University of Leicester
Browse
Evans.pdf (1.24 MB)

Infrared spectroscopy of the 2022 eruption of the recurrent nova U Sco

Download (1.24 MB)
journal contribution
posted on 2023-08-09, 10:03 authored by A Evans, DPK Banerjee, CE Woodward, TR Geballe, RD Gehrz, KL Page, S Starrfield
We present near-infrared spectroscopy of the 2022 eruption of the recurrent nova U Sco, over the period from 5.4 to 45.6 d after outburst. This is the most intensive infrared study of this nova. Our observations started early after the outburst and extended almost to the end of the 'Super Soft' X-ray phase. A major find is the presence of coronal lines from day 9.41, one of the earliest appearances of these in any nova, classical, or recurrent. The temperature of the coronal gas is 7 × 105 K. There is also evidence for the presence of much cooler (≲2.5 × 104 K) gas. Remarkable changes are seen in the He I 1.083 μ m line, the strength of which declines, then recovers, in anticorrelation with the X-ray behaviour. We conclude that shock ionization is the dominant excitation mechanism for the coronal line emission. There is evidence in the infrared spectra for the presence of black body emission at ∼20 000 K, which we tentatively identify with the irradiated secondary, and for free-free/free-bound emission. For the previously determined binary inclination of 82.7◦, the implied ejection velocities are as high as 22 000 km s−1. These velocities appear unprecedented in nova outflows, and are comparable to those seen in supernovae, thereby marking U Sco as a truly remarkable object.

History

Author affiliation

School of Physics & Astronomy, University of Leicester

Version

  • VoR (Version of Record)

Published in

Monthly Notices of the Royal Astronomical Society

Volume

522

Issue

4

Pagination

4841 - 4851

Publisher

Oxford University Press (OUP)

issn

0035-8711

eissn

1365-2966

Copyright date

2023

Available date

2023-08-09

Language

en

Usage metrics

    University of Leicester Publications

    Categories

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC