Type II and anomalous Cepheids in the Kepler K2 mission

Abstract

We present the results of the analysis of Type II and anomalous Cepheids using the data from the Kepler K2 mission. The precise light curves of these pulsating variable stars are the key to study the details of their pulsation, such as the period-doubling effect or the presence of additional modes. We applied the Automated Extended Aperture Photometry (autoEAP) to obtain the light curves of the targeted variable stars which were observed. The light curves were Fourier analyzed. We investigated twelve stars observed by the K2 mission, seven Type II and five anomalous Cepheids. Among the Type II Cepheids EPIC 210622262 shows period-doubling, and four stars have modulation present in their light curves which are different from the period-doubling effect. We calculated the high-order Fourier parameters for the short-period Cepheids. We also determined physical parameters by fitting model atmospheres to the spectral energy distributions. The determined distances using the parallaxes measured by the Gaia space telescope have limited precision below 16 mag for these types of pulsating stars, regardless if the inverse method is used or the statistical method to calculate the distances. The BaSTI evolutionary models were compared to the luminosities and effective temperatures. Most of the Type II Cepheids are modeled with low metallicity models, but for a few of them solar-like metallicity ([Fe/H]=0.06) model is required. The anomalous Cepheids are compared to low-metallicity single stellar models. We do not see signs of binarity among our sample stars.

arXiv comment21 pages, 13 figures, accepted for publication in MNRAS

References in corpus (82)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Astropy: A Community Python Package for Astronomy
• Gaia Data Release 2. Summary of the contents and survey properties
• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• The Gaia mission
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• Estimating distances from parallaxes IV: Distances to 1.33 billion stars in Gaia Data Release 2
• The K2 Mission: Characterization and Early results
• A 3D Dust Map Based on Gaia, Pan-STARRS 1 and 2MASS
• The All-Sky Automated Survey for Supernovae (ASAS-SN) Light Curve Server v1.0
• The Revised TESS Input Catalog and Candidate Target List
• Gaia Early Data Release 3: Parallax bias versus magnitude, colour, and position
• The GALAH+ Survey: Third Data Release
• The UKIDSS Galactic Plane Survey
• The Catalina Surveys Periodic Variable Star Catalog
• The ASAS-SN Catalog of Variable Stars I: The Serendipitous Survey
• Revised Catalog of GALEX Ultraviolet Sources. I. The All-sky Survey: GUVcat_AIS
• The Star-formation History and Accretion-Disk Fraction Among the K-Type Members of the Scorpius-Centaurus OB Association
• The Updated BaSTI Stellar Evolution Models and Isochrones: I. Solar Scaled Calculations
• The K2 Ecliptic Plane Input Catalog (EPIC) and Stellar Classifications of 138,600 Targets in Campaigns 1-8
• The ATLAS All-Sky Stellar Reference Catalog
• Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18
• Galaxy Zoo: Passive Red Spirals
• Probing the Outer Galactic halo with RR Lyrae from the Catalina Surveys
• Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia EDR3 stars brighter than G=18.5
• Abundance Estimates for 16 Elements in 6 Million Stars from LAMOST DR5 Low-Resolution Spectra
• 3D maps of interstellar dust in the Local Arm: using $Gaia$, 2MASS and APOGEE-DR14
• The ASAS-SN Catalog of Variable Stars II: Uniform Classification of 412,000 Known Variables
• K2SC: Flexible systematics correction and detrending of K2 light curves using Gaussian Process regression
• Empirical, Accurate Masses and Radii of Single Stars with TESS and Gaia
• Rotation of Low-Mass Stars in Upper Scorpius and Rho Ophiuchus with K2
• A re-classification of Cepheids in the Gaia Data Release 2
• The International Deep Planet Survey II: The frequency of directly imaged giant exoplanets with stellar mass
• Scaling K2. I. Revised Parameters for 222,088 K2 Stars and a K2 Planet Radius Valley at 1.9 $R_{\oplus }$
• The ASAS-SN Catalog of Variable Stars V: Variables in the Southern Hemisphere
• Period-luminosity relations of type II Cepheids in the Magellanic Clouds
• Machine Learning Regression of stellar effective temperatures in the second $Gaia$ Data Release
• Large Magellanic Cloud Near-Infrared Synoptic Survey. IV. Leavitt Laws for Type II Cepheid Variables
• Discovery of period doubling in BL Herculis stars of the OGLE survey. Observations and theoretical models
• Observations of Cepheids with the MOST satellite: Contrast between Pulsation Modes
• Empirical Bolometric Fluxes and Angular Diameters of 1.6 Million Tycho-2 Stars and Radii of 350,000 Stars with \emph{Gaia} DR1 Parallaxes
• Anomalous Cepheids in the Large Magellanic Cloud: Insight into their origin and connection with the star formation history
• TESS observations of Cepheid stars: first light results
• The period-luminosity and period-radius relations of Type II and anomalous Cepheids
• Bright metal-poor variables: why "Anomalous" Cepheids?
• Survey of non-linear hydrodynamic models of type-II Cepheids
• High-precision distance measurements with classical pulsating stars
• First results on RR Lyrae stars with the TESS space telescope: untangling the connections between mode content, colors and distances
• Synthetic properties of bright metal-poor variables. I. "Anomalous" Cepheids
• Catalogue of variable stars in open cluster fields
• The OGLE Collection of Variable Stars. Classical, Type II, and Anomalous Cepheids toward the Galactic Center
• Evolutionary and pulsation properties of Type II Cepheids
• Period doubling and Blazhko modulation in BL Herculis hydrodynamic models
• On the separation between RR Lyrae and Type II Cepheids and their importance for distance determination: the case of $\omega$ Cen
• CoRoT space photometry of seven Cepheids
• Analysing the spectral energy distributions of Galactic classical Cepheids
• Luminosities and infrared excess in Type II and anomalous Cepheids in the Large and Small Magellanic Clouds
• A theoretical framework of BL Her stars. I. Effect of metallicity and convection parameters on period-luminosity and period-radius relations
• Extended Aperture Photometry of K2 RR Lyrae stars
• Periodicities of the RV Tau-type pulsating star DF Cygni: a combination of Kepler data with ground-based observations
• First observations of W Virginis stars with K2: detection of period doubling
• On Binary Channels to Anomalous Cepheids
• An absolute calibration of the near-infrared Period-Luminosity Relations of Type II Cepheids in the Milky Way and in the Large Magellanic Cloud
• Type II Cepheids Pulsating in the First Overtone from the OGLE Survey
• The spectroscopic binaries RV Tauri and DF Cygni
• Evidence for Binarity and Possible Disk Obscuration in Kepler Observations of the Pulsating RV Tau Variable DF Cygni
• Homogeneous Photometry VI: Variable Stars in the Leo I Dwarf Spheroidal Galaxy
• Diversity of dynamical phenomena in type II Cepheids of the OGLE collection
• From the Inner to Outer Milky Way: A Photometric Sample of 2.6 Million Red Clump Stars
• Chaos in hydrodynamic BL Herculis models
• Chaotic dynamics in the pulsation of DF Cygni, as observed by Kepler
• Finest light curve details, physical parameters, and period fluctuations of CoRoT RR Lyrae stars
• T Tauri stars in the SuperWASP and NSVS surveys
• Automated Extended Aperture Photometry of K2 variable stars
• Eclipsing Spotted Giant Star With K2 and Historical Photometry
• The Synthetic-Oversampling Method: Using Photometric Colors to Discover Extremely Metal-Poor Stars
• Metal-Poor Type II Cepheids with Periods Less Than Three Days
• Anomalous Cepheids discovered in a sample of Galactic short period Type II Cepheids
• OGLE-GAL-ACEP-091 -- The First Known Multi-Mode Anomalous Cepheid
• A young hierarchical triple system harbouring a candidate debris disc

Cited by in corpus (2)

• Cepheid Metallicity in the Leavitt Law (C- MetaLL) survey: VI: Radial abundance gradients of 29 chemical species in the Milky Way Disk
• Decoding the RVb Enigma of DF Cyg: Pulsations, Circumstellar Disks, and Post-RGB Evolution Revealed by Multi-Wavelength Observations