Search

Intermediate mass stars (IMSs) represent the link between low-mass and high-mass stars and cover a key mass range for giant planet formation. In this paper, we present a spectroscopic survey of 241 young IMS candidates with IR-excess, the most complete unbiased sample to date within 300 pc. We combined VLT/X-Shooter spectra with BVR photometric observations and Gaia DR3 distances to estimate fundamental stellar parameters such as Teff, mass, radius, age, and luminosity. We further selected those stars within the intermediate mass range 1.5, Comment: 19 pages, 11 figures, Accepted to MNRAS

In Europe wildlife animals such as the red fox (Vulpes vulpes) are considered the main reservoir for Angiostrongylus vasorum as well as a potential threat for domestic dog infection. Though this parasite is endemic in fox populations, data on A. vasorum infection in wolves (Canis lupus italicus) are still scant, having only recently been described in Northwestern Spain, in Italy, in Croatia and in Slovakia. Based on the rising number of cases of canine lungworm infection in Central Italy (Abruzzo region), the aim of the present study was to investigate the infection by A. vasorum in fox and wolf populations sharing the same geographical area of dogs. From October 2008 to November 2019, A. vasorum specimens were collected, through routine post-mortem examination, from 56 carcasses (44 foxes and 12 wolves). Adult parasites were searched for in the right side of the heart and in pulmonary artery of all carcasses. First stage of larvae (L1) was searched in faeces using the Baermann technique and in lungs by tissue impressions. Overall, 230 adult specimens were collected and identified on a morphological basis. To confirm the morphological identification, 4 adult specimens (n = 3 from fox, n = 1 from wolf) were molecularly identified as A. vasorum by amplification of partial fragment of nuclear 18S rRNA (~1700 bp) genes. The anatomo-pathological and parasitological examinations indicated the presence of A. vasorum in 33 foxes (75%) and in 8 wolves (66.7%). The level of prevalence of infested wolves was higher than the previous one reported in other European countries. Interestingly, the prevalence of infection in foxes herein recorded was higher than that described in dogs (8.9%) living in the same geographical area. This result may confirm the hypothesis that the spread of canine angiostrongylosis is linked to fox populations infection., Graphical abstract Image 1, Highlights • Angiostrongylus vasorum was found in dead foxes and wolves in Chieti province, Italy. • The prevalence in foxes was higher than that described in dogs. • The prevalence in wolves was higher than the previous one reported in European countries. • The spread of canine angiostrongylosis is linked to fox populations infection. • The province of Chieti appears to be an enzootic focus for canine angiostrongylosis.

Magnetohydrodynamic (MHD) and photoevaporative winds are thought to play an important role in the evolution and dispersal of planet-forming disks. Here, we analyze high-resolution ($\Delta v \sim$ 7 kms$^{-1}$) optical spectra from a sample of 115 T Tauri stars in the $\sim 5-10$ Myr Upper Sco association and focus on the [O I]$\lambda$6300 and H$\alpha$ lines to trace disk winds and accretion, respectively. Our sample covers a large range in spectral type and we divide it into Warm (G0-M3) and Cool (later than M3) to facilitate comparison with younger regions. We detect the [O I]$\lambda$6300 line in 45 out of 87 upper sco sources with protoplanetary disks and 32 out of 45 are accreting based on H$\alpha$ profiles and equivalent widths. All [O I] $\lambda$6300 Upper Sco profiles have a low-velocity (centroid $< -30$ kms$^{-1}$, LVC) emission and most (36/45) can be fit by a single Gaussian (SC). The SC distribution of centroid velocities and FWHMs is consistent with MHD disk winds. We also find that the Upper Sco sample follows the same accretion luminosity$-$LVC [O I]$\lambda$6300 luminosity relation and the same anti-correlation between SC FWHM and WISE W3-W4 spectral index as the younger samples. These results indicate that accretion and disk winds coevolve and that, as inner disks clear out, wind emission arises further away from the star. Finally, our large spectral range coverage reveals that Cool stars have larger FWHMs normalized by stellar mass than Warm stars indicating that [O I]$\lambda$6300 emission arises closer in towards lower mass/lower luminosity stars., Comment: 47 pages, 32 figures; ApJ accepted

Since the very beginning of the COVID-19 pandemic, SARS-CoV-2 detection has been described in several animal species. A total of 625 outbreaks in animals have been reported globally, affecting 17 species in 32 countries and the human source of infection has been recognized including pet owners, zookeepers, and farmers. In this report, we describe the case of a paucisymptomatic dog in Italy infected with SARS-CoV-2 from a household with three confirmed human cases of COVID-19 living in Pesaro (Marche region, Italy). The dog showed high viral RNA titers in the nasal and oropharyngeal swabs. In the nasal swab, SARS-CoV-2 RNA lasted for a least a week. By sequencing, the strain was assigned to the AY.23 lineage (PANGO), one of the sub-lineages of the major SARS-CoV-2 Delta variant of concern (VOC). Although we did not process the swabs of the three human cases, we strongly suspect a human origin for the dog infection. In this regard, AY.23 sequences, although never released thus far in the Marche region, were detected in the neighboring regions. Our findings highlight once more the need for a One Health approach for SARS-CoV-2 surveillance, management, and control, thus preventing viral spillover from animals to humans.

Cucullanus carettae Baylis, 1923 (Nematoda: Cucullanidae) is found worldwide in loggerhead turtles (Caretta caretta). Regarding the Mediterranean, C. carettae has been identified in the Tyrrhenian and the Ionian Sea and a unique description of a Cucullanus sp. specimen in loggerheads from the Adriatic Sea has been reported in the literature so far. In the framework of a bio-monitoring project of the Abruzzo and Molise coasts, a parasitological survey was performed on stranded and by-caught sea turtles, at the Istituto Zooprofilattico of Abruzzo and Molise “G. Caporale.” During necropsy, the gastrointestinal system of 72 stranded loggerhead turtles was analyzed for the presence of endoparasites and fecal samples were collected for coprological examination. Adult C. carettae (n = 123) was found in the upper intestine of one loggerhead turtle, associated with chronic lymphoplasmocytic enteritis. Additionally, five stool samples (6.9%) were positive for Cucullanus sp. eggs. Molecular characterization of adult nematodes was carried out to study phylogenetic relationships among the Cucullanus species. To our knowledge, this is the first morphological and molecular identification of C. carettae in loggerhead turtles from the Adriatic Sea. Additional studies on the distribution of this parasite in the Mediterranean are encouraged.

Understanding the occurrence of Earth-sized planets in the habitable zone of Sun-like stars is essential to the search for Earth analogues. Yet a lack of reliable Kepler detections for such planets has forced many estimates to be derived from the close-in ($2, Comment: 27 pages, 12 figures, 3 tables; Accepted for publication in AJ

This work presents ground-based spectrally-resolved water emission at R = 30000-100000 over infrared wavelengths covered by JWST (2.9-12.8 $\mu$m). Two new surveys with iSHELL and VISIR are combined with previous spectra from CRIRES and TEXES to cover parts of multiple ro-vibrational and rotational bands observable within telluric transmission bands, for a total of $\approx160$ spectra and 85 disks (30 of which are JWST targets in Cycle 1). The general expectation of a range of regions and excitation conditions traced by infrared water spectra is for the first time supported by the combined kinematics and excitation as spectrally resolved at multiple wavelengths. The main findings from this analysis are: 1) water lines are progressively narrower from the ro-vibrational bands at 2-9 $\mu$m to the rotational lines at 12 $\mu$m, and partly match a broad (BC) and narrow (NC) emission components, respectively, as extracted from ro-vibrational CO spectra; 2) rotation diagrams of resolved water lines from upper level energies of 4000-9500 K show vertical spread and curvatures indicative of optically thick emission ($\approx 10^{18}$ cm$^{-2}$) from a range of excitation temperatures ($\approx 800$-1100 K); 3) the new 5 $\mu$m spectra demonstrate that slab model fits to the rotational lines at $> 10$ $\mu$m strongly over-predict the ro-vibrational emission bands at $< 9$ $\mu$m, implying non-LTE vibrational excitation. We discuss these findings in the context of emission from a disk surface and a molecular inner disk wind, and provide a list of guidelines to support the analysis of spectrally-unresolved JWST spectra., Comment: Accepted for publication on AJ

Planet formation by pebble accretion requires an efficient inward flux of icy pebbles to explain the many mini-Neptunes and super-Earths discovered by Kepler within 1 au. Recently, hints of large-scale pebble migration have been found in the anticorrelation between the line ratio of water-to-other volatiles detected in medium-resolution (R ∼ 700) Spitzer/IRS spectra and the dust disk radius measured at millimeter wavelengths with the Atacama Large Millimeter Array. Here, we select three disks in Taurus that span the range of measured line flux ratios (a factor of ∼5) and dust disk radii (1 order of magnitude) and model their Spitzer/IRS spectra assuming gas in local thermodynamic equilibrium to retrieve the water column density in their inner disks. We find that, at the Spitzer/IRS resolution and sensitivity, large uncertainties in the retrieved column densities preclude resolving the expected difference of a factor of ∼5 in water abundance. Next, we simulate higher-resolution (∼3000) JWST/MIRI spectra at the signal-to-noise ratio of ∼100, which will be obtained via the Guaranteed Time and General Observation programs and apply the same retrieval approach used with Spitzer/IRS spectra. We show that the improved resolution and sensitivity of JWST/MIRI significantly reduce the uncertainties in the retrieved water column densities and will enable quantifying the difference in the inner water column of small versus large dust disks.

Kepler's short-period exoplanet population has revealed evolutionary features such as the Radius Valley and the Hot Neptune desert that are likely sculpted by atmospheric loss over time. These findings suggest that the primordial planet population is different from the Gyr-old Kepler population, and motivates exoplanet searches around young stars. Here, we present pterodactyls , a data reduction pipeline specifically built to address the challenges in discovering exoplanets around young stars and to work with TESS Primary Mission 30-min cadence photometry, since most young stars were not pre-selected TESS 2-min cadence targets. pterodactyls builds on publicly available and tested tools in order to extract, detrend, search, and vet transiting young planet candidates. We search five clusters with known transiting planets: Tucana-Horologium Association, IC 2602, Upper Centaurus Lupus, Ursa Major and Pisces Eridani. We show that pterodactyls recovers seven out of the eight confirmed planets and one out of the two planet candidates, most of which were initially detected in 2-min cadence data. For these clusters, we conduct injection-recovery tests to characterize our detection efficiency, and compute an intrinsic planet occurrence rate of 49+-20% for sub-Neptunes and Neptunes (1.8-6 Re) within 12.5 days, which is higher than Kepler's Gyr-old occurrence rates of 6.8+-0.3%. This potentially implies that these planets have shrunk with time due to atmospheric mass loss. However, a proper assessment of the occurrence of transiting young planets will require a larger sample unbiased to planets already detected. As such, pterodactyls will be used in future work to search and vet for planet candidates in nearby clusters and moving groups., 27 pages, 19 figures, 3 tables; Accepted for publication in AJ

The Large UV/Optical/IR Surveyor (LUVOIR) is a concept for a guest observer-driven observatory that will revolutionize astrophysics, solar system studies, and exoplanet science. This WP summarizes parts of the study Final Report, including science goals, concept designs, key technology needs, development schedule, and project management.

Understanding the origin of accretion and dispersal of protoplanetary disks is fundamental for investigating planet formation. Recent numerical simulations show that launching winds are unavoidable when disks undergo magnetically driven accretion and/or are exposed to external UV radiation. Observations also hint that disk winds are common. We explore how the resulting wind mass loss rate can be used as a probe of both disk accretion and dispersal. As a proof-of-concept study, we focus on magnetocentrifugal winds, MRI (magnetorotational instability) turbulence, and external photoevapotaion. By developing a simple, yet physically motivated disk model and coupling it with simulation results available in the literature, we compute the mass loss rate as a function of external UV flux for each mechanism. We find that different mechanisms lead to different levels of mass loss rate, indicating that the origin of disk accretion and dispersal can be determined, by observing the wind mass loss rate resulting from each mechanism. This determination provides important implications for planet formation. This work thus shows that the ongoing and future observations of the wind mass loss rate for protoplanetary disks are paramount to reliably constrain how protoplanetary disks evolve with time and how planet formation takes place in the disks., Comment: 16 pages; 7 figures, 5 tables, accepted for publication in ApJL; no change in the conclusions; the additional Monte-Carlo based, parameter study was conducted, following the referee's comment

We perform a comprehensive demographic study of the CO extent relative to dust of the disk population in the Lupus clouds, in order to find indications of dust evolution and possible correlations with other properties. We increase up to 42 the number of disks of the region with measured CO and dust sizes ($R_{\mathrm{CO}}$, $R_{\mathrm{dust}}$) from observations with the Atacama Large Millimeter/submillimeter Array (ALMA). The sizes are obtained from modeling the ${^{12}}$CO $J = 2-1$ line emission and continuum emission at $\sim 0.89$ mm with an empirical function (Nuker profile or Gaussian function). The CO emission is more extended than the dust continuum, with a $R_{68\%}^{\mathrm{CO}}$/$R_{68\%}^{\mathrm{dust}}$ median value of 2.5, for the entire population and for a sub-sample with high completeness. 6 disks, around $15\%$ of the Lupus disk population have a size ratio above 4. Based on thermo-chemical modeling, this value can only be explained if the disk has undergone grain growth and radial drift. These disks do not have unusual properties in terms of stellar mass ($M_{\star}$), disk mass ($M_{\mathrm{disk}}$), CO and dust sizes ($R_{\mathrm{CO}}$, $R_{\mathrm{dust}}$), and mass accretion. We search for correlations between the size ratio and $M_{\star}$, $M_{\mathrm{disk}}$, $R_{\mathrm{CO}}$ and $R_{\mathrm{dust}}$: only a weak monotonic anti-correlation with the $R_{\mathrm{dust}}$ is found. The lack of strong correlations is remarkable and suggests that the bulk of the population may be in a similar evolutionary stage, independent of the stellar and disk properties. These results should be further investigated, since the optical depth difference between CO and dust continuum may play a role in the inferred size ratios. Lastly, the CO emission for the majority of the disks is consistent with optically thick emission and an average CO temperature of around 30 K., Comment: Accepted for publication on A&A, 14 pages of main text with 5 figures, and 11 pages of appendices A, B, C, D, E and F with 13 figures

We report the first characterisation of the individual discs in the intermediate separation binary systems KK Oph and HD 144668 at millimetre wavelengths. In both systems the circum-primary and the circum-secondary discs are detected in the millimetre continuum emission, but not in $^{13}$CO nor C$^{18}$O lines. Even though the disc structure is only marginally resolved, we find indications of large-scale asymmetries in the outer regions of the primary discs, most likely due to perturbation by the companion. The derived dust masses are firmly above debris disc level for all stars. The primaries have about three times more dust in their discs than the secondaries. In the case of HD 144668 the opacity spectral index of the primary and secondary differ by the large margin of 0.69 which may be a consequence of the secondary disc being more compact. Upper limits on the gas masses imply less than 0.1 M$_{\textrm{jup}}$ in any of these discs, meaning that giant planets can no longer form in them. Considering that there have been no massive gas discs identified to date in intermediate separation binaries (i.e., binaries at a few hundred au separation), this opens space for speculation whether their binarity causes the removal of gas, with tidal interaction truncating the discs and hence shortening the accretion timescale. More systematic studies in this respect are sorely needed., Comment: 12 pages. Accepted for publication in MNRAS

Spectro-astrometry is used to investigate the low velocity component (LVC) of the optical forbidden emission from the T Tauri stars RU Lupi and AS 205 N. Both stars also have high velocity forbidden emission (HVC) which is tracing a jet. For AS 205 N, analysis reveals a complicated outflow system. For RU Lupi, the [O I] 6300 and [S II] 6716, 6731 LV narrow component (NC) is offset along the same position angle (PA) as the HVC but with a different velocity gradient than the jet, in that displacement from the stellar position along the rotation axis is decreasing with increasing velocity. From the LVC NC PA and velocity gradient, it is inferred that the NC is tracing a wide angled MHD disk wind. A photoevaporative wind is ruled out. This is supported by a comparison with a previous spectro-astrometric study of the CO fundamental line. The decrease in offset with increasing velocity is interpreted as tracing an increase in the height of the wind with increasing disk radius. This is one of the first measurements of the spatial extent of the forbidden emission line LVC NC (~ 40 au, 8 au for RU~Lupi in the [S II] 6731 and [O I] 6300 lines) and the first direct confirmation that the LVC narrow component can trace an MHD disk wind., Comment: Accepted by ApJ, 16 pages, 11 figures

The role of resident or migratory birds in dispersal of tick species and tick-borne pathogens is still poorly known in Italy. We report here the results of a 3-year project based on sampling ticks from migratory birds, as well as from the vegetation at three stop-over sites for migrants, namely the islands of Ventotene (Latium), Asinara (Sardinia) and Ustica (Sicily). During the spring seasons from 2017-2019, in total 2681 ticks were collected, 2344 of which were sampled from migratory birds and 337 from the vegetation. Ticks were identified by morphology or by molecular tools when necessary. In total, 16 tick species were identified among which the following were exclusively found on birds: Hyalomma rufipes (43.3%), Hy. truncatum (0.1%), Ixodes frontalis (11.8%), Ix. inopinatus (0.2%), Ix. ricinus (3%), Haemaphysalis punctata (0.08%), Hae. erinacei (0.1%), Amblyomma variegatum (0.08%) and Argas vulgaris 0.1%), whereas five species were exclusively collected from the vegetation: Rhipicephalus bursa (10.5%), Rh. turanicus (5.9%), Rh. sanguineus sensu lato (2%), Rh. pusillus (2.4%), Hae. sulcata (0.08%). Hy. marginatum (10.3%) and Ix. ventalloi (9.3%) were found both on birds and on the vegetation on the island Ustica. It is worth noting that the search for ticks on the vegetation did not detect allochthonous tick species. Although we found several interesting local species and allochthonous ticks like Hy. rufipes, Am. variegatum and Ar. vulgaris on birds, further investigations are needed to better define the possible role of migratory birds in the introduction of ticks and tick-borne diseases in Italy, above all after the evidence of imported ticks positive to Crimean Congo hemorrhagic fever (CCHF) virus in several European countries.

Debris discs are dusty belts of planetesimals around main-sequence stars, similar to the asteroid and Kuiper belts in our solar system. The planetesimals cannot be observed directly, yet they produce detectable dust in mutual collisions. Observing the dust, we can try to infer properties of invisible planetesimals. Here we address the question of what is the best way to measure the location of outer planetesimal belts that encompass extrasolar planetary systems. A standard method is using resolved images at mm-wavelengths, which reveal dust grains with sizes comparable to the observational wavelength. Smaller grains seen in the infrared (IR) are subject to several non-gravitational forces that drag them away from their birth rings, and so may not closely trace the parent bodies. In this study, we examine whether imaging of debris discs at shorter wavelengths might enable determining the spatial location of the exo-Kuiper belts with sufficient accuracy. We find that around M-type stars the dust best visible in the mid-IR is efficiently displaced inward from their birth location by stellar winds, causing the discs to look more compact in mid-IR images than they actually are. However, around earlier-type stars where the majority of debris discs is found, discs are still the brightest at the birth ring location in the mid-IR regime. Thus, sensitive IR facilities with good angular resolution, such as MIRI on JWST, will enable tracing exo-Kuiper belts in nearby debris disc systems., 16 pages

Infrared spectroscopy with medium to high spectral resolution is essential to characterize the gas content of circumstellar disks. Unfortunately, conducting continuum and line radiative transfer of thermochemical disk models is too time-consuming to carry out large parameter studies. Simpler approaches using a slab model to fit continuum-subtracted spectra require the identification of either the global or local continuum. Continuum subtraction, particularly when covering a broad wavelength range, is challenging but critical in rich molecular spectra as hot (several hundreds K) molecular emission lines can also produce a pseudo continuum. In this work, we present CLIcK, a flexible tool to simultaneously fit the continuum and line emission. The DDN01 continuum model (Dullemond et al. 2001) and a plane-parallel slab of gas in local thermodynamic equilibrium are adopted to simulate the continuum and line emission respectively, both of them are fast enough for homogeneous studies of large disk samples. We applied CLIcK to fit the observed water spectrum of the AA Tau disk and obtained water vapor properties that are consistent with literature results. We also demonstrate that CLIcK properly retrieves the input parameters used to simulate the water spectrum of a circumstellar disk. CLIcK will be a versatile tool for the interpretation of future James Webb Space Telescope spectra., Accepted for publication in A&A, 9 pages, 9 figures

ALMA has observed a plethora of ring-like structures in planet forming discs at distances of 10-100 au from their host star. Although several mechanisms have been invoked to explain the origin of such rings, a common explanation is that they trace new-born planets. Under the planetary hypothesis, a natural question is how to reconcile the apparently high frequency of gap-carving planets at 10-100 au with the paucity of Jupiter mass planets observed around main sequence stars at those separations. Here, we provide an analysis of the new-born planet population emerging from observations of gaps in discs, under the assumption that the observed gaps are due to planets. We use a simple estimate of the planet mass based on the gap morphology, and apply it to a sample of gaps recently obtained by us in a survey of Taurus with ALMA. We also include additional data from recent published surveys, thus analysing the largest gap sample to date, for a total of 48 gaps. The properties of the purported planets occupy a distinctively different region of parameter space with respect to the known exo-planet population, currently not accessible through planet finding methods. Thus, no discrepancy in the mass and radius distribution of the two populations can be claimed at this stage. We show that the mass of the inferred planets conforms to the theoretically expected trend for the minimum planet mass needed to carve a dust gap. Finally, we estimate the separation and mass of the putative planets after accounting for migration and accretion, for a range of evolutionary times, finding a good match with the distribution of cold Jupiters., Comment: 9 pages, 5 figures, re-submitted to MNRAS after referee's comments

KH 15D is a well-known spectroscopic binary because of its unique and dramatic photometric variability. The variability is explained by a circumbinary dust ring but the ring itself was never directly detected. We present a new interpretation of the double-peaked [O~{\scriptsize I}]\,$\lambda$6300 profiles as originating from the hot disk surface of KH 15D. By modeling these profiles, we measure emitting radii between $\sim$0.5--5 au, basically a gaseous ring very similar in radial extent to the dust ring inferred from modeling the system's photometric variability. We also discuss the possibility that external photoevaporation driven by UV photons from the nearby massive star HD~47887 has truncated the outer edge of the disk to the observed value., Comment: 8 pages, 5 figures, accepted by ApJL

M-stars are the most common hosts of planetary systems in the Galaxy. Protoplanetary disks around M-stars thus offer a prime opportunity to study the chemistry of planet-forming environments. We present an Atacama Large Millimeter/submillimeter Array survey of molecular line emission toward a sample of five protoplanetary disks around M4–M5 stars (FP Tau, J0432+1827, J1100-7619, J1545-3417, and Sz 69). These observations can resolve chemical structures down to tens of astronomical units. Molecular lines of 12CO, 13CO, C18O, C2H, and HCN are detected toward all five disks. Lines of H2CO and DCN are detected toward 2/5 and 1/5 disks, respectively. For disks with resolved C18O, C2H, HCN, and H2CO emission, we observe substructures similar to those previously found in disks around solar-type stars (e.g., rings, holes, and plateaus). C2H and HCN excitation conditions estimated interior to the pebble disk edge for the bright disk J1100-7619 are consistent with previous measurements around solar-type stars. The correlation previously found between C2H and HCN fluxes for solar-type disks extends to our M4–M5 disk sample, but the typical C2H/HCN ratio is higher for the M4–M5 disk sample. This latter finding is reminiscent of the hydrocarbon enhancements found by previous observational infrared surveys in the innermost (

We present a study of the Trapezium cluster in Orion. We analyze flux-calibrated Very Large Telescope/Multi-Unit Spectroscopic Explorer spectra of 361 stars to simultaneously measure the spectral types, reddening, and the optical veiling due to accretion. We find that the extinction law from Cardelli et al. with a total-to-selective extinction value of R V = 5.5 is more suitable for this cluster. For 68% of the sample the new spectral types are consistent with literature spectral types within two subclasses but, as expected, we derive systematically later types than the literature by one to two subclasses for the sources with significant accretion levels. Here we present an improved Hertzsprung–Russell (H-R) diagram of the Trapezium cluster, in which the contamination by optical veiling on spectral types and stellar luminosities has been properly removed. A comparison of the locations of the stars in the H-R diagram with the non-magnetic and magnetic pre-main-sequence evolutionary tracks indicates an age of 1–2 Myr. The magnetic pre-main-sequence evolutionary tracks can better explain the luminosities of the low-mass stars. In the H-R diagram, the cluster exhibits a large luminosity spread (σ(Log L ⋆/L ⊙) ∼ 0.3). By collecting a sample of 14 clusters/groups with different ages, we find that the luminosity spread tends to be constant (σ(Log L ⋆/L ⊙) ∼ 0.2–0.25) after 2 Myr, which suggests that age spread is not the main cause of the luminosity spread. There are ∼0.1 dex larger luminosity spreads for the younger clusters, e.g., the Trapezium cluster, than the older clusters, which can be explained by the starspots, accretion history, and circumstellar disk orientations.

We utilize ALMA archival data to estimate the dust disk size of 152 protoplanetary disks in Lupus (1-3 Myr), Chamaeleon I (2-3 Myr), and Upper-Sco (5-11 Myr). We combine our sample with 47 disks from Tau/Aur and Oph whose dust disk radii were estimated, as here, through fitting radial profile models to visibility data. We use these 199 homogeneously derived disk sizes to identify empirical disk-disk and disk-host property relations as well as to search for evolutionary trends. In agreement with previous studies, we find that dust disk sizes and millimeter luminosities are correlated, but show for the first time that the relationship is not universal between regions. We find that disks in the 2-3 Myr-old Cha I are not smaller than disks in other regions of similar age, and confirm the Barenfeld et al. (2017) finding that the 5-10 Myr USco disks are smaller than disks belonging to younger regions. Finally, we find that the outer edge of the Solar System, as defined by the Kuiper Belt, is consistent with a population of dust disk sizes which have not experienced significant truncation., Comment: ApJ accepted, 38 pages, 16 figures, 68k compatible

We conduct a pebble-driven planet population synthesis study to investigate the formation of planets around very low-mass stars and brown dwarfs, in the (sub)stellar mass range between $0.01 \ M_{\odot}$ and $0.1 \ M_{\odot}$. Based on the extrapolation of numerical simulations of planetesimal formation by the streaming instability, we obtain the characteristic mass of the planetesimals and the initial masses of the protoplanets (largest bodies from the planetesimal size distributions), in either the early self-gravitating phase or the later non-self-gravitating phase of the protoplanetary disk evolution. We find that the initial protoplanets form with masses that increase with host mass, orbital distance and decrease with disk age. Around late M-dwarfs of $0.1 \ M_{\odot}$, these protoplanets can grow up to Earth-mass planets by pebble accretion. However, around brown dwarfs of $0.01 \ M_{\odot}$, planets do not grow larger than Mars mass when the initial protoplanets are born early in self-gravitating disks, and their growth stalls at around $0.01$ Earth-mass when they are born late in non-self-gravitating disks. Around these low mass stars and brown dwarfs, we find no channel for gas giant planet formation because the solid cores remain too small. When the initial protoplanets form only at the water-ice line, the final planets typically have ${\gtrsim} 15\%$ water mass fraction. Alternatively, when the initial protoplanets form log-uniformly distributed over the entire protoplanetary disk, the final planets are either very water-rich (water mass fraction ${\gtrsim}15\%$) or entirely rocky (water mass fraction ${\lesssim}5\%$)., 12 pages, 8 figures, accepted in A&A

The continuous flow of billions of birds between Africa and Europe creates an "ecological bridge" between physically remote areas. Migratory birds fly south from their breeding grounds during late summer/fall and fly back in spring. These movements regulate the spread of internal and external parasites, as well as pathogens of potential public health concern. The aim of the present study was to investigate the possible introduction of exotic tick species and tick-borne pathogens into Europe via migratory birds. At the bird observatory of Ventotene island (Italy), 443 feeding ticks were collected from 249 birds captured and ringed during their northbound migration in spring 2013. Each tick was identified by morphological and molecular methods and then tested for bacterial and viral pathogens: Borrelia burgdorferi s.l., Rickettsia spp., Ehrlichia ruminantium and Coxiella burnetii, Crimean Congo haemorrhagic fever virus (CCHFV) and Flavivirus. Morphological and molecular identification confirmed Hyalomma rufipes as the most abundant species among the collected arthropods (366/443; 82.6%) followed by Hyalomma marginatum (10/433; 2.3%). Rickettsia aeschlimannii was identified in 158 ticks, while one engorged Amblyomma variegatum nymph was infected with Rickettsia africae. The other bacteria were not detected in any specimen. Among viruses, RNA belonging to West Nile virus and other Flavivirus were detected whereas all ticks were negative for CCHFV RNA. These results confirm how migratory birds play a role in carrying Rickettsia-infected ticks, as well as viruses of zoonotic importance, from Africa into Europe. To what extent tick species are capable of establishing a permanent population once introduced in naive areas, is far from defined and deserve further investigation.

Ectoparasitic insects play a major role in veterinary medicine. Fleas infest man and animals and are the most frequent external parasites of companion animals worldwide. Some species are known to be vectors of zoonotic pathogens. Dogs and cats may play an important role either as reservoir of some of the pathogens or as transport vehicles for infected eas between their natural reservoirs and human beings, thus playing a crucial step in the transmission cycle of ea-borne diseases. This article reviews relevant literature on morphology, classi cation, host speci city, geographical distribution, and seasonality of eas infesting dogs and cats in order to improve their timely identi cation, prevention, and control.

Magnetohydrodynamic (MHD) and photoevaporative winds are thought to play an important role in the evolution and dispersal of planet-forming disks. We report the first high-resolution ($\Delta v\sim$6\kms) analysis of [S II] $\lambda$4068, [O I] $\lambda$5577, and [O I] $\lambda$6300 lines from a sample of 48 T Tauri stars. Following Simon et al. (2016), we decompose them into three kinematic components: a high-velocity component (HVC) associated with jets, and a low-velocity narrow (LVC-NC) and broad (LVC-BC) components. We confirm previous findings that many LVCs are blueshifted by more than 1.5 kms$^{-1}$ thus most likely trace a slow disk wind. We further show that the profiles of individual components are similar in the three lines. We find that most LVC-BC and NC line ratios are explained by thermally excited gas with temperatures between 5,000$-$10,000 K and electron densities $\sim10^{7}-10^{8}$ cm$^{-3}$. The HVC ratios are better reproduced by shock models with a pre-shock H number density of $\sim10^{6}-10^{7}$ cm$^{-3}$. Using these physical properties, we estimate $\dot{M}_{\rm wind}/\dot{M}_{\rm acc}$ for the LVC and $\dot{M}_{\rm jet}/\dot{M}_{\rm acc}$ for the HVC. In agreement with previous work, the mass carried out in jets is modest compared to the accretion rate. With the likely assumption that the NC wind height is larger than the BC, the LVC-BC $\dot{M}_{\rm wind}/\dot{M}_{\rm acc}$ is found to be higher than the LVC-NC. These results suggest that most of the mass loss occurs close to the central star, within a few au, through an MHD driven wind. Depending on the wind height, MHD winds might play a major role in the evolution of the disk mass., Comment: 45 pages, 23 figures, and 7 tables, accepted by ApJ

We present a survey of optical [OI] emission at 6300 \AA\ toward 65 TTauri stars at the spectral resolution of $\sim7$ km/s. Past work identified a highly blueshifted velocity component (HVC) tracing microjets, and a less blueshifted low-velocity-component (LVC) attributed to winds. We focus here on the LVC kinematics to investigate links between winds, jets, accretion, and disk dispersal. We track the behavior of four types of LVC components: a broad and narrow component ("BC" and "NC") in LVCs that are decomposed into two Gaussians, which typically have an HVC, and the single-Gaussian LVC profiles separated into those that have an HVC ("SCJ") and those that do not ("SC"). LVC centroid velocities and line widths correlate with HVC equivalent width and accretion luminosity, suggesting that LVC/winds and HVC/jets are kinematically linked and connected to accretion. The deprojected HVC velocity correlates with accretion luminosity, showing that faster jets come with higher accretion. BC and NC kinematics correlate and their blueshifts are maximum at $\sim 35^{\circ}$, suggesting a conical wind geometry with this semi-opening angle. Only SCs include $n_{13-31}$ up to $\sim3$ and their properties correlate with this infrared index, showing that [OI] emission recedes to larger radii as the inner dust is depleted, tracing less dense/hot gas and a decrease in wind velocity. All together, these findings support a scenario where optically thick, accreting inner disks launch radially-extended MHD disk winds that feed jets, and where inner disk winds recede to larger radii and jets disappear in concert with dust depletion., Comment: Accepted for publication on ApJ

The maintenance of tick-borne disease agents in the environment strictly depends on the relationship between tick vectors and their hosts, which act as reservoirs for these pathogens. A pilot study aimed to investigate wild rodents as reservoirs for zoonotic tick-borne pathogens (Borrelia burgdorferi sensu lato (s.l.), Coxiella burnetii, Francisella tularensis, and Anaplasma phagocytophilum) was carried out in an area of Gran Sasso e Monti della Laga National Park (Abruzzi Region, central Italy), a wide protected area where, despite sporadic reports of infection in humans and animals, eco-epidemiological data on these diseases are still not available. Rodents were trapped and released at the capture site after the collection of feeding ticks and blood samples. In all, 172 ticks were collected; the most frequent species was Ixodes acuminatus (53%). Out of 88 tick pools, 11 resulted positive for C. burnetii and 13 for B. burgdorferi s.l.; the Borrelia afzelii genospecies was identified in one Ixodes ricinus tick collected from one Apodemus sp. rodent. Out of 143 blood samples, seven Apodemus spp. and five Myodes glareolus were positive for B. burgdorferi s.l. and two Apodemus spp. were positive for C. burnetii. All samples (ticks and blood) were negative for F. tularensis and A. phagocytophilum. This is the first report of B. burgdorferi s.l. in the environment for Abruzzi Region. Data on the presence of B. burgdorferi s.l. are similar to that observed in other Mediterranean countries. The present work is also the first report of C. burnetii in wild rodents in Italy. C. burnetii infection has been largely investigated in Italy in ruminant farms by serology and molecular methods, but information on ecology and on the wild cycle are still lacking. Further studies including genotyping should be performed and species-specific differences between wild rodent reservoirs of Q fever and Lyme disease agents should be investigated.

We present high-resolution (0.11 × 0.06 arcsec2) 3 mm ALMA observations of the highly inclined transition disc around the star T Cha. Our continuum image reveals multiple dust structures: an inner disc, a spatially resolved dust gap, and an outer ring. When fitting sky-brightness models to the real component of the 3 mm visibilities, we infer that the inner emission is compact (≤1 au in radius), the gap width is between 18 and 28 au, and the emission from the outer ring peaks at ̃36 au. We compare our ALMA image with previously published 1.6 μm VLT/SPHERE imagery. This comparison reveals that the location of the outer ring is wavelength dependent. More specifically, the peak emission of the 3 mm ring is at a larger radial distance than that of the 1.6 μm ring, suggesting that millimeter-sized grains in the outer disc are located farther away from the central star than micron-sized grains. We discuss different scenarios to explain our findings, including dead zones, star-driven photoevaporation, and planet-disc interactions. We find that the most likely origin of the dust gap is from an embedded planet, and estimate - for a single planet scenario - that T Cha's gap is carved by a 1.2MJup planet.

The Large Ultraviolet/Optical/Infrared Surveyor (LUVOIR) is one of four large mission concepts currently undergoing community study for consideration by the 2020 Astronomy and Astrophysics Decadal Survey. LUVOIR is being designed to pursue an ambitious program of exoplanetary discovery and characterization, cosmic origins astrophysics, and planetary science. The LUVOIR study team is investigating two large telescope apertures (9- and 15-meter primary mirror diameters) and a host of science instruments to carry out the primary mission goals. Many of the exoplanet, cosmic origins, and planetary science goals of LUVOIR require high-throughput, imaging spectroscopy at ultraviolet (100 – 400 nm) wavelengths. The LUVOIR Ultraviolet Multi-Object Spectrograph, LUMOS, is being designed to support all of the UV science requirements of LUVOIR, from exoplanet host star characterization to tomography of circumgalactic halos to water plumes on outer solar system satellites. LUMOS offers point source and multi-object spectroscopy across the UV bandpass, with multiple resolution modes to support different science goals. The instrument will provide low (R = 8,000 – 18,000) and medium (R = 30,000 – 65,000) resolution modes across the far-ultraviolet (FUV: 100 – 200 nm) and nearultraviolet (NUV: 200 – 400 nm) windows, and a very low resolution mode (R = 500) for spectroscopic investigations of extremely faint objects in the FUV. Imaging spectroscopy will be accomplished over a 3 × 1.6 arcminute field-of-view by employing holographically-ruled diffraction gratings to control optical aberrations, microshutter arrays (MSA) built on the heritage of the Near Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope (JWST), advanced optical coatings for high-throughput in the FUV, and next generation large-format photon-counting detectors. The spectroscopic capabilities of LUMOS are augmented by an FUV imaging channel (100 – 200nm, 13 milliarcsecond angular resolution, 2 × 2 arcminute field-of-view) that will employ a complement of narrow- and medium-band filters. The instrument definition, design, and development are being carried out by an instrument study team led by the University of Colorado, Goddard Space Flight Center, and the LUVOIR Science and Technology Definition Team. LUMOS has recently completed a preliminary design in Goddard’s Instrument Design Laboratory and is being incorporated into the working LUVOIR mission concept. In this proceeding, we describe the instrument requirements for LUMOS, the instrument design, and technology development recommendations to support the hardware required for LUMOS. We present an overview of LUMOS’ observing modes and estimated performance curves for effective area, spectral resolution, and imaging performance. Example “LUMOS 100-hour Highlights” observing programs are presented to demonstrate the potential power of LUVOIR’s ultraviolet spectroscopic capabilities.

The mass of a protoplanetary disk limits the formation and future growth of any planet. Masses of protoplanetary disks are usually calculated from measurements of the dust continuum emission by assuming an interstellar gas-to-dust ratio. To investigate the utility of CO as an alternate probe of disk mass, we use ALMA to survey $^{13}$CO and C$^{18}$O J = $3-2$ line emission from a sample of 93 protoplanetary disks around stars and brown dwarfs with masses from 0.03 -- 2 M$_{\odot}$ in the nearby Chamaeleon I star-forming region. We detect $^{13}$CO emission from 17 sources and C$^{18}$O from only one source. Gas masses for disks are then estimated by comparing the CO line luminosities to results from published disk models that include CO freeze-out and isotope-selective photodissociation. Under the assumption of a typical ISM CO-to-H$_2$ ratios of $10^{-4}$, the resulting gas masses are implausibly low, with an average gas mass of $\sim$ 0.05 M$_{Jup}$ as inferred from the average flux of stacked $^{13}$CO lines. The low gas masses and gas-to-dust ratios for Cha I disks are both consistent with similar results from disks in the Lupus star-forming region. The faint CO line emission may instead be explained if disks have much higher gas masses, but freeze-out of CO or complex C-bearing molecules is underestimated in disk models. The conversion of CO flux to CO gas mass also suffers from uncertainties in disk structures, which could affect gas temperatures. CO emission lines will only be a good tracer of the disk mass when models for C and CO depletion are confirmed to be accurate., Comment: accepted for publication in ApJ

Young stellar objects (YSOs) may undergo periods of active accretion (outbursts), during which the protostellar accretion rate is temporarily enhanced by a few orders of magnitude. Whether or not these accretion outburst YSOs possess similar dust/gas reservoirs to each other, and whether or not their dust/gas reservoirs are similar as quiescent YSOs, are issues not yet clarified. The aim of this work is to characterize the millimeter thermal dust emission properties of a statistically significant sample of long and short duration accretion outburst YSOs (i.e., FUors and EXors) and the spectroscopically identified candidates of accretion outbursting YSOs (i.e., FUor-like objects). We have carried out extensive Submillimeter Array (SMA) observations mostly at $\sim$225 GHz (1.33 mm) and $\sim$272 GHz (1.10 mm), from 2008 to 2017. We covered accretion outburst YSOs located at $$3-$\sigma$ significance. Detected sources except for the two cases of V883 Ori and NGC 2071 MM3 were observed with $\sim$1$"$ angular resolution. Overall our observed targets show a systematically higher millimeter luminosity distribution than those of the $M_{*}>$0.3 $M_{\odot}$ Class II YSOs in the nearby ($\lesssim$400 pc) low-mass star-forming molecular clouds (e.g., Taurus, Lupus, Upp Scorpio, and Chameleon I). In addition, at 1 mm our observed confirmed binaries or triple-system sources are systematically fainter than the rest of the sources even though their 1 mm fluxes are broadly distributed. We may have detected $\sim$30-60\% millimeter flux variability from V2494 Cyg and V2495 Cyg, from the observations separated by $\sim$1 year., Comment: 23 pages, 17 figures, accepted to A&A

Rings are the most frequently revealed substructure in ALMA dust observations of protoplanetary disks, but their origin is still hotly debated. In this paper, we identify dust substructures in 12 disks and measure their properties to investigate how they form. This subsample of disks is selected from a high-resolution ($\sim0.12''$) ALMA 1.33 mm survey of 32 disks in the Taurus star-forming region, which was designed to cover a wide range of sub-mm brightness and to be unbiased to previously known substructures. While axisymmetric rings and gaps are common within our sample, spiral patterns and high contrast azimuthal asymmetries are not detected. Fits of disk models to the visibilities lead to estimates of the location and shape of gaps and rings, the flux in each disk component, and the size of the disk. The dust substructures occur across a wide range of stellar mass and disk brightness. Disks with multiple rings tend to be more massive and more extended. The correlation between gap locations and widths, the intensity contrast between rings and gaps, and the separations of rings and gaps could all be explained if most gaps are opened by low-mass planets (super-Earths and Neptunes) in the condition of low disk turbulence ($\alpha=10^{-4}$). The gap locations are not well correlated with the expected locations of CO and N$_2$ ice lines, so condensation fronts are unlikely to be a universal mechanism to create gaps and rings, though they may play a role in some cases., Comment: 23 pages, 11 figures, ApJ accepted

Summary Dourine is trypanosomosis that affects equids, it's mainly sexually transmitted. The disease was first eradicated in Italy in the 1940s, but there was then a serious epidemic in the mid-70s. After sporadic reports at the end of the 1990s, in May 2011 it was reported once more. Clinical diagnosis of dourine can be complex, as clinical signs and gross lesions are not always present. Direct laboratory diagnosis is also problematic, given the low number of parasites normally present in infected tissues and the mild, short-lasting parasitaemia. This article describes the epidemiological, clinical and laboratory data enabling confirmation of the suspicion of dourine in Italy in the 2011 epidemic.

Characterization of the properties of young brown dwarfs are important to constraining the formation of objects at the extreme low-mass end of the initial mass function. While young brown dwarfs share many properties with solar-mass T Tauri stars, differences may be used as tests of how the physics of accretion/outflow and disk chemistry/dissipation depend on the mass of the central object. This article summarizes the presentations and discussions during the splinter session on “Disks, accretion and outflows of brown dwarfs” held at the CoolStars17 conference in Barcelona in June 2012. Recent results in the field of brown dwarf disks and outflows include the determination of brown dwarf disk masses and geometries based on Herschel far-IR photometry (70–160 µm), accretion properties based on X-Shooter spectra, and new outflow detections in the very low-mass regime. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

To investigate the potential connection between the intense X-ray emission from young, low-mass stars and the lifetimes of their circumstellar, planet-forming disks, we have compiled the X-ray luminosities ($L_X$) of M stars in the $\sim$8 Myr-old TW Hya Association (TWA) for which X-ray data are presently available. Our investigation includes analysis of archival Chandra data for the TWA binary systems TWA 8, 9, and 13. Although our study suffers from poor statistics for stars later than M3, we find a trend of decreasing $L_X/L_{bol}$ with decreasing $T_{eff}$ for TWA M stars wherein the earliest-type (M0--M2) stars cluster near $\log{(L_X/L_{bol})} \approx -3.0$ and then $\log{(L_X/L_{bol})}$ decreases, and its distribution broadens, for types M4 and later. The fraction of TWA stars that display evidence for residual primordial disk material also sharply increases in this same (mid-M) spectral type regime. This apparent anticorrelation between the relative X-ray luminosities of low-mass TWA stars and the longevities of their circumstellar disks suggests that primordial disks orbiting early-type M stars in the TWA have dispersed rapidly as a consequence of their persistent large X-ray fluxes. Conversely, the disks orbiting the very lowest-mass pre-MS stars and pre-MS brown dwarfs in the Association may have survived because their X-ray luminosities and, hence, disk photoevaporation rates are very low to begin with, and then further decline relatively early in their pre-MS evolution., Comment: 28 pages, 4 figures; to appear in The Astronomical Journal

In this work, we report the discovery of a candidate planetary-mass object with a photoevaporating protoplanetary disk, Proplyd 133-353, which is near the massive star $\theta^{1}$ Ori C at the center of the Orion Nebula Cluster (ONC). The object was known to have extended emission pointing away from $\theta^{1}$ Ori C, indicating ongoing external photoevaporation. Our near-infrared spectroscopic data suggests that the central source of Proplyd 133-353 is substellar ($\sim$M9.5), might have a mass probably less than 13 Jupiter mass and an age younger than 0.5 Myr. Proplyd 133-353 shows a similar ratio of X-ray luminosity to stellar luminosity to other young stars in the ONC with a similar stellar luminosity, and has a similar proper motion to the mean one of confirmed ONC members. We propose that Proplyd 133-353 was formed in a very low-mass dusty cloud near $\theta^{1}$ Ori C as a second-generation of star formation, which can explain both its young age and the presence of its disk., Comment: 6 pages, 4 figures. Accepted for publication in ApJL

We present models of giant planet migration in evolving protoplanetary discs. We show that disc clearing by EUV photoevaporation can have a strong effect on the distribution of giant planet semi-major axes. During disc clearing planet migration is slowed or accelerated in the region where photoevaporation opens a gap in the disc, resulting in "deserts" where few giant planets are found and corresponding "pile-ups" at smaller and larger radii. However, the precise locations and sizes of these features are strong functions of the efficiency of planetary accretion, and therefore also strongly dependent on planet mass. We suggest that photoevaporative disc clearing may be responsible for the pile-up of ~Jupiter-mass planets at ~1AU seen in exoplanet surveys, and show that observations of the distribution of exoplanet semi-major axes can be used to test models of both planet migration and disc clearing.

Summary Migratory birds are considered one of the main sources for West Nile virus (WNV) introduction into European countries. Following the WNV epidemic in the late summer of 1998 in a marshy area of Tuscany (Padule of Fucecchio), an extensive ornithological surveillance programme was carried out in the infected areas from 2006 to 2008. Several species of migratory and resident birds were trapped, sampled and serologically tested. The results of this surveillance programme gave a useful indication of potential sources of WNV re-introduction and spread into Italy. The area under study was also investigated and classified into ecological areas through satellite image processing. In August 2008, the WNV infection re-emerged in Italy in the area surrounding the Po river delta, involving three regions: Lombardy, Emilia Romagna and Veneto. Several surveillance activities were immediately put in place, including the extensive monitoring of wild birds found dead or trapped in the framework of other surveillance programmes. These activities were also prolonged in the 2009, when the virus circulation re-occurred at the border of the area already infected in 2008. The possible epidemiological role of the different species of migratory and resident birds is discussed, in relation to the different ecological patterns identified in the area and their potential ability to introduce, spread and support the endemization of WNV infection.

A capture operation to ascertain health status in free-ranging buffaloes from six different areas in the Caprivi Strip in the northeast corner of Namibia was conducted in October 2009. Basic information on the ticks and tick-borne pathogens normally found in wildlife from this area are scarce. The objective of this study was to assess the host status of African buffaloes, Syncerus caffer, for ixodid ticks and two selected tick-borne pathogens in the Caprivi Strip, a key area bordering Angola, Zambia, Botswana, and Zimbabwe. Four different tick species have been identified among the 233 collected specimens, and, of 95 tested buffaloes, 54 (57%) were positive for Theileria parva, whereas only 3 (3%) showed evidence of being infected with Ehrlichia ruminantium.

The objective of the present study was to examine the phylogenetic position of Setaria cervi based on sequences of mitochondrial cytochrome c oxidase subunit 1 (cox1) gene. A fragment of the cox1 gene from two morphologically identified S. cervi collected from red deer (Cervus elaphus) from Italy were amplified, sequenced, and compared with corresponding sequences of other filarioid nematode species. Phylogenetic studies using Bayesian analysis revealed S. cervi as monophyletic with other Setaria species, confirming S. cervi as a member of the Setaria genus. S. cervi appeared to be sister species to Setaria labiatopapillosa and Setaria digitata. Setaria tundra and Setaria equina, the other two Setaria species presented in the Italian fauna, formed a sister group to the clade consisting of S. cervi, S. labiatopapillosa, and S. digitata. In addition to phylogenetic clarification, our study is the first molecular identification of S. cervi, which may be useful for further molecular identification and differen- tiation of this filarial worm from other filarioid nematode species, especially in the earlier developmental stages of its life cycle

Chemistry plays an important role in the structure and evolution of protoplanetary disks, with implications for the composition of comets and planets. This is the first of a series of papers based on data from DISCS, a Submillimeter Array survey of the chemical composition of protoplanetary disks. The six Taurus sources in the program (DM Tau, AA Tau, LkCa 15, GM Aur, CQ Tau and MWC 480) range in stellar spectral type from M1 to A4 and offer an opportunity to test the effects of stellar luminosity on the disk chemistry. The disks were observed in 10 different lines at ~3" resolution and an rms of ~100 mJy beam-1 at ~0.5 km s-1. The four brightest lines are CO 2-1, HCO+ 3-2, CN 2_3-1_2 and HCN 3-2 and these are detected toward all sources (except for HCN toward CQ Tau). The weaker lines of CN 2_2-1_1, DCO+ 3-2, N2H+ 3-2, H2CO 3_03-2_02 and 4_14-3_13 are detected toward two to three disks each, and DCN 3-2 only toward LkCa 15. CH3OH 4_21-3_12 and c-C3H2 are not detected. There is no obvious difference between the T Tauri and Herbig Ae sources with regard to CN and HCN intensities. In contrast, DCO+, DCN, N2H+ and H2CO are detected only toward the T Tauri stars, suggesting that the disks around Herbig Ae stars lack cold regions for long enough timescales to allow for efficient deuterium chemistry, CO freeze-out, and grain chemistry.

The Kepler survey provides a statistical census of planetary systems out to the habitable zone. Because most planets are non-transiting, orbital architectures are best estimated using simulated observations of ensemble populations. Here, we introduce EPOS, the Exoplanet Population Observation Simulator, to estimate the prevalence and orbital architectures of multi-planet systems based on the latest Kepler data release, DR25. We estimate that at least 42% of sun-like stars have nearly coplanar planetary systems with 7 or more exoplanets. The fraction of stars with at least one planet within 1 au could be as high as 100% depending on assumptions about the distribution of single transiting planets. We estimate an occurrence rate of planets in the habitable zone around sun-like stars of eta_earth=36+-14%. The innermost planets in multi-planet systems are clustered around an orbital period of 10 days (0.1 au), reminiscent of the protoplanetary disk inner edge or could be explained by a planet trap at that location. Only a small fraction of planetary systems have the innermost planet at long orbital periods, with fewer than ~8% and ~3% having no planet interior to the orbit of Mercury and Venus, respectively. These results reinforce the view that the solar system is not a typical planetary system, but an outlier among the distribution of known exoplanetary systems. We predict that at least half of the habitable zone exoplanets are accompanied by (non-transiting) planets at shorter orbital periods, hence knowledge of a close-in exoplanet could be used as a way to optimize the search for Earth-size planets in the Habitable Zone with future direct imaging missions., Comment: Accepted in AAS journals, code available on github

We follow the microlensing approach and quantify the occurrence of Kepler exoplanets as a function of planet-to-star mass ratio, q, rather than planet radius or mass. For planets with radii ~1-6 R_earth and periods

The paper presents new high angular resolution ALMA 1.3 mm dust continuum observations of the protoplanetary system AS 209 in the Ophiuchus star forming region. The dust continuum emission is characterized by a main central core and two prominent rings at $r = 75\,$au and $r = 130\,$au intervaled by two gaps at at $r = 62\,$au and $r = 103\,$au. The two gaps have different widths and depths, with the inner one being narrower and shallower. We determined the surface density of the millimeter dust grains using the 3D radiative transfer disk code \textsc{dali}. According to our fiducial model the inner gap is partially filled with millimeter grains while the outer gap is largely devoid of dust. The inferred surface density is compared to 3D hydrodynamical simulations (FARGO-3D) of planet-disk interaction. The outer dust gap is consistent with the presence of a giant planet ($M_{\rm planet} \sim 0.8\,M_{\rm Staturn}$); the planet is responsible for the gap opening and for the pile-up of dust at the outer edge of the planet orbit. The simulations also show that the same planet can give origin to the inner gap at $r = 62\,$au. The relative position of the two dust gaps is close to the 2:1 resonance and we have investigated the possibility of a second planet inside the inner gap. The resulting surface density (including location, width and depth of the two dust gaps) are in agreement with the observations. The properties of the inner gap pose a strong constraint to the mass of the inner planet ($M_{\rm planet} < 0.1\,M_{\rm J}$). In both scenarios (single or pair of planets), the hydrodynamical simulations suggest a very low disk viscosity ($��< 10^{-4}$). Given the young age of the system (0.5 - 1 Myr), this result implies that the formation of giant planets occurs on a timescale of $\lesssim$ 1\,Myr., Accepted by A&A

(abbreviated) We report detection with the Spitzer Space Telescope of cool dust surrounding solar type stars. The observations were performed as part of the Legacy Science Program, ``Formation and Evolution of Planetary Systems'' (FEPS). From the overall FEPS sample (Meyer et al. 2006) of 328 stars having ages ~0.003-3 Gyr we have selected sources with 70 um flux densities indicating excess in their spectral energy distributions above expected photospheric emission........ .....The rising spectral energy distributions towards - and perhaps beyond - 70 um imply dust temperatures T_dust 1/3 of the debris sources we find that multiple temperature components are suggested, implying a spatial distribution of dust extending over many tens of AU. Because the disks are dominated by collisional processes, the parent body (planetesimal) belts may be extended as well. Preliminary assessment of the statistics of cold debris around sun-like stars shows that ~10% of FEPS targets with masses between 0.6 and 1.8 Msun and ages between 30 Myr and 3 Gyr exhibit 70 um emission in excess of the expected photospheric flux density. We find that fractional excess amplitudes appear higher for younger stars and that there may be a trend in 70 um excess frequency with stellar mass., article accepted to ApJ

We present high-resolution echelle spectra of [Ne II] 12.81 micron emission from the classical T Tauri star (CTTS) TW Hya obtained with MICHELLE on Gemini North. The line is centered at the stellar radial velocity and has an intrinsic FWHM of 21\pm 4 km/s. The line width is broader than other narrow emission lines typically associated with the disk around TW Hya. If formed in a disk, the line broadening could result from turbulence in a warm disk atmosphere, Keplerian rotation at an average distance of 0.1 AU from the star, or a photoevaporative flow from the optically-thin region of the disk. We place upper limits on the [Ne II] emission flux from the CTTSs DP Tau and BP Tau., Accepted by ApJ. 18 pages, including 2 figures and 2 tables