The Solar Neighborhood XLVIII: Nine Giant Planets Orbiting Nearby K Dwarfs, and the CHIRON Spectrograph’s Radial Velocity Performance [PDF]
Astronomical Journal, 2021 We report initial results of a large radial velocity survey of K dwarfs up to a distance of 50 pc from the solar system, to look for stellar, brown dwarf, and Jovian planets using radial velocities from the CHIRON spectrograph on the CTIO/SMARTS 1.5 m ...
L. Paredes +7 more
semanticscholar +1 more source
Revisiting Radial Velocity Measurements of the K2-18 System with the Line-by-Line Framework [PDF]
, 2022 The cross-correlation function and template matching techniques have dominated the world of precision radial velocities for many years. Recently, a new technique, named line-by-line, has been developed as an outlier resistant way to efficiently extract ...
M. Radica +11 more
semanticscholar +1 more source
Measuring precise radial velocities on individual spectral lines [PDF]
Astronomy & Astrophysics, 2018 Context. Stellar activity is the main limitation to the detection of an Earth-twin using the radial-velocity (RV) technique. Despite many efforts in trying to mitigate the effect of stellar activity using empirical and statistical techniques, it seems ...
X. Dumusque
semanticscholar +1 more source
Data‐driven performance metrics for neural network learning
International Journal of Adaptive Control and Signal Processing, EarlyView., 2023 Summary Effectiveness of data‐driven neural learning in terms of both local mimima trapping and convergence rate is addressed. Such issues are investigated in a case study involving the training of one‐hidden‐layer feedforward neural networks with the extended Kalman filter, which reduces the search for the optimal network parameters to a state ...
Angelo Alessandri +2 more
wiley +1 more source
Advanced Engineering Materials, EarlyView., 2023 A novel method for tracking structural changes in gels using widely accessible microcomputed tomography is presented and validated for various hydro‐, alco‐, and aerogels. The core idea of the method is to track positions of micrometer‐sized tracer particles entrapped in the gel and relate them to the density of the gel network.
Anja Hajnal +3 more
wiley +1 more source
The Planetary Mass–Radius Relation and Its Dependence on Orbital Period as Measured by Transit Timing Variations and Radial Velocities [PDF]
, 2017 The two most common techniques for measuring planetary masses—the radial velocity (RV) and the transit timing variation (TTV) techniques—have been observed to yield systematically different masses for planets of similar radii.
S. Mills, T. Mazeh
semanticscholar +1 more source
Deriving High-Precision Radial Velocities [PDF]
, 2017 This chapter describes briefly the key aspects behind the derivation of precise radial velocities. I start by defining radial velocity precision in the context of astrophysics in general and exoplanet searches in particular.
P. Figueira
semanticscholar +1 more source
Radial velocities and metallicities from infrared Ca II triplet spectroscopy of open clusters II. Berkeley 23, King 1, NGC 559, NGC 6603 and NGC 7245 [PDF]
, 2015 Context: Open clusters are key to studying the formation and evolution of the Galactic disc. However, there is a deficiency of radial velocity and chemical abundance determinations for open clusters in the literature.
R. Carrera +17 more
semanticscholar +1 more source
The M 4 Core Project with HST – IV. Internal kinematics from accurate radial velocities of 2771 cluster members [PDF]
, 2015 We present a detailed study of the internal kinematics of the Galactic Globular Cluster M 4 (NGC 6121), by deriving the radial velocities from 7250 spectra for 2771 stars distributed from the upper part of the Red Giant Branch down to the Main Sequence ...
L. Malavolta +8 more
semanticscholar +1 more source
Bayesian re-analysis of the radial velocities of Gliese 581. Evidence in favour of only four planetary companions [PDF]
, 2011 Aims. The Gliese 581 planetary system has received attention because it has been proposed to host a low-mass planet in its habitable zone. We re-analyse the radial velocity measurements reported to contain six planetary signals to see whether these ...
M. Tuomi
semanticscholar +1 more source