Related papers: An improved quantification of HD 147379 b
We investigate the radial velocity variation of GJ 581 based on measurements from the HARPS and Keck HIRES spectrographs. A Fourier pre-whitening procedure is able to extract four planetary signals in the HARPS data and two from the Keck…
The star Kepler-1625 recently attracted considerable attention when an analysis of the stellar photometric time series from the Kepler mission was interpreted as showing evidence of a large exomoon around the transiting Jupiter-sized planet…
We report on radial velocity time series for two M0.0V stars, GJ338B and GJ338A, using the CARMENES spectrograph, complemented by ground-telescope photometry from Las Cumbres and Sierra Nevada observatories. We aim to explore the presence…
Stellar activity poses one of the main obstacles for the detection and characterisation of small exoplanets around cool stars, as it can induce radial velocity (RV) signals that can hide or mimic the presence of planetary companions.…
Stellar activity is the ultimate source of radial-velocity (RV) noise in the search for Earth-mass planets orbiting late-type main-sequence stars. We analyse the performance of four different indicators and the chromospheric index $\log…
The HIRES spectrograph, mounted on the $10$-m Keck-I telescope, belongs to a small group of radial-velocity (RV) instruments that produce stellar RVs with long-term precision down to $\sim1$ ms$^{-1}$. In $2017$, the HIRES team published…
The CARMENES instrument was conceived to deliver high-accuracy radial velocity (RV) measurements with long-term stability to search for temperate rocky planets around a sample of nearby cool stars. The broad wavelength coverage was designed…
The CARMENES survey is searching for Earth-like planets orbiting M dwarfs using the radial velocity method. Studying the stellar activity of the target stars is important to avoid false planet detections and to improve our understanding of…
Transmission spectroscopy presents one of the most successful approaches for investigating the atmospheres of exoplanets. We analyzed the near-infrared high-resolution transmission spectrum of a hot Saturn, HD 149026 b, taken using CARMENES…
CARMENES is a dual-channel high-resolution spectrograph at the 3.5 m Calar Alto telescope designed to detect low-mass planets around late-type dwarfs by measuring their radial velocities (RVs). High thermal stability in both the visible…
I present an empirical model for predicting a star's radial velocity jitter from its B-V color, activity level, and absolute magnitude. This model is based on observations of 450 well- observed stars from Keck Observatory for the California…
The doppler measurements of stars are diluted and distorted by stellar activity noise. Different choices of noise models and statistical methods have led to much controversy in the confirmation of exoplanet candidates obtained through…
We cross-match the GALEX and Kepler surveys to create a unique dataset with both ultraviolet (UV) measurements and highly precise photometric variability measurements in the visible light spectrum. As stellar activity is driven by magnetic…
We present three transit observations of HD 189733 b obtained with the high-resolution spectrograph CARMENES at Calar Alto. A strong absorption signal is detected in the near-infrared He I triplet at 10830 \AA{} in all three transits.…
Context. Variability caused by stellar activity represents a challenge to the discovery and characterization of terrestrial exoplanets and complicates the interpretation of atmospheric planetary signals. Aims. We aim to use a detailed…
Kepler-419 is a planetary system discovered by the Kepler photometry which is known to harbour two massive giant planets: [...] Here we present new radial velocity (RV) measurements secured over more than two years with the SOPHIE…
We explore the feasibility of detecting Earth analogs around Sun-like stars using the radial velocity method by investigating one of the largest radial velocities datasets for the one of the most stable radial-velocity stars HD20794. We…
The study of multiple extrasolar planetary systems has the opportunity to obtain constraints for the planetary masses and orbital inclinations via the detection of mutual perturbations. The analysis of precise radial velocity measurements…
We conduct experiments on both real and synthetic radial velocity (RV) data to quantify the impact that observing cadence, the number of RV observations, and undetected companions all have on the accuracy of small planet mass measurements.…
Radial velocity surveys are examined in terms of eigenmode analysis within the framework of CDM-like family of models. Rich surveys such as MARK III and SFI, which consist of more than $10^{3}$ radial velocities, are found to have a few…