A search for period changes of eight short-period Type II Cepheids

Yacob, Alemiye M; Бердников, Л. Н.; Pastukhova, E. N.; Kniazev, A. Y.; Whitelock, P. A.

doi:10.1093/mnras/stac2167

Cited by 4 publications

(3 citation statements)

References 46 publications

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“…In history, the period/frequency variation of the dominating pulsation mode of some kinds of pulsating stars can be obtained via the accumulation of the TML lasts for several decades by O − C method (such as Cepheid (Csörnyei (Li et al 2018), HADS (Xue et al 2022), and SX Phe stars (Xue & Niu 2020)). An interesting but often overlooked detail is that it always exists dispersions in the O − C diagrams, which are always one or more orders of magnitude larger than the TML uncertainties (Csörnyei et al 2022;Yacob et al 2022;Li et al 2018;Xue & Niu 2020;Xue et al 2022). This phenomenon not only happens for multi-mode pulsating stars, but also for the single-mode ones.…”

Section: Discussionmentioning

confidence: 99%

Uncorrelated Amplitude and Frequency Variations of the Harmonics in SX Phoenicis Star XX Cygni

Niu¹,

Xue²

2023

Preprint

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Harmonics are quite common in pulsating stars, and they are always considered to mimic the behaviors of their independent parent pulsation modes and not taken as the key information for asteroseismology. Here, we report an SX Phoenicis star XX Cygni, whose periodogram is dominated by the fundamental frequency f 0 = 7.41481 ± 0.00004 c d −1 and its 19 harmonics. According to the analysis of the archival data from TESS , we find that both the amplitudes and frequencies of the fundamental mode and the harmonics vary within TESS Sectors 14-17 and 54-57, which might be caused by the contamination by neighbouring stars. What is more interesting is that, the harmonics show significantly uncorrelated amplitude and frequency variations over time. Some possible origins and interesting issues are proposed to scheme the further research of this hidden corner in current asteroseismology.

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Section: Discussionmentioning

confidence: 99%

Uncorrelated Amplitude and Frequency Variations of the Harmonics in SX Phoenicis Star XX Cygni

Niu¹,

Xue²

2023

Preprint

View full text Add to dashboard Cite

show abstract

“…In history, the period/frequency variation of the dominating pulsation mode of some kinds of pulsating stars can be obtained via the accumulation of the TML lasts for several decades by O − C method (such as Cepheid; Csörnyei et al 2022;Yacob et al 2022;RR Lyrae stars;Li et al 2018;HADS;Xue et al 2022;and SX Phe stars;Xue & Niu 2020). An interesting but often overlooked detail is that it always exists dispersions in the O − C diagrams, which are always one or more orders of magnitude larger than the TML uncertainties (Li et al 2018;Xue & Niu 2020;Csörnyei et al 2022;Xue et al 2022;Yacob et al 2022). This phenomenon not only happens for multimode pulsating stars, but also for the single-mode ones.…”

Section: Discussionmentioning

confidence: 99%

Uncorrelated Amplitude and Frequency Variations of the Harmonics in SX Phoenicis Star XX Cygni

Niu

Liu

Xue

2023

View full text Add to dashboard Cite

Harmonics are quite common in pulsating stars. They are always considered to mimic the behaviors of their independent parent pulsation modes, and are not taken for key information in asteroseismology. Here, we report an SX Phoenicis star XX Cygni, whose periodogram is dominated by the fundamental frequency f 0 = 7.41481 ± 0.00004 c day−1 and its 19 harmonics. According to the analysis of the archival data from the Transiting Exoplanet Survey Satellite (TESS), we find that both the amplitudes and frequencies of the fundamental mode and the harmonics vary within TESS Sectors 14–17 and 54–57, which might be caused by the contamination of neighboring stars. What is more interesting is that the harmonics show significantly uncorrelated amplitude and frequency variations over time. Some possible origins and interesting issues are proposed to scheme further research of this hidden corner in current asteroseismology.

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“…Some stars, however, are predicted to pulsate and consequently vary regularly in brightness with a very precise period. Comparing how a star's period changes from a hundred years or so ago to today provides one of the few direct tests of the theories of advanced stellar evolution (Karmakar et al, 2022;Osborn, 2000;Yacob et al, 2022).…”

Section: (D)mentioning

confidence: 99%

Astronomy’s Photographic Glass Plates: Demonstrating Value Through Use Cases

Whitten,

Boegen,

Levine

et al. 2024

ISTL

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Astronomy's extensive collections of photographic glass plates contain historical images and spectra of celestial objects, documenting more than a century of the observable cosmos. Many reveal changes, both sudden (explosive), periodic, or gradual (evolutionary), which is material of immense interest for time-domain studies because of the long time-base they cover. Those early photographic observations also furnished all the basic data which supported our early understanding of the universe, and from which modern stellar classifications have been derived. Once the ubiquitous workhorse detector, plates or film are now replaced by electronic detectors, and systems are modified to take advantage of advances in telescope technology. This change poses challenges of preservation and accessibility for the plates, leading administrators to question the usefulness of the older materials in relation to the cost of their care and preservation. The following paper details many examples of reusing or re-purposing those plates, demonstrates their unique value to modern astronomy and the history of science, and makes a strong case for committing resources towards their long-term preservation and ultimately their comprehensive digitization.

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A search for period changes of eight short-period Type II Cepheids

Cited by 4 publications

References 46 publications

Uncorrelated Amplitude and Frequency Variations of the Harmonics in SX Phoenicis Star XX Cygni

Uncorrelated Amplitude and Frequency Variations of the Harmonics in SX Phoenicis Star XX Cygni

Uncorrelated Amplitude and Frequency Variations of the Harmonics in SX Phoenicis Star XX Cygni

Astronomy’s Photographic Glass Plates: Demonstrating Value Through Use Cases

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