TEMPORAL VARIABILITY of INTERSTELLAR Na i ABSORPTION TOWARD the MONOCEROS LOOP

Cody Dirks, David M. Meyer

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

We report the first evidence of temporal variability in the interstellar Na i absorption toward HD 47240, which lies behind the Monoceros Loop supernova remnant (SNR). Analysis of multi-epoch Kitt Peak coudé feed spectra from this sight line taken over an eight-year period reveals significant variation in both the observed column density and the central velocities of the high-velocity gas components in these spectra. Given the ∼1.3 mas yr-1 proper motion of HD 47240 and an SNR distance of 1.6 kpc, this variation would imply ∼10 au fluctuations within the SNR shell. Similar variations have been previously reported in the Vela SNR, suggesting a connection between the expanding SNR gas and the observed variations. We speculate on the potential nature of the observed variations toward HD 47240 in the context of the expanding remnant gas interacting with the ambient interstellar medium.

Original languageEnglish (US)
Article number45
JournalAstrophysical Journal
Volume819
Issue number1
DOIs
StatePublished - Mar 1 2016

Keywords

  • ISM: atoms
  • ISM: clouds
  • ISM: supernova remnants

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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