TY  - THES
AU  - Aizpuru Vargas, Luis Lauro
TI  - Investigation on gravitational star-disk encounters producing ʻOumuamua and Borisov-like Interstellar Objects
PB  - University Bonn
VL  - Masterarbeit
M1  - FZJ-2020-05018
SP  - 85 p.
PY  - 2020
N1  - Masterarbeit, University Bonn, 2020
AB  - The recent discovery of two Inter-Stellar Objects (ISO) in our own Solar System has promptedastronomers to come up with theoretical explanations on how they are produced.  Most newlyformed stars are initially surrounded by a protoplanetary disk.  The main hypothesis is thatthese ISOs were planetesimals in such disks and that through one mechanism or another becameunbounded from their host stellar system.  These same stars and their disks are preferentiallyformed in stellar clusters.  The gravitational effects that result from the interaction betweendisks and stars are thus common and relevant for the understanding of the fate of such disks.Amongst  these  mechanisms  there  is  the  gravitational  stellar  fly-by  encounter.   The  partialdestruction of the disk by the perturber star produces a varying number of unbounded plan-etesimals.  Several studies have looked into the effects of stellar fly-bys on disks both for theco-planar prograde case and for inclined retrograde cases.  They investigated properties such asfinal disk size or final fate of the test particles.  However, the particles that become unboundhave attracted little attention so far.  This work focuses on the particles that become unboundduring  such  fly-bys,  contributing  to  the  ISO  population.   We  perform  numerical  simulationsof a range of parabolic inclined encounters with varying pertuber star masses and periastrondistances for the encounters.  The parameter space explored in this work is relevant for a typ-ical  young  open  stellar  cluster  environment.   Here  we  focus  on  the  relative  amount  and  thevelocities  of  ISOs  produced  during  such  fly-bys.   We  found  that  the  velocity  distribution  ofunbounded test particles varies according to the different possible combination of parameters.Nonetheless, the final ejection velocities were found to be in the range between 0.3 km/s and3.0 km/s.  Using the results of this particular work along with the available literature on thevelocities of ISOs produced by other sources, we can make a quantitative distinction betweenthe different types of ISOs.  As a follow up study, more precise cluster simulations accountingfor the IMF function, binary populations and viscous disks would provide a more realistic andcomprehensive study of the production of ISOs in clusters.
LB  - PUB:(DE-HGF)19
UR  - https://juser.fz-juelich.de/record/888554
ER  -