The Kepler Cepheid V1154 Cyg revisited: light curve modulation and detection of granulation

Abstract

We present a detailed analysis of the bright Cepheid-type variable star V1154 Cygni using 4 years of continuous observations by the Kepler space telescope. We detected 28 frequencies using standard Fourier transform method.We identified modulation of the main pulsation frequency and its harmonics with a period of ~159 d. This modulation is also present in the Fourier parameters of the light curve and the O-C diagram. We detected another modulation with a period of about 1160 d. The star also shows significant power in the low-frequency region that we identified as granulation noise. The effective timescale of the granulation agrees with the extrapolated scalings of red giant stars. Non-detection of solar-like oscillations indicates that the pulsation inhibits other oscillations. We obtained new radial velocity observations which are in a perfect agreement with previous years data, suggesting that there is no high mass star companion of V1154 Cygni. Finally, we discuss the possible origin of the detected frequency modulations.

10 pages, 9 figures, accepted for publication in MNRAS

References in corpus (10)

• The connection between stellar granulation and oscillation as seen by the Kepler mission
• HD 181068: A Red Giant in a Triply-Eclipsing Compact Hierarchical Triple System
• Visibilities and bolometric corrections for stellar oscillation modes observed by Kepler
• Kepler photometry of the prototypical Blazhko star RR Lyr: An old friend seen in a new light
• Frequency analysis of Cepheids in the Large Magellanic Cloud. New types of classical Cepheid pulsators
• Long time-scale behavior of the Blazhko effect from rectified Kepler data
• Observations of Cepheids with the MOST satellite: Contrast between Pulsation Modes
• Polaris the Cepheid returns: 4.5 years of monitoring from ground and space
• V473 Lyrae, a unique second-overtone Cepheid with two modulation cycles
• Multidimensional realistic modelling of Cepheid-like variables-II: Analysis of a Cepheid model

Cited by in corpus (22)

• TESS observations of Cepheid stars: first light results
• High-precision distance measurements with classical pulsating stars
• The Secret Lives of Cepheids: $\delta$ Cep -- the Prototype of a New Class of Pulsating X-ray Variable Stars
• Multiplicity of Galactic Cepheids from long-baseline interferometry. IV. New detected companions from MIRC and PIONIER observations
• HARPS-N high spectral resolution observations of Cepheids I. The Baade-Wesselink projection factor of δ Cep revisited
• Study of changes in the pulsation period of 148 Galactic Cepheid variables
• TESS Data for Asteroseismology (T'DA) Stellar Variability Classification Pipeline: Set-Up and Application to the Kepler Q9 Data
• VELOcities of CEpheids (VELOCE) I. High-precision radial velocities of Cepheids
• Probing Polaris' Puzzling Radial Velocity Signals - Pulsational (In-)Stability, Orbital Motion, and Bisector Variations
• Revisiting the Kepler non-Blazhko RR Lyrae sample: Cycle-to-cyle variations and additional modes
• Frequency analysis of OGLE-IV photometry for classical Cepheids in Galactic fields: non-radial modes and modulations
• On Granulation and Irregular Variation of Red Supergiants
• V473 Lyr, a modulated, period-doubled Cepheid, and U TrA, a double-mode Cepheid observed by MOST
• Spectroscopic and photometric time series of the bright RRc star T Sex
• The phase curve of the ultra-hot Jupiter WASP-167b as seen by TESS
• Precise Fourier parameters of Cepheid Radial Velocity Curves
• Two Different Weak Modulations in ab-type RR Lyrae Variable V838 Cyg, and Potential Influence of Metal Abundance on Blazhko Modulation
• Modelling Stochastic Signatures in Classical Pulsators
• Period Variations for the Cepheid VZ Cyg
• A Multi-Year Photopolarimetric Study of the Semi-Regular Variable V CVn and Identification of Analogue Sources
• Variable stars with the Kepler space telescope
• The VELOCE modulation zoo III. Detecting additional pulsation modes in optical spectra of classical Cepheids using semi-partial distance correlation periodograms