Transiting Exoplanet Survey Satellite (TESS) Observations of Flares and Quasi-Periodic Pulsations from Low-Mass Stars and Potential Impact on Exoplanets

Ramsay, Gavin; Kolotkov, Dmitrii Y.; Doyle, J. G.; Doyle, Lauren

doi:10.1007/s11207-021-01899-x

Cited by 21 publications

(13 citation statements)

References 75 publications

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“…For L = 700 Mm, r min = 30 Mm, ρ 0 = 3 × 10 −12 g cm −3 , B ||0 = 30 G, typical for stellar coronae (see e.g. Monsignori Fossi et al 1996;Mitra-Kraev et al 2005;Mathioudakis et al 2006;Kuznetsov & Kolotkov 2021;Ramsay et al 2021), and a broad range of electric currents I 0 = 10 8 -10 12 A (see e.g. Khodachenko et al 2009), we obtain P about 10 4 s. This value is consistent with the observed period.…”

Section: Discussionsupporting

confidence: 88%

Multi-wavelength quasi-periodic pulsations in a stellar superflare

Kolotkov,

Nakariakov,

Holt

et al. 2021

Preprint

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We present the first multi-wavelength simultaneous detection of QPP in a superflare (more than a thousand times stronger than known solar flares) on a cool star, in soft X-rays (SXR, with XMM-Newton) and white light (WL, with Kepler). It allowed for the first-ever analysis of oscillatory processes in a stellar flare simultaneously in thermal and non-thermal emissions, conventionally considered to come from the corona and chromosphere of the star, respectively. The observed QPP have periods 1.5 ± 0.15 hours (SXR) and 3 ± 0.6 hours (WL), and correlate well with each other. The unique relationship between the observed parameters of QPP in SXR and WL allowed us to link them with oscillations of the electric current in the flare loop, which directly affect the dynamics of non-thermal electrons and indirectly (via Ohmic heating) the thermal plasma. These findings could be considered in favour of the equivalent LCR-contour model of a flare loop, at least in the extreme conditions of a stellar superflare.

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Section: Discussionsupporting

confidence: 88%

Multi-wavelength quasi-periodic pulsations in a stellar superflare

Kolotkov,

Nakariakov,

Holt

et al. 2021

Preprint

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“…The term describes a series of reconnection events associated with periodic changes in the magnetic connectivity and topology of the field, the periodicity of which is derived from the relaxation of a perturbed field from a finite, aperiodic driver. As a mechanism, oscillatory reconnection has been proposed as a possible driving force behind quasi-periodic pulsations (QPPs) of solar flares (e.g., Kupriyanova et al 2016;Van Doorsselaere et al 2016;Pugh et al 2017;Yuan et al 2019;Hayes et al 2020;Li et al 2020aLi et al , 2020bLi et al , 2021Clarke et al 2021) and stellar flares (e.g., Broomhall et al 2019;Guarcello et al 2019;Jackman et al 2019;Notsu et al 2019;Vida et al 2019;Mancuso et al 2020;Ramsay et al 2021). Detailed reviews of a wide variety of suggested mechanism(s) behind QPPs can be found in McLaughlin et al (2018), Kupriyanova et al (2020), and Zimovets et al (2021).…”

Section: Introductionmentioning

confidence: 99%

“…Kupriyanova et al 2016;Van Doorsselaere et al 2016;Pugh et al 2017;Yuan et al 2019;Hayes et al 2020;Li et al 2020aLi et al ,b, 2021Clarke et al 2021) and stellar flares (e.g. Broomhall et al 2019;Guarcello et al 2019;Jackman et al 2019;Notsu et al 2019;Vida et al 2019;Mancuso et al 2020;Ramsay et al 2021). Detailed reviews of a wide variety of suggested mechanism(s) behind QPPs can be found in McLaughlin et al (2018), Kupriyanova et al (2020), and Zimovets et al (2021).…”

Section: Introductionmentioning

confidence: 99%

The Independence of Oscillatory Reconnection Periodicity from the Initial Pulse

Karampelas

McLaughlin²,

Botha³

et al. 2022

ApJ

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Oscillatory reconnection can manifest through the interaction between the ubiquitous MHD waves and omnipresent null points in the solar atmosphere and is characterized by an inherent periodicity. In the current study, we focus on the relationship between the period of oscillatory reconnection and the strength of the wave pulse initially perturbing the null point, in a hot coronal plasma. We use the PLUTO code to solve the fully compressive, resistive MHD equations for a 2D magnetic X-point. Using wave pulses with a wide range of amplitudes, we perform a parameter study to obtain values for the period, considering the presence and absence of anisotropic thermal conduction separately. In both cases, we find that the resulting period is independent of the strength of the initial perturbation. The addition of anisotropic thermal conduction only leads to an increase in the mean value for the period, in agreement with our previous study. We also consider a different type of initial driver and we obtain an oscillation period matching the independent trend previously mentioned. Thus, we report for the first time on the independence between the type and strength of the initializing wave pulse and the resulting period of oscillatory reconnection in a hot coronal plasma. This makes oscillatory reconnection a promising mechanism to be used within the context of coronal seismology.

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“…Since the stars have a range in brightness and distance, they are not equally sensitive to flares < 10 34 erg. However, the rate of flares with energies >10 34 erg place CD-56 1032A and TIC 55497266 in the region where high energy flares may deplete the Ozone layer of any Earth-like planet in the host stars habitable zone (see for example Günther et al 2020;Ramsay et al 2021).…”

Section: Transiting Exoplanet Survey Satellite (Tess)mentioning

confidence: 99%

“…High rotation rates (< 10 days) and convective cores, particularly in late type M dwarfs (> M4), generate complex powerful global magnetic fields with large stable star spots (Kochukhov 2021;Günther et al 2020). Hence these stars can regularly produce flares with energies in excess of ∼ 10 32 ergs up to ∼ 10 35 ergs and superflares with energies surpassing 10 36 ergs (Osten et al 2010;Davenport 2016;Schmidt et al 2019;Ramsay et al 2021). It is thought these stellar flares occur via the same magnetic reconnection process as observed in solar flares, and this process also leads to the expulsion of plasma into the stellar atmosphere, known as a stellar coronal mass ejection (CME).…”

Section: Introductionmentioning

confidence: 99%

Searching for stellar flares from low mass stars using ASKAP and TESS

Rigney¹,

Ramsay²,

Carley³

et al. 2022

Preprint

Self Cite

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Solar radio emission at low frequencies (<1 GHz) can provide valuable information on processes driving flares and coronal mass ejections (CMEs). Radio emission has been detected from active M dwarf stars, suggestive of much higher levels of activity than previously thought. Observations of active M dwarfs at low frequencies can provide information on the emission mechanism for high energy flares and possible stellar CMEs. Here, we conducted two observations with the Australian Square Kilometre Pathfinder Telescope (ASKAP) totalling 26 hours and scheduled to overlap with the Transiting Exoplanet Survey Satellite (TESS) Sector 36 field, utilising the wide fields of view of both telescopes to search for multiple M dwarfs. We detected variable radio emission in Stokes I centered at 888 MHz from four known active M dwarfs. Two of these sources were also detected with Stokes V circular polarisation. When examining the detected radio emission characteristics, we were not able distinguish between the models for either electron cyclotron maser or gyrosynchrotron emission. These detections add to the growing number of M dwarfs observed with variable low frequency emission.

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Transiting Exoplanet Survey Satellite (TESS) Observations of Flares and Quasi-Periodic Pulsations from Low-Mass Stars and Potential Impact on Exoplanets

Cited by 21 publications

References 75 publications

Multi-wavelength quasi-periodic pulsations in a stellar superflare

Multi-wavelength quasi-periodic pulsations in a stellar superflare

The Independence of Oscillatory Reconnection Periodicity from the Initial Pulse

Searching for stellar flares from low mass stars using ASKAP and TESS

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