Eta Carinae's 2014.6 Spectroscopic Event: The Extraordinary He II and N II Features

Abstract

Eta Carinae's spectroscopic events (periastron passages) in 2003, 2009, and 2014 differed progressively. He II 4687 and nearby N II multiplet 5 have special significance because they respond to very soft X-rays and the ionizing UV radiation field (EUV). HST/STIS observations in 2014 show dramatic increases in both features compared to the previous 2009.1 event. These results appear very consistent with a progressive decline in the primary wind density, proposed years ago on other grounds. If material falls onto the companion star near periastron, the accretion rate may now have become too low to suppress the EUV

To appear in the Astrophysical Journal Letters

References in corpus (4)

• Possible Implications of Mass Accretion in Eta Carinae
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• The Chrysalis Opens? Photometry from the Eta Carinae HST Treasury Project, 2002-2006
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• The X-ray properties of Eta Carinae during its 2020 X-ray minimum
• $\eta$ Carinae: high angular resolution continuum, H30$\alpha$ and He30$\alpha$ ALMA images
• The Altered State of $\eta$Carinae: HST's Photometric Record 1998--2021