A Deep Search for Five Molecules in the Debris Disk around 49 Ceti

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Is the molecular gas in circumstellar debris disks the remnant of primordial gas or second-generation material produced in collisions of planetesimals and exocomets? It appears as if most disks are leaning towards a second-generation formation scenario yet several systems do not fit this scenario and with CO as the only detected molecular gas, the key to understanding the origin and evolution lies in understanding the molecular chemistry. We present a deep molecular survey of the nearby debris disk 49 Ceti with 0.900” angular resolution of five tracer molecules (HCN, CN, HCO+, SiO, CH3OH 1(1,1)-0(0,0) and 4(1,3)-3(0,3)) using the Atacama Large Millimeter/ submillimeter Array ( ALMA). We utilize previous spatially resolved observations of CO emission which revealed gas that is axisymmetric and consistent with Keplerian rotation to employ the spectral shifting and spatial averaging method pioneered by Matra (2017). Previous observations of 49 Ceti during ALMA Cycle 1 reached an rms noise of 3 mJy/beam in each 0.41km/s-wide channel at a spatial resolution of 0.5”. Our survey will average across all bands for a resolution of 0.8km/s and improve the expected sensitivity by an order of magnitude.

    Item Description
    Name(s)
    Date
    May 01, 2019
    Extent
    73 pages
    Language
    eng
    Genre
    Physical Form
    electronic
    Discipline
    Rights and Use
    In Copyright - Non-Commercial Use Permitted
    Digital Collection
    PID
    ir:2588