Published February 26, 2021 | Version v1
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Characterizing Young, Cool M-Stars and their Planet-Forming Disks

  • 1. Center for Astrophysics | Harvard & Smithsonian
  • 2. University of Chicago
  • 3. Pennsylvania State University
  • 4. University of Michigan
  • 5. University of Virginia
  • 6. Instituto de Astrofísica
  • 7. Kavli Institute for Astronomy and Astrophysics
  • 8. University of Arizona




M-stars are the most common hosts of planetary systems in the local Galaxy.  Observations of protoplanetary disks around these cool stars are remarkable tools for understanding the environment within which their planets form.  In this poster (and haiku), we present a small sample of protoplanetary disks around M-stars (spectral types M4-M5).  Using spectrally and spatially resolved ALMA observations of a range of molecular lines, we measure the dynamical masses of these stars and characterize the chemistry in their disks.  We find that dynamical masses for our sample exceed fiducial stellar evolutionary model predictions, and we use this discrepancy to constrain the nature of young, cool M-stars. In terms of chemistry, we find that the distribution of key molecular probes, which offer insight into the organic chemistry and C/N/O ratios, are different both between and across disks around these M-stars. This diversity is similar to what has been previously observed towards solar-type stars.  Overall, we find similar patterns of chemistry between our M-star sample and solar-type disks, and we investigate hydrocarbons as one important possible exception.  We also discuss future observations, which are crucial to obtain a holistic view of the chemistry of planet formation around the "coolest" stars.



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