Period–colour and amplitude–colour relations for OGLE-δ Scuti stars in the Galactic bulge and LMC

Deka, Mami; Deb, Sukanta; Das, Susmita; Kurbah, Kerdaris; Bellinger, Earl P.; Bhardwaj, Anupam

doi:10.1093/mnras/stac2457

Cited by 6 publications

(3 citation statements)

References 53 publications

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“…Furthermore, Deka et al (2022) studied 3202 δ Sct stars in the Galactic bulge from the OGLE-IV catalogue (Soszyński et al 2021) and the Large Magellanic Cloud (LMC) from OGLE-III. Their analysis revealed a broken PLR for the bulge δ Sct stars, but not for those in the LMC.…”

Section: Previous Plrs For δ Sct Starsmentioning

confidence: 99%

The PL diagram for δ Sct stars: back in business as distance estimators

Garca Hernández,

Pascual-Granado,

Lares-Martiz

et al. 2022

Proc. IAU

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In this work, we focus on the period-luminosity relation (PLR) of δ Sct stars, in which mode excitation and selection mechanisms are still poorly constrained, and whose structure and oscillations are affected by rotation. We review the PLRs in the recent literature, and add a new inference from a large sample of δ Sct. We highlight the difficulty in identifying the fundamental mode and show that rotation-induced surface effects can impact the measured luminosities, explaining the broadening of the PLR. We derive a tight relation between the low-order large separation and the fundamental radial mode frequency (F0) that holds for rotating stars, thus paving the way towards mode identification. We show that the PLRs we obtain for different samples are compatible with each other and with the recent literature, and with most observed δ Sct stars when taking rotation effects into account. We also find that the highest-amplitude peak in the frequency spectrum corresponds to the fundamental modein most δ Sct, thus shedding some light on their elusive mode selection mechanism.

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Section: Previous Plrs For δ Sct Starsmentioning

confidence: 99%

The PL diagram for δ Sct stars: back in business as distance estimators

Garca Hernández,

Pascual-Granado,

Lares-Martiz

et al. 2022

Proc. IAU

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show abstract

“…The computational codes and numerical methods as described in Yecko et al (1998) and Kolláth et al (2002) were used in those studies to carry out the pulsation modelings. Recently, using -, Das et al ( 2020) presented theoretical explanations of the observed PC and AC relations at maximum and minimum light for the pulsating stars such as RR Lyraes, type I and type II Cepheids, whereas the same was provided for the Scuti stars by Deka et al (2022).…”

Section: Introductionmentioning

confidence: 99%

A multiphase study of theoretical and observed light curves of classical Cepheids in the Magellanic Clouds

Kurbah¹,

Deb²,

Das³

et al. 2023

Preprint

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We present an analysis of the theoretical and observed light curve parameters of the fundamental mode (FU) classical Cepheids in the Magellanic Clouds in -and -photometric bands. The state-of-the-art 1D non-linear radial stellar pulsation (RSP) code in MESA ( -) has been utilized to generate the theoretical light curves using four sets of convection parameters. Theoretical light curves with two chemical compositions: = 0.008 and = 0.004 appropriate for the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC), respectively, covered a wide range of periods (3 < (d) < 32). The observed light curves are taken from the OGLE-IV database. We compare theoretical and observed Fourier parameters (FPs), and investigate the period-luminosity (PL), period-colour (PC), and amplitude-colour (AC) relations as a function of pulsation phase for short (log < 1), long (log > 1) and all periods. The multiphase relations obtained from theoretical and observed light curves in the PL/PC/AC plane are found to be dynamic in nature, with the effect more pronounced at Φ ∼ 0.75 − 0.85. Furthermore, a contrasting behaviour of the theoretical/observed multiphase PL and PC relations between the short and long periods has been found for both LMC and SMC. The analysis shows that multiphase PL relations are more stringent to test the models with observations over the FPs. Distances to the LMC/SMC determined using long period Cepheids are found to be in good agreement with the literature values when the term 21 is added to the PL relation.

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“…Theoretical pulsation properties of Cepheid variables have been investigated by Bono and his group in the 1990s (Bono et al 1998(Bono et al , 1999(Bono et al , 2000Caputo et al 2000a,b). The comparison between the observed and theoretical period-color (PC), amplitude-color (AC) and period-luminosity (PL) relations for Cepheids, RR Lyraes, and δ Scuti stars in the Galaxy and the Magellanic Clouds in the literature were mostly done at maximum, minimum, and mean light (Kanbur et al 2004;Kanbur and Ngeow 2006;Kanbur et al 2007;Das et al 2020;De Somma et al 2020;Deka et al 2022;De Somma et al 2022). However, the relation at mean light is the average of the relations at all phases, hence, investigating the Cepheid PL/PC relations at other phases of the stars provides a better understanding of the pulsational properties of the stars.…”

Section: Introductionmentioning

confidence: 99%

A multiphase study of classical Cepheids in the Magellanic Clouds- Models and Observations

Kurbah,

Kanbur,

Deb

et al. 2022

Proc. IAU

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This work presents the study of multiphase relations of classical Cepheids in the Magellanic Clouds for short periods (log P < 1) and long periods (log P > 1). From the analysis, it has been found that the multiphase relations obtained using the models as well as observations are highly dynamic with pulsational phase. The multiphase relations for short and long periods are found to display contrasting behaviour for both LMC and SMC. It has been observed that the multiphase relations obtained using the models agree better with the observations in the PC plane in most phases in comparison to the PL plane. Multiphase relations obtained using the models display a clear distinction among different convection sets in most phases. Comparison of models and observations in the multiphase plane is one way to test the models with the observations and to constrain the theory of stellar pulsation.

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Period–colour and amplitude–colour relations for OGLE-δ Scuti stars in the Galactic bulge and LMC

Cited by 6 publications

References 53 publications

The PL diagram for δ Sct stars: back in business as distance estimators

The PL diagram for δ Sct stars: back in business as distance estimators

A multiphase study of theoretical and observed light curves of classical Cepheids in the Magellanic Clouds

A multiphase study of classical Cepheids in the Magellanic Clouds- Models and Observations

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