CaltechAUTHORS
Published July 10, 2022 | Version Published + Accepted Version
Journal Article Open

Eta Carinae: An Evolving View of the Central Binary, Its Interacting Winds and Its Foreground Ejecta

Creators

  • 1. ROR icon Goddard Space Flight Center
  • 2. ROR icon Space Telescope Science Institute
  • 3. ROR icon University of Pittsburgh
  • 4. ROR icon Malmö University
  • 5. ROR icon Catholic University of America
  • 6. ROR icon Universidade de São Paulo
  • 7. ROR icon National Autonomous University of Honduras
  • 8. ROR icon University of Maryland, Baltimore County
  • 9. ROR icon San Jose State University
  • 10. ROR icon University of Montreal
  • 11. ROR icon Infrared Processing and Analysis Center
  • 12. ROR icon Embry–Riddle Aeronautical University
  • 13. ROR icon University of Delaware
  • 14. ROR icon University of Birmingham
  • 15. ROR icon Max Planck Institute for Radio Astronomy

Abstract

FUV spectra of η Car, recorded across two decades with HST/STIS, document multiple changes in resonant lines caused by dissipating extinction in our line of sight. The FUV flux has increased nearly tenfold, which has led to increased ionization of the multiple shells within the Homunculus and photodestruction of H₂. Comparison of observed resonant line profiles with CMFGEN model profiles allows separation of wind–wind collision and shell absorptions from the primary wind P Cygni profiles. The dissipating occulter preferentially obscured the central binary and interacting winds relative to the very extended primary wind. We are now able to monitor changes in the colliding winds with orbital phase. High-velocity transient absorptions occurred across the most recent periastron passage, indicating acceleration of the primary wind by the secondary wind, which leads to a downstream, high-velocity bow shock that is newly generated every orbital period. There is no evidence of changes in the properties of the binary winds.

Additional Information

© 2022. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received 2022 April 14; revised 2022 May 16; accepted 2022 May 29; published 2022 July 13. N.R. acknowledges funding from HST programs 15611 and 15992, which were accepted as supplementary observations associated with CHANDRA programs 20200564 and 21200197. M.F.C. is supported under the CRESST-II cooperative agreement #80GSFC17M0002 with the NASA/Goddard Space Flight Center. A.D. acknowledges FAPESP for support through process 2011/51680-6. A.J.F.M. is grateful for financial aid from NSERC (Canada). The work of F.N. is supported by NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation. C.M.P.R. acknowledges support from the National Science Foundation under grant No. AST-1747658. T.R.G. received no direct support for this study. We thank the referee for the careful and very prompt review of this lengthy study. Facility: HST(STIS). Software: CMFGEN (Hillier & Lanz 2001; Hillier 2011).

Attached Files

Published - Gull_2022_ApJ_933_175.pdf

Accepted Version - 2205.15116.pdf

Files

2205.15116.pdf

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Additional details

Identifiers

Eprint ID
115786
Resolver ID
CaltechAUTHORS:20220722-769177000

Related works

Describes
https://arxiv.org/abs/2205.15116 (URL)

Funding

NASA
GO-15611
NASA Hubble Fellowship
GO-15992
NASA
GO-20200564
NASA
GO-21200197
NASA
80GSFC17M0002
Fundação de Amparo à Pesquisa do Estado de Sao Paulo (FAPESP)
2011/51680-6
Natural Sciences and Engineering Research Council of Canada (NSERC)
NSF
AST-1747658

Dates

Created
2022-07-25
Created from EPrint's datestamp field
Updated
2022-07-25
Created from EPrint's last_modified field