Year: 2016
Type: article
Abstract: ABSTRACT We present medium-resolution, near-ultraviolet Very Large Telescope/FLAMES observations of the star USNO-A0600-15865535. We adapt a standard method of stellar typing to our measurement of the shape of the Balmer ϵ absorption line to demonstrate that USNO-A0600-15865535 is a blue horizontal branch star, residing in the lower stellar halo at a distance of 4.4 kpc from the Sun. We measure the H & K lines of singly ionized calcium and find two isolated velocity components, one originating in the disk, and one associated with the high-velocity cloud complex WD. This detection demonstrated that complex WD is closer than ∼4.4 kpc and is the first distance constraint on the +100 km s−1 Galactic complex of clouds. We find that complex WD is not in corotation with the Galactic disk, which has been assumed for decades. We examine a number of scenarios and find that the most likely scenario is that complex WD was ejected from the solar neighborhood and is only a few kiloparsecs from the Sun.
Authors: J. E. G. Peek, Rongmon Bordoloi, Hugues Sana, Julia Roman-Duval, Jason Tumlinson, Yong Zheng
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Funders: National Science Foundation, Smithsonian Institution, National Aeronautics and Space Administration, Johns Hopkins University, Space Telescope Science Institute, University of Edinburgh, Queen's University Belfast, Durham University, Queen's University, Max-Planck-Gesellschaft, National Central University, Eötvös Loránd Tudományegyetem, Max-Planck-Institut für Astronomie, Smithsonian Astrophysical Observatory, Science Mission Directorate, U.S. Naval Observatory, Planetary Science Division, Los Alamos National Laboratory
Awards: G1968183688, G2171960263, G2299114855, G433322167, G4474636675, G4518818167, G58316358, G618131832, G6273510985, A NEO SEARCH PROGRAM USING THE PAN-STARRS PS1 TELESCOPETHE GOAL OF THE PROPOSED RESEARCH IS TO USE T, G7187964967, Pan-STARRS1: Operations; Public Data Release; Education and Outreach, G833430883, G8934477357
OpenAlex ID: W2499324006