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MACHO Project photometry of 45 LMC FO/SO beat Cepheids which pulsate in the first and second overtone (FO and SOo, respectively) has been analysed to determine the lightcurve characteristics for the SO mode of Cepheid pulsation. We predict…

This is the first of two papers reporting measurements from a program to determine the Hubble constant to 5% precision from a refurbished distance ladder. We present new observations of 110 Cepheid variables in the host galaxies of two…

We present multi-band Period-Luminosity (PL) relations for first-overtone mode Cepheids in the Small Magellanic Cloud (SMC). We derive optical band PL relations and the Wesenheit function using $VI$ mean magnitudes from the Optical…

Astrophysics of Galaxies · Physics 2016-03-23 Anupam Bhardwaj , Chow-Choong Ngeow , Shashi M. Kanbur , Harinder P. Singh

The Period-Luminosity (PL) relation is usually derived using time-averaged magnitudes, which require multiple-epoch observations to determine periods and adequately sample the light curves. Although single-epoch observations are more…

Instrumentation and Methods for Astrophysics · Physics 2025-09-16 Mahdi Abdollahi , Atefeh Javadi , Barry F. Madore , Wendy L. Freedman , Hamidreza Mahani

Due to the importance of accurate Fourier parameters, we devise a method that is more appropriate for deriving these parameters on low-quality data than the traditional Fourier fitting. Based on the accurate light curves of 248 fundamental…

Astrophysics · Physics 2009-11-11 G. Kovacs , G. Kupi

Accurate radial velocities ($v_{\rm rad}$) of Cepheids are mandatory within the context of distance measurements via the Baade-Wesselink technique. The most common $v_{\rm rad}$ derivation method consists in cross-correlating the observed…

The period of pulsation and the structure of the light curve for Cepheid and RR Lyrae variables depend on the fundamental parameters of the star: mass, radius, luminosity, and effective temperature. Here we train artificial neural networks…

Solar and Stellar Astrophysics · Physics 2020-01-08 Earl P. Bellinger , Shashi M. Kanbur , Anupam Bhardwaj , Marcella Marconi

Recent work on Ultra Long Period Cepheids (ULPCs) has suggested their usefulness as a distance indicator, but has not commented on their relationship as compared with other types of variable stars. In this work, we use Fourier analysis to…

Solar and Stellar Astrophysics · Physics 2016-11-18 Chow-Choong Ngeow , Scott Lucchini , Shashi Kanbur , Brittany Barrett , Bin Lin

Cepheid stars play a considerable role as extragalactic distances indicators, thanks to the simple empirical relation between their pulsation period and their luminosity. They overlap with that of secondary distance indicators, such as Type…

To broaden the understanding of classical Cepheid structure, evolution and atmospheres, we have extended our continuing secret lives of Cepheids program by obtaining XMM/Chandra X-ray observations, and Hubble space telescope (HST) / cosmic…

Solar and Stellar Astrophysics · Physics 2012-06-20 Scott G. Engle , Edward F. Guinan

We present the results of near-infrared observations of extragalactic Cepheids made with the Near Infrared Camera and Multi-Object Spectrometer on board the Hubble Space Telescope. The variables are located in the galaxies IC 1613, IC 4182,…

We accurately determine a new Cepheid distance to M101 (NGC 5457) using archival HST/ACS V and I time series photometry of two fields within the galaxy. We make a slight modification to the ISIS image subtraction package to obtain optimal…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Benjamin J. Shappee , K. Z. Stanek

In this presentation I summarize recent work on Cepheid research carried out at the National Central University. The mid-infrared period-luminosity (P-L) relations for Cepheids are important in the James Webb Space Telescope era for…

Solar and Stellar Astrophysics · Physics 2011-11-10 Chow-Choong Ngeow

Anomalous Cepheids (ACs) are less studied metal-poor pulsating stars ([Fe/H]<-1.5) compared to Classical Cepheids (CCs) and RR Lyrae stars. They follow distinct Period-Luminosity (PL) and Period-Wesenheit (PW) relations and pulsate in…

We present the analysis of multiband time-series data for a sample of 24 Cepheids in the field of the Large Magellanic Cloud cluster NGC1866. Very accurate BVI VLT photometry is combined with archival UBVI data, covering a large temporal…

Solar and Stellar Astrophysics · Physics 2016-03-09 I. Musella , M. Marconi , P. B. Stetson , G. Raimondo , E. Brocato , R. Molinaro , V. Ripepi , R. Carini , G. Coppola , A. R. Walker , D. L. Welch

We undertake a new test of the metallicity sensitivity of the Leavitt Law for Classical Cepheids. We derive an empirical calibration of the apparent luminosities of Cepheids as measured from the optical through the mid-infrared (0.45-8.0um)…

Solar and Stellar Astrophysics · Physics 2015-05-27 Wendy L. Freedman , Barry F. Madore

We present Period-Luminosity-Color and Period-Luminosity relations of classical Cepheids constructed for about 1280 Cepheids from the LMC and 2140 from the SMC. High quality BVI observations (120-360 epochs in the I-band and 15-40 in the…

Astrophysics · Physics 2007-05-23 A. Udalski , M. Szymanski , M. Kubiak , G. Pietrzynski , I. Soszynski , P. Wozniak , K. Zebrun

We present a new set of Cepheid, full amplitude, nonlinear, convective models which are pulsationally unstable in the second overtone (SO). Hydrodynamical models were constructed by adopting a chemical composition typical for Cepheids in…

Astrophysics · Physics 2009-11-06 G. Bono , F. Caputo , M. Marconi

The form and metallicity-dependence of Spitzer mid-infrared Cepheid relations are a source of debate. Consequently, Spitzer 3.6 and 4.5 um period-magnitude and period-color diagrams were re-examined via robust routines, thus providing the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 D. Majaess , D. G. Turner , W. Gieren

We present the first analysis of Cepheid stars observed by the TESS space mission in Sectors 1 to 5. Our sample consists of 25 pulsators: ten fundamental mode, three overtone and two double-mode classical Cepheids, plus three Type II and…

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