FAST OSCILLATIONS IN THE X-RAY LIGHT CURVE OF eta CARINAE

Z. Abraham*, D. Falceta-Goncalves

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

eta Carinae is a binary system formed by two massive stars, loosing mass through strong winds. The wind-wind interactions originate shocks that rise the plasma temperature to 10(6-8) K, producing X-ray emission. Although the overall shape of the light curve can be explained and it is used to calculate the orbital eccentricity, the observed short quasi-periodic oscillations have not been explained yet. In our work we propose that these oscillations are produced by the nutation of the rotation axis of eta Carinae, which is not be perpendicular to the orbital plane. Since in eta Carinae, both the mass loss rate and the wind velocity are latitude dependent, the intensity of the emitted X-rays will be a function of the latitude at which the stellar surface intercepts the orbital plane. By assuming an angle of about 30 degrees between the rotation axis and the perpendicular to the orbital plane, an nutation amplitude of about 5 degrees and a nutation period of 22 days, we were able to reproduce very well the observed X-ray light curve.

Original languageEnglish
Title of host publicationXII IAU REGIONAL LATIN AMERICAN MEETING
EditorsG Magris, G Bruzual, L Carigi
Place of PublicationMEXICO CITY
PublisherUNIVERSIDAD NACIONAL AUTONOMA MEXICO INSTITUTO ASTRONOMIA
Pages46-47
Number of pages2
ISBN (Print)978-970-32-5298-5
Publication statusPublished - 2009
Event12th IAU Regional Latin American Meeting of Astronomy - Isla Margarita, United Kingdom
Duration: 22 Oct 200726 Oct 2007

Publication series

NameREVISTA MEXICANA DE ASTRONOMIA Y ASTROFISICA, SERIE DE CONFERENCIAS
PublisherUNIVERSIDAD NACIONAL AUTONOMA MEXICO INSTITUTO ASTRONOMIA
Volume35
ISSN (Print)1405-2059

Conference

Conference12th IAU Regional Latin American Meeting of Astronomy
Country/TerritoryUnited Kingdom
CityIsla Margarita
Period22/10/0726/10/07

Keywords

  • stars: binaries
  • stars: individual (eta Carinae)
  • stars: winds, outflows
  • WIND-WIND COLLISION
  • BINARY-SYSTEM

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