A survey for variable young stars with small telescopes – III. Warm spots on the active star V1598 Cyg

Froebrich, D.; Scholz, A.; Eislöffel, J.; Stecklum, B.

doi:10.1093/mnras/staa2275

Cited by 9 publications

(6 citation statements)

References 47 publications

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“…Koen ( 2021b ) furthermore showed that a number of K2 CPV light curves can be modelled by mixtures of large circular cool and hot surface spots. Note in this regard that there is support in the literature for the presence of bright spots on late type stars with magnetic fields (Walkowicz & Ha wle y 2009 ;Rice, Strassmeier & Kopf 2011 ;Donati et al 2014 ;Koen 2015 ;Morris et al 2018 ;Froebrich et al 2020 ).…”

mentioning

confidence: 54%

Multifilter observations of the complex periodic variations in eight pre-main sequence stars

Koen

2022

Monthly Notices of the Royal Astronomical Society

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Follow up time series photometry through various combinations of the BVRCIC filter set is presented for 8 young stars. The complex periodic variability of 7 of the stars was first discovered in TESS photometry, while one star was first observed by K2. The periods of the stars are short – 0.2-0.4 d. Reddening, effective temperatures, and bolometric magnitudes are estimated by fitting spectral energy distributions. The new photometry typically covers several cycles of variability. In some cases photometry was obtained in more than one observing season. All new light curves differ from those obtained from satellite missions, in some cases substantially so. Amplitudes are almost always larger the shorter the effective wavelength of the filter, but the relationship can be weak or non-monotonic. Given that all but one of the stars are in associations older than 10 Myr, it seems unlikely that protoplanetary disks play an important role in the complex variability patterns. Modelling of the wavelength dependence of amplitudes in terms of dust absorption in debris disks is explored. The conclusion is that excesses of small grains as compared with the average Galactic composition would be required.

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confidence: 54%

Multifilter observations of the complex periodic variations in eight pre-main sequence stars

Koen

2022

Monthly Notices of the Royal Astronomical Society

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“…One object, 7896 (V1598 Cyg), is situated clearly above the main sequence. This source has no infrared excess and Froebrich et al (2020) concluded that it is most likely a close binary and/or a foreground YSO. Most of the sources have no or only marginal infrared excess.…”

Section: Foreground Ysosmentioning

confidence: 99%

“…We are only aware of two other known periods amongst our periodic variable sample. One is in the YSO list (7181, LkHA 146, Ibryamov et al (2018)) and one in the non-YSO list (7896, V 1598 Cyg, Froebrich et al (2020)). With the one exception from Bhardwaj et al (2019), all published periods agree with the ones found in our analysis.…”

Section: Comparison With Published Periodsmentioning

confidence: 99%

A survey for variable young stars with small telescopes: IV -- Rotation Periods of YSOs in IC5070

Froebrich,

Derezea,

Scholz

et al. 2021

Preprint

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Studying rotational variability of young stars is enabling us to investigate a multitude of properties of young star-disk systems. We utilise high cadence, multi-wavelength optical time series data from the Hunting Outbursting Young Stars citizen science project to identify periodic variables in the Pelican Nebula (IC 5070). A double blind study using nine different period-finding algorithms was conducted and a sample of 59 periodic variables was identified. We find that a combination of four period finding algorithms can achieve a completeness of 85 % and a contamination of 30 % in identifying periods in inhomogeneous data sets. The best performing methods are periodograms that rely on fitting a sine curve. Utilising Gaia EDR3 data, we have identified an unbiased sample of 40 periodic YSOs, without using any colour or magnitude selections. With a 98.9 % probability we can exclude a homogeneous YSO period distribution. Instead we find a bi-modal distribution with peaks at three and eight days. The sample has a disk fraction of 50 %, and its statistical properties are in agreement with other similarly aged YSOs populations. In particular, we confirm that the presence of the disk is linked to predominantly slow rotation and find a probability of 4.8 × 10 −3 that the observed relation between period and presence of a disk has occurred by chance. In our sample of periodic variables, we also find pulsating giants, an eclipsing binary, and potential YSOs in the foreground of IC 5070.

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Section: Comparison With Published Periodsmentioning

confidence: 99%

A survey for variable young stars with small telescopes – IV. Rotation periods of YSOs in IC 5070

Froebrich

Derezea

Scholz

et al. 2021

Monthly Notices of the Royal Astronomical Society

Self Cite

View full text Add to dashboard Cite

Studying rotational variability of young stars is enabling us to investigate a multitude of properties of young star-disc systems. We utilize high cadence, multiwavelength optical time series data from the Hunting Outbursting Young Stars citizen science project to identify periodic variables in the Pelican Nebula (IC 5070). A double blind study using nine different period-finding algorithms was conducted and a sample of 59 periodic variables was identified. We find that a combination of four period finding algorithms can achieve a completeness of 85 per cent and a contamination of 30 per cent in identifying periods in inhomogeneous data sets. The best performing methods are periodograms that rely on fitting a sine curve. Utilizing Gaia EDR3 data, we have identified an unbiased sample of 40 periodic young stellar objects (YSOs), without using any colour or magnitude selections. With a 98.9 per cent probability, we can exclude a homogeneous YSO period distribution. Instead, we find a bi-modal distribution with peaks at 3 and 8 d. The sample has a disc fraction of 50 per cent, and its statistical properties are in agreement with other similarly aged YSOs populations. In particular, we confirm that the presence of the disc is linked to predominantly slow rotation and find a probability of 4.8 × 10−3 that the observed relation between period and presence of a disc has occurred by chance. In our sample of periodic variables, we also find pulsating giants, an eclipsing binary, and potential YSOs in the foreground of IC 5070.

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A survey for variable young stars with small telescopes – III. Warm spots on the active star V1598 Cyg

Cited by 9 publications

References 47 publications

Multifilter observations of the complex periodic variations in eight pre-main sequence stars

Multifilter observations of the complex periodic variations in eight pre-main sequence stars

A survey for variable young stars with small telescopes: IV -- Rotation Periods of YSOs in IC5070

A survey for variable young stars with small telescopes – IV. Rotation periods of YSOs in IC 5070

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