TESS observations of Cepheid stars: first light results

Abstract

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 seven anomalous Cepheids. The targets were chosen from fields with different stellar densities, both from the Galactic field and from the Magellanic System. Three targets have 2-minute cadence light curves available by the TESS Science Processing Operations Center: for the rest, we prepared custom light curves from the full-frame images with our own differential photometric FITSH pipeline. Our main goal was to explore the potential and the limitations of TESS concerning the various subtypes of Cepheids. We detected many low amplitude features: weak modulation, period jitter, and timing variations due to light-time effect. We also report signs of non-radial modes and the first discovery of such a mode in an anomalous Cepheid, the overtone star XZ Cet, which we then confirmed with ground-based multicolor photometric measurements. We prepared a custom photometric solution to minimize saturation effects in the bright fundamental-mode classical Cepheid, $\beta$ Dor with the lightkurve software, and we revealed strong evidence of cycle-to-cycle variations in the star. In several cases, however, fluctuations in the pulsation could not be distinguished from instrumental effects, such as contamination from nearby sources which also varies between sectors. Finally, we discuss how precise light curve shapes will be crucial not only for classification purposes but also to determine physical properties of these stars.

arXiv comment30 pages, 18 figures, accepted for publication in ApJS

References in corpus (93)

• Astropy: A Community Python Package for Astronomy
• The NumPy array: a structure for efficient numerical computation
• Gaia Data Release 2. Summary of the contents and survey properties
• The Gaia mission
• The Transiting Exoplanet Survey Satellite
• Final Results from the Hubble Space Telescope Key Project to Measure the Hubble Constant
• Milky Way Cepheid Standards for Measuring Cosmic Distances and Application to Gaia DR2: Implications for the Hubble Constant
• New Parallaxes of Galactic Cepheids from Spatially Scanning the Hubble Space Telescope: Implications for the Hubble Constant
• Hubble Space Telescope Fine Guidance Sensor Parallaxes of Galactic Cepheid Variable Stars: Period-Luminosity Relations
• Evidence for a systematic offset of -80 micro-arcseconds in the Gaia DR2 parallaxes
• The ASAS-SN Catalog of Variable Stars II: Uniform Classification of 412,000 Known Variables
• Using Cepheids to determine the galactic abundance gradient I. The solar neighbourhood
• FITSH -- a software package for image processing
• Insights into the Cepheid distance scale
• Accurate dynamical mass determination of a classical Cepheid in an eclipsing binary system
• A re-classification of Cepheids in the Gaia Data Release 2
• Rate of Period Change as a Diagnostic of Cepheid Properties
• High resolution spectroscopy for Cepheids distance determination. I. Line asymmetry
• The Konkoly Blazhko Survey: Is light-curve modulation a common property of RRab stars?
• Optical and Near-Infrared UBVRIJHK Photometry for the RR Lyrae stars in the Nearby Globular Cluster M4 (NGC 6121)
• Gaia Data Release 1. Testing the parallaxes with local Cepheids and RR Lyrae stars
• On the Blazhko Effect in RR Lyrae Stars
• Physical parameters and the projection factor of the classical Cepheid in the binary system OGLE-LMC-CEP-0227
• The Cepheid period -- luminosity -- metallicity relation based on Gaia DR2 data
• Kepler photometry of RRc stars: peculiar double-mode pulsations and period doubling
• High resolution spectroscopy for Cepheids distance determination. III. A relation between gamma-velocities and gamma-asymmetries
• High resolution spectroscopy for Cepheids distance determination. II. A period- projection factor relation
• Kepler photometry of the prototypical Blazhko star RR Lyr: An old friend seen in a new light
• Multiplicity of Galactic Cepheids and RR Lyrae stars from Gaia DR2 - I. Binarity from proper motion anomaly
• [Fe/H] relations for c-type RR Lyrae Variables based upon Fourier Coefficients
• Frequency analysis of Cepheids in the Large Magellanic Cloud. New types of classical Cepheid pulsators
• MOST photometry of the RRd Lyrae variable AQ Leo: Two radial modes, 32 combination frequencies, and beyond
• On the evolutionary and pulsation mass of Classical Cepheids: III. the case of the eclipsing binary Cepheid CEP0227 in the Large Magellanic Cloud
• The Eclipsing Binary Cepheid OGLE-LMC-CEP-0227 in the Large Magellanic Cloud: pulsation modelling of light and radial velocity curves
• Period and light curve fluctuations of the Kepler Cepheid V1154 Cyg
• Observational calibration of the projection factor of Cepheids. II. Application to nine Cepheids with HST/FGS parallax measurements
• Nonlinear Analysis of the Lightcurve of the Variable Star R Scuti
• Discovery of period doubling in BL Herculis stars of the OGLE survey. Observations and theoretical models
• Tuning in on Cepheids: Radial velocity amplitude modulations. A source of systematic uncertainty for Baade-Wesselink distances
• Observations of Cepheids with the MOST satellite: Contrast between Pulsation Modes
• The Araucaria Project: High-precision Cepheid astrophysics from the analysis of variables in double-lined eclipsing binaries
• Overtone and multi-mode RR Lyrae stars in the globular cluster M3
• Investigating Cepheid $\ell$ Carinae's Cycle-to-cycle Variations via Contemporaneous Velocimetry and Interferometry
• Anomalous Cepheids in the Large Magellanic Cloud: Insight into their origin and connection with the star formation history
• The VMC Survey. VIII. First results for Anomalous Cepheids
• Gaia Data Release 2: All-sky classification of high-amplitude pulsating stars
• Discovery of Cycle-to-cycle Modulated Spectral Line Variability and Velocity Gradients in Long-period Cepheids
• Survey of non-linear hydrodynamic models of type-II Cepheids
• The Kepler Cepheid V1154 Cyg revisited: light curve modulation and detection of granulation
• Polaris the Cepheid returns: 4.5 years of monitoring from ground and space
• Binary Properties from Cepheid Radial Velocities (CRaV)
• The ISLAnds Project III: Variable Stars in Six Andromeda Dwarf Spheroidal Galaxies
• Double-mode radial-non-radial RR Lyrae stars in the OGLE photometry of the Galactic bulge
• A Comparative Study of Multiwavelength Theoretical and Observed Light Curves of Cepheid Variables
• Proper identification of RR Lyrae Stars brighter than 12.5 mag
• When a Period Is Not a Full Stop: Light Curve Structure Reveals Fundamental Parameters of Cepheid and RR Lyrae Stars
• Double-mode radial-non-radial RR Lyrae stars. OGLE-IV photometry of two high cadence fields in the Galactic bulge
• An Updated Census of RR~Lyrae Stars in the Globular Cluster $\omega$~Centauri (NGC\,5139)
• Period doubling and Blazhko modulation in BL Herculis hydrodynamic models
• Non-radial pulsation in first overtone Cepheids of the Small Magellanic Cloud
• The census of non-radial pulsation in first-overtone RR Lyrae stars of the OGLE Galactic bulge collection
• CoRoT space photometry of seven Cepheids
• Variable turbulent convection as the cause of the Blazhko effect - testing the Stothers model
• Pulsation period variations in the RRc Lyrae star KIC 5520878
• Luminosities and infrared excess in Type II and anomalous Cepheids in the Large and Small Magellanic Clouds
• V473 Lyrae, a unique second-overtone Cepheid with two modulation cycles
• Image-based Classification of Variable Stars: First Results from Optical Gravitational Lensing Experiment Data
• Cepheid investigations using the Kepler space telescope
• Observational studies of Cepheid amplitudes. II Metallicity dependence of pulsation amplitudes
• Extended Aperture Photometry of K2 RR Lyrae stars
• The long-period Galactic Cepheid RS Puppis - III. A geometric distance from HST polarimetric imaging of its light echoes
• First observations of W Virginis stars with K2: detection of period doubling
• Periodicities of the RV Tau-type pulsating star DF Cygni: a combination of Kepler data with ground-based observations
• $12660$ spotted stars toward the OGLE Galactic bulge fields
• Investigating light curve modulation via kernel smoothing. II. New additional modes in single-mode OGLE classical Cepheids
• Amplitude variations of modulated RV Tauri stars support the dust obscuration model of the RVb phenomenon
• Unstable standard candles. Periodic light curve modulation in fundamental mode classical Cepheids
• On Binary Channels to Anomalous Cepheids
• Type II Cepheids Pulsating in the First Overtone from the OGLE Survey
• Probing Polaris' Puzzling Radial Velocity Signals - Pulsational (In-)Stability, Orbital Motion, and Bisector Variations
• Evidence for Binarity and Possible Disk Obscuration in Kepler Observations of the Pulsating RV Tau Variable DF Cygni
• A theoretical scenario for Galactic RR Lyrae in the Gaia database: constraints on the parallax offset
• Can turbulent convective variations drive the Blazhko cycle? Dynamical investigation of the Stothers idea
• Diversity of dynamical phenomena in type II Cepheids of the OGLE collection
• Chaotic dynamics in the pulsation of DF Cygni, as observed by Kepler
• The dynamical mass and evolutionary status of the type-II Cepheid in the eclipsing binary system OGLE-LMC-T2CEP-211 with a double-ring disk
• Finest light curve details, physical parameters, and period fluctuations of CoRoT RR Lyrae stars
• On the Metallicity Dependence of Classical Cepheid Light Amplitudes
• V473 Lyr, a modulated, period-doubled Cepheid, and U TrA, a double-mode Cepheid observed by MOST
• OGLE-ing the Magellanic System: Cepheids in the Bridge
• Anomalous Cepheids discovered in a sample of Galactic short period Type II Cepheids
• The anomalous Cepheid XZ Ceti
• On the Paradoxical Impact of Blending by Red Clump Giants

Cited by in corpus (34)

• Gaia DR3: Specific processing and validation of all-sky RR Lyrae and Cepheid stars -- The Cepheid sample
• TESS-Gaia Light Curve: a PSF-based TESS FFI light curve product
• First results on RR Lyrae stars with the TESS space telescope: untangling the connections between mode content, colors and distances
• Triply eclipsing triple stars in the northern TESS fields: TICs 193993801, 388459317 and 52041148
• Study of changes in the pulsation period of 148 Galactic Cepheid variables
• Cepheids with giant companions. I. Revealing a numerous population of double-lined binary Cepheids
• Accretion variability from minutes to decade timescales in the classical T Tauri star CR Cha
• VELOcities of CEpheids (VELOCE) I. High-precision radial velocities of Cepheids
• Asteroseismology of RR Lyrae stars with non-radial modes
• Variable stars in Local Group Galaxies -- V. The fast and early evolution of the low-mass Eridanus II dSph galaxy
• The OmegaWhite Survey for Short-Period Variable Stars VII: High amplitude, short period blue variables
• Frequency analysis of OGLE-IV photometry for classical Cepheids in Galactic fields: non-radial modes and modulations
• Accretion variability of the multiple T Tauri system VW Cha
• Frequency analysis of the first-overtone RR Lyrae stars based on the Extended Aperture Photometry from the K2 data
• V994 Her: A Unique Triply Eclipsing Sextuple Star System
• Time series analysis of bright TESS RRc stars: Additional modes, phase variations and more
• New Periodograms Separating Orbital Radial Velocities and Spectral Shape Variation
• First Overtone Cepheids of the OGLE Magellanic Cloud Collection -- beyond radial modes
• The TESS Mission Target Selection Procedure
• To Grow Old and Peculiar: A Survey of Anomalous Variable Stars in M80 and Age Determination using K2 and Gaia
• Non-radial modes in classical Cepheids. What to look for in spectroscopy?
• MOCKA -- A PLATO mock asteroseismic catalogue: Simulations for gravity-mode oscillators
• Non-evolutionary effects on period change in Magellanic Cepheids I. New binary systems revealed from Light Travel Time Effect
• The VELOCE Modulation Zoo I. Spectroscopic detection of non-radial modes in the first-overtone Cepheids BG Crucis, QZ Normae, V0391 Normae, and V0411 Lacertae
• On the incidence rate of RR Lyrae stars with non-radial modes
• Short- and long-term variations of the high mass accretion rate classical T Tauri star DR Tau
• Optimal frequency-domain analysis for spacecraft time series: Introducing the missing-data multitaper power spectrum estimator
• Type II and anomalous Cepheids in the Kepler K2 mission
• Pulsation in TESS Objects of Interest
• Testing ultralow amplitude Cepheid candidates in the Galactic disk by TESS and Gaia
• Connections between the cycle-to-cycle light curve and O-C variations of the non-Blazhko RR Lyrae stars
• The VELOCE modulation zoo III. Detecting additional pulsation modes in optical spectra of classical Cepheids using semi-partial distance correlation periodograms
• Exploring Low-Amplitude Variability in First Overtone Cepheids with TESS
• Double Mode Cepheids from the Zwicky Transient Facility Survey