TY  - JOUR
AU  - Pfalzner, Susanne
AU  - Govind, Amith
TI  - Close Stellar Flybys Common in Low-mass Clusters
JO  - The astrophysical journal / 1
VL  - 921
IS  - 1
SN  - 0004-637X
CY  - London
PB  - Institute of Physics Publ.
M1  - FZJ-2021-06091
SP  - 90 -
PY  - 2021
AB  - Numerous protoplanetary disks show distinct spiral arms features. While possibly caused by a range of processes, detailed pattern analysis points at close stellar flybys as cause for some of them. Surprisingly, these disks reside in young low-mass clusters, where close stellar flybys are expected to be rare. This fact motivated us to take a fresh look at the frequency of close flybys in low-mass clusters. In the solar neighborhood, low-mass clusters have smaller half-mass radii than their more massive counterparts. We show that this observational fact results in the mean and central stellar density of low-mass clusters being approximately the same as in high-mass clusters, which is rarely reflected in theoretical studies. We perform N-body simulations of the stellar dynamics in young clusters obeying the observed mass–radius relation. Taking the mean disk truncation radius as a proxy for the degree of influence of the environment, we find that the influence of the environment on disks is more or less the same in low- and high-mass clusters. Even the fraction of small disks (<10 au) is nearly identical. Our main conclusion is that the frequency of close flybys seems to have been severely underestimated for low-mass clusters. A testable prediction of this hypothesis is that low-mass clusters should contain 10%–15% of disks smaller than 30 au truncated by flybys. These truncated disks should be distinguishable from primordially small disks by their steep outer edge.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000716744900001
DO  - DOI:10.3847/1538-4357/ac19aa
UR  - https://juser.fz-juelich.de/record/904521
ER  -