The Unexpected Spectrum of the Innermost Ejecta of the Red Hypergiant VY CMa
AuthorHumphreys, Roberta M.
Ziurys, L. M.
Bernal, J. J.
Gordon, Michael S.
Helton, L. Andrew
Jones, Terry J.
Richards, A. M. S.
AffiliationUniv Arizona, Dept Astron
Univ Arizona, Dept Chem
stars: individual (VY Canis Majoris)
stars: winds, outflows
MetadataShow full item record
PublisherIOP PUBLISHING LTD
CitationRoberta M. Humphreys et al 2019 ApJL 874 L26
JournalASTROPHYSICAL JOURNAL LETTERS
Rights© 2019. The American Astronomical Society. All rights reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at firstname.lastname@example.org.
AbstractHubble Space Telescope/STIS spectra of the small clumps and filaments closest to the central star in VY CMa reveal that the very strong K I emission and TiO and VO molecular emission, long thought to form in a dusty circumstellar shell, actually originate in a few small clumps hundreds of au from the star. The K I lines are 10-20 times stronger in these nearest ejecta than on the star. The observations also confirm VO as a circumstellar molecule. In this Letter we discuss the spectra of the features, their motions and ages, and the identification of the molecular emission. The strength of the atomic and molecular features in the small clumps present an astrophysical problem for the excitation process. We show that the clumps must have a nearly clear line of sight to the star's radiation.
VersionFinal published version
SponsorsNASA from the Space Telescope Science Institute [GO-15076]; National Science Foundation [AST-1515568]