Far-UV observations of H, C, N and O in exocomets of Beta Pic
Abstract
The Beta Pictoris system is a young planetary system embedded in a debris disk that is continually replenished by the collision and evaporation of planetesimals and exocomets. As a result of the edge-on inclination of the debris disk, the gas component of the disk and transiting exocomets can be observed in great detail using absorption spectroscopy. In February 2014, our COS observations yielded the first detection of exocomets in the far-UV. Several new exocometary species were detected for the first time including HI, CII, NI, OI and all the ionization states of Si. The measured radial velocities of these two exocomets are consistent with the two dynamically different exocomet populations known to exist in the Beta Pictoris system. We propose to determine the abundance of key species in a larger sample of exocomets and test the hypothesis that the two dynamically different exocomet populations have different compositions. This can be achieved by the acquisition of several spectra at different epochs. This will allow us to better distinguish the signatures of the interstellar medium, the gas disk and the transiting exocomets. Measuring the abundance of the key species H, C, N and O in a larger sample of evaporating exocomets will enable us to trace the condensation and evaporation processes present in the late stages of planetary formation. Notably, such abundance measurements are only possible via far-UV observations. These measurements will provide insight into the origins of the exocomets of the Beta Pictoris system.
- Publication:
-
HST Proposal
- Pub Date:
- December 2015
- Bibcode:
- 2015hst..prop14089S