Abstract. We derive the spectral types of the cool giants in about 100 symbiotic systems. Our classification is mainly based on near IR spectra in order to avoid the contamination of the spectrum by the nebula and the hot component in the visual region. The accuracy of our spectral types is approximately one spectral subclass, similar to previous near IR classification work, and much better than visual spectral type estimates.Strong, intrinsic spectral type variations (> 2 spectral subtypes) are only seen in systems containing pulsating mira variables.We present a catalogue of spectral types for cool giants in symbiotic systems which also includes determinations taken from the literature. The catalogue gives spectral types for the cool giants in about 170 systems which is nearly the full set of confirmed symbiotics.Based on our classifications we discuss the distribution of spectral types of the cool giants in galactic symbiotic binaries. We find that the spectral types cluster strongly between M3 and M6, with a peak at M5. The distribution of systems with a mira variable component peaks even later, at spectral types M6 and M7. This is a strong bias towards late spectral types when compared to red giants in the solar neighbourhood. Also the frequency of mira variables is much larger among symbiotic giants. This predominance of very late M-giants in symbiotic systems seems to indicate that large mass loss is a key ingredient for triggering symbiotic activity on a white dwarf companion.Further we find for symbiotic systems a strong correlation between the spectral type of the cool giant and the orbital period. In particular we find a tight relation for the minimum orbital period for symbiotic systems with Based on observations obtained with the 1.52 m and 3.6 m telescopes of the European Southern Observatory (ESO), the 1.93 m telescope of the Observatoire de Haute-Provence (OHP), the 2.3 m telescope of the Australian National University (ANU) at Siding Spring, and the William Herschel Telescope (WHT) at La Palma. This research has made use of the AFOEV database, operated at CDS, France. red giants of a given spectral type. This limiting line in the spectral type -orbital period diagram seems to be equivalent with the relation R ≤ 1 /2, where R is the radius of the red giant and 1 the distance from the center of the giant to the inner Lagrangian point L 1 . This correlation possibly discloses that symbiotic stars are -with probably only one exception in our sample -well detached binary systems.

Aims. The SHINE program is a high-contrast near-infrared survey of 600 young, nearby stars aimed at searching for and characterizing new planetary systems using VLT/SPHERE's unprecedented high-contrast and high-angular-resolution imaging capabilities. It is also intended to place statistical constraints on the rate, mass and orbital distributions of the giant planet population at large orbits as a function of the stellar host mass and age to test planet-formation theories. Methods. We used the IRDIS dual-band imager and the IFS integral field spectrograph of SPHERE to acquire high-contrast coronagraphic differential near-infrared images and spectra of the young A2 star HIP 65426. It is a member of the ∼ 17 Myr old Lower Centaurus-Crux association. Results. At a separation of 830 mas (92 au projected) from the star, we detect a faint red companion. Multi-epoch observations confirm that it shares common proper motion with HIP 65426. Spectro-photometric measurements extracted with IFS and IRDIS between 0.95 and 2.2 µm indicate a warm, dusty atmosphere characteristic of young low-surface-gravity L5-L7 dwarfs. Hot-start evolutionary models predict a luminosity consistent with a 6 − 12 M Jup , T eff = 1300 − 1600 K and R = 1.5 ± 0.1 R Jup giant planet. Finally, the comparison with Exo-REM and PHOENIX BT-Settl synthetic atmosphere models gives consistent effective temperatures but with slightly higher surface gravity solutions of log(g) = 4.0−5.0 with smaller radii (1.0 − 1.3 R Jup ). Conclusions. Given its physical and spectral properties, HIP 65426 b occupies a rather unique placement in terms of age, mass, and spectral-type among the currently known imaged planets. It represents a particularly interesting case to study the presence of clouds as a function of particle size, composition, and location in the atmosphere, to search for signatures of non-equilibrium chemistry, and finally to test the theory of planet formation and evolution.

Context. In recent years, our understanding of giant planet formation progressed substantially. There have even been detections of a few young protoplanet candidates still embedded in the circumstellar disks of their host stars. The exact physics that describes the accretion of material from the circumstellar disk onto the suspected circumplanetary disk and eventually onto the young, forming planet is still an open question. Aims. We seek to detect and quantify observables related to accretion processes occurring locally in circumstellar disks, which could be attributed to young forming planets. We focus on objects known to host protoplanet candidates and/or disk structures thought to be the result of interactions with planets. Methods. We analyzed observations of six young stars (age 3.5 − 10 Myr) and their surrounding environments with the SPHERE/ZIMPOL instrument on the Very Large Telescope (VLT) in the Hα filter (656 nm) and a nearby continuum filter (644.9 nm). We applied several point spread function (PSF) subtraction techniques to reach the highest possible contrast near the primary star, specifically investigating regions where forming companions were claimed or have been suggested based on observed disk morphology. Results. We redetect the known accreting M-star companion HD142527 B with the highest published signal to noise to date in both Hα and the continuum. We derive new astrometry (r = 62.8 +2.1 −2.7 mas and PA = (98.7 ± 1.8) • ) and photometry (∆N_Ha=6.3 +0.2 −0.3 mag, ∆B_Ha=6.7 ± 0.2 mag and ∆Cnt_Ha=7.3 +0.3 −0.2 mag) for the companion in agreement with previous studies, and estimate its mass accretion rate (Ṁ ≈ 1 − 2 × 10 −10 M yr −1 ). A faint point-like source around HD135344 B (SAO206462) is also investigated, but a second deeper observation is required to reveal its nature. No other companions are detected. In the framework of our assumptions we estimate detection limits at the locations of companion candidates around HD100546, HD169142, and MWC 758 and calculate that processes involving Hα fluxes larger than ∼ 8 × 10 −14 − 10 −15 erg/s/cm 2 (Ṁ > 10 −10 − 10 −12 M yr −1 ) can be excluded. Furthermore, flux upper limits of ∼ 10 −14 − 10 −15 erg/s/cm 2 (Ṁ < 10 −11 − 10 −12 M yr −1 ) are estimated within the gaps identified in the disks surrounding HD135344 B and TW Hya. The derived luminosity limits exclude Hα signatures at levels similar to those previously detected for the accreting planet candidate LkCa15 b.

The SpHere INfrared Exoplanet (SHINE) project is a 500-star survey performed with SPHERE on the Very Large Telescope for the purpose of directly detecting new substellar companions and understanding their formation and early evolution. Here we present an initial statistical analysis for a subsample of 150 stars spanning spectral types from B to M that are representative of the full SHINE sample. Our goal is to constrain the frequency of substellar companions with masses between 1 and 75 M Jup and semimajor axes between 5 and 300 au. For this purpose, we adopt detection limits as a function of angular separation from the survey data for all stars converted into mass and projected orbital separation using the BEX-COND-hot evolutionary tracks and known distance to each system. Based on the results obtained for each star and on the 13 detections in the sample, we use a Markov chain Monte Carlo tool to compare our observations to two different types of models. The first is a parametric model based on observational constraints, and the second type are numerical models that combine advanced core accretion and gravitational instability planet population synthesis. Using the parametric model, we show that the frequencies of systems with at least one substellar companion are 23.0 +13.5 −9.7 %, 5.8 +4.7 −2.8 %, and 12.6 +12.9 −7.1 % for BA, FGK, and M stars, respectively. We also demonstrate that a planet-like formation pathway probably dominates the mass range from 1-75 M Jup for companions around BA stars, while for M dwarfs, brown dwarf binaries dominate detections. In contrast, a combination of binary star-like and planet-like formation is required to best fit the observations for FGK stars. Using our population model and restricting our sample to FGK stars, we derive a frequency of 5.7 +3.8 −2.8 %, consistent with predictions from the parametric model. More generally, the frequency values that we derive are in excellent agreement with values obtained in previous studies.

Abstract. We present the results of an intensive monitoring program of the jet absorptions in the symbiotic system MWC 560, obtained with the FEROS echelle spectrograph at the ESO 1.5 m Telescope. MWC 560 is a unique jet source because the line of sight lies practically parallel to the jet axis so that the outflowing gas is seen as absorption in the continuum of the accreting object, in the emission line spectrum of the accretion disk and temporary also in the spectrum of the red giant companion. Highly variable, blue-shifted jet absorption components, due to H i, He i, Na i, Ca ii and Fe ii are observed, which are detached from the undisplaced, narrow emission line components. The allowed emission lines from neutral and singly ionized heavy elements vary simultaneously with the strongly variable continuum emission. Therefore they can be attributed to the irradiated (chromospheric) layers of the neutral part of the accretion disk. The fluxes of forbidden emission lines are practically constant because they originate in a much larger volume. The structure and variability of the jet absorptions indicate the presence of three distinct outflow regions along the jet axis: i. An initial acceleration region above the disk with low velocities <600 km s −1 which covers only partly the central continuum source; ii. A highly variable outflow region covering the continuum source and up to about half of the line emission from the disk. This region shows repeatedly high velocity components ≈1800−2500 km s −1 which are decelerated to <1500 km s −1 within one to a few days. The appearance of high velocity components is anti-correlated and therefore closely related to the low velocity absorptions of region i. The life time of the high velocity components suggests that region ii extends to about one to a few AU from the jet source; iii. A steady flow at an intermediate velocity of ≈900−1300 km s −1 at a distance of the order ∼10 AU from the jet source. This component covers the hot continuum source and the entire narrow line region of the accretion disk. At the beginning of our campaign region iii covers also the extended red giant companion with two absorption components at 1250 km s −1 and 1140 km s −1 , which can be considered as terminal velocities v∞ of the jet outflow. The components disappear during the following several weeks as expected for the end of an occultation phase of the red giant by the collimated jet occuring probably regularly once per binary orbit. Several fast moving (1300−1700 km s −1 ), narrow absorptions are present in the Ca ii resonance lines. The high speed, low column density, and the long life time (∼months) suggest that these are radiative bow shocks in the jet cocoon generated by the collision of the transient high velocity components with slower moving jet material. A geometric model for the jet outflow in MWC 560 is presented. System parameters are derived based on our spectroscopic data and previous studies. Beside other parameters a binary separation of the order 4 AU, a jet inclination of <16•...