From X-ray dips to eclipse

Witnessing disk reformation in the recurrent nova U Sco

J. U. Ness, B. E. Schaefer, A. Dobrotka, A. Sadowski, J. J. Drake, R. Barnard, A. Talavera, R. Gonzalez-Riestra, K. L. Page, M. Hernanz, G. Sala, Sumner Starrfield

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

The tenth recorded outburst of the recurrent eclipsing nova USco was observed simultaneously in X-ray, UV, and optical by XMM-Newton on days 22.9 and 34.9 after the outburst. Two full passages of the companion in front of the nova ejecta were observed, as was the reformation of the accretion disk. On day 22.9, we observed smooth eclipses in UV and optical but deep dips in the X-ray light curve that disappeared by day 34.9, yielding clean eclipses in all bands. X-ray dips can be caused by clumpy absorbing material that intersects the line of sight while moving along highly elliptical trajectories. Cold material from the companion could explain the absence of dips in UV and optical light. The disappearance of X-ray dips before day 34.9 implies significant progress in the formation of the disk. The X-ray spectra contain photospheric continuum emission plus strong emission lines, but no clear absorption lines. Both continuum and emission lines in the X-ray spectra indicate a temperature increase from day 22.9 to day 34.9. We find clear evidence in the spectra and light curves for Thompson scattering of the photospheric emission from the white dwarf. Photospheric absorption lines can be smeared out during scattering in a plasma of fast electrons. We also find spectral signatures of resonant line scattering that lead to the observation of the strong emission lines. Their dominance could be a general phenomenon in high-inclination systems such as Cal87.

Original languageEnglish (US)
Article number43
JournalAstrophysical Journal
Volume745
Issue number1
DOIs
StatePublished - Jan 20 2012

Fingerprint

eclipses
dip
x rays
scattering
outburst
light curve
general phenomena
continuums
spectral signatures
ejecta
XMM-Newton telescope
accretion disks
newton
line of sight
inclination
trajectory
accretion
trajectories
plasma
electron

Keywords

  • novae, cataclysmic variables
  • stars: individual (U Sco)

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

From X-ray dips to eclipse : Witnessing disk reformation in the recurrent nova U Sco. / Ness, J. U.; Schaefer, B. E.; Dobrotka, A.; Sadowski, A.; Drake, J. J.; Barnard, R.; Talavera, A.; Gonzalez-Riestra, R.; Page, K. L.; Hernanz, M.; Sala, G.; Starrfield, Sumner.

In: Astrophysical Journal, Vol. 745, No. 1, 43, 20.01.2012.

Research output: Contribution to journalArticle

Ness, JU, Schaefer, BE, Dobrotka, A, Sadowski, A, Drake, JJ, Barnard, R, Talavera, A, Gonzalez-Riestra, R, Page, KL, Hernanz, M, Sala, G & Starrfield, S 2012, 'From X-ray dips to eclipse: Witnessing disk reformation in the recurrent nova U Sco', Astrophysical Journal, vol. 745, no. 1, 43. https://doi.org/10.1088/0004-637X/745/1/43
Ness JU, Schaefer BE, Dobrotka A, Sadowski A, Drake JJ, Barnard R et al. From X-ray dips to eclipse: Witnessing disk reformation in the recurrent nova U Sco. Astrophysical Journal. 2012 Jan 20;745(1). 43. https://doi.org/10.1088/0004-637X/745/1/43
Ness, J. U. ; Schaefer, B. E. ; Dobrotka, A. ; Sadowski, A. ; Drake, J. J. ; Barnard, R. ; Talavera, A. ; Gonzalez-Riestra, R. ; Page, K. L. ; Hernanz, M. ; Sala, G. ; Starrfield, Sumner. / From X-ray dips to eclipse : Witnessing disk reformation in the recurrent nova U Sco. In: Astrophysical Journal. 2012 ; Vol. 745, No. 1.
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