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High-excitation emission lines near eta Carinae, and its likely companion star by Mehner, Andrea; Davidson, Kris; Ferland, Gary J.; Humphreys, Roberta M. is a scholarly article available to read on EtoBox.

What is High-excitation emission lines near eta Carinae, and its likely companion star about?

In order to study the distribution of gas and ionizing radiation around eta Car and their implications for its likely companion star, we have examined high-excitation emission lines of [Ne III], [Fe III], etc., in spectra obtained with the HST/STIS instrument during 1998-2004. Our principal results, some of them unexpected, are: (1) The high-excitation fluxes varied systematically and non-trivially throughout eta Car's 5.5-year spectroscopic cycle. Instead of rising to a plateau after the 1998 "event," they changed continuously with a maximum in mid-cycle. (2) At one significant location a brief, strong secondary maximum occurred just before the 2003.5 spectroscopic event. (3) These emission lines are strongly concentrated at the "Weigelt knots" several hundred AU northwest of the star. With less certainty, [Ne III] appears to be somewhat more concentrated than [Fe III]. (4) A faster, blue-shifted component of each feature appears concentrated near the star and elongated perpendicular to the system's bipolar axis. This structure may be related to the equatorial outflow and/or to dense material known to exist along our line of sight to the star. (5) Using the photoionization program

Author

Mehner, Andrea; Davidson, Kris; Ferland, Gary J.; Humphreys, Roberta M.

Published

2009

Language

EN