Medium-resolution integral-field spectrographs (IFS) coupled with adaptive-optics such as Keck/OSIRIS, VLT/MUSE, or SINFONI are appearing as a new avenue for enhancing the detection and characterization capabilities of young, gas giant exoplanets at large heliocentric distances ( >5 au). We analyzed K-band VLT/SINFONI medium-resolution (R-lambda similar to 5577) observations of the young giant exoplanet HIP 65426 b. Our dedicated IFS data analysis toolkit (TExTRIS) optimized the cube building, star registration, and allowed for the extraction of the planet spectrum. A Bayesian inference with the nested sampling algorithm coupled with the self-consistent forward atmospheric models BT-SETTL15 and Exo-REM using the ForMoSA tool yields T-eff = 1560 +/- 100 K, log(g) = 20 au) by core accretion (CA hereafter). However, a formation by gravitational instability (GI hereafter) cannot be ruled out. The metallicity is compatible with the bulk enrichment of massive Jovian planets from the Bern planet population models. Finally, we measure a radial velocity of 26 +/- 15 km s(-1) compatible with our revised measurement on the star. This is the fourth imaged exoplanet for which a radial velocity can be evaluated, illustrating the potential of such observations for assessing the coevolution of imaged systems belonging to star forming regions, such as HIP 65426. ; Programme National de Planetologie through project grant "ISEP" French National Research Agency (ANR) European Commission ANR-14-CE33-0018 French Chilean Lab for Astronomy (FCLA) UMI-3886 European Research Council (ERC) 757561 Aparece en contenido como:European Research Council (ERC) under the European Union Swiss National Science Foundation (SNSF) P400P2_186765 German Research Foundation (DFG) KU 2849/7-1 Aparece en contenido como:DFG priority program SPP 1992 "Exploring the Diversity of Extrasolar Planets" Swiss National Science Foundation (SNSF) European Commission BSSGI0_155816 "Programme National de Physique Stellaire" (PNPS) "Programme National de Planetologie" of CNRS/INSU, France Programme National de Planetologie through project grant "EXO-SPEC" ; Versión publicada - versión final del editor
Context. We initiated a deep-imaging survey of Scorpius-Centaurus A-F stars in 2015. These stars are predicted to host warm inner and cold outer belts of debris reminiscent of the architecture of emblematic systems such as HR 8799. Aims. We present resolved images of a ring of debris around the F5-type star HD 141011 that was observed as part of our survey. We aim to set constraints on the properties of the disk, compare them to those of other resolved debris disks in Sco-Cen, and detect companions. Methods. We obtained high-contrast coronagraphic observations of HD 141011 in 2015, 2016, and 2019 with VLT/SPHERE. We removed the stellar halo using angular differential imaging. We searched for scattered light emission from a disk in the residuals and applied a forward-modeling approach to retrieve its morphological and photometric properties. We combined our radial velocity and imaging data to derive detection probabilities for companions co-planar with the disk orientation. Results. We resolve a narrow ring of debris that extends up to ∼1.100 (∼141 au) from the star in the IRDIS and IFS data obtained in 2016 and 2019. The disk is not detected in the 2015 data which are of poorer quality. The disks is best reproduced by models of a noneccentric ring centered on the star with an inclination of 69.1 ± 0.9 ◦ , a position angle of −24.6 ± 1.7 ◦ , and a semimajor axis of 127.5 ± 3.8 au. The combination of radial velocity and imaging data excludes brown-dwarf (M > 13.6 MJup) companions coplanar with the disk from 0.1 to 0.9 au and from 20 au up to 500 au (90% probability). Conclusions. HD 141011 adds to the growing list of debris disks that are resolved in Sco-Cen. It is one of the faintest disks that are resolved from the ground and has a radial extent and fractional width (∼12.5%) reminiscent of Fomalhaut. Its moderate inclination and large semimajor axis make it a good target for the James Webb Space Telescope and should allow a deeper search for putative companions shaping the dust distribution. ; French National Research Agency (ANR) ANR-14-CE33-0018 ANR-20-CE31-0012 France from the CNRS-D2P PICS grant France from the Programmes Nationaux de Planetologie et de Physique Stellaire (PNP) France from the Programmes Nationaux de Planetologie et de Physique Stellaire (PNPS) European Research Council (ERC) 885 593 Istituto Nazionale Astrofisica (INAF) Agenzia Spaziale Italiana (ASI) 2018-16-HH.0 PRIN-INAF 2019 "Planetary systems at young ages (PLATEA)" Australian Research Council FT170100040 DP180104235 ANID, -Millennium Science Initiative Program NCN19_171 Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) CONICYT FONDECYT 1180395 French National Research Agency (ANR) ANR10 LABX56 Spanish Government AyA2017-84089 European Commission 776403 Universidad de Valparaiso ; Versión publicada - versión final del editor
Context. Open clusters are recognised as excellent tracers of Galactic thin-disc properties. At variance with intermediate-age and old open clusters, for which a significant number of studies is now available, clusters younger than ≲ 150 Myr have been mostly overlooked in terms of their chemical composition until recently (with few exceptions). On the other hand, previous investigations seem to indicate an anomalous behaviour of young clusters, which includes (but is not limited to) slightly sub-solar iron (Fe) abundances and extreme, unexpectedly high barium (Ba) enhancements. Aims. In a series of papers, we plan to expand our understanding of this topic and investigate whether these chemical peculiarities are instead related to abundance analysis techniques. Methods. We present a new determination of the atmospheric parameters for 23 dwarf stars observed by the Gaia-ESO survey in five young open clusters (τ < 150 Myr) and one star-forming region (NGC 2264). We exploit a new method based on titanium (Ti) lines to derive the spectroscopic surface gravity, and most importantly, the microturbulence parameter. A combination of Ti and Fe lines is used to obtain effective temperatures. We also infer the abundances of Fe » I, Fe » II, Ti » I, Ti » II, Na » I, Mg » I, Al » I, Si » I, Ca » I, Cr » I, and Ni » I. Results. Our findings are in fair agreement with Gaia-ESO iDR5 results for effective temperatures and surface gravities, but suggest that for very young stars, the microturbulence parameter is over-estimated when Fe lines are employed. This affects the derived chemical composition and causes the metal content of very young clusters to be under-estimated. Conclusions. Our clusters display a metallicity [Fe/H] between +0.04 ± 0.01 and +0.12 ± 0.02; they are not more metal poor than the Sun. Although based on a relatively small sample size, our explorative study suggests that we may not need to call for ad hoc explanations to reconcile the chemical composition of young open clusters with Galactic chemical evolution models. ; With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)
Context. Proxima Centauri is the closest star to the Sun and it is known to host an Earth-like planet in its habitable zone; very recently a second candidate planet was proposed based on radial velocities. At quadrature, the expected projected separation of this new candidate is larger than 1 arcsec, making it a potentially interesting target for direct imaging.Aims. While identification of the optical counterpart of this planet is expected to be very difficult, successful identification would allow for a detailed characterization of the closest planetary system.Methods. We searched for a counterpart in SPHERE images acquired over four years through the SHINE survey. In order to account for the expected large orbital motion of the planet, we used a method that assumes the circular orbit obtained from radial velocities and exploits the sequence of observations acquired close to quadrature in the orbit. We checked this with a more general approach that considers Keplerian motion, called K-stacker.Results. We did not obtain a clear detection. The best candidate has signal-to-noise ratio (S/N) = 6.1 in the combined image. A statistical test suggests that the probability that this detection is due to random fluctuation of noise is away from the astrometric motion of Proxima as measured from early Gaia data. This, together with the unexpectedly high flux associated with our direct imaging detection, means we cannot confirm that our candidate is indeed Proxima c.Conclusions. On the other hand, if confirmed, this would be the first observation in imaging of a planet discovered from radial velocities and the second planet (after Fomalhaut b) of reflecting circumplanetary material. Further confirmation observations should be done as soon as possible. ; Progetto Premiale 2015 FRONTIERA of the Italian Ministry of Education, University, and Research OB.FU. 1.05.06.11 CONICYT + PAI/Convocatoria nacional subvención a la instalación en la academia, convocatoria 2017 + Folio PAI77170087 European Union (EU) 664931 Swiss National Science Foundation (SNSF) PZ00P2180098 Ministry of Education, Universities and Research (MIUR) Research Projects of National Relevance (PRIN) Programme National de Planetologie (PNP) Programme National de Physique Stellaire (PNPS) of CNRS-INSU French National Research Agency (ANR) ANR10 LABX56 Centre National de la Recherche Scientifique (CNRS) French National Research Agency (ANR) ANR-14-CE330018 ESO Centre National de la Recherche Scientifique (CNRS) MPIA (Germany) Istituto Nazionale Astrofisica (INAF) FINES (Switzerland) NOVA (Netherlands) European Union (EU) RII3-Ct-2004-001566 226604 312430 European Union (EU) RII3-Ct-2004-001566 226604 312430 French National Research Agency (ANR) ANR-15-IDEX-02
Context. The existence of hot Jupiters is still not well understood. Two main channels are thought to be responsible for their current location: a smooth planet migration through the protoplanetary disk or the circularization of an initial highly eccentric orbit by tidal dissipation leading to a strong decrease in the semimajor axis. Different formation scenarios result in different observable effects, such as orbital parameters (obliquity and eccentricity) or frequency of planets at different stellar ages. Aims. In the context of the GAPS Young Objects project, we are carrying out a radial velocity survey with the aim of searching and characterizing young hot-Jupiter planets. Our purpose is to put constraints on evolutionary models and establish statistical properties, such as the frequency of these planets from a homogeneous sample. Methods. Since young stars are in general magnetically very active, we performed multi-band (visible and near-infrared) spectroscopy with simultaneous GIANO-B + HARPS-N (GIARPS) observing mode at TNG. This helps in dealing with stellar activity and distinguishing the nature of radial velocity variations: stellar activity will introduce a wavelength-dependent radial velocity amplitude, whereas a Keplerian signal is achromatic. As a pilot study, we present here the cases of two known hot Jupiters orbiting young stars: HD 285507 b and AD Leo b. Results. Our analysis of simultaneous high-precision GIARPS spectroscopic data confirms the Keplerian nature of the variation in the HD 285507 radial velocities and refines the orbital parameters of the hot Jupiter, obtaining an eccentricity consistent with a circular orbit. Instead, our analysis does not confirm the signal previously attributed to a planet orbiting AD Leo. This demonstrates the power of the multi-band spectroscopic technique when observing active stars. ; With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)