Radial-velocity follow-up of stars harbouring transiting planets detected by TESS is expected to require very large amounts of expensive telescope time in the next few years. Therefore, scheduling strategies should be implemented to maximize the amount of information gathered about the target planetary systems. We consider myopic and non-myopic versions of a novel uniform-in-phase scheduler, as well as a random scheduler, and compare these scheduling strategies with respect to the bias, accuracy and precision achieved in recovering the mass and orbital parameters of transiting and non-transiting planets. This comparison is carried out based on realistic simulations of radial-velocity follow-up with ESPRESSO of a sample of 50 TESS target stars, with simulated planetary systems containing at least one transiting planet with a radius below $4R_{\oplus}$. Radial-velocity datasets were generated under reasonable assumptions about their noise component, including that resulting from stellar activity, and analysed using a fully Bayesian methodology. We find the random scheduler leads to a more biased, less accurate, and less precise, estimation of the mass of the transiting exoplanets. No significant differences are found between the results of the myopic and non-myopic implementations of the uniform-in-phase scheduler. With only about 22 radial velocity measurements per dataset, our novel uniform-in-phase scheduler enables an unbiased (at the level of 1\%) measurement of the masses of the transiting planets, while keeping the average relative accuracy and precision around 16\% and 23\% respectively. The number of non-transiting planets detected is similar for all the scheduling strategies considered, as well as the bias, accuracy and precision with which their masses and orbital parameters are recovered.
WASP-47 hosts a remarkable planetary system containing a hot Jupiter (WASP-47 b; P = 4.159 days) with an inner super-Earth (WASP-47 e; P = 0.7896 days), a close-orbiting outer Neptune (WASP-47 d; P = 9.031 days), and a long period giant planet (WASP-47 c; P = 588.4 days). We use the new TESS photometry to refine the orbital ephemerides of the transiting planets in the system, particularly the hot Jupiter WASP-47 b, for which we find an update equating to a 17.4 min shift in the transit time. We report new radial velocity measurements from the ESPRESSO spectrograph for WASP-47, which we use to …
LHS 1140 is an M dwarf known to host two known transiting planets at orbital periods of 3.77 and 24.7 days. The external planet (LHS 1140 b) is a rocky super-Earth that is located in the middle of the habitable zone of this low-mass star, placing this system at the forefront of the habitable exoplanet exploration. We further characterize this system by improving the physical and orbital properties and search for additional planetary-mass components in the system, also exploring the possibility of co-orbitals. We collected 113 new radial velocity observations with ESPRESSO over a 1.5-year time …
Twenty-four years after the discoveries of the first exoplanets, the radial-velocity (RV) method is still one of the most productive techniques to detect and confirm exoplanets. But stellar magnetic activity can induce RV variations large enough to make it difficult to disentangle planet signals from the stellar noise. In this context, HD41248 is an interesting planet-host candidate, with RV observations plagued by activity-induced signals. We report on ESPRESSO observations of HD41248 and analyse them together with previous observations from HARPS with the goal of evaluating the presence of o…
[Abridged] We exploit the extreme radial velocity (RV) precision of the ultra-stable echelle spectrograph ESPRESSO on the VLT to unveil the physical properties of the transiting sub-Neptune TOI-130 b, uncovered by TESS orbiting the nearby, bright, late F-type star HD 5278 (TOI-130) with a period $P_{\rm b}=14.3$. We use 43 ESPRESSO high-resolution spectra and broad-band photometry information to derive accurate stellar atmospheric and physical parameters of HD 5278. We exploit the TESS light curve (LC) and spectroscopic diagnostics to gauge the impact of stellar activity on the ESPRESSO RVs. W…
Context. Planets around stars in the solar neighbourhood will be prime targets for characterisation with upcoming large space- and ground-based facilities. Since large-scale exoplanet searches will not be feasible with such telescopes, it is crucial to use currently available data and instruments to find possible target planets before next generation facilities come online. Aims. We aim at detecting new extrasolar planets around stars in the solar neighbourhood by blind radial velocity (RV) search with ESPRESSO. Our target sample consist of nearby stars (d < 11 pc) with little (< 10) or no pre…
A compact multi-planet system transiting HIP 29442 (TOI-469) discovered by TESS and ESPRESSO. Radial velocities lead to the detection of transits with low signal-to-noise ratio
The ESPRESSO spectrograph is a new powerful tool to detect and characterize extrasolar planets. Its design allows unprecedented radial velocity precision (down to a few tens of cm/s) and long-term thermo-mechanical stability. We present the first standalone detection of an extrasolar planet by blind radial velocity search using ESPRESSO and aim at showing the power of the instrument in characterizing planetary signals at different periodicities in long time spans. We use 41 ESPRESSO measurements of HD\,22496 within a time span of 895 days with a median photon noise of 18 cm/s. A radial velocit…
The small transiting planet population revealed by ESPRESSO with extreme precision radial velocities
Université de Genève（日内瓦大学）；Universidade do Porto（波尔图大学）；Institut d’Estudis Espacials de Catalunya (IEEC)（加泰罗尼亚空间研究所）；Institut de Ciències de l’Espai (ICE, CSIC)（空间科学研究所）；Space Research Institute, Austrian Academy of Sciences（奥地利科学院空间研究所）
Revisiting the Exo-Mercury Candidate GJ 367 b with ESPRESSO and a Self-Consistent Tidal Distortion Model
Institute for Astronomy, University of Hawai‘i（夏威夷大学天体物理研究所）；Department of Astronomy, California Institute of Technology（加州理工学院天文学系）；Department of Astronomy, University of Chicago（芝加哥大学天文学系）；Department of Physics & Astronomy, The University of California, Irvine（加州大学尔湾分校物理与天文学系）；Dipartimento di Fisica, Università degli Studi di Torino（都灵大学物理系）；Institut für Astrophysik und Geophysik, Georg-August-Universität Göttingen（哥廷根大学天文与地球物理研究所）；Anton Pannekoek Institute for Astronomy, University of Amsterdam（阿姆斯特丹大学安东·范佩内克天体物理研究所）；Department of Astronomy, University of Illinois at Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校天文学系）；Center for Astrophysical Surveys, National Center for Supercomputing Applications（国家超级计算应用中心天体物理调查中心）；Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University（奥胡斯大学物理与天文学系恒星天体物理中心）
Densities of small planets around the M dwarfs TOI-4336 A and TOI-4342 with ESPRESSO: Three sub-Neptunes, one super-Earth, and a Neptune-mass candidate
Observatoire de Genève, Département d’Astronomie, Université de Genève（日内瓦天文台，天文学系，日内瓦大学）；Institut Trottier de recherche sur les exoplanètes, Département de Physique, Université de Montréal（特罗蒂埃系外行星研究所，物理系，蒙特利尔大学）；Institute for Particle Physics and Astrophysics, ETH Zürich（粒子物理学与天体物理学研究所，苏黎世联邦理工学院）；Centro de Astrobiología (CAB), CSIC-INTA（天体生物学中心（CAB），西班牙国家研究委员会-国家航空航天技术研究所）；Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP（天体物理学与空间科学研究所，波尔图大学，CAUP）；Departamento de Matemática y Física Aplicadas, Universidad Católica de la Santísima Concepción（应用数学与物理系，天主教神圣启示大学）；Univ. Grenoble Alpes, CNRS, IPAG（格勒诺布尔阿尔卑斯大学，法国国家科学研究中心，IPAG）；Department of Physics and Astronomy, McMaster University（物理与天文学系，麦克马斯特大学）；Center for Astrophysics | Harvard & Smithsonian（天体物理中心，哈佛大学与史密森尼学会）
We provide a database of transit times and updated ephemerides for 382 planets based on data from the NASA Transiting Exoplanet Survey Satellite (TESS) and previously reported transit times which were scraped from the literature in a semi-automated fashion. In total, our database contains 8,667 transit timing measurements for 382 systems. About 240 planets in the catalog are hot Jupiters (i.e. planets with mass $>$0.3$M_{\rm Jup}$ and period $<$10 days) that have been observed by TESS. The new ephemerides are useful for scheduling follow-up observations and searching for long-term period chang…
The bright star $π$ Men was chosen as the first target for a radial velocity follow-up to test the performance of ESPRESSO, the new high-resolution spectrograph at the ESO's Very-Large Telescope (VLT). The star hosts a multi-planet system (a transiting 4 M$_\oplus$ planet at $\sim$0.07 au, and a sub-stellar companion on a $\sim$2100-day eccentric orbit) which is particularly appealing for a precise multi-technique characterization. With the new ESPRESSO observations, that cover a time span of 200 days, we aim to improve the precision and accuracy of the planet parameters and search for additio…
In the blooming field of exoplanetary science, NASA's Kepler Space Telescope has revolutionized our understanding of exoplanets. Kepler's very precise and long-duration photometry is ideal for detecting planetary transits around Sun-like stars. The forthcoming Transiting Exoplanet Survey Satellite (TESS) is expected to continue Kepler's legacy. Along with transits, the Doppler technique remains an invaluable tool for discovering planets. The next generation of spectrographs, such as G-CLEF, promises precision radial velocity measurements. In this paper, we explore the possibility of detecting …
Rapid planetary rotation can cause the equilibrium shape of a planet to be oblate. While planetary oblateness has mostly been probed by examining the subtle ingress and egress features in photometric transit light curves, we investigate the effect of oblateness on the spectroscopic Rossiter-McLaughlin (RM) signals. We found that a giant planet, with planet-to-star radius ratio of 0.15 and Saturn-like oblateness of 0.098, can cause spectroscopic signatures with amplitudes up to 1.1 ms$^{-1}$ which is detectable by high-precision spectrographs such as ESPRESSO. We also found that the spectroscop…
We report on the discovery and characterisation of three planets orbiting the F8 star HD~28109, which sits comfortably in \tess's continuous viewing zone. The two outer planets have periods of $\rm 56.0067 \pm 0.0003~days$ and $\rm 84.2597_{-0.0008}^{+0.0010}~days$, which implies a period ratio very close to that of the first-order 3:2 mean motion resonance, exciting transit timing variations (TTVs) of up to $\rm 60\,mins$. These two planets were first identified by \tess, and we identified a third planet in the \textcolor{black}{\tess photometry} with a period of $\rm 22.8911 \pm 0.0004~days$…
We report the discovery of four transiting giant planets around K dwarfs. The planets HATS-47b, HATS-48Ab, HATS-49b, and HATS-72b have masses of $0.369_{-0.021}^{+0.031}$ $M_{J}$, $0.243_{-0.030}^{+0.022}$ $M_{J}$, $0.353_{-0.027}^{+0.038}$ $M_{J}$ and $0.1254\pm0.0039$ $M_{J}$, respectively, and radii of $1.117\pm0.014$ $R_{J}$, $0.800\pm0.015$ $R_{J}$, $0.765\pm0.013$ $R_{J}$, and $0.7224\pm0.0032$ $R_{J}$, respectively. The planets orbit close to their host stars with orbital periods of $3.9228$ d, $3.1317$ d, $4.1480$ d and $7.3279$ d, respectively. The hosts are main sequence K dwarfs wit…
The relative rarity of giant planets around low mass stars compared with solar-type stars is a key prediction from core accretion planet formation theory. In this paper we report on the discovery of four gas giant planets that transit low mass late K and early M dwarfs. The planets HATS-74Ab (TOI 737b), HATS-75b (TOI 552b), HATS-76b (TOI 555b), and HATS-77b (TOI 730b), were all discovered from the HATSouth photometric survey and followed-up using TESS and other photometric facilities. We use the new ESPRESSO facility at the VLT to confirm and systems and measure their masses. We find that that…
We present the discovery of TOI-3235 b, a short-period Jupiter orbiting an M-dwarf with a stellar mass close to the critical mass at which stars transition from partially to fully convective. TOI-3235 b was first identified as a candidate from TESS photometry, and confirmed with radial velocities from ESPRESSO, and ground-based photometry from HATSouth, MEarth-South, TRAPPIST-South, LCOGT, and ExTrA. We find that the planet has a mass of $\mathrm{0.665\pm0.025\,M_J}$ and a radius of $\mathrm{1.017\pm0.044\,R_J}$. It orbits close to its host star, with an orbital period of $\mathrm{2.5926\,d}$,…
Constraining Small Planet Compositions for Future Missions
Institute for Astronomy, University of Edinburgh（爱丁堡大学天体物理研究所）；Centre for Exoplanet Science, University of Edinburgh（爱丁堡大学系外行星科学中心）；HH Wills Physics Laboratory, University of Bristol（布里斯托尔大学HH威尔斯物理实验室）；School of Physics & Astronomy, University of Birmingham（伯明翰大学物理与天文学院）；Weltraumforschung und Planetologie, Physikalisches Institut, University of Bern（伯尔尼大学物理研究所空间研究与行星科学）；European Space Agency (ESA), European Space Research and Technology Centre (ESTEC)（欧洲航天局（ESA）欧洲空间研究与技术中心（ESTEC））；Department of Physics, University of Warwick（华威大学物理系）；Center for Astrophysics, Harvard & Smithsonian（哈佛-史密森天体物理中心）；INAF - Osservatorio Astrofisico di Torino（意大利国家天体物理研究所都灵天文台）；Fundación G. Galilei - INAF (Telescopio Nazionale Galileo)（G.伽利略基金会-INAF（伽利略国家望远镜））
Utilizing a global network of telescopes to update the ephemeris for the highly eccentric planet HD 80606 b and to ensure the efficient scheduling of JWST
Giant Outer Transiting Exoplanet Mass (GOT 'EM) Survey: III. Recovery and Confirmation of a Temperate, Mildly Eccentric, Single-Transit Jupiter Orbiting TOI-2010
We report the discovery of a Neptune-like planet (LP 714-47 b, P = 4.05204 d, m_b = 30.8 +/- 1.5 M_earth , R_b = 4.7 +/- 0.3 R_earth ) located in the 'hot Neptune desert'. Confirmation of the TESS Object of Interest (TOI 442.01) was achieved with radial-velocity follow-up using CARMENES, ESPRESSO, HIRES, iSHELL, and PFS, as well as from photometric data using TESS, Spitzer, and ground-based photometry from MuSCAT2, TRAPPIST- South, MONET-South, the George Mason University telescope, the Las Cumbres Observatory Global Telescope network, the El Sauce telescope, the TUBITAK National Observatory, …
Searching for hot water world candidates with CHEOPS: II. A low-density super-Earth orbiting the K dwarf TOI-2211
European Space Agency (ESA)（欧洲空间局（ESA））；University of St Andrews（圣安德鲁斯大学）；Space Research Institute, Austrian Academy of Sciences（奥地利科学院空间研究所）；University of Bern（伯尔尼大学）；ETH Zurich（苏黎世联邦理工学院）；University of Kansas（堪萨斯大学）；Observatoire astronomique de l’Université de Genève（日内瓦大学天文台）；University of Leiden（莱顿大学）；Université de Liège（列日大学）
Determining the architecture of multi-planetary systems is one of the cornerstones of understanding planet formation and evolution. Resonant systems are especially important as the fragility of their orbital configuration ensures that no significant scattering or collisional event has taken place since the earliest formation phase when the parent protoplanetary disc was still present. In this context, TOI-178 has been the subject of particular attention since the first TESS observations hinted at a 2:3:3 resonant chain. Here we report the results of observations from CHEOPS, ESPRESSO, NGTS, an…
LTT 1445 is a hierarchical triple M-dwarf star system located at a distance of 6.86 parsecs. The primary star LTT 1445A (0.257 M_Sun) is known to host the transiting planet LTT 1445Ab with an orbital period of 5.4 days, making it the second closest known transiting exoplanet system, and the closest one for which the host is an M dwarf. Using TESS data, we present the discovery of a second planet in the LTT 1445 system, with an orbital period of 3.1 days. We combine radial velocity measurements obtained from the five spectrographs ESPRESSO, HARPS, HIRES, MAROON-X, and PFS to establish that the …
