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Stellar activity is the main limitation to the detection of Earth-twins using the RV technique. Despite many efforts in trying to mitigate the effect of stellar activity using empirical and statistical techniques, it seems that we are…

Solar and Stellar Astrophysics · Physics 2018-12-05 Xavier Dumusque

Characterization of the atmospheres of transiting exoplanets relies on accurate measurements of the extent of the optically thick area of the planet at multiple wavelengths with a precision $\lesssim$100 parts per million (ppm).…

Earth and Planetary Astrophysics · Physics 2017-09-06 Giuseppe Morello , Angelos Tsiaras , Ian D. Howarth , Derek Homeier

Doppler effect and Hubble effect in different models of space-time related to the space-time velocity of an observer are considered. The Doppler effect and Doppler shift frequency parameter are connected with the kinematic characteristics…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Sawa Manoff

We derive the scaling of differential rotation in both slowly- and rapidly-rotating convection zones using order of magnitude methods. Our calculations apply across stars and fluid planets and all rotation rates, as well as to both…

Solar and Stellar Astrophysics · Physics 2020-09-02 Adam S. Jermyn , Shashikumar M. Chitre , Pierre Lesaffre , Christopher A. Tout

We present the discovery of 34 comoving systems containing an ultra-cool dwarf found by means of the NOIRLab Source Catalog (NSC) DR2. NSC's angular resolution of $\sim$1" allows for the detection of small separation binaries with…

A multi-domain spectral method for computing very high precision 3-D stellar models is presented. The boundary of each domain is chosen in order to coincide with a physical discontinuity (e.g. the star's surface). In addition, a…

Astrophysics · Physics 2009-06-11 S. Bonazzola , E. Gourgoulhon , J. -A. Marck

A transiting planet eclipses part of the rotating stellar surface, thereby producing an anomalous Doppler shift of the stellar spectrum. Here I review how this "Rossiter-McLaughlin Effect" can be used to characterize exoplanetary systems.…

Astrophysics · Physics 2007-05-23 Joshua N. Winn

Phase curves, or the change in observed illumination of the planet as it orbits around its host star, help us to characterize their atmospheres. However, the variability of the host star can make their detection challenging: the presence of…

Earth and Planetary Astrophysics · Physics 2019-01-16 Diego Hidalgo , Roi Alonso , Enric Palle

Following the construction of the general effective theory for dark matter direct detection in 1203.3542, we perform an analysis of the experimental constraints on the full parameter space of elastically scattering dark matter. We review…

High Energy Physics - Phenomenology · Physics 2012-11-14 A. Liam Fitzpatrick , Wick Haxton , Emanuel Katz , Nicholas Lubbers , Yiming Xu

Radial differential rotation is an important parameter for stellar dynamo theory and for understanding angular momentum transport. We investigate the potential of using a large number of similar stars simultaneously to constrain their…

Solar and Stellar Astrophysics · Physics 2016-02-03 Hannah Schunker , Jesper Schou , Warrick Ball , Martin Bo Nielsen , Laurent Gizon

We describe a technique for deriving effective temperatures, surface gravities, rotation velocities, and radial velocities from high resolution near-IR spectra. The technique matches the observed near-IR spectra to spectra synthesized from…

Astrophysics · Physics 2009-11-10 G. W. Doppmann , D. T. Jaffe

Effects of magnetic field on stellar differential rotation are studied by comparing magnetohydrodynamic (MHD) models and their hydrodynamic (HD) counterparts in the broad range of rotation rate and in varying initial rotation profile.…

Solar and Stellar Astrophysics · Physics 2015-06-11 Jun Mabuchi , Youhei Masada , Akira Kageyama

Rapid planetary rotation can cause the equilibrium shape of a planet to be oblate. While planetary oblateness has mostly been probed by examining the subtle ingress and egress features in photometric transit light curves, we investigate the…

Earth and Planetary Astrophysics · Physics 2020-07-31 B. Akinsanmi , S. C. C. Barros , N. C. Santos , M. Oshagh , L. M. Serrano

Future generations of precise radial velocity (RV) surveys aim to achieve sensitivity sufficient to detect Earth mass planets orbiting in their stars' habitable zones. A major obstacle to this goal is astrophysical radial velocity noise…

Earth and Planetary Astrophysics · Physics 2016-04-27 Andrew Vanderburg , Peter Plavchan , John Asher Johnson , David R. Ciardi , Jonathan Swift , Stephen R. Kane

The measurement of Doppler velocity shifts in spectra is a ubiquitous theme in astronomy, usually handled by computing the cross-correlation of the signals, and finding the location of its maximum. This paper addresses the problem of the…

Astrophysics · Physics 2008-11-26 Carlos Allende Prieto

Context. The surface structures and dynamics of cool stars are characterized by the presence of convective motions and turbulent flows which shape the emergent spectrum. Aims. We used realistic three-dimensional radiative hydrodynamical…

Solar and Stellar Astrophysics · Physics 2018-03-14 A. Chiavassa , L. Casagrande , R. Collet , Z. Magic , L. Bigot , F. Thevenin , M. Asplund

High-precision astrometric and radial-velocity observations require accurate modelling of stellar motions in order to extrapolate measurements over long time intervals, and to detect deviations from uniform motion caused for example by…

Instrumentation and Methods for Astrophysics · Physics 2014-10-22 Alexey G. Butkevich , Lennart Lindegren

With about 700 confirmed extrasolar planets, it is time to move beyond discovery and towards characterization. Perhaps the most basic parameter of an extrasolar planet is its mass; however, this is very difficult to determine if the planet…

Earth and Planetary Astrophysics · Physics 2015-06-16 Kevin Gullikson , Michael Endl

Micro-Doppler-based target classification capabilities of the automotive radars can provide high reliability and short latency to the future active safety automotive features. A large number of pedestrians surrounding vehicle in practical…

Signal Processing · Electrical Eng. & Systems 2018-08-02 Petro Khomchuk , Inna Stainvas , Igal Bilik

Stellar magnetic activity produces time-varying distortions in the photospheric line profiles of solar-type stars. These lead to systematic errors in high-precision radial-velocity measurements, which limit efforts to discover and measure…