2015/04/02 by Laura Ingleby, Catherine Espaillat, Nuria Calvet +6 · 1 citation
Physics and Astronomy · #Accretion (finance) #Accretion disc #Astro and Planetary Science #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Hubble space telescope #Infrared #Physics #RADIUS #Space Telescope Imaging Spectrograph #Stars #Stellar, planetary, and galactic studies #astro-ph.SR
paper · pdf · doi:10.1088/0004-637x/805/2/149
22 pages, 5 figures, Accepted to ApJ
arxiv created 2015/04/02 · openalex publication_date 2015/05/28 · arxiv updated 2015/06/03 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
We analyze three epochs of ultraviolet, optical, and near-infrared (NIR) observations of the Taurus transitional disk GM Aur using the Hubble Space Telescope Imaging Spectrograph (STIS) and the Infrared Telescope Facility SpeX spectrograph. Observations were separated by one week and three months in order to study variability over multiple timescales. We calculate accretion rates for each epoch of observations using the STIS spectra and find that those separated by one week had similar accretion rates ( ) while the epoch obtained three months later had a substantially lower accretion rate ( ). We find that the decline in accretion rate is caused by lower densities of material in the accretion flows, as opposed to a lower surface coverage of the accretion columns. During the low accretion rate epoch, we also observe lower fluxes at both far-ultraviolet (FUV) and IR wavelengths, which trace molecular gas and dust in the disk, respectively. We find that this can be explained by a lower dust and gas mass in the inner disk. We attribute the observed variability to inhomogeneities in the inner disk, near the corotation radius, where gas and dust may co-exist near the footprints of the magnetospheric flows. These FUV–NIR data offer a new perspective on the structure of the inner disk, the stellar magnetosphere, and their interaction.