TY - JOUR
T1 - ETA carinae's 2014.6 spectroscopic event
T2 - The extraordinary he II and N II features
AU - Davidson, Kris
AU - Mehner, Andrea
AU - Humphreys, Roberta M.
AU - Martin, John C.
AU - Ishibashi, Kazunori
N1 - Publisher Copyright:
© 2015. The American Astronomical Society. All rights reserved.
PY - 2015/3/1
Y1 - 2015/3/1
N2 - Eta Carinae's spectroscopic events (periastron passages) in 2003, 2009, and 2014 differed progressively. He ii λ4687 and nearby N ii multiplet 5 have special significance because they respond to very soft X-rays and the ionizing UV radiation field (EUV). Hubble Space Telescope (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.
AB - Eta Carinae's spectroscopic events (periastron passages) in 2003, 2009, and 2014 differed progressively. He ii λ4687 and nearby N ii multiplet 5 have special significance because they respond to very soft X-rays and the ionizing UV radiation field (EUV). Hubble Space Telescope (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.
KW - X-rays: stars
KW - circumstellar matter
KW - stars: individual (n Carinae)
KW - stars: massive
KW - stars: variables: general
KW - stars: winds, outflows
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U2 - 10.1088/2041-8205/801/1/L15
DO - 10.1088/2041-8205/801/1/L15
M3 - Article
AN - SCOPUS:84924188827
SN - 2041-8205
VL - 801
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 1
M1 - L15
ER -