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Metal-poor Wolf-Rayet star enriching the ISM by nitrogen in the galaxy NGC 4068

Published online by Cambridge University Press:  29 August 2024

Anastasiya Yarovova*
Affiliation:
Lomonosov Moscow State University, Sternberg Astronomical Institute, Universitetsky pr. 13, Moscow 119234, Russia
Oleg Egorov
Affiliation:
Lomonosov Moscow State University, Sternberg Astronomical Institute, Universitetsky pr. 13, Moscow 119234, Russia Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraß e 12-14, D-69120 Heidelberg, Germany
Alexei Moiseev
Affiliation:
Lomonosov Moscow State University, Sternberg Astronomical Institute, Universitetsky pr. 13, Moscow 119234, Russia Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnii Arkhyz 369167, Russia
Olga Maryeva
Affiliation:
Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnii Arkhyz 369167, Russia Astronomical Institute of the Czech Academy of Sciences, Fričova 298, 25165 Ondřejov, Czech Republic

Abstract

We discovered a nebula in the low-metallicity (Z=0.1 ) nearby ( Mpc) dwarf galaxy NGC 4068, which reveals broad Hα line profile and unusual emission line fluxes in its spectrum. The object also shows significant nitrogen overabundance, not typical for metal-poor environment. We assumed that the nebula could be ionized by an evolved massive star with , Wolf-Rayet or Blue Supergiant, and built models of the nebula using Cloudy and CMFGEN codes. Our models successfully reproduce the optical emission spectrum of the object, including the peculiar [SII]/[NII] ratio and the presence of the HeII λ4686 line.

Type
Poster Paper
Copyright
© The Author(s), 2024. Published by Cambridge University Press on behalf of International Astronomical Union

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