Abstract
ABSTRACT We present the results of ALMA band 7 observations of dust and CO gas in the disks around 7 objects with spectral types ranging between M5.5 and M7.5 in Upper Scorpius OB1, and one M3 star in Ophiuchus. We detect unresolved continuum emission in all but one source, and the 12CO J = 3 − 2 line in two sources. We constrain the dust and gas content of these systems using a grid of models calculated with the radiative transfer code MCFOST, and find disk dust masses between 0.1 and 1 M ⊕, suggesting that the stellar mass/disk mass correlation can be extrapolated for brown dwarfs (BDs) with masses as low as 0.05 M ⊙. The one disk in Upper Sco in which we detect CO emission, 2MASS J15555600, is also the disk with the warmest inner disk, as traced by its H–[4.5] photometric color. Using our radiative transfer grid, we extend the correlation between stellar luminosity and mass-averaged disk dust temperature, originally derived for stellar mass objects, to the BD regime to ⟨ T dust ⟩ ≈ 22 ( L * / L ⊙ ) 0.16 K ?> , applicable to spectral types of M5 and later. This is slightly shallower than the relation for earlier spectral type objects and yields warmer low-mass disks. The two prescriptions cross at 0.27 L ⊙, corresponding to masses between 0.1 and 0.2 M ⊙ depending on age.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.