Related papers: Color difference makes a difference: four planet c…
We present a detailed analysis of time-resolved optical spectra of the ZZ Ceti white dwarf, HS 0507+0434B. Using the wavelength dependence of observed mode amplitudes, we deduce the spherical degree, l, of the modes, most of which have l=1.…
The neutral sodium resonance doublet (Na i D) has been detected in the upper atmosphere of several close-in gas giants, through high-resolution transmission spectroscopy. We aim to investigate whether its variability is linked to the…
We present an analysis of 1524 spectra of Vega spanning 10 years, in which we search for periodic radial velocity variations. A signal with a periodicity of 0.676 days and a semi-amplitude of ~10 m/s is consistent with the rotation period…
Extra-solar planet search programs require high-precision velocity measurements. They need to study how to disentangle radial-velocity variations due to Doppler motion from the noise induced by stellar activity. We monitored the active K2V…
Stellar variability strongly impacts the search for low-mass exoplanets with radial velocity techniques. Two types of planet-free time series can be used to quantify this impact: models and direct solar observations after a subtraction of…
With an emphasis in detecting Earth-like planets set forth by the 2010 Decadal Survey and in searching for planets around M dwarfs set forth by the 2008 Exoplanet Task Force, radial velocity surveys with infrared echelle spectrometers will…
M-dwarf stars are promising targets for identifying and characterizing potentially habitable planets. K2-3 is a nearby (45 pc), early-type M dwarf hosting three small transiting planets, the outermost of which orbits close to the inner edge…
We present the detection of a peculiar high-frequency noise component in the 20 second cadence SAP (Simple Aperture Photometry) light curve of TESS (Transiting Exoplanets Survey Satellite). This effect (labeled as blue noise) may be…
Rotating radio transients (RRATs) are sporadically emitting pulsars detectable only through searches for single pulses. While over 100 RRATs have been detected, only a small fraction (roughly 20\%) have phase-connected timing solutions,…
We present the performances of a radial velocity measurement method that we developed for A-F type stars. These perfomances are evaluated through an extensive set of simulations, together with actual radial velocity observations of such…
Insufficient instrument thermo-mechanical stability is one of the many roadblocks for achieving 10cm/s Doppler radial velocity (RV) precision, the precision needed to detect Earth-twins orbiting Solar-type stars. Highly temperature and…
The ever increasing level of precision achieved by present and future radial-velocity instruments is opening the way to discovering very low-mass, long-period planets (e.g. solar-system analogs). These systems will be detectable as…
We present a deep-learning based approach for measuring small planetary radial velocities in the presence of stellar variability. We use neural networks to reduce stellar RV jitter in three years of HARPS-N sun-as-a-star spectra. We develop…
We perform a systematic search for rings around 168 Kepler planet candidates with sufficient signal-to-noise ratios that are selected from all the short-cadence data. We fit ringed and ringless models to their lightcurves, and compare the…
We present the results of a radial velocity survey of a sample of Hyades stars, and discuss the effects of stellar activity on radial velocity measurements. The level of radial velocity scatter due to rotational modulation of stellar…
We have used the SHARC II camera at Caltech Submillimeter Observatory to make 350 and 450 micron images of the Vega dust disk at spatial resolutions (FWHM) of 9.7" and 11.1", respectively. The images show a ring-like morphology (radius \~…
Aims: Stellar activity may complicate the analysis of high-precision radial-velocity spectroscopic data when looking for exoplanets signatures. We aim at quantifying the impact of stellar spots on stars with various spectral types and…
We derive expectations for signatures in the measured travel times of waves that interact with thermal anomalies and jets. A series of numerical experiments that involve the dynamic linear evolution of an acoustic wave field in a solar-like…
The smooth spin-down of young pulsars is perturbed by two non-deterministic phenomenon, glitches and timing noise. Although the timing noise provides insights into nuclear and plasma physics at extreme densities, it acts as a barrier to…
Jupiter-mass planets with large semi-major axes ($a > 1.0$ AU) occur at a higher rate around evolved intermediate mass stars. There is a pronounced paucity of close-in ($a < 0.6$ AU), intermediate period ($5 < P < 100$ days), low-mass…