New and improved rotational periods of magnetic CP stars from ASAS-3, KELT, and MASCARA data

Bernhard, Klaus; Hümmerich, Stefan; Paunzen, E.

doi:10.1093/mnras/staa462

Cited by 35 publications

(37 citation statements)

References 78 publications

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“…In summary, the quality of the ZTF data is comparable to that of other photometric ground-based surveys like ASAS-3, KELT, MASCARA, or SuperWASP (Bernhard et al 2015b(Bernhard et al , 2020, while extending to much fainter magnitudes. The ZTF is therefore well suited to searching for new ACV variables and an analysis of their light curve characteristics.…”

Section: Light Curvessupporting

confidence: 54%

A case study of ACV variables discovered in the Zwicky Transient Facility survey

Faltová

Kallova

Prišegen

et al. 2021

A&A

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Context. Magnetic chemically peculiar (mCP) stars exhibit complex atmospheres that allow the investigation of the interplay of atomic diffusion, magnetic fields, and stellar rotation. A non-uniform surface distribution of chemical elements and the non-alignment of the rotational and magnetic axes result in the variability of several observables. Photometrically variable mCP stars are referred to as α 2 Canum Venaticorum (ACV) variables. Aims. The present work presents a case study of known variables from the Zwicky Transient Facility (ZTF) survey, with the aim of investigating the survey's suitability for the detection and study of new ACV variables. Methods. Using suitable selection criteria based on the known characteristics of ACV variables, candidate ACV stars were selected from the ZTF Catalog of Periodic Variable Stars. All light curves were inspected in detail to select the most promising candidates. Where available, low-resolution spectra from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) were employed to classify the stars on the MK system and confirm their status as mCP stars. Results. We have identified 86 new promising ACV star candidates. Fifteen of these stars have LAMOST spectra available that, in all cases, confirm them as classical mCP stars, which highlights the viability of our approach. We present astrophysical parameters for all sample stars that can be sorted into four subgroups characterized by distinct light curve shapes. Anti-phase variations in different photometric passbands, in particular, is a unique characteristic of a subset of ACV stars readily usable for their identification. The availability of data in three different passbands (g, r, and i) is a major advantage of the ZTF survey. Conclusions. On the basis of our experience with other photometric surveys and the analysis of light curves, we conclude that the ZTF is well suited to the search for, and the analysis of, ACV variables that are not considered in the available ZTF variable star catalogs. Further work will focus on the development and refinement of a search algorithm to correctly identify these stars in ZTF data and, subsequently, in massive photometric time series databases in general.

show abstract

Section: Light Curvessupporting

confidence: 54%

A case study of ACV variables discovered in the Zwicky Transient Facility survey

Faltová

Kallova

Prišegen

et al. 2021

A&A

View full text Add to dashboard Cite

show abstract

“…In summary, the quality of the ZTF data is comparable to that of other photometric ground-based surveys like ASAS-3, KELT, MASCARA, or SuperWASP (Bernhard et al 2015b(Bernhard et al , 2020, while extending to much fainter magnitudes. The ZTF is therefore well suited to search for new ACV variables and an analysis of their light curve characteristics.…”

Section: Light Curvessupporting

confidence: 54%

A case study of ACV variables discovered in the Zwicky Transient Facility survey

Faltová,

Kallová,

Prišegen

et al. 2021

Preprint

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Context. Magnetic chemically peculiar (mCP) stars exhibit complex atmospheres that allow the investigation of the interplay of atomic diffusion, magnetic fields, and stellar rotation. A non-uniform surface distribution of chemical elements and the non-alignment of the rotational and magnetic axes result in the variability of several observables. Photometrically variable mCP stars are referred to as α 2 Canum Venaticorum (ACV) variables. Aims. The present work presents a case study of known variables from the Zwicky Transient Facility (ZTF) survey, with the aim of investigating the survey's suitability for the detection and study of new ACV variables. Methods. Using suitable selection criteria based on the known characteristics of ACV variables, candidate ACV stars were selected from the ZTF Catalog of Periodic Variable Stars. All light curves were inspected in detail to select the most promising candidates. Where available, low-resolution spectra from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) were employed to classify the stars on the MK system and confirm their status as mCP stars.Results. We have identified 86 new promising ACV star candidates. 15 of these stars have LAMOST spectra available, which, in all cases, confirm them as classical mCP stars, which highlights the viability of our approach. We present astrophysical parameters for all sample stars, which can be sorted into four subgroups characterized by distinct light curve shapes. Anti-phase variations in different photometric passbands, in particular, is a unique characteristic of a subset of ACV stars readily usable for their identification. The availability of data in three different passbands (g, r, and i) is a major advantage of the ZTF survey. Conclusions. On the basis of our experience with other photometric surveys and the analysis of light curves, we conclude that the ZTF is well suited for the search for, and the analysis of, ACV variables, which, however, are not considered in the available ZTF variable star catalogues. Further work will be concerned with the development and refinement of a search algorithm to correctly identify these stars in ZTF data and, subsequently, in massive photometric time-series databases in general.

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“…The rotation period of the star has been under debate for several years, with fits to both photometric and magnetic data being used to determine it (Hensberge et al 1981;Kudryavtsev et al 2006;Kudryavtsev & Romanyuk 2012). Most recently, Bernhard et al (2020) calculated the period of the star as 8.677 ± 0.002 d which is representative of the other periods reported. TIC 176516923 was observed by TESS in sector 6 only.…”

Section: Tic 176516923mentioning

confidence: 99%

TESS cycle 1 observations of roAp stars with 2-min cadence data

Holdsworth

Cunha

Kurtz

et al. 2021

Monthly Notices of the Royal Astronomical Society

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We present the results of a systematic search for new rapidly oscillating Ap (roAp) stars using the 2-min cadence data collected by the Transiting Exoplanet Survey Satellite (TESS) during its Cycle 1 observations. We identify 12 new roAp stars. Amongst these stars we discover the roAp star with the longest pulsation period, another with the shortest rotation period, and six with multiperiodic variability. In addition to these new roAp stars, we present an analysis of 44 known roAp stars observed by TESS during Cycle 1, providing the first high-precision and homogeneous sample of a significant fraction of the known roAp stars. The TESS observations have shown that almost 60 per cent (33) of our sample of stars are multiperiodic, providing excellent cases to test models of roAp pulsations, and from which the most rewarding asteroseismic results can be gleaned. We report four cases of the occurrence of rotationally split frequency multiplets that imply different mode geometries for the same degree modes in the same star. This provides a conundrum in applying the oblique pulsator model to the roAp stars. Finally, we report the discovery of non-linear mode interactions in α Cir (TIC 402546736, HD 128898) around the harmonic of the principal mode – this is only the second case of such a phenomenon.

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New and improved rotational periods of magnetic CP stars from ASAS-3, KELT, and MASCARA data

Cited by 35 publications

References 78 publications

A case study of ACV variables discovered in the Zwicky Transient Facility survey

A case study of ACV variables discovered in the Zwicky Transient Facility survey

A case study of ACV variables discovered in the Zwicky Transient Facility survey

TESS cycle 1 observations of roAp stars with 2-min cadence data

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