Fast photometric variability of very low mass stars in IC 348: detection of superflare in an M dwarf

Ghosh, Samrat; Mondal, Soumen; Dutta, Somnath; Das, Ramkrishna; Joshi, Santosh; Lata, Sneh; Khata, Dhrimadri; Panja, Alik

doi:10.1093/mnras/staa3574

Cited by 3 publications

(3 citation statements)

References 133 publications

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“…Frames per bin (bin size) dwarfs and would rotate in and out of view in much the same way as the cloud features of lower mass objects (e.g. Barnes et al 2002;Frasca et al 2009;Scholz et al 2009;Goulding et al 2012;Ghosh et al 2021;Johnson et al 2021). The properties of such variability can be highly dependent on the spot distribution and fractional spot coverage of a given object; some M-dwarfs have a very high coverage with multiple starspots covering as much as 20-50% of their fractional surface area inhomogeneously (e.g.…”

Section: Variability Interpretationmentioning

confidence: 99%

Measuring the variability of directly imaged exoplanets using vector Apodizing Phase Plates combined with ground-based differential spectrophotometry

Sutlieff¹,

Birkby²,

Stone³

et al. 2023

Preprint

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Clouds and other features in exoplanet and brown dwarf atmospheres cause variations in brightness as they rotate in and out of view. Ground-based instruments reach the high contrasts and small inner working angles needed to monitor these faint companions, but their small fieldsof-view lack simultaneous photometric references to correct for non-astrophysical variations. We present a novel approach for making ground-based light curves of directly imaged companions using high-cadence differential spectrophotometric monitoring, where the simultaneous reference is provided by a double-grating 360°vector Apodizing Phase Plate (dgvAPP360) coronagraph. The dgvAPP360 enables high-contrast companion detections without blocking the host star, allowing it to be used as a simultaneous reference. To further reduce systematic noise, we emulate exoplanet transmission spectroscopy, where the light is spectrally-dispersed and then recombined into white-light flux. We do this by combining the dgvAPP360 with the infrared ALES integral field spectrograph on the Large Binocular Telescope Interferometer. To demonstrate, we observed the red companion HD 1160 B (separation ∼780 mas) for one night, and detect 8.8% semi-amplitude sinusoidal variability with a ∼3.24 h period in its detrended white-light curve. We achieve the greatest precision in ground-based high-contrast imaging light curves of sub-arcsecond companions to date, reaching 3.7% precision per 18-minute bin. Individual wavelength channels spanning 3.59-3.99 µm further show tentative evidence of increasing variability with wavelength. We find no evidence yet of a systematic noise floor, hence additional observations can further improve the precision. This is therefore a promising avenue for future work aiming to map storms or find transiting exomoons around giant exoplanets.

show abstract

Section: Variability Interpretationmentioning

confidence: 99%

Measuring the variability of directly imaged exoplanets using vector Apodizing Phase Plates combined with ground-based differential spectrophotometry

Sutlieff¹,

Birkby²,

Stone³

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…Such superflare activity depends on the size and distribution of the star spots. A minor disturbance in chromosphere activity can enhance the flare energy to that of the superflare range without any other excitation mechanism (Yang et al 2017;Ghosh et al 2021). Furthermore, it is interesting to note that the high-energy particles and photons from such superflare events play an important role in the habitability of nearby planets, if any (Airapetian et al 2020;Aizawa et al 2022).…”

Section: Flare Events In Bdsmentioning

confidence: 99%

“…They provided the optical light curves of young cluster members (Cody et al 2017;Ansdell et al 2018;Cody & Hillenbrand 2018;Rebull et al 2018). Several similar kinds of studies have been performed using ground-based telescopes to probe the characteristics of BDs in young star-forming regions, e.g., Taurus (Luhman et al 2009;Esplin & Luhman 2017), IC348 (Ghosh et al 2021), σ Ori (Caballero et al 2004), and Upper Scorpius (Cody & Hillenbrand 2018;Lodieu et al 2018). In recent years, the Transiting Exoplanet Survey Satellite (TESS; Ricker et al 2015) has also provided highcadence, high-precision light curves of young objects, covering many young clusters, including the extended Taurus starforming region.…”

Section: Introductionmentioning

confidence: 99%

TESS Photometric Variability of Young Brown Dwarfs in the Taurus Star-forming Region

Kumbhakar,

Mondal,

Ghosh

et al. 2023

ApJ

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We present a comprehensive analysis of TESS high-quality light curves from sectors 43 and 44 of a few samples of young (∼2–3 Myr) brown dwarfs in the Taurus molecular cloud. They are well characterized and bona fide members of Taurus. We aim to search for the fast rotations of brown dwarfs and to picturize their dynamic atmosphere and surface features. Out of 11 young BDs, we found that 72% are periodic, in the period range of 1–7 days; among them, three BDs have periods <1.5 day and the period of one object is estimated for the first time. The sinusoidal periodic variations are related to a large spot or group of small spots corotating with the objects. Interestingly, we have detected four flare events in three young BDs, with one object, MHO 4, showing two flares in two different sectors. From the flared light curves, we have estimated the total bolometric flared energy in a range of 1035–1036 erg, which is close to the superflare energy range (≥1034 erg). To produce such kinds of superflare events, we have calculated the required magnetic field strength, which comes out at the order of a few kilogauss. Such superflares have a strong effect on the habitability of planets around M dwarfs.

show abstract

Measuring the variability of directly imaged exoplanets using vector Apodizing Phase Plates combined with ground-based differential spectrophotometry

Sutlieff

Birkby

Stone

et al. 2023

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Clouds and other features in exoplanet and brown dwarf atmospheres cause variations in brightness as they rotate in and out of view. Ground-based instruments reach the high contrasts and small inner working angles needed to monitor these faint companions, but their small fields-of-view lack simultaneous photometric references to correct for non-astrophysical variations. We present a novel approach for making ground-based light curves of directly imaged companions using high-cadence differential spectrophotometric monitoring, where the simultaneous reference is provided by a double-grating 360° vector Apodizing Phase Plate (dgvAPP360) coronagraph. The dgvAPP360 enables high-contrast companion detections without blocking the host star, allowing it to be used as a simultaneous reference. To further reduce systematic noise, we emulate exoplanet transmission spectroscopy, where the light is spectrally-dispersed and then recombined into white-light flux. We do this by combining the dgvAPP360 with the infrared ALES integral field spectrograph on the Large Binocular Telescope Interferometer. To demonstrate, we observed the red companion HD 1160 B (separation ∼780 mas) for one night, and detect $8.8\%$ semi-amplitude sinusoidal variability with a ∼3.24 h period in its detrended white-light curve. We achieve the greatest precision in ground-based high-contrast imaging light curves of sub-arcsecond companions to date, reaching $3.7\%$ precision per 18-minute bin. Individual wavelength channels spanning 3.59-3.99 µm further show tentative evidence of increasing variability with wavelength. We find no evidence yet of a systematic noise floor, hence additional observations can further improve the precision. This is therefore a promising avenue for future work aiming to map storms or find transiting exomoons around giant exoplanets.

show abstract

Fast photometric variability of very low mass stars in IC 348: detection of superflare in an M dwarf

Cited by 3 publications

References 133 publications

Measuring the variability of directly imaged exoplanets using vector Apodizing Phase Plates combined with ground-based differential spectrophotometry

Measuring the variability of directly imaged exoplanets using vector Apodizing Phase Plates combined with ground-based differential spectrophotometry

TESS Photometric Variability of Young Brown Dwarfs in the Taurus Star-forming Region

Measuring the variability of directly imaged exoplanets using vector Apodizing Phase Plates combined with ground-based differential spectrophotometry

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