Variability of young stars: Determination of rotational periods of weak‐line T Tauri stars in the Cepheus‐Cassiopeia star‐forming region

Koeltzsch, A.; Mugrauer, M.; Raetz, St.; Schmidt, T. O. B.; Roell, T.; Eisenbeiss, T.; Hohle, M. M.; Vaňko, M.; Ginski, C.; Marka, C.; Moualla, M.; Schreyer, K.; Broeg, C.; Neuhäuser, R.

doi:10.1002/asna.200911204

Cited by 3 publications

(1 citation statement)

References 11 publications

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“…However, for planets less massive than Hot Jupiters, the radial velocity method was found to be severely hampered by the inherent stellar variability and radial velocity jitter of the young host stars (Saar & Donahue 1997;Paulson et al 2004;Brems et al 2019). Recent methods such as those employed by Korhonen et al (2015); Rajpaul et al (2015) have pushed this limit down to approximately Neptune-sized planets for some solar-like stars, however Earth-sized planets are currently still beyond the capabilities of these methods for young active stars.…”

Section: Introductionmentioning

confidence: 99%

A search for young exoplanets in Sectors 1-5 of the TESS Full-Frame-Images

Battley,

Pollacco,

Armstrong

2020

Preprint

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Young (<1Gyr) exoplanets represent a critically important area of exoplanet research, as they offer the opportunity to learn about the formation and early dynamic history of exoplanetary systems. However, finding young exoplanets is significantly complicated by the fast rotation and complex activity of their young host stars, which are often not well handled by state-of-the-art automatic pipelines. This work presents an alternative LOWESS-based pipeline focused specifically on detrending young stellar light-curves from the 30min-cadence Full Frame Images (FFIs) produced by the Transiting Exoplanet Survey Satellite (TESS), and includes improvements such as automatic peak-cutting of stellar variability and interpolation over masked transits to improve periodogram visibility and returned transit shapes. This work presents the details of the developed pipeline, along with initial results from its application to young stars within stellar associations in sectors 1-5 of the TESS data. While no new exoplanet candidate signals were found in this work, interesting results included the recovery of all known 2min TOIs around young stars in sectors 1-5 from 30min data alone, the recovery of the young exoplanet DS Tuc Ab, a number of young eclipsing binaries and a wide array of interesting rotation. A sensitivity analysis was also undertaken for each star, showing how recovery of injected planets varied with both depth and period for each individual target. Challenges for future searches for young exoplanets are discussed, the largest being stellar rotation with periods less than 1 day and a lack of a large sample of confirmed young stars.

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Section: Introductionmentioning

confidence: 99%

A search for young exoplanets in Sectors 1-5 of the TESS Full-Frame-Images

Battley,

Pollacco,

Armstrong

2020

Preprint

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A search for young exoplanets in Sectors 1–5 of the TESS full-frame images

Battley

Pollacco

2020

Monthly Notices of the Royal Astronomical Society

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Young (<1 Gyr) exoplanets represent a critically important area of exoplanet research, as they offer the opportunity to learn about the formation and early dynamic history of exoplanetary systems. However, finding young exoplanets is significantly complicated by the fast rotation and complex activity of their young host stars, which are often not well handled by state-of-the-art automatic pipelines. This work presents an alternative LOWESS-based pipeline focused specifically on detrending young stellar light curves from the 30-min cadence full-frame images produced by the Transiting Exoplanet Survey Satellite (TESS), and includes improvements such as automatic peak cutting of stellar variability and interpolation over masked transits to improve periodogram visibility and returned transit shapes. This work presents the details of the developed pipeline, along with initial results from its application to young stars within stellar associations in Sectors 1–5 of the TESS data. While no new exoplanet candidate signals were found in this work, interesting results included the recovery of all known 2-min TOIs around young stars in Sectors 1–5 from 30-min data alone, the recovery of the young exoplanet DS Tuc Ab, a number of young eclipsing binaries and a wide array of interesting rotation. A sensitivity analysis was also undertaken for each star, showing how the recovery of injected planets varied with both depth and period for each individual target. Challenges for future searches for young exoplanets are discussed, the largest being stellar rotation with periods less than 1 d and a lack of a large sample of confirmed young stars.

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The verification of periodicity with the use of recurrent neural networks

Miller,

Lucas,

Sun

et al. 2024

RAS Techniques and Instruments

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The ability to automatically and robustly self-verify periodicity present in time-series astronomical data is becoming more important as data sets rapidly increase in size. The age of large astronomical surveys has rendered manual inspection of time-series data less practical. Previous efforts in generating a false alarm probability to verify the periodicity of stars have been aimed towards the analysis of a constructed periodogram. However, these methods feature correlations with features that do not pertain to periodicity, such as light curve shape, slow trends and stochastic variability. The common assumption that photometric errors are Gaussian and well determined is also a limitation of analytic methods. We present a novel machine learning based technique which directly analyses the phase folded light curve for its false alarm probability. We show that the results of this method are largely insensitive to the shape of the light curve, and we establish minimum values for the number of data points and the amplitude to noise ratio.

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Variability of young stars: Determination of rotational periods of weak‐line T Tauri stars in the Cepheus‐Cassiopeia star‐forming region

Abstract: We report on observation and determination of rotational periods of ten weak-line T Tauri

Cited by 3 publications

References 11 publications

A search for young exoplanets in Sectors 1-5 of the TESS Full-Frame-Images

A search for young exoplanets in Sectors 1-5 of the TESS Full-Frame-Images

A search for young exoplanets in Sectors 1–5 of the TESS full-frame images

The verification of periodicity with the use of recurrent neural networks

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