The beta Pictoris b Hill sphere transit campaign. II. Searching for the signatures of the beta Pictoris exoplanets through time delay analysis of the delta Scuti pulsations

Abstract

The system is the closest known stellar system with directly detected gas giant planets, an edge-on circumstellar disc, and evidence of falling sublimating bodies and transiting exocomets. The inner planet has also been indirectly detected with radial velocity (RV) measurements. The star is a known pulsator, and the long-term stability of these pulsations opens up the possibility of indirectly detecting the gas giant planets through time delays of the pulsations due to a varying light travel time. We search for phase shifts in the pulsations consistent with the known planets and c and carry out an analysis of the stellar pulsations of beta Pictoris over a multi-year timescale. We used photometric data collected by the BRITE-Constellation, bRing, ASTEP, and TESS to derive a list of the strongest and most significant pulsations. We carried out an analysis with the open-source python package maelstrom to study the stability of the pulsation modes of beta Pictoris in order to determine the long-term trends in the observed pulsations. We did not detect the expected signal for or . The expected time delay is 6 seconds for and 24 seconds for . With simulations, we determined that the photometric noise in all the combined data sets cannot reach the sensitivity needed to detect the expected timing drifts. An analysis of the pulsational modes of beta Pictoris using maelstrom showed that the modes themselves drift on the timescale of a year, fundamentally limiting our ability to detect exoplanets around beta Pictoris via pulsation timing.