@article{fdi:010092055,
  title = {{S}eparating the causes of {O}-{C} variations in an {RR} {L}yrae star with the {B}lazhko effect},
  author = {{S}ylla, {S}. and {K}olenberg, {K}. and {K}lotz, {A}. and {C}olas, {F}ran{\c{c}}ois and {B}aratoux, {D}avid and {L}e {B}orgne, {J}. {F}. and {B}enkhaldoun, {Z}. and {D}enoux, {E}. and {N}dao, {A}. {S}.},
  editor = {},
  language = {{ENG}},
  abstract = {{C}ontext. {T}o date, puzzlingly few bona fide {RR} {L}yrae stars have been identified in binaries. {B}inarity in pulsating stars can be revealed through well-timed photometric data over sufficiently long time bases because of the light travel time effect ({LTTE}) on the pulsations, which manifests as variation in the timings of maximum light in the {O}-{C} (observed minus calculated) diagram. {H}owever, {O}-{C} variations can also have other causes, such as the {B}lazhko effect or a sudden or gradual change in the main pulsation period. {A}ims. {W}e approach this challenge by disentangling the {B}lazhko effect and period changes from the potential {LTTE} on {V}1109 {C}as, an {RR} {L}yrae star suspected to be part of a binary system based on its {O}-{C} data in the {GEOS} database. {I}n doing so, we aim to uncover the subtler signals indicative of a companion ({LTTE}). {M}ethods. {W}e analysed nine years of ground-based photometric data, using {F}ourier analysis to model the pulsation modulated by the {B}lazhko effect. {F}rom the fit to the observed light curves, we constructed a refined {O}-{C} diagram without the scatter caused by {B}lazhko modulation. {S}ubsequently, we considered different possible scenarios, because distinguishing intrinsic period changes or breaks from the {LTTE} is challenging. {R}esults. {I}f the remaining {O}-{C} variation is due to a period break, refining the {O}-{C} diagram can almost entirely remove the trends. {I}f we interpret the variation as an {LTTE}, we can consider possible configurations. {W}hile we currently favour a period break as the explanation for the residual {O}-{C} variations, more data on the star in the forthcoming years will help reveal whether the {O}-{C} variations are due to the {LTTE} or intrinsic period changes. {C}onclusions. {O}ur study, based on a detailed light-curve fitting of {V}1109 {C}as, offers insights into the discernment between {B}lazhko modulation, intrinsic period breaks, and the {LTTE} in binary systems. {O}ur results highlight the complexity of determining binarity from {O}-{C} data traditionally used for detecting binary motion, calling for caution in this process.},
  keywords = {methods: data analysis ; techniques: photometric ; telescopes surveys ; binaries: general ; stars: variables: {RR} {L}yrae},
  booktitle = {},
  journal = {{A}stronomy and {A}strophysics},
  volume = {691},
  numero = {},
  pages = {{A}108 [11 p.]},
  ISSN = {0004-6361},
  year = {2024},
  DOI = {10.1051/0004-6361/202450674},
  URL = {https://www.documentation.ird.fr/hor/fdi:010092055},
}