Hawaii, Honolulu, HI 96822, USA

5. Stefano Facchini

   University of Milan

   Affiliation as printed

   Università degli Studi di Milano, Via Giovanni Celoria 16, 20133 Milano, Italy

6. G. Beccari

   European Southern Observatory

   Affiliation as printed

   European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany

7. T. Birnstiel

   Excellence Cluster Origins · Ludwig-Maximilians-Universität München

   Affiliation as printed

   Exzellenzcluster ORIGINS, Boltzmannstr. 2, 85748 Garching, Germany

   University Observatory, Faculty of Physics, Ludwig-Maximilians-Universität München, Scheinerstr. 1, 81679 Munich, Germany

8. C. Ginski Aachen Leiden Observatory

   Leiden University · Leiden Observatory · University of Amsterdam

   Affiliation as printed

   Anton Pannekoek Institute for Astronomy (API), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands

   Leiden Observatory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands

9. A. Hacar

   University of Vienna

   Affiliation as printed

   Department of Astrophysics, University of Vienna, Türkenschanzstrasse 17, 1180 Vienna, Austria

10. Michael Küffmeier

    Max Planck Institute for Extraterrestrial Physics · University of Virginia

    Affiliation as printed

    Department of Astronomy, University of Virginia, Charlottesville, VA 22904, USA

    Max-Planck Institute for Extraterrestrial Physics, Gießenbachstraße 1, 85748 Garching, Germany

11. L. Testi

    University of Bologna

    Affiliation as printed

    Alma Mater Studiorum Università di Bologna, Dipartimento di Fisica e Astronomia (DIFA), Via Gobetti 93/2, 40129 Bologna, Italy

12. Łukasz Tychoniec

    European Southern Observatory

    Affiliation as printed

    European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany

13. Hsi-Wei Yen

    Institute of Astronomy and Astrophysics, Academia Sinica · Academia Sinica

    Affiliation as printed

    Academia Sinica Institute of Astronomy and Astrophysics, 11F of Astro-Math Bldg, 1, Sec. 4, Roosevelt Rd, Taipei 10617, Taiwan