Optical flares and flaring oscillations on the M-type eclipsing binary CU Cancri

Qian, S.‐B.; Zhang, J.; Zhu, L.-Y.; Liu, L.; Liao, Wuping; Zhao, En-Guang; He, Jiajia; Li, L.-J.; Li, K.; Dai, Zhenwen

doi:10.1111/j.1365-2966.2012.21157.x

Cited by 41 publications

(31 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There are very few detailed studies of optical flares on UFRs due to constraints in their detection limit, detection timing, and very less flare frequency. Recent studies on optical flares done with ground-based observatories on DV Psc (Pi et al, 2014) and CU Cnc (Qian et al, 2012) show flare frequency of ∼2 flares per day and ∼1 flare per day, respectively, which is similar to that for LO Peg. However, several other studies done with Kepler satellite (Hawley et al, 2014;Lurie et al, 2015) on M dwarfs reveal that flare frequency varies over a wide range of ∼1 flare per month to ∼10 flares per day.…”

Section: Discussionmentioning

confidence: 62%

LO Peg: surface differential rotation, flares, and spot-topographic evolution

Karmakar

Pandey

Саванов

et al. 2016

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

Using the wealth of ∼24 yr multiband data, we present an in-depth study of the starspot cycles, surface differential rotations (SDR), optical flares, evolution of star-spot distributions, and coronal activities on the surface of young, single, main-sequence, ultrafast rotator (UFR) LO Peg. From the long-term V -band photometry, we derive rotational period of LO Peg to be 0.4231 ± 0.0001 d. Using the seasonal variations on the rotational period, the SDR pattern is investigated, and shows a solar-like pattern of SDR. A cyclic pattern with period of ∼2.7 yr appears to be present in rotational period variation. During the observations, 20 optical flares are detected with a flare frequency of ∼1 flare per two days and with flare energy of ∼10 31−34 erg. The surface coverage of cool spots is found to be in the range of ∼9-26 per cent. It appears that the high-and low-latitude spots are interchanging their positions. Quasi-simultaneous observations in X-ray, UV, and optical photometric bands show a signature of an excess of X-ray and UV activities in spotted regions.

show abstract

Section: Discussionmentioning

confidence: 62%

LO Peg: surface differential rotation, flares, and spot-topographic evolution

Karmakar

Pandey

Саванов

et al. 2016

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

show abstract

“…QPP in some stellar flares observed from the ground (Rodono 1974;Zhilyaev et al 2000;Mathioudakis et al 2006;Contadakis et al 2010;Qian et al 2012) have been interpreted as analogous to flare QPP in the Sun, in spite of the very different light emission properties described above. These QPP generally have very short periods and last for several cycles.…”

Section: Resultsmentioning

confidence: 99%

“…There are no recorded observations of QPP in white-light solar flares. The reported optical observations of QPP in stellar flares (Rodono 1974;Zhilyaev et al 2000;Mathioudakis et al 2006;Contadakis et al 2010;Qian et al 2012;Anfinogentov et al 2013), which have periods ranging from a few seconds to tens of minutes, are whole-disk essentially white-light observations. They cannot therefore be directly compared with solar flare QPP.…”

Section: Introductionmentioning

confidence: 99%

Oscillations in stellar superflares

Balona¹,

Broomhall²,

Kosovichev³

et al. 2015

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Two different mechanisms may act to induce quasi-periodic pulsations (QPP) in wholedisk observations of stellar flares. One mechanism may be magneto-hydromagnetic (MHD) forces and other processes acting on flare loops as seen in the Sun. The other mechanism may be forced local acoustic oscillations due to the high-energy particle impulse generated by the flare (known as 'sunquakes' in the Sun). We analyze shortcadence Kepler data of 257 flares in 75 stars to search for QPP in the flare decay branch or post-flare oscillations which may be attributed to either of these two mechanisms. About 18 percent of stellar flares show a distinct bump in the flare decay branch of unknown origin. The bump does not seem to be a highly-damped global oscillation because the periods of the bumps derived from wavelet analysis do not correlate with any stellar parameter. We detected damped oscillations covering several cycles (QPP), in seven flares on five stars. The periods of these oscillations also do not correlate with any stellar parameter, suggesting that these may be a due to flare loop oscillations. We searched for forced global oscillations which might result after a strong flare. To this end, we investigated the behaviour of the amplitudes of solar-like oscillations in eight stars before and after a flare. However, no clear amplitude change could be detected. We also analyzed the amplitudes of the self-excited pulsations in two δ Scuti stars and one γ Doradus star before and after a flare. Again, no clear amplitude changes were found. Our conclusions are that a new process needs to be found to explain the high incidence of bumps in stellar flare light curves, that flare loop oscillations may have been detected in a few stars and that no conclusive evidence exists as yet for flare induced global acoustic oscillations (starquakes).

show abstract

“…Therefore, the photometric solutions with cool-star-spots were adopted. The surface cool-star-spots can make the observed LCs distorted, especially in short waves (U −, B− and V −band), such as CU Cnc (Qian et al 2012). Generally, the coolstar-spots tend to occur around some longitude forming active longitude belts Ç akirli et al 2003).…”

Section: Discussionmentioning

confidence: 99%

NSVS 01286630: a detached binary with a close-in companion

Zhang

Qian

Liao

et al. 2018

Res. Astron. Astrophys.

View full text Add to dashboard Cite

New photometric observations of NSVS 01286630 were performed and two sets of four-color (B, V , R c , I c ) light curves (LCs) were obtained. Using the 2013 version of the Wilson-Devinney (W − D) code, we analyzed these data. The photometric solutions reveal that NSVS 01286630 is an active detached eclipsing binary (EB) with a high orbit inclination(nearly 90 • ). Remarkably, the temperature of the primary component (the hotter star) is higher than the secondary one, but, the value of mass ratio q( M2 M1 ) for NSVS 0128663 is more than 1, which can be explained that the surface of the secondary component of NSVS 01286630is covered with big cool-star-spots. Based on our new CCD mid-eclipse times and the data published until now, the variations of the mid-eclipse times were reanalyzed in detail using a weighted least-squares method. It is discovered that the (O − C) diagram of the system shows a cyclic oscillation with a period of 3.61 yr and an amplitude of 0.001 days. The cyclic variation may be caused by the light travel time effect (LTTE) due to the presence of a third companion, whose mass we calculated is M 3 sin(i 3 )=0.11 M ⊙ . The third body may affect the orbital evolution of the central binary system by transferring the angular momentum.

show abstract

Optical flares and flaring oscillations on the M-type eclipsing binary CU Cancri

Cited by 41 publications

References 42 publications

LO Peg: surface differential rotation, flares, and spot-topographic evolution

LO Peg: surface differential rotation, flares, and spot-topographic evolution

Oscillations in stellar superflares

NSVS 01286630: a detached binary with a close-in companion

Contact Info

Product

Resources

About