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Modeling and Calibration of Gaia, Hipparcos, and Tycho-2 astrometric data for the detection of dark companions
(2024-03-28)
Hidden within the Gaia satellite’s multiple data releases lies a valuable cache of dark companions. To facilitate the efficient and reliable detection of these companions via combined analyses involving the Gaia, Hipparcos, ...
Mitigating Modal Noise in Multimode Circular Fibres by Optical Agitation using a Galvanometer
(2024-01-02)
Modal noise appears due to the non-uniform and unstable distribution of light intensity among the finite number of modes in multimode fibres. It is an important limiting factor in measuring radial velocity precisely by ...
A blue depression in the optical spectra of M dwarfs
(2023-05-12)
A blue depression is found in the spectra of M dwarfs from 4000 to 4500A. This depression shows an increase toward lower temperatures though is particularly sensitive to gravity and metallicity. It is the single most ...
AlH lines in the blue spectrum of Proxima Centauri
(2022-11-30)
The recently-computed ExoMol line lists for isotopologues of AlH are used to analyse the blue spectrum (4000-4500 {\AA}) of Proxima Cen (M5.5 V). Comparison of the observed and computed spectra enables the identification ...
Stellar Atmospheric Parameters of M-type Stars from LAMOST DR8
(2022-06-23)
The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) Low Resolution Spectroscopic Survey (LRS) provides massive spectroscopic data of M-type stars, and the derived stellar parameters could bring vital ...
Optimized modeling of Gaia-Hipparcos astrometry for the detection of the smallest cold Jupiter and confirmation of seven low mass companions
(2021-08-03)
To fully constrain the orbits of low mass circumstellar companions, we conduct combined analyses of the radial velocity data as well as the Gaia and Hipparcos astrometric data for eight nearby systems. Our study shows that ...
Exploring the robustness of Keplerian signals to the removal of active and telluric features
(2020-10-22)
We examine the influence of activity- and telluric-induced radial velocity signals on high resolution spectra taken with an iodine absorption cell. We exclude 2 Angstrom spectral chunks containing active and telluric lines ...
The impact of unresolved magnetic spots on high precision radial velocity measurements
(2020-07-23)
The Doppler method of exoplanet detection has been extremely successful, but suffers from contaminating noise from stellar activity. In this work a model of a rotating star with a magnetic field based on the geometry of ...
Detection of the nearest Jupiter analog in radial velocity and astrometry data
(2019-10-21)
The presence of Jupiter is crucial to the architecture of the Solar System and models underline this to be a generic feature of planetary systems. We find the detection of the difference between the position and motion ...
PEXO : a global modeling framework for nanosecond timing, microsecond astrometry, and μm/s radial velocities
(2019-10-15)
The ability to make independent detections of the signatures of exoplanets with complementary telescopes and instruments brings a new potential for robust identification of exoplanets and precision characterization. We ...