Disconnecting the Dots: Re-examining the Nature of Stellar “Strings” in the Milky Way
Abstract

Recent analyses of Gaia data have resulted in the identification of new stellar structures, including a new class of extended stellar filaments called stellar “strings,” first proposed by Kounkel & Covey. We explore the spatial, kinematic, and chemical composition of strings to demonstrate that these newfound structures are largely inconsistent with being physical objects whose members share a common origin. Examining the 3D spatial distribution of string members, we find that the spatial dispersion around the claimed string spine does not improve in the latest Gaia DR3 data release—despite tangible gains in the signal-to-noise ratio of the parallax measurements—counter to expectations of a bona fide structure. Using the radial velocity dispersion of the strings (averaging$σVr=16kms−1$) to estimate their virial masses, we find that all strings are gravitationally unbound. Given the finding that the strings are dispersing, the reported stellar ages of the strings are typically 120× larger than their measured dispersal times. Finally, we validate prior work that stellar strings are more chemically homogeneous than their local field stars but show it is possible to obtain the same signatures of chemical homogeneity by drawing random samples of stars from spatially, temporally, and kinematically more »

Authors:
; ;
Publication Date:
NSF-PAR ID:
10371199
Journal Name:
The Astrophysical Journal
Volume:
936
Issue:
2
Page Range or eLocation-ID:
Article No. 160
ISSN:
0004-637X
Publisher:
DOI PREFIX: 10.3847
National Science Foundation
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