A correlation between accretion and outflow rates for Class II Young Stellar Objects with full and transition disks

arXiv (Cornell University)

Abstract

Magnetothermal (MHD) winds and jets originate in a wide range of regions of protoplanetary disks (1-30 au) and are thought to be the primary mechanisms driving accretion onto the central star. One indirect signature of these processes is the free-free emission from ionized gas close to the star. We analyze a sample of 31 Class II disks: 18 full disks (FD) and 13 transition disks (TD). All sources show evidence of excess free-free emission over the contribution of the thermal dust. We investigate the origin of this emission and whether it is associated with other observables. We first analyzed a sample of objects in Taurus, exploring correlations with the properties of the central star, the disk, and other disk-wind tracers. We compared our findings with a sample of TD for which free-free emission was shown to be likely associated with an MHD-wind/jet. We found no correlation between the detected free-free emission and either the X-ray or the [OI]6300A line properties. We found a strong correlation between the ionized mass loss rate, as inferred from the free-free emission, and the accretion rate, suggesting that free-free emission in FD is associated with an MHD-wind/jet. The detected free-free emission in both TD and FD is likely similarly associated with an ionized gas close to the star from an MHD-wind/jet. The free-free emission detected in TD shows hints of shallower correlations with accretion properties than in FD. Whereas the efficiency in transforming accretion into outflow might differ in TD and FD, considering the correlations between free-free emission and accretion properties, this difference could simply result from a bias toward strong accretors in the TD sample. Therefore, observations of a more complete and uniform sample are necessary to determine whether this change in correlations holds only for strong accretors or for TD in general.

Authors 10

1. Alessia A. Rota Aachen Leiden Observatory

   Leiden University · Leiden Observatory

   Affiliation as printed

   Leiden Observatory , Leiden University , P.O. 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 , P.O. Box 9513 , 2300 RA Leiden , The Netherlands

3. A. Garufi

   Istituto di Radioastronomia di Bologna

   Affiliation as printed

   INAF -Istituto di Radioastronomia , Via Gobetti 101 , I-40129 , Bologna , Italy

4. Carlos Carrasco‐González

   Universidad Nacional Autónoma de México

   Affiliation as printed

   Instituto de Radioastronomía y Astrofísica ( IRyA-UNAM) , Morelia , Michoacán 58089 , Mexico

5. Enrique Macías

   European Southern Observatory

   Affiliation as printed

   European Southern Observatory , Karl-Schwarzschild-Strasse 2 , D-85748 Garching , Germany

6. Ilaria Pascucci

   University of Arizona

   Affiliation as printed

   Lunar and Planetary Laboratory , University of Arizona , Tucson , AZ 85721 , USA

7. Andrew D. Sellek Aachen Leiden Observatory

   Leiden University · Leiden Observatory

   Affiliation as printed

   Leiden Observatory , Leiden University , P.O. Box 9513 , 2300 RA Leiden , The Netherlands

8. L. Testi

   University of Bologna

   Affiliation as printed

   Dipartimento di Fisica e Astronomia Augusto Righi , Università di Bologna , Viale Berti Pichat 6/2 , Bologna , Italy

9. A. Isella

   Rice University

   Affiliation as printed

   Department of Physics and Astronomy , Rice University , 6100 Main Street , MS-108 , Houston , TX 77005 , USA

10. Stefano Facchini

    University of Milan

    Affiliation as printed

    Dipartimento di Fisica , Universitá degli Studi di Milano , Via Celoria 16 , 20133 Milano , Italy