Eclipsing binaries are important benchmark objects to test and calibrate stellar structure and evolution models. This is especially true for binaries with a fully convective M-dwarf component for ...which direct measurements of these stars' masses and radii are difficult using other techniques. Within the potential of M-dwarfs to be exoplanet host stars, the accuracy of theoretical predictions of their radius and effective temperature as a function of their mass is an active topic of discussion. Not only the parameters of transiting exoplanets but also the success of future atmospheric characterisation rely on accurate theoretical predictions. We present the analysis of five eclipsing binaries with low-mass stellar companions out of a sub-sample of 23, for which we obtained ultra high-precision light curves using the CHEOPS satellite. The observation of their primary and secondary eclipses are combined with spectroscopic measurements to precisely model the primary parameters and derive the M-dwarfs mass, radius, surface gravity, and effective temperature estimates using the PYCHEOPS data analysis software. Combining these results to the same set of parameters derived from TESS light curves, we find very good agreement (better than 1\% for radius and better than 0.2% for surface gravity). We also analyse the importance of precise orbits from radial velocity measurements and find them to be crucial to derive M-dwarf radii in a regime below 5% accuracy. These results add five valuable data points to the mass-radius diagram of fully-convective M-dwarfs.
We investigate the exoplanet candidate TOI-1422b, which was discovered by the TESS space telescope around the high proper-motion G2V star TOI-1422 (\(V=10.6\) mag), 155pc away, with the primary goal ...of confirming its planetary nature and characterising its properties. We monitored TOI-1422 with the HARPS-N spectrograph for 1.5 years to precisely quantify its radial velocity variation. The radial velocity measurements are analyzed jointly with TESS photometry and we also check for blended companions through high-spatial resolution images using the AstraLux instrument. We estimate that the parent star has a radius and a mass of \(R^*=1.019_{-0.013}^{+0.014} R_{\odot}\), \(M^*=0.981_{-0.065}^{+0.062} M_{\odot}\), respectively. Our analysis confirms the planetary nature of TOI-1422b and also suggests the presence of a Neptune-mass planet on a more distant orbit, the candidate TOI-1422c, which is not detected in TESS light curves. The inner planet, TOI-1422b, orbits on a period \(P_{\rm b}=12.9972\pm0.0006\) days and has an equilibrium temperature \(T_{\rm eq, b}=867\pm17\) K. With a radius of \(R_{\rm b}=3.96^{+0.13}_{-0.11} R_{\oplus}\), a mass of \(M_{\rm b}=9.0^{+2.3}_{-2.0} M_{\oplus}\) and, consequently, a density of \(\rho_{\rm b}=0.795^{+0.290}_{-0.235}\) g cm\(^{-3}\), it can be considered a warm Neptune-size planet. Compared to other exoplanets of similar mass range, TOI-1422b is among the most inflated ones and we expect this planet to have an extensive gaseous envelope that surrounds a core with a mass fraction around \(10\%-25\%\) of the total mass of the planet. The outer non-transiting planet candidate, TOI-1422c, has an orbital period of \(P_{\rm c}=29.29^{+0.21}_{-0.20}\) days, a minimum mass, \(M_{\rm c}\sin{i}\), of \(11.1^{+2.6}_{-2.3} M_{\oplus}\), an equilibrium temperature of \(T_{\rm eq, c}=661\pm13\) K and, therefore, if confirmed, it could be considered as another warm Neptune.
We report the discovery and characterization of the transiting extrasolar planet TOI-1710\(\:\)b. It was first identified as a promising candidate by the Transiting Exoplanet Survey Satellite (TESS). ...Its planetary nature was then established with SOPHIE and HARPS-N spectroscopic observations via the radial-velocity method. The stellar parameters for the host star are derived from the spectra and a joint Markov chain Monte-Carlo (MCMC) adjustment of the spectral energy distribution and evolutionary tracks of TOI-1710. A joint MCMC analysis of the TESS light curve and the radial-velocity evolution allows us to determine the planetary system properties. From our analysis, TOI-1710\(\:\)b is found to be a massive warm super-Neptune (\(M_{\rm p}=28.3\:\pm\:4.7\:{\rm M}_{\rm Earth}\) and \(R_{\rm p}=5.34\:\pm\:0.11\:{\rm R}_{\rm Earth}\)) orbiting a G5V dwarf star (\(T_{\rm eff}=5665\pm~55\mathrm{K}\)) on a nearly circular 24.3-day orbit (\(e=0.16\:\pm\:0.08\)). The orbital period of this planet is close to the estimated rotation period of its host star \(P_{\rm rot}=22.5\pm2.0~\mathrm{days}\) and it has a low Keplerian semi-amplitude \(K=6.4\pm1.0~\mathrm{m\:s^{-1}}\); we thus performed additional analyses to show the robustness of the retrieved planetary parameters. With a low bulk density of \(1.03\pm0.23~\mathrm{g\:cm^{-3}}\) and orbiting a bright host star (\(J=8.3\), \(V=9.6\)), TOI-1710\(\:\)b is one of the best targets in this mass-radius range (near the Neptunian desert) for atmospheric characterization via transmission spectroscopy, a key measurement in constraining planet formation and evolutionary models of sub-Jovian planets.
We present the discovery of two new transiting extrasolar planet candidates identified as TOI-1296.01 and TOI-1298.01 by the Transiting Exoplanet Survey Satellite (TESS). The planetary nature of ...these candidates has been secured with the SOPHIE high-precision spectrograph through the measurement of the companion's mass with the radial velocity method. Both planets are similar to Saturn in mass and have similar orbital periods of a few days. They, however, show discrepant radii and therefore different densities. The radius discrepancy might be explained by the different levels of irradiation by the host stars. The subgiant star TOI-1296 hosts a low-density planet with 1.2 RJup while the less luminous, lower-size star TOI-1298 hosts a much denser planet with a 0.84 RJup radius, resulting in bulk densities of 0.198 and 0.743 g/cm3, respectively. In addition, both stars are strongly enriched in heavy elements, having metallicities of 0.44 and 0.49 dex, respectively. The planet masses and orbital periods are 0.298 (0.039) MJup and 3.9443715 days for TOI-1296b, and 0.356 (0.032) MJup and 4.537164 days for TOI-1298b.
Axial liquid mixing was studied in gas–liquid systems (bubble columns) and two types of gas–liquid–solid system (the turbulent and inverse turbulent beds) for different types of gas sparger (membrane ...and perforated plate). In the turbulent and inverse turbulent beds, solids, larger and lighter than water and of large diameter (3–4
mm) are fluidized only by an upward gas flow. In two-phase systems, the type of gas sparger has a strong effect on the gas flow regime and consequently on the axial liquid mixing. A general diagram with co-ordinates Pe versus Fr
(1/3) has been established in order to explain all the results. It allows the hydrodynamic characteristics to be predicted by a simple measurement of the axial liquid dispersion coefficient
E
zl
. In the gas–liquid–solid reactors tested, the effect of the gas sparger on axial liquid mixing can be pronounced. A flow regime diagram is proposed, which shows a heterogeneous flow behaviour independent of the gas sparger when the solid content of the column is sufficiently high.
We present the discovery of two new hot Jupiters identified from the WASP survey, WASP-186b and WASP-187b (TOI-1494.01 and TOI-1493.01). Their planetary nature was established from SOPHIE ...spectroscopic observations, and additional photometry was obtained from TESS. Stellar parameters for the host stars are derived from spectral line, IRFM, and isochrone placement analyses. These parameters are combined with the photometric and radial velocity data in an MCMC method to determine the planetary properties. WASP-186b is a massive Jupiter (4.22 +/- 0.18 M_J, 1.11 +/-0.03 R_J) orbiting a mid-F star on a 5.03 day eccentric (e=0.327 +/- 0.008) orbit. WASP-187b is a low density (0.80 +/- 0.09 M_J, 1.64 +/- 0.05 R_J) planet in a 5.15 day circular orbit around a slightly evolved early F-type star.
We report on the discovery of a hot Jupiter-type exoplanet, CoRoT-17b, detected by the CoRoT satellite. It has a mass of 2.43 ± 0.30 MSUBJup/SUB and a radius of 1.02 ± 0.07 RSUBJup/SUB, while its ...mean density is 2.82 ± 0.38 g/cmSUP3/SUP. CoRoT-17b is in a circular orbit with a period of 3.7681 ± 0.0003 days. The host star is an old (10.7 ± 1.0 Gyr) main-sequence star, which makes it an intriguing object for planetary evolution studies. The planet's internal composition is not well constrained and can range from pure H/He to one that can contain ~380 earth masses of heavier elements. The CoRoT space mission, launched on December 27th 2006, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA (RSSD and Science Programme), Germany and Spain. Part of the observations were obtained at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii. Based on observations made with HARPS spectrograph on the 3.6-m European Organisation for Astronomical Research in the Southern Hemisphere telescope at La Silla Observatory, Chile (ESO program 184.C-0639). Based on observations made with the IAC80 telescope operated on the island of Tenerife by the Instituto de Astrofísica de Canarias in the Spanish Observatorio del Teide. Part of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation.
Distinguishing classes within substellar objects and understanding their formation and evolution need larger samples of substellar companions such as exoplanets, brown dwarfs, and low-mass stars. In ...this paper, we look for substellar companions using radial velocity surveys of FGK stars with the SOPHIE spectrograph at the Observatoire de Haute-Provence. We assign here the radial velocity variations of 27 stars to their orbital motion induced by low-mass companions. We also constrained their plane-of-the-sky motion using HIPPARCOS and Gaia Data Release 1 measurements, which constrain the true masses of some of these companions. We report the detection and characterization of six cool Jupiters, three brown dwarf candidates, and 16 low-mass stellar companions. We additionally update the orbital parameters of the low-mass star HD 8291 B, and we conclude that the radial velocity variations of HD 204277 are likely due to stellar activity despite resembling the signal of a giant planet. One of the new giant planets, BD+631405 b, adds to the population of highly eccentric cool Jupiters, and it is presently the most massive member. Two of the cool Jupiter systems also exhibit signatures of an additional outer companion. The orbital periods of the new companions span 30 days to 11.5 years, their masses 0.72 Jupiter mass to 0.61 Solar mass, and their eccentricities 0.04 to 0.88. These discoveries probe the diversity of substellar objects and low-mass stars, which will help constrain the models of their formation and evolution.
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 10m.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 the cold Jupiter population. Methods. Analyzing the radial velocity data from six bright solar-like stars taken over a period of up to 15 years, we attempt the detection and confirmation of Keplerian signals. Results. We announce the discovery of six planets, one per system, with minimum masses in the range 2.99-8.3 Mjup and orbital periods between 200 days and 10 years. The data do not provide enough evidence to support the presence of additional planets in any of these systems. The analysis of stellar activity indicators confirms the planetary nature of the detected signals. Conclusions. These six planets belong to the cold and massive Jupiter population, and four of them populate its eccentric tail. In this respect, HD 80869 b stands out as having one of the most eccentric orbits, with an eccentricity of 0.862^{+0.028}_{-0.018}. These planets can thus help to better constrain the migration and evolution processes at play in the gas giant population. Furthermore, recent works presenting the correlation between small planets and cold Jupiters indicate that these systems are good candidates to search for small inner planets.
The accuracy of theoretical mass, radius and effective temperature values for M-dwarf stars is an active topic of debate. Differences between observed and theoretical values have raised the ...possibility that current theoretical stellar structure and evolution models are inaccurate towards the low-mass end of the main sequence. To explore this issue we use the CHEOPS satellite to obtain high-precision light curves of eclipsing binaries with low mass stellar companions. We use these light curves combined with the spectroscopic orbit for the solar-type companion to measure the mass, radius and effective temperature of the M-dwarf star. Here we present the analysis of three eclipsing binaries. We use the pycheops data analysis software to fit the observed transit and eclipse events of each system. Two of our systems were also observed by the TESS satellite -- we similarly analyse these light curves for comparison. We find consistent results between CHEOPS and TESS, presenting three stellar radii and two stellar effective temperature values of low-mass stellar objects. These initial results from our on-going observing programme with CHEOPS show that we can expect to have ~24 new mass, radius and effective temperature measurements for very low mass stars within the next few years.
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