Revisiting the classics: on the evolutionary origin of the ‘Fe <scp>ii</scp>’ and ‘He/N’ spectral classes of novae-Reference-Cited by-同舟云学术

Revisiting the classics: on the evolutionary origin of the ‘Fe ii’ and ‘He/N’ spectral classes of novae

Published:2023-11-08 Issue:3 Volume:527 Page:9303-9321
ISSN:0035-8711
Container-title:Monthly Notices of the Royal Astronomical Society
language:en
Short-container-title:

Author:

Aydi E¹^ORCID,Chomiuk L¹^ORCID,Strader J¹,Sokolovsky K V²³^ORCID,Williams R E⁴⁵,Buckley D A H⁶⁷^ORCID,Ederoclite A⁸^ORCID,Izzo L⁹¹⁰^ORCID,Kyer R¹^ORCID,Linford J D¹¹^ORCID,Kniazev A³⁶¹²¹³^ORCID,Metzger B D¹⁴¹⁵^ORCID,Mikołajewska J¹⁶^ORCID,Molaro P¹⁷¹⁸^ORCID,Molina I¹,Mukai K¹⁹²⁰^ORCID,Munari U²¹,Orio M²²²³^ORCID,Panurach T¹²⁴^ORCID,Shappee B J²⁵^ORCID,Shen K J²⁶^ORCID,Sokoloski J L²⁷,Urquhart R¹,Walter F M²⁸^ORCID

Affiliation:

1. Department of Physics and Astronomy, Center for Data Intensive and Time Domain Astronomy, Michigan State University , East Lansing, MI 48824 , USA

2. Department of Astronomy, University of Illinois at Urbana-Champaign , 1002 W. Green Street, Urbana, IL 61801 , USA

3. Sternberg Astronomical Institute, Moscow State University , Universitetskii pr. 13, 119992 Moscow , Russia

4. Department of Astronomy & Astrophysics, University of California , 1156 High St, Santa Cruz, CA 95064 , USA

5. Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218 , USA

6. South African Astronomical Observatory , P. O. Box 9, 7935 Observatory , South Africa

7. Department of Astronomy, University of Cape Town , Private Bag X3, Rondebosch 7701 , South Africa

8. Centro de Estudios de Física del Cosmos de Aragón , Plaza San Juan 1, E-44001, Teruel , Spain

9. UK Astronomy Technology Centre, Royal Observatory , Blackford Hill, Edinburgh, EH9 3HJ , UK

10. DARK, Niels Bohr Institute, University of Copenhagen , Jagtvej 128, DK-2200 Copenhagen Ø , Denmark

11. National Radio Astronomy Observatory , P. O. Box O, Socorro, NM 87801 , USA

12. Southern African Large Telescope Foundation , P. O. Box 9, Observatory 7935 , South Africa

13. Special Astrophysical Observatory , Nizhnij Arkhyz, Karachai-Circassia 369167 , Russia

14. Department of Physics and Columbia Astrophysics Laboratory, Columbia University , New York, NY 10027 , USA

15. Center for Computational Astrophysics, Flatiron Institute , 162 5th Avenue, New York, NY 10010 , USA

16. Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences , Bartycka 18, PL 00-716 Warsaw , Poland

17. INAF − Osservatorio Astronomico di Trieste , Via G. B. Tiepolo 11, I-34143 Trieste TS , Italy

18. Institute of Fundamental Physics of the Universe , Via Beirut, 2, I-34151 Trieste TS , Italy

19. CRESST and X-ray Astrophysics Laboratory, NASA/GSFC , Greenbelt, MD 20771 , USA

20. Department of Physics, University of Maryland , Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 , USA

21. INAF Astronomical Observatory of Padova , I-36012 Asiago (VI) , Italy

22. INAF – Osservatorio di Padova , vicolo dell’Osservatorio 5, I-35122 Padova , Italy

23. Department of Astronomy, University of Wisconsin , 475 N. Charter St., Madison, WI 53704 , USA

24. Department of Physics, Center for Materials Research, Norfolk State University , Norfolk, VA 23504 , USA

25. Institute for Astronomy, University of Hawai’i , 2680 Woodlawn Drive, Honolulu, HI 96822 , USA

26. Department of Astronomy and Theoretical Astrophysics Center, University of California , Berkeley, CA 94720 , USA

27. Columbia Astrophysics Laboratory and Department of Physics, Columbia University , New York, NY 10027 , USA

28. Department of Physics & Astronomy, Stony Brook University , Stony Brook, NY 11794-3800 , USA

Abstract

ABSTRACT The optical spectra of novae are characterized by emission lines from the hydrogen Balmer series and either Fe ii or He/N, leading to their traditional classification into two spectral classes: ‘Fe ii’ and ‘He/N’. For decades, the origins of these spectral features were discussed in the literature in the contexts of different bodies of gas or changes in the opacity of the ejecta, particularly associated with studies by R. E. Williams and S. N. Shore. Here, we revisit these major studies with dedicated, modern data sets, covering the evolution of several novae from early rise to peak all the way to the nebular phase. Our data confirm previous suggestions in the literature that the ‘Fe ii’ and ‘He/N’ spectral classes are phases in the spectroscopic evolution of novae driven primarily by changes in the opacity, ionization, and density of the ejecta, and most if not all novae go through at least three spectroscopic phases as their eruptions evolve: an early He/N (phase 1; observed during the early rise to visible peak and characterized by P Cygni lines of He i and N ii/iii), then an Fe ii (phase 2; observed near visible peak and characterized by P Cygni lines of Fe ii and O i), and then a later He/N (phase 3; observed during the decline and characterized by emission lines of He i/ii, N ii/iii), before entering the nebular phase. This spectral evolution seems to be ubiquitous across novae, regardless of their speed class; however the duration of each of these phases differs based on the speed class of the nova.

Publisher

Oxford University Press (OUP)

Subject

Space and Planetary Science,Astronomy and Astrophysics

Link

https://academic.oup.com/mnras/advance-article-pdf/doi/10.1093/mnras/stad3342/53050152/stad3342.pdf

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