Simultaneous detection of a large flare in the X-ray and optical regions on the RS CVn-type star II Peg

Doyle, J. G.; Kellett, B. J.; Byrne, P. B.; Avgoloupis, S.; Mavridis, L. N.; Seiradakis, J. H.; Bromage, G. E.; Tsuru, Takeshi Go; Makishima, Kazuo; McHardy, I. M.

doi:10.1093/mnras/248.3.503

Cited by 39 publications

(23 citation statements)

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“…Adding the energies for all the observed chromospheric lines during each flare, we obtained a total flare energy of 1.3 × 10 34 erg for the first flare and 5.5 × 10 34 erg for the second flare, integrating over a period of ∼7.3 and ∼5.5 hours respectively. These values for the energy released are comparable to other RS CVn flares (Doyle et al 1991;Foing et al 1994). …”

Section: Energy Releasedsupporting

confidence: 86%

Simultaneous optical and X-ray observations of flares and rotational modulation on the RS CVn binary HR 1099 (V711 Tau) from the MUSICOS 1998 campaign

García-Álvarez¹,

Foing²,

Montes³

et al. 2002

A&A

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Abstract. We Maps of the distribution of the spotted regions on the photosphere of the binary components were derived using the Maximum Entropy and Tikhonov photometric regularization criteria. Rotational modulation was observed in Hα and He  D 3 in anti-correlation with the photometric light curves. Both flares occurred at the same binary phase (0.85), suggesting that these events took place in the same active region. Simultaneous X-ray observations, performed by ASM on board RXTE, show several flare-like events, some of which correlate well with the observed optical flares. Rotational modulation in the X-ray light curve has been detected with minimum flux when the less active G5 V star was in front. A possible periodicity in the X-ray flare-like events was also found.

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Section: Energy Releasedsupporting

confidence: 86%

Simultaneous optical and X-ray observations of flares and rotational modulation on the RS CVn binary HR 1099 (V711 Tau) from the MUSICOS 1998 campaign

García-Álvarez¹,

Foing²,

Montes³

et al. 2002

A&A

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“…II Peg is also known to produce powerful X-ray flares, and an analysis of a flare having triggered the Burst Alert Telescope onboard SWIFT by Osten et al (2007) yielded a total energy loss of about 6 ×10 36 erg at energies above 10 eV. Earlier, a very large flare on II Peg had been observed using the GINGA satellite, but the various flare phases were not covered completely in the different wavebands, so that the estimates of the overall energy release remained somewhat uncertain (Doyle et al 1991).…”

Section: Discussionmentioning

confidence: 99%

Superflares on AB Doradus observed with TESS

Schmitt

Ioannidis

Robrade

et al. 2019

A&A

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We present short-cadence data of the ultra-active star AB Dor measured by the Transiting Exoplanet Survey Satellite (TESS). In the TESS light curves of AB Dor, we found numerous flare events in addition to time-variable rotational modulation with an amplitude of up to 7%. We identified eight superflares (releasing more than 1034 erg) and studied their morphologies and energetics. We compared these flares to both the most energetic solar flare seen in total solar irradiance measurements as well as to a very energetic flare on AB Dor observed by XMM-Newton, the superflare nature of which we also demonstrate. The total energy of both the solar flare and the event on AB Dor emitted in the optical exceed their respective X-ray outputs possibly by an order of magnitude, suggesting that the dominant energy loss of such flares actually occurs at optical wavelengths. Superflares are found to take place on AB Dor at a rate of about one per week, and due to the star’s proximity and brightness can be studied in excruciating detail. Thus the TESS data offer a superb possibility to study the frequency and energetics of superflare events for stars in the solar neighborhood and at large.

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“…Observations of stellar flares with the Ginga satellite have detected X-ray emission out to 20 keV in a few large flares. Pan et al (1997) found peak temperatures near 100 MK and and emission measures near 10 54 cm −3 from a large flare identified with the M dwarf star EQ1839.6+8002, and flare peak temperatures from 60-80 MK were determined for flares on the active binaries Algol, UX Ari, and II Peg (Stern et al 1992;Tsuru et al 1989;Doyle et al 1991).…”

Section: Comparison To Other Superflaresmentioning

confidence: 98%

THE MOUSE THAT ROARED: A SUPERFLARE FROM THE dMe FLARE STAR EV LAC DETECTED BYSWIFTAND KONUS-WIND

Osten

Godet

Drake

et al. 2010

ApJ

103

114

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We report on a large stellar flare from the nearby dMe flare star EV Lac observed by the Swift and Konus-Wind satellites and the Liverpool Telescope. It is the first large stellar flare from a dMe flare star to result in a Swift trigger based on its hard X-ray intensity. Its peak f X from 0.3-100 keV of 5.3×10 −8 erg cm −2 s −1 is nearly 7000 times larger than the star's quiescent coronal flux, and the change in magnitude in the white filter is ≥4.7. This flare also caused a transient increase in EV Lac's bolometric luminosity (L bol ) during the early stages of the flare, with a peak estimated L X /L bol ∼3.1. We apply flare loop hydrodynamic modeling to the plasma parameter temporal changes to derive a loop semi-length of l/R ⋆ = 0.37±0.07. The soft X-ray spectrum of the flare reveals evidence of iron Kα emission at 6.4 keV. We model the Kα emission as fluorescence from the hot flare source irradiating the photospheric iron, and derive loop heights of h/R ⋆ =0.1, consistent within factors of a few with the heights inferred from hydrodynamic modeling. The Kα emission feature shows variability on time scales of ∼200 s which is difficult to interpret using the pure fluorescence hypothesis. We examine Kα emission produced by collisional ionization from accelerated particles, and find parameter values for the spectrum of accelerated particles which can accommodate the increased amount of Kα flux and the lack of observed nonthermal emission in the 20-50 keV spectral region.

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Simultaneous detection of a large flare in the X-ray and optical regions on the RS CVn-type star II Peg

Cited by 39 publications

References 0 publications

Simultaneous optical and X-ray observations of flares and rotational modulation on the RS CVn binary HR 1099 (V711 Tau) from the MUSICOS 1998 campaign

Simultaneous optical and X-ray observations of flares and rotational modulation on the RS CVn binary HR 1099 (V711 Tau) from the MUSICOS 1998 campaign

Superflares on AB Doradus observed with TESS

THE MOUSE THAT ROARED: A SUPERFLARE FROM THE dMe FLARE STAR EV LAC DETECTED BYSWIFTAND KONUS-WIND

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