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Journal articles on the topic 'Radial velocity (HARPS. SOPHIE...)'

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Published: 8 June 2024

Last updated: 31 July 2025

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1

Baycroft, Thomas A., Amaury H. M. J. Triaud, and Dong Lai. "Progress report on the BEBOP search for circumbinary planets with radial velocities." Proceedings of the International Astronomical Union 18, S382 (2022): 51–58. http://dx.doi.org/10.1017/s1743921323004180.

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AbstractThe BEBOP (Binaries Escorted By Orbiting Planets) survey is a search for circumbinary planets using the radial velocity spectrographs HARPS and SOPHIE, currently focusing on single-lined binaries with a mass ratio < 0.3. Circumbinary systems are an important testing ground for planet formation theories as the dynamically complex influence of the binary makes planet formation and survival more difficult. Here we present the results of the survey so far including: confirmed planets such as BEBOP-1c the first circumbinary planet detected in radial velocity; the status of our observatio

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Rey, J., F. Bouchy, M. Stalport, et al. "Brown dwarf companion with a period of 4.6 yr interacting with the hot Jupiter CoRoT-20 b." Astronomy & Astrophysics 619 (November 2018): A115. http://dx.doi.org/10.1051/0004-6361/201833180.

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We report the discovery of an additional substellar companion in the CoRoT-20 system based on six years of HARPS and SOPHIE radial velocity follow-up. CoRoT-20 c has a minimum mass of 17 ± 1 MJup and orbits the host star in 4.59 ± 0.05 yr, with an orbital eccentricity of 0.60 ± 0.03. This is the first identified system with an eccentric hot Jupiter and an eccentric massive companion. The discovery of the latter might be an indication of the migration mechanism of the hot Jupiter, via the Lidov–Kozai effect. We explore the parameter space to determine which configurations would trigger this typ

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Husnoo, Nawal, Frédéric Pont, Tsevi Mazeh, Daniel Fabrycky, Guillaume Hébrard, and Claire Moutou. "Revisiting the eccentricities of hot Jupiters." Proceedings of the International Astronomical Union 6, S276 (2010): 243–47. http://dx.doi.org/10.1017/s1743921311020254.

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AbstractMost short period transiting exoplanets have circular orbits, as expected from an estimation of the circularisation timescale using classical tidal theory. Interestingly, a small number of short period transiting exoplanets seem to have orbits with a small eccentricity. Such systems are valuable as they may indicate that some key physics is missing from formation and evolution models. We have analysed the results of a campaign of radial velocity measurements of known transiting planets with the SOPHIE and HARPS spectrographs using Bayesian methods and obtained new constraints on the or

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Borgniet, S., A. M. Lagrange, N. Meunier, et al. "Extrasolar planets and brown dwarfs around AF-type stars." Astronomy & Astrophysics 621 (January 2019): A87. http://dx.doi.org/10.1051/0004-6361/201833431.

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Context. The impact of stellar mass on the properties of giant planets is still not fully understood. Main-sequence (MS) stars more massive than the Sun remain relatively unexplored in radial velocity (RV) surveys, due to their characteristics which hinder classical RV measurements. Aims. Our aim is to characterize the close (up to ~2 au) giant planet (GP) and brown dwarf (BD) population around AF MS stars and compare this population to stars with different masses. Methods. We used the SOPHIE spectrograph located on the 1.93 m telescope at Observatoire de Haute-Provence to observe 125 northern

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Grandjean, A., A. M. Lagrange, N. Meunier, et al. "A SOPHIE RV search for giant planets around young nearby stars (YNS)." Astronomy & Astrophysics 650 (June 2021): A39. http://dx.doi.org/10.1051/0004-6361/202039672.

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Context. The search of close (a ≲ 5 au) giant planet (GP) companions with radial velocity (RV) around young stars and the estimate of their occurrence rates is important to constrain the migration timescales. Furthermore, this search will allow the giant planet occurrence rates to be computed at all separations via the combination with direct imaging techniques. The RV search around young stars is a challenge as they are generally faster rotators than older stars of similar spectral types and they exhibit signatures of magnetic activity (spots) or pulsation in their RV time series. Specific an

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Cretignier, M., X. Dumusque, N. C. Hara, and F. Pepe. "YARARA: Significant improvement in RV precision through post-processing of spectral time series." Astronomy & Astrophysics 653 (September 2021): A43. http://dx.doi.org/10.1051/0004-6361/202140986.

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Aims. Even the most precise radial-velocity instruments gather high-resolution spectra that present systematic errors that a data reduction pipeline cannot identify and correct for efficiently by simply analysing a set of calibrations and a single science frame. In this paper we aim at improving the radial-velocity precision of HARPS measurements by ‘cleaning’ individual extracted spectra using the wealth of information contained in spectral time series. Methods. We developed YARARA, a post-processing pipeline designed to clean high-resolution spectra of instrumental systematics and atmospheri

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Dumusque, X., M. Cretignier, D. Sosnowska, et al. "Three years of HARPS-N high-resolution spectroscopy and precise radial velocity data for the Sun." Astronomy & Astrophysics 648 (April 2021): A103. http://dx.doi.org/10.1051/0004-6361/202039350.

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Context. The solar telescope connected to HARPS-N has been observing the Sun since the summer of 2015. Such a high-cadence, long-baseline data set is crucial for understanding spurious radial-velocity signals induced by our Sun and by the instrument. On the instrumental side, this data set allowed us to detect sub- m s−1 systematics that needed to be corrected for. Aims. The goals of this manuscript are to (i) present a new data reduction software for HARPS-N, (ii) demonstrate the improvement brought by this new software during the first three years of the HARPS-N solar data set, and (iii) rel

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Damasso, M., A. S. Bonomo, N. Astudillo-Defru, et al. "Eyes on K2-3: A system of three likely sub-Neptunes characterized with HARPS-N and HARPS." Astronomy & Astrophysics 615 (July 2018): A69. http://dx.doi.org/10.1051/0004-6361/201732459.

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Context. 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 of the stellar (optimistic) habitable zone. The K2-3 system is well suited for follow-up characterization studies aimed at determining accurate masses and bulk densities of the three planets. Aims. Using a total of 329 radial velocity measurements collected over 2.5 years with the HARPS-N and HARPS spectrographs and a proper treatment of the stella

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Bonfils, X., J. M. Almenara, R. Cloutier, et al. "Radial velocity follow-up of GJ1132 with HARPS." Astronomy & Astrophysics 618 (October 2018): A142. http://dx.doi.org/10.1051/0004-6361/201731884.

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The source GJ1132 is a nearby red dwarf known to host a transiting Earth-size planet. After its initial detection, we pursued an intense follow-up with the HARPS velocimeter. We now confirm the detection of GJ1132b with radial velocities alone. We refined its orbital parameters, and in particular, its mass (mb = 1.66 ± 0.23 M⊕), density (ρb = 6.3 ± 1.3 g cm−3), and eccentricity (eb < 0.22; 95%). We also detected at least one more planet in the system. GJ1132c is a super-Earth with period Pc = 8.93 ± 0.01 days and minimum mass mc sinic = 2.64 ± 0.44 M⊕. Receiving about 1.9 times more flux th

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Zhao, Lily L., Xavier Dumusque, Eric B. Ford, et al. "The Extreme Stellar-signals Project. III. Combining Solar Data from HARPS, HARPS-N, EXPRES, and NEID." Astronomical Journal 166, no. 4 (2023): 173. http://dx.doi.org/10.3847/1538-3881/acf83e.

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Abstract We present an analysis of Sun-as-a-star observations from four different high-resolution, stabilized spectrographs—HARPS, HARPS-N, EXPRES, and NEID. With simultaneous observations of the Sun from four different instruments, we are able to gain insight into the radial velocity precision and accuracy delivered by each of these instruments and isolate instrumental systematics that differ from true astrophysical signals. With solar observations, we can completely characterize the expected Doppler shift contributed by orbiting Solar System bodies and remove them. This results in a data set

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Delisle, J. B., D. Ségransan, X. Dumusque, et al. "The HARPS search for southern extra-solar planets." Astronomy & Astrophysics 614 (June 2018): A133. http://dx.doi.org/10.1051/0004-6361/201732529.

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We report the discovery of four super-Earth planets around HD 215152, with orbital periods of 5.76, 7.28, 10.86, and 25.2 d, and minimum masses of 1.8, 1.7, 2.8, and 2.9 M⊕ respectively. This discovery is based on 373 high-quality radial velocity measurements taken by HARPS over 13 yr. Given the low masses of the planets, the signal-to-noise ratio is not sufficient to constrain the planet eccentricities. However, a preliminary dynamical analysis suggests that eccentricities should be typically lower than about 0.03 for the system to remain stable. With two pairs of planets with a period ratio

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Haywood, R. D., A. Collier Cameron, D. Queloz, et al. "Disentangling planetary orbits from stellar activity in radial-velocity surveys." International Journal of Astrobiology 13, no. 2 (2014): 155–57. http://dx.doi.org/10.1017/s147355041300044x.

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AbstractThe majority of extra-solar planets have been discovered (or confirmed after follow-up) through radial-velocity (RV) surveys. Using ground-based spectrographs such as High Accuracy Radial Velocity Planetary Search (HARPS) and HARPS-North, it is now possible to detect planets that are only a few times the mass of the Earth. However, the presence of dark spots on the stellar surface produces RV signals that are very similar in amplitude to those caused by orbiting low-mass planets. Disentangling these signals has thus become the biggest challenge in the detection of Earth-mass planets us

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Carleo, Ilaria, Silvano Desidera, Alessandro Sozzetti, et al. "Disproving the High-eccentricity Planet HD 220773b." Research Notes of the AAS 8, no. 6 (2024): 161. http://dx.doi.org/10.3847/2515-5172/ad57b5.

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Abstract HD 220773 has been announced to host a giant planet in an eccentric orbit. Global Architecture of Planetary Systems collaboration followed this target up with the HARPS-N spectrograph at Telescopio Nazionale Galileo, in order to search for additional small planets in the system. This radial velocity monitoring produced approximately 130 HARPS-N data points, leading to the refutation of the announced planet.

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Trifonov, Trifon, Lev Tal-Or, Mathias Zechmeister, Adrian Kaminski, Shay Zucker, and Tsevi Mazeh. "Public HARPS radial velocity database corrected for systematic errors." Astronomy & Astrophysics 636 (April 2020): A74. http://dx.doi.org/10.1051/0004-6361/201936686.

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Context. The High Accuracy Radial velocity Planet Searcher (HARPS) spectrograph has been mounted since 2003 at the ESO 3.6 m telescope in La Silla and provides state-of-the-art stellar radial velocity (RV) measurements with a precision down to ∼1 m s−1. The spectra are extracted with a dedicated data-reduction software (DRS), and the RVs are computed by cross-correlating with a numerical mask. Aims. This study has three main aims: (i) Create easy access to the public HARPS RV data set. (ii) Apply the new public SpEctrum Radial Velocity AnaLyser (SERVAL) pipeline to the spectra, and produce a m

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Hartmann, M., and A. P. Hatzes. "A radial-velocity survey of Ap stars with HARPS." Astronomy & Astrophysics 582 (October 2015): A84. http://dx.doi.org/10.1051/0004-6361/201425320.

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Borsa, F., M. Rainer, A. S. Bonomo, et al. "The GAPS Programme with HARPS-N at TNG." Astronomy & Astrophysics 631 (October 16, 2019): A34. http://dx.doi.org/10.1051/0004-6361/201935718.

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Aims. In the framework of the GAPS project, we observed the planet-hosting star KELT-9 (A-type star, v sin i ~ 110 km s−1) with the HARPS-N spectrograph at the Telescopio Nazionale Galileo. In this work we analyse the spectra and the extracted radial velocities to constrain the physical parameters of the system and to detect the planetary atmosphere of KELT-9b. Methods. We extracted the mean stellar line profiles from the high-resolution optical spectra via an analysis based on the least-squares deconvolution technique. Then we computed the stellar radial velocities with a method optimised for

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Teixeira, Ramachrisna, Christine Ducourant, Gael Chauvin, Alberto G. O. Krone–Martins, Mickael Bonnefoy, and Inseok Song. "Membership status of TWA22AB." Proceedings of the International Astronomical Union 5, S266 (2009): 540–43. http://dx.doi.org/10.1017/s1743921309992006.

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AbstractUsing the ESO NTT/SUSI2 telescope, we observed TWA22AB during five different observing runs over 1.2 years to measure its trigonometric parallax and proper motion. HARPS at the ESO 3.6m telescope was also used to measure the system's radial velocity over 2 years. Based on trigonometric-parallax, proper-motion and radial-velocity measurements, we re-analyzed the membership of TWA22AB of the young, nearby associations TW Hydrae, β Pictoris and Tucana–Horologium.

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Artigau, Étienne, Charles Cadieux, Neil J. Cook, et al. "Line-by-line Velocity Measurements: an Outlier-resistant Method for Precision Velocimetry." Astronomical Journal 164, no. 3 (2022): 84. http://dx.doi.org/10.3847/1538-3881/ac7ce6.

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Abstract We present a new algorithm for precision radial velocity (pRV) measurements, a line-by-line (LBL) approach designed to handle outlying spectral information in a simple but efficient manner. The effectiveness of the LBL method is demonstrated on two data sets, one obtained with SPIRou on Barnard’s star, and the other with the High Accuracy Radial velocity Planet Searcher (HARPS) on Proxima Centauri. In the near-infrared, the LBL provides a framework for meters-per-second-level accuracy in pRV measurements despite the challenges associated with telluric absorption and sky emission lines

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Lagrange, A. M., K. De Bondt, N. Meunier, M. Sterzik, H. Beust та F. Galland. "Constraints on planets aroundβ Pic with Harps radial velocity data". Astronomy & Astrophysics 542 (25 травня 2012): A18. http://dx.doi.org/10.1051/0004-6361/201117985.

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Suárez Mascareño, A., R. Rebolo, J. I. González Hernández, et al. "HADES RV programme with HARPS-N at TNG." Astronomy & Astrophysics 612 (April 2018): A89. http://dx.doi.org/10.1051/0004-6361/201732143.

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We aim to investigate the presence of signatures of magnetic cycles and rotation on a sample of 71 early M-dwarfs from the HADES RV programme using high-resolution time-series spectroscopy of the Ca II H&K and Hα chromospheric activity indicators, the radial velocity series, the parameters of the cross correlation function and the V -band photometry. We used mainly HARPS-N spectra, acquired over 4 yr, and add HARPS spectra from the public ESO database and ASAS photometry light-curves as support data, extending the baseline of the observations of some stars up to 12 yr. We provide log10(R′H

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Demangeon, O. D. S., S. Dalal, G. Hébrard, et al. "The SOPHIE search for northern extrasolar planets." Astronomy & Astrophysics 653 (September 2021): A78. http://dx.doi.org/10.1051/0004-6361/202141079.

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Context. Due to their low transit probability, the long-period planets are, as a population, only partially probed by transit surveys. Radial velocity surveys thus have a key role to play, in particular for giant planets. Cold Jupiters induce a typical radial velocity semi-amplitude of 10 m s−1, which is well within the reach of multiple instruments that have now been in operation for more than a decade. Aims. We take advantage of the ongoing radial velocity survey with the SOPHIE high-resolution spectrograph, which continues the search started by its predecessor ELODIE to further characterize

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Santerne, Alexandre, Claire Moutou, and François Bouchy. "Resolving blended radial velocities." Proceedings of the International Astronomical Union 6, S276 (2010): 549–50. http://dx.doi.org/10.1017/s174392131102117x.

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AbstractIn space, photometric surveys are very efficient to detect small transiting planets or stars which are contaminated by blended eclipsing binaries. We present some simulations compared to radial velocity (RV) observations obtained with the SOPHIE spectrograph (OHP, France) in order to determine the true nature of a brown dwarf candidate revealed by CoRoT: a background eclipsing binary diluted by a foreground star.

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Coffinet, A., C. Lovis, X. Dumusque, and F. Pepe. "New wavelength calibration of the HARPS spectrograph." Astronomy & Astrophysics 629 (August 29, 2019): A27. http://dx.doi.org/10.1051/0004-6361/201833272.

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Context. Doppler spectroscopy has been used in astronomy for more than 150 yr. In particular, it has permitted us to detect hundreds of exoplanets over the past 20 yr, and the goal today of detecting Earth-like planets requires a precision around 0.1 m s−1 or better. Doppler spectroscopy has also been and will be of major importance for other studies such as the variability of fundamental constants and cosmological studies. For all these applications, it is crucial to have the best possible wavelength calibration. Despite the fact that the HARPS spectrograph has been operational at the 3.6-m E

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Bouchy, F. "Future Doppler Ground-Based Search for Solar-Like Oscillations with HARPS." International Astronomical Union Colloquium 185 (2002): 474–75. http://dx.doi.org/10.1017/s0252921100016857.

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Observations of solar-like oscillation frequencies allow us to constrain the theory of structure and evolution of stars with an outer convective zone. Recent improvements in radial velocity measurements have led to p-mode detection on Procyon (Martic et al., 1999) and β Hydri (Bedding et al., 2001; Carrier et al., 2001a). Very recently, characterization of the p-modes of α Cen A has been made with the spectrograph CORALIE mounted on the 1.2-m Swiss telescope at the ESO La Silla Observatory (Bouchy & Carrier, 2001, Carrier et al., these proceedings). The power of the radial velocity techniq

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Cloutier, R., N. Astudillo-Defru, R. Doyon, et al. "Confirmation of the radial velocity super-Earth K2-18c with HARPS and CARMENES." Astronomy & Astrophysics 621 (January 2019): A49. http://dx.doi.org/10.1051/0004-6361/201833995.

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In an earlier campaign to characterize the mass of the transiting temperate super-Earth K2-18b with HARPS, a second, non-transiting planet was posited to exist in the system at ~9 days. Further radial velocity follow-up with the CARMENES spectrograph visible channel revealed a much weaker signal at 9 days, which also appeared to vary chromatically and temporally, leading to the conclusion that the origin of the 9-day signal was more likely related to stellar activity than to a planetary presence. Here we conduct a detailed reanalysis of all available RV time-series – including a set of 31 prev

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Hagelberg, Janis, Damien Ségransan, Stéphane Udry, and François Wildi. "GRAPHIC: The Geneva Reduction and Analysis Pipeline for High-contrast Imaging of planetary Companions." Proceedings of the International Astronomical Union 8, S299 (2013): 38–39. http://dx.doi.org/10.1017/s174392131300776x.

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AbstractWe present a new analysis and reduction pipeline for the detection of planetary companions using Angular Differential Imaging. The pipeline uses Fourier transforms for image shifting and rotation in order to achieve very low signal loss. Furthermore it is parallelised in order to run on computer clusters of up to 1024 cores. The pipeline was developed in Geneva for the ongoing direct imaging campaign for stars with radial velocity drifts in the HARPS and CORALIE radial-velocity planet-search surveys. In addition to that, a disk mode has been implemented in the context of observations o

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González-Álvarez, E., A. Petralia, G. Micela, et al. "HADES RV Programme with HARPS-N at TNG." Astronomy & Astrophysics 649 (May 2021): A157. http://dx.doi.org/10.1051/0004-6361/202140490.

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Context. The high number of super-Earth and Earth-like planets in the habitable zone detected around M-dwarf stars in recent years has revealed these stellar objects to be the key to planetary radial velocity (RV) searches. Aims. Using the HARPS-N spectrograph within The HArps-n red Dwarf Exoplanet Survey (HADES) we have reached the precision needed to detect small planets with a few Earth masses using the spectroscopic radial velocity technique. HADES is mainly focused on the M-dwarf population of the northern hemisphere. Methods. We obtained 138 HARPS-N RV measurements between 2013 May and 2

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Hébrard, G., F. Bouchy, F. Pont, et al. "Misaligned spin-orbit in the XO-3 planetary system?" Proceedings of the International Astronomical Union 4, S253 (2008): 508–11. http://dx.doi.org/10.1017/s1743921308027075.

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AbstractThe SOPHIE Consortium started a large program of exoplanets search and characterization in the Northern hemisphere with the new spectrograph SOPHIE at the 1.93-m telescope of Haute-Provence Observatory, France. The objectives of this program are to characterize the zoo of exoplanets and to bring strong constraints on their processes of formation and evolution using the radial velocity technique. We present here new SOPHIE measurements of the transiting planet host star XO-3. This allowed us to observe the Rossiter-McLaughlin effect and to refine the parameters of the planet. The unusua

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Zechmeister, M., A. Reiners, P. J. Amado, et al. "Spectrum radial velocity analyser (SERVAL)." Astronomy & Astrophysics 609 (December 22, 2017): A12. http://dx.doi.org/10.1051/0004-6361/201731483.

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Context. The CARMENES survey is a high-precision radial velocity (RV) programme that aims to detect Earth-like planets orbiting low-mass stars. Aims. We develop least-squares fitting algorithms to derive the RVs and additional spectral diagnostics implemented in the SpEctrum Radial Velocity AnaLyser (SERVAL), a publicly available python code. Methods. We measured the RVs using high signal-to-noise templates created by coadding all available spectra of each star. We define the chromatic index as the RV gradient as a function of wavelength with the RVs measured in the echelle orders. Additionall

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Burleigh, M. "The Next Generation Transit Survey." Proceedings of the International Astronomical Union 14, S339 (2017): 22. http://dx.doi.org/10.1017/s1743921318002132.

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AbstractThis talk introduced and described the Next Generation Transit Survey (NGTS), which is a new ground-based transit survey operating at the ESO Paranal Observatory. NGTS has been designed to achieve better photometric precision than previous ground-based surveys; it aims to detect Neptune-sized planets around Sun-like stars, and sub-Neptunes around M dwarfs that are sufficiently bright for radial-velocity confirmation and mass determination. NGTS is also optimised for ground-based follow up of exoplanet candidates from TESS and PLATO. I presented early results from the survey, and descri

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Cersullo, F., A. Coffinet, B. Chazelas, C. Lovis, and F. Pepe. "New wavelength calibration for echelle spectrographs using Fabry-Pérot etalons." Astronomy & Astrophysics 624 (April 2019): A122. http://dx.doi.org/10.1051/0004-6361/201833852.

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Context. The study of Earth-mass extrasolar planets via the radial-velocity technique and the measurement of the potential cosmological variability of fundamental constants call for very-high-precision spectroscopy at the level of δλ/λ < 10−9. Only an accurate wavelength calibration of the spectrograph can guarantee that the aimed precision is achieved over a multi-exposure and multi-epoch data set. Wavelength accuracy is obtained by providing two fundamental ingredients: 1) an absolute and information-rich wavelength source and 2) the ability of the spectrograph and its data reduction of t

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Hojjatpanah, S., M. Oshagh, P. Figueira, et al. "The correlation between photometric variability and radial velocity jitter." Astronomy & Astrophysics 639 (July 2020): A35. http://dx.doi.org/10.1051/0004-6361/202038035.

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Context. Characterizing the relation between stellar photometric variability and radial velocity (RV) jitter can help us to better understand the physics behind these phenomena. The current and upcoming high precision photometric surveys such as TESS, CHEOPS, and PLATO will provide the community with thousands of new exoplanet candidates. As a consequence, the presence of such a correlation is crucial in selecting the targets with the lowest RV jitter for efficient RV follow-up of exoplanetary candidates. Studies of this type are also crucial to design optimized observational strategies to mit

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Wise, Alexander, Peter Plavchan, Xavier Dumusque, Heather Cegla, and Duncan Wright. "Spectral Line Depth Variability in Radial Velocity Spectra." Astrophysical Journal 930, no. 2 (2022): 121. http://dx.doi.org/10.3847/1538-4357/ac649b.

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Abstract Stellar active regions, including spots and faculae, can create radial velocity (RV) signals that interfere with the detection and mass measurements of low-mass exoplanets. In doing so, these active regions affect each spectral line differently, but the origin of these differences is not fully understood. Here we explore how spectral line variability correlated with S-index (Ca H and K emission) is related to the atomic properties of each spectral line. Next, we develop a simple analytic stellar atmosphere model that can account for the largest sources of line variability with S-index

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Maldonado, J., A. Petralia, M. Damasso, et al. "HADES RV programme with HARPS-N at TNG." Astronomy & Astrophysics 651 (July 2021): A93. http://dx.doi.org/10.1051/0004-6361/202141141.

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Context. It is now well-established that small, rocky planets are common around low-mass stars. However, the detection of such planets is challenged by the short-term activity of host stars. Aims. The HARPS-N red Dwarf Exoplanet Survey programme is a long-term project at the Telescopio Nazionale Galileo aimed at monitoring nearby, early-type, M dwarfs, using the HARPS-N spectrograph to search for small, rocky planets. Methods. A total of 174 HARPS-N spectroscopic observations of the M0.5V-type star GJ 9689 taken over the past seven years have been analysed. We combined these data with photomet

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Dumusque, Xavier, Cristophe Lovis, Stephane Udry, and Nuno C. Santos. "Stellar noise and planet detection. II. Radial-velocity noise induced by magnetic cycles." Proceedings of the International Astronomical Union 6, S276 (2010): 530–32. http://dx.doi.org/10.1017/s1743921311021090.

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AbstractFor the 451 stars of the HARPS high precision program, we study correlations between the radial-velocity (RV) variation and other parameters of the Cross Correlated Function (CCF). After a careful target selection, we found a very good correlation between the slope of the RV-activity index (log(R'HK)) correlation and the Teff for dwarf stars. This correlation allow us to correct RV from magnetic cycles given the activity index and the Teff.

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Anna John, A., A. Collier Cameron, J. P. Faria, et al. "Sub-m s−1 upper limits from a deep HARPS-N radial-velocity search for planets orbiting HD 166620 and HD 144579." Monthly Notices of the Royal Astronomical Society 525, no. 2 (2023): 1687–704. http://dx.doi.org/10.1093/mnras/stad2381.

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ABSTRACT Minimizing the impact of stellar variability in radial velocity (RV) measurements is a critical challenge in achieving the 10 cm s−1 precision needed to hunt for Earth twins. Since 2012, a dedicated programme has been underway with HARPS-N, to conduct a blind RV rocky planets search (RPS) around bright stars in the Northern hemisphere. Here we describe the results of a comprehensive search for planetary systems in two RPS targets, HD 166620 and HD 144579. Using wavelength-domain line-profile decorrelation vectors to mitigate the stellar activity and performing a deep search for planet

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Dalal, S., F. Rescigno, M. Cretignier, et al. "Trio of super-Earth candidates orbiting K-dwarf HD 48948: a new habitable zone candidate." Monthly Notices of the Royal Astronomical Society 531, no. 4 (2024): 4464–81. http://dx.doi.org/10.1093/mnras/stae1367.

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ABSTRACT We present the discovery of three super-Earth candidates orbiting HD 48948, a bright K-dwarf star with an apparent magnitude of $m_V$ = 8.58 mag. As part of the HARPS-N Rocky Planet Search programme, we collect 189 high-precision radial velocity measurements using the HARPS-N spectrograph from 2013 October 6, to 2023 April 16. Various methodologies are applied to extract the radial velocities from the spectra, and we conduct a comprehensive comparative analysis of the outcomes obtained through these diverse extraction techniques. To ensure the robustness of our findings, we employ sev

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Unger, N., D. Ségransan, D. Queloz, et al. "The HARPS search for southern extra-solar planets." Astronomy & Astrophysics 654 (October 2021): A104. http://dx.doi.org/10.1051/0004-6361/202141351.

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Context. We present precise radial-velocity measurements of five solar-type stars observed with the HARPS Echelle spectrograph mounted on the 3.6-m telescope in La Silla (ESO, Chile). With a time span of more than 10 yr and a fairly dense sampling, the survey is sensitive to low mass planets down to super-Earths on orbital periods up to 100 days. Aims. Our goal was to search for planetary companions around the stars HD 39194, HD 93385, HD 96700, HD 154088, and HD 189567 and use Bayesian model comparison to make an informed choice on the number of planets present in the systems based on the rad

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El Morsy, Mona, Thayne Currie, Danielle Bovie, et al. "Dynamical and Atmospheric Characterization of the Substellar Companion HD 33632 Ab from Direct Imaging, Astrometry, and Radial-velocity Data*." Astrophysical Journal 981, no. 1 (2025): 20. https://doi.org/10.3847/1538-4357/ada3be.

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Abstract We present follow-up SCExAO/CHARIS H- and K-band (R ∼ 70) high-contrast integral field spectroscopy and Keck/NIRC2 photometry of directly imaged brown dwarf companion HD 33632 Ab and new radial-velocity data for the system from the SOPHIE spectrograph, complemented by Hipparcos and Gaia astrometry. These data enable more robust spectral characterization compared to lower-resolution spectra from the discovery paper and more than double the available astrometric and radial-velocity baseline. HD 33632 Ab’s spectrum is well reproduced by a field L8.5–L9.5 dwarf. Using the Exo-REM atmosphe

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Hara, N. C., F. Bouchy, M. Stalport, et al. "The SOPHIE search for northern extrasolar planets." Astronomy & Astrophysics 636 (April 2020): L6. http://dx.doi.org/10.1051/0004-6361/201937254.

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Aims. Since 2011, the SOPHIE spectrograph has been used to search for Neptunes and super-Earths in the northern hemisphere. As part of this observational program, 290 radial velocity measurements of the 6.4 V magnitude star HD 158259 were obtained. Additionally, TESS photometric measurements of this target are available. We present an analysis of the SOPHIE data and compare our results with the output of the TESS pipeline. Methods. The radial velocity data, ancillary spectroscopic indices, and ground-based photometric measurements were analyzed with classical and ℓ1 periodograms. The stellar a

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Wright, Duncan J., Christopher G. Tinney, and Robert A. Wittenmyer. "Habitable Zone Super-Earths with Non-Stabilised Spectrographs." Proceedings of the International Astronomical Union 8, S293 (2012): 68–70. http://dx.doi.org/10.1017/s1743921313012556.

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AbstractDetecting the small velocity amplitudes (≤ 10 m/s) produced by habitable zone rocky planets around M Dwarfs requires radial velocity precisions of a few m s−1. However, an iodine absorption cell, commonly used as a high precision wavelength reference on non-stabilised spectrographs, is not efficient for very red and faint objects like M Dwarfs. Instead, arc lamps have to be used. With the exception of the ultra-stabilised HARPS spectrograph, achieving ~m s−1 calibration with arc lamps has not been possible because typical spectrographs experience drifts of several hundred m s−1 due to

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Collier Cameron, A., A. Mortier, D. Phillips, et al. "Three years of Sun-as-a-star radial-velocity observations on the approach to solar minimum." Monthly Notices of the Royal Astronomical Society 487, no. 1 (2019): 1082–100. http://dx.doi.org/10.1093/mnras/stz1215.

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Abstract The time-variable velocity fields of solar-type stars limit the precision of radial-velocity determinations of their planets’ masses, obstructing detection of Earth twins. Since 2015 July, we have been monitoring disc-integrated sunlight in daytime using a purpose-built solar telescope and fibre feed to the HARPS-N stellar radial-velocity spectrometer. We present and analyse the solar radial-velocity measurements and cross-correlation function (CCF) parameters obtained in the first 3 yr of observation, interpreting them in the context of spatially resolved solar observations. We descr

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Pai Asnodkar, Anusha, Ji Wang, B. Scott Gaudi, et al. "KELT-9 as an Eclipsing Double-lined Spectroscopic Binary: A Unique and Self-consistent Solution to the System." Astronomical Journal 163, no. 2 (2022): 40. http://dx.doi.org/10.3847/1538-3881/ac32c7.

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Abstract Transiting hot Jupiters present a unique opportunity to measure absolute planetary masses due to the magnitude of their radial velocity signals and known orbital inclination. Measuring planet mass is critical to understanding atmospheric dynamics and escape under extreme stellar irradiation. Here we present the ultrahot Jupiter system KELT-9 as a double-lined spectroscopic binary. This allows us to directly and empirically constrain the mass of the star and its planetary companion without reference to any theoretical stellar evolutionary models or empirical stellar scaling relations.

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Lanza, A. F., L. Malavolta, S. Benatti, et al. "The GAPS Programme with HARPS-N at TNG." Astronomy & Astrophysics 616 (August 2018): A155. http://dx.doi.org/10.1051/0004-6361/201731010.

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Aims. Stellar activity is the ultimate source of radial-velocity (hereinafter 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 R′HK in detecting RV variations induced by stellar activity in 15 slowly rotating (υ sin i ≤ 5 km s−1), weakly active (log R′HK ≤ −4.95) solar-like stars observed with the high-resolution spectrograph High Accuracy Radial velocity Planet Searcher for the Northern hemisphere (HARPS-N). Methods. We consider indicators of the asymmetry of the cross

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Esposito, M., D. J. Armstrong, D. Gandolfi, et al. "HD 219666 b: a hot-Neptune from TESS Sector 1." Astronomy & Astrophysics 623 (March 2019): A165. http://dx.doi.org/10.1051/0004-6361/201834853.

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We report on the confirmation and mass determination of a transiting planet orbiting the old and inactive G7 dwarf star HD 219666 (M⋆ = 0.92 ± 0.03 M⊙, R⋆ = 1.03 ± 0.03 R⊙, τ⋆ = 10 ± 2 Gyr). With a mass of Mb = 16.6 ± 1.3 M⊕, a radius of Rb = 4.71 ± 0.17 R⊕, and an orbital period of Porb ≃ 6 days, HD 219666 b is a new member of a rare class of exoplanets: the hot-Neptunes. The Transiting Exoplanet Survey Satellite (TESS) observed HD 219666 (also known as TOI-118) in its Sector 1 and the light curve shows four transit-like events, equally spaced in time. We confirmed the planetary nature of the

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Bennett, David P., Clément Ranc, and Rachel B. Fernandes. "No Sub-Saturn-mass Planet Desert in the CORALIE/HARPS Radial-velocity Sample." Astronomical Journal 162, no. 6 (2021): 243. http://dx.doi.org/10.3847/1538-3881/ac2a2b.

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Abstract We analyze the CORALIE/HARPS sample of exoplanets found by the Doppler radial-velocity method for signs of the predicted gap or “desert” at 10–100 M ⊕ caused by runaway gas accretion at semimajor axes of <3 au. We find that these data are not consistent with this prediction. This result is similar to the finding by the MOA gravitational microlensing survey that found no desert in the exoplanet distribution for exoplanets in slightly longer period orbits and somewhat lower host masses (Suzuki et al. 2018). Together, these results imply that the runaway gas accretion scenario of the

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Dumusque, X. "Measuring precise radial velocities on individual spectral lines." Astronomy & Astrophysics 620 (November 29, 2018): A47. http://dx.doi.org/10.1051/0004-6361/201833795.

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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 that we are facing an obstacle that will be extremely difficult to overcome using current techniques. Aims. In this paper, we investigate a novel approach to derive precise RVs considering the wealth of information present in high-resolution spectra. Methods. This new method consists of building a master spectrum from all available observations a

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de Beurs, Zoe L., Andrew Vanderburg, Christopher J. Shallue, et al. "Identifying Exoplanets with Deep Learning. IV. Removing Stellar Activity Signals from Radial Velocity Measurements Using Neural Networks." Astronomical Journal 164, no. 2 (2022): 49. http://dx.doi.org/10.3847/1538-3881/ac738e.

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Abstract Exoplanet detection with precise radial velocity (RV) observations is currently limited by spurious RV signals introduced by stellar activity. We show that machine-learning techniques such as linear regression and neural networks can effectively remove the activity signals (due to starspots/faculae) from RV observations. Previous efforts focused on carefully filtering out activity signals in time using modeling techniques like Gaussian process regression. Instead, we systematically remove activity signals using only changes to the average shape of spectral lines, and use no timing inf

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Delisle, J. B., N. Unger, N. C. Hara, and D. Ségransan. "Efficient modeling of correlated noise." Astronomy & Astrophysics 659 (March 2022): A182. http://dx.doi.org/10.1051/0004-6361/202141949.

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The radial velocity method is a very productive technique used to detect and confirm extrasolar planets. The most recent spectrographs, such as ESPRESSO or EXPRES, have the potential to detect Earth-like planets around Sun-like stars. However, stellar activity can induce radial velocity variations that dilute or even mimic the signature of a planet. A widely recognized method for disentangling these signals is to model the radial velocity time series, jointly with stellar activity indicators, using Gaussian processes and their derivatives. However, such modeling is prohibitive in terms of comp

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Standing, Matthew R., Amaury H. M. J. Triaud, João P. Faria, et al. "BEBOP II: sensitivity to sub-Saturn circumbinary planets using radial-velocities." Monthly Notices of the Royal Astronomical Society 511, no. 3 (2022): 3571–83. http://dx.doi.org/10.1093/mnras/stac113.

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ABSTRACT BEBOP is a radial-velocity survey that monitors a sample of single-lined eclipsing binaries, in search of circumbinary planets by using high-resolution spectrographs. Here, we describe and test the methods we use to identify planetary signals within the BEBOP data and establish how we quantify our sensitivity to circumbinary planets by producing detection limits. This process is made easier and more robust by using a diffusive nested sampler. In the process of testing our methods, we notice that contrary to popular wisdom, assuming circular orbits in calculating detection limits for a

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