The systemic velocity of eta Carinae

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31 Scopus citations


High-resolution spectra of molecular hydrogen in the Homunculus nebula allow for the first direct measurement of the systemic velocity of η Carinae. Near-infrared long-slit data for H2 1-0 S(1) λ21218 obtained with the Phoenix spectrometer on the Gemini South telescope give V sys = -8.1 ± 1 km s-1 (heliocentric), or V LSR = -19.7 ± 1 km s-1, from the average of the near and far sides of the Homunculus. This measurement considerably improves the precision for the value of -7 ± 10 km s-1 inferred from neighbouring O-type stars in the Carina nebula. New near-infrared spectra also provide a high-resolution line profile of [Fe II] λ16435 emission from gas condensations known as the Weigelt objects without contamination from the central star, revealing a line shape with complex kinematic structure. Previously, uncertainty in the kinematics of the Weigelt knots was dominated by the adopted systemic velocity of η Car.

Original languageEnglish (US)
Pages (from-to)L15-L18
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
StatePublished - Jun 11 2004


  • Circumstellar matter
  • Stars: individual: η Car

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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