<i>TESS</i> cycle 1 observations of roAp stars with 2-min cadence data

Holdsworth, Daniel Luke; Cunha, M. S.; Kurtz, D. W.; Antoci, V.; Hey, Daniel R.; Bowman, D. M.; Kobzar, Oleh; Buzasi, Derek L.; Kochukhov, O.; Niemczura, E.; Özuyar, Doğuş; Shi, Fangtian; Szabo, Robert M.; Samadi-Ghadim, A.; Bognár, Zs.; Fox-Machado, L.; Khalack, V.; Lares-Martiz, M.; Lovekin, Catherine; Mikołajczyk, P.; Mkrtichian, D. E.; Pascual-Granado, J.; Paunzen, E.; Richey-Yowell, Tyler; Sódor, Á.; Sikora, J.; Yang, Tao-Zhi; Brunsden, E.; David-Uraz, Alexandre; Derekas, A.; Hernández, A. García; Guzik, Joyce A.; Hatamkhani, N; Handberg, R.; Lambert, Trystan S; Lampens, P.; Murphy, Simon J.; Monier, Richard; Pollard, K. R.; Quitral-Manosalva, P.; Ramón-Ballesta, A.; Smalley, B.; Статева, И.; Vanderspek, R.

doi:10.1093/mnras/stab1578

Cited by 23 publications

(7 citation statements)

References 212 publications

(403 reference statements)

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“…The relation between rotation period and roAp pulsations is not yet known, hence the increased sample provides more data to examine this. Holdsworth et al (2021) found that 68% of the 56 roAp stars with TESS data show rotational modulation from spots. This is useful for precise determination of the rotation period, but it is only for stars with Prot < ∼ 22 d, as a consequence of the 27-d TESS sectors.…”

Section: A7 Be Star Historymentioning

confidence: 98%

“…This problem has become clear in photometry from TESS observations of roAp stars, particularly HD 6532 , and also other stars (Holdsworth et al 2021). The amplitudes of the multiplet frequencies generated by oblique pulsation provide information about the mode geometry.…”

Section: Nonlinear Pulsation: Combination Frequencies -Opportunities ...mentioning

confidence: 99%

“…TESS observed 960 stars classified as Ap in 2-min cadence in all 13 sectors of cycle 1 to determine the fraction of Ap stars that are roAp stars, and to find new roAp stars for further analysis. In addition, a team searched the light curves of over 50 000 stars hotter than T eff = 6000 K for the signature of roAp pulsation in the FTs (Holdsworth et al 2021). Together with earlier examinations of Ap stars in subsets of TESS cycle 1 sectors by Balona et al (2019) and Cunha et al (2019 found 12 new roAp stars and further analyzed 44 previously known ones.…”

Section: A7 Be Star Historymentioning

confidence: 99%

“…The finding of new roAp stars also leads to objects with higher amplitudes suitable for future high time resolution spectroscopic study with large telescopes. Holdsworth et al (2021) provide first analyses of the roAp stars with TESS data, characterizing their pulsation and rotation. As in the study of HD 86181 (Shi et al 2021), many stars have rotationally split multiplets useful for constraints on mode geometry, and some stars have multiple modes suitable for future asteroseismic modeling to determine fundamental parameters such as mass, age, luminosity, and overall metallicity in the pulsation cavity.…”

Section: A7 Be Star Historymentioning

confidence: 99%

“…Bigot & Dziembowski (2002) showed that the pulsation axis is not necessarily the magnetic axis, but is still inclined to the rotation axis (see also Bigot & Kurtz 2011). has recently reviewed the roAp stars, and Holdsworth et al (2021) give a detailed introduction to them in their report on TESS cycle 1 observations. I refer the reader to these two papers for the many references to the theoretical and observational literature on roAp stars.…”

Section: Nonlinear Pulsation: Combination Frequencies -Opportunities ...mentioning

confidence: 99%

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Asteroseismology across the HR diagram

Kurtz¹

2022

Preprint

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Asteroseismology has grown from its beginnings three decades ago to a mature field teeming with discoveries and applications. This phenomenal growth has been enabled by space photometry with precision 10 − 100 times better than ground-based observations, with nearly continuous light curves for durations of weeks to years, and by large scale ground-based surveys spanning years designed to detect all timevariable phenomena. The new high precision data are full of surprises, deepening our understanding of the physics of stars.• This review explores asteroseismic developments from the last decade primarily as a result of light curves from the Kepler and TESS space missions for: massive upper main-sequence OBAF stars, pre-mainsequence stars, peculiar stars, classical pulsators, white dwarfs and subdwarfs, and tidally interacting close binaries. • The space missions have increased the numbers of pulsators in many classes by an order of magnitude. • Asteroseismology measures fundamental stellar parameters and stellar interior physics -mass, radius, age, metallicity, luminosity, distance, magnetic fields, interior rotation, angular momentum transfer, convective overshoot, core burning stage -supporting disparate fields such as galactic archeology, exoplanet host stars, supernovae progenitors, gamma ray and gravitational wave precursors, close binary star origins and evolution, and standard candles. • Stars are the luminous tracers of the universe. Asteroseismology significantly improves models of stellar structure and evolution on which all inference from stars depends.

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Section: A7 Be Star Historymentioning

confidence: 98%

Section: Nonlinear Pulsation: Combination Frequencies -Opportunities ...mentioning

confidence: 99%

Section: A7 Be Star Historymentioning

confidence: 99%

Section: A7 Be Star Historymentioning

confidence: 99%

Section: Nonlinear Pulsation: Combination Frequencies -Opportunities ...mentioning

confidence: 99%

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Asteroseismology across the HR diagram

Kurtz¹

2022

Preprint

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Long-period Ap stars discovered with TESS data: The northern ecliptic hemisphere

Mathys

Kurtz

Holdsworth

2022

A&A

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The rotation periods of the magnetic Ap stars span five to six orders of magnitude. While it is well established that period differentiation must have taken place at the pre-main sequence stage, the physical processes that lead to it remain elusive. The existence of Ap stars that have rotation periods of tens to hundreds of years is particularly intriguing, and their study represents a promising avenue to gain additional insight into the origin and evolution of rotation in Ap stars. Historically, almost all the longest period Ap stars known have been found to be strongly magnetic; very few weakly magnetic Ap stars with very long periods have been identified and studied. To remedy that, we showed how a systematic search based on the analysis of TESS photometric data could be performed to identify super-slowly rotating Ap (ssrAp) stars independently of the strengths of their magnetic fields, with the intention to characterise the distribution of the longest Ap star rotation periods in an unbiased manner. We successfully applied this method to the analysis of the TESS 2-min cadence observations of Ap stars of the southern ecliptic hemisphere. For our present study, we applied the same approach to the analysis of the TESS 2-min cadence observations of Ap stars of the northern ecliptic hemisphere. We confirm that the technique leads to the reliable identification of ssrAp star candidates in an unbiased manner. We find 67 Ap stars with no rotational variability in the northern ecliptic hemisphere TESS data. Among them, 46 are newly identified ssrAp star candidates, which is double the number found in the southern ecliptic hemisphere. We confirm that super-slow rotation tends to occur less frequently in weakly magnetic Ap stars than in strongly magnetic stars. We present new evidence of the existence of a gap between ∼2 kG and ∼3 kG in the distribution of the magnetic field strengths of long period Ap stars. We also confirm that the incidence of roAp stars is higher than average in slowly rotating Ap stars. We report the unexpected discovery of nine definite and five candidate δ Sct stars, and of two eclipsing binaries. This work paves the way for a systematic, unbiased study of the longest period Ap stars, with a view to characterise the correlations between their rotational, magnetic, and pulsational properties.

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Photometric variability of the LAMOST sample of magnetic chemically peculiar stars as seen by TESS

Labadie-Bartz¹,

Hümmerich²,

Bernhard³

et al. 2023

A&A

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Context. High-quality light curves from space-based missions have opened up a new window on the rotational and pulsational properties of magnetic chemically peculiar (mCP) stars and have fuelled asteroseismic studies. They allow the internal effects of surface magnetic fields to be probed and numerous astrophysical parameters to be derived with great precision. Aims. We present an investigation of the photometric variability of a sample of 1002 mCP stars discovered in the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) archival spectra with the aims of measuring their rotational periods and identifying interesting objects for follow-up studies. Methods. Transiting Exoplanet Survey Satellite (TESS) data were available for 782 mCP stars and were analysed using a Fourier two-term frequency fit to determine the stars’ rotational periods. The rotational signal was then subtracted from the light curve to identify additional non-rotational variability signals. A careful pixel-level blending analysis was performed to check whether the variability originates in the target star or a nearby blended neighbour. We investigated correlations between the observed rotational periods, fractional age on the main sequence, mass, and several other observables. Results. We present rotational periods and period estimates for 720 mCP stars. In addition, we have identified four eclipsing binary systems that likely host an mCP star, as well as 25 stars with additional signals consistent with pulsation (12 stars with frequencies above 10 day−1 and 13 stars with frequencies below 10 day−1). We find that more evolved stars have longer rotation periods, which is in agreement with the assumption of the conservation of angular momentum during the main-sequence evolution. Conclusions. With our work, we increase the sample size of mCP stars with known rotation periods and identify prime candidates for detailed follow-up studies. This enables two paths towards future investigations: population studies of even larger samples of mCP stars and the detailed characterisation of high-value targets.

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

Cited by 23 publications

References 212 publications

Asteroseismology across the HR diagram

Asteroseismology across the HR diagram

Long-period Ap stars discovered with TESS data: The northern ecliptic hemisphere

Photometric variability of the LAMOST sample of magnetic chemically peculiar stars as seen by TESS

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