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Abstract We report new spectroscopic and interferometric observations of the Pleiades binary star Atlas, which played an important role nearly 3 decades ago in settling the debate over the distance to the cluster from ground-based and space-based determinations. We use the new measurements, together with other published and archival astrometric observations, to improve the determination of the 291 day orbit and the distance to Atlas (136.2 ± 1.4 pc). We also derive the main properties of the components, including their absolute masses (5.04 ± 0.17M_⊙and 3.64 ± 0.12M_⊙), sizes, effective temperatures, projected rotational velocities, and chemical compositions. We find that the more evolved primary star is rotationally distorted, and we are able to estimate its oblateness and the approximate orientation of its spin axis from the interferometric observations. The spin axis may well be aligned with the orbital axis. Models of stellar evolution from the Modules for Experiments in Stellar Astrophysics (or MESA) that account for rotation provide a good match to all of the primary’s global properties, and point to an initial angular rotation rate on the zero-age main sequence of about 55% of the breakup velocity. The current location of the star in the Hertzsprung–Russell diagram is near the very end of the hydrogen-burning main sequence, at an age of about 105 Myr, according to these models. Our spectroscopic analysis of the more slowly rotating secondary indicates that it is a helium-weak star, with other chemical anomalies. 

TheβPictoris 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,βPictoris c, has also been indirectly detected with radial velocity (RV) measurements. The star is a knownδScuti 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 theδScuti pulsations consistent with the known planetsβPictoris b and c and carry out an analysis of the stellar pulsations ofβPictoris 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 significantδScuti pulsations. We carried out an analysis with the open-source python package maelstrom to study the stability of the pulsation modes ofβPictoris in order to determine the long-term trends in the observed pulsations. We did not detect the expected signal forβPictoris b orβPictoris c. The expected time delay is 6 s forβPictoris c and 24 s forβPictoris b. 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 ofβPictoris using maelstrom showed that the modes themselves drift on the timescale of a year, fundamentally limiting our ability to detect exoplanets aroundβPictoris via pulsation timing. 

Abstract Photonic technologies offer numerous functionalities that can be used to realize astrophotonic instruments. The most spectacular example to date is the ESO Gravity instrument at the Very Large Telescope in Chile that combines the light-gathering power of four 8 m telescopes through a complex photonic interferometer. Fully integrated astrophotonic devices stand to offer critical advantages for instrument development, including extreme miniaturization when operating at the diffraction-limit, as well as integration, superior thermal and mechanical stabilization owing to the small footprint, and high replicability offering significant cost savings. Numerous astrophotonic technologies have been developed to address shortcomings of conventional instruments to date, including for example the development of photonic lanterns to convert from multimode inputs to single mode outputs, complex aperiodic fiber Bragg gratings to filter OH emission from the atmosphere, complex beam combiners to enable long baseline interferometry with for example, ESO Gravity, and laser frequency combs for high precision spectral calibration of spectrometers. Despite these successes, the facility implementation of photonic solutions in astronomical instrumentation is currently limited because of (1) low throughputs from coupling to fibers, coupling fibers to chips, propagation and bend losses, device losses, etc, (2) difficulties with scaling to large channel count devices needed for large bandwidths and high resolutions, and (3) efficient integration of photonics with detectors, to name a few. In this roadmap, we identify 24 key areas that need further development. We outline the challenges and advances needed across those areas covering design tools, simulation capabilities, fabrication processes, the need for entirely new components, integration and hybridization and the characterization of devices. To realize these advances the astrophotonics community will have to work cooperatively with industrial partners who have more advanced manufacturing capabilities. With the advances described herein, multi-functional integrated instruments will be realized leading to novel observing capabilities for both ground and space based platforms, enabling new scientific studies and discoveries.