Avaliação do efeito de diferentes substratos sobre o desenvolvimento de Euterpe Edulis (Mart.) e Roystonea regia (Kunth).

O trabalho foi realizado de janeiro a setembro de 2009, em casa de vegetação, na Embrapa Clima Temperado, Estação Experimental Cascata/RS. Não existem informações silviculturais da E. edulis e da R. regia nesta região do Estado, por essa razão, é necessário buscar um sistema que possibilite expandir a produção de palmeiras. O objetivo foi o de avaliar o efeito de diferentes substratos sobre o desenvolvimento inicial das plantas de E. eduli e R. regia. Os tratamentos foram: T1 , Plantmax®; T2 , solo mato; T3 ,solo argiloso; T4 ,solo mato/solo argiloso 1:1; T5 ,solo mato/casca arroz carbonizada 3:1; T6 ,solo mato/casca arroz carbonizada 1:1; T7 ,solo mato/casca arroz in natura 1:1; T8 ,solo argiloso/casca arroz carbonizada 3:1; T9 ,solo argiloso/casca arroz carbonizada 1:1; T10 ,solo argiloso/casca arroz in natura 1:1. O delineamento de blocos foi ao acaso, com quatro repetições, e quatro plantas por unidade experimental. A avaliações foram realizadas em intervalos quinzenais. Observou-se E. edulis bom crescimento vegetativo T2 e T3. R. regia, verificou-se boas respostas T5, T1, T6, e T10. Conclui-se que a utilização dos substratos solo mato ou solo argiloso, e a mistura casca de arroz in natura ou carbonizada, apresentara bom crescimento vegetativo das plantas

K2-113b: A dense hot-Jupiter transiting a solar analogue

We present the discovery of K2-113b, a dense hot-Jupiter discovered using photometry from Campaign 8 of the Kepler-2 (K2) mission and high-resolution spectroscopic follow up obtained with the FEROS spectrograph. The planet orbits a $V=13.68$ solar analogue in a $P=5.81760^{+0.00003}_{-0.00003}$ day orbit, has a radius of $0.93^{+0.10}_{-0.07}R_J$ and a mass of $1.29^{+0.13}_{-0.14}M_J$. With a density of $1.97^{+0.60}_{-0.53}$ gr/cm$^3$, the planet is among the densest systems known having masses below 2 $M_J$ and $T_{eq} > 1000$, and is just above the temperature limit at which inflation mechanisms are believed to start being important. Based on its mass and radius, we estimate that K2-113b should have a heavy element content on the order of $\sim$ 110 $M_{\oplus}$ or greater.Comment: 8 pages, 7 figures. Accepted to MNRAS; added new photometry from newest version of EVEREST, which allows for a constrain on the secondary eclipse dept

A discontinuity in the TeffT_{\rm eff}-radius relation of M-dwarfs

We report on 13 new high-precision measurements of stellar diameters for low-mass dwarfs obtained by means of near-infrared long-baseline interferometry with PIONIER at the Very Large Telescope Interferometer. Together with accurate parallaxes from Gaia DR2, these measurements provide precise estimates for their linear radii, effective temperatures, masses, and luminosities. This allows us to refine the effective temperature scale, in particular towards the coolest M-dwarfs. We measure for late-type stars with enhanced metallicity slightly inflated radii, whereas for stars with decreased metallicity we measure smaller radii. We further show that Gaia DR2 effective temperatures for M-dwarfs are underestimated by $\sim$ 8.2 % and give an empirical $M_{G}$-$T_{\rm eff}$ relation which is better suited for M-dwarfs with $T_{\rm eff}$ between 2600 and 4000 K. Most importantly, we are able to observationally identify a discontinuity in the $T_{\rm eff}$-radius plane, which is likely due to the transition from partially convective M-dwarfs to the fully convective regime. We found this transition to happen between 3200 K and 3340 K, or equivalently for stars with masses $\approx 0.23 M_{\odot}$. We find that in this transition region the stellar radii are in the range from 0.18 to 0.42$R_{\odot}$ for similar stellar effective temperatures.Comment: 11 pages, 9 figures, accepted in MNRA

TOI-431/HIP 26013: A super-Earth and a sub-Neptune transiting a bright, early K dwarf, with a third RV planet

We present the bright (Vmag = 9.12), multiplanet system TOI-431, characterized with photometry and radial velocities (RVs). We estimate the stellar rotation period to be 30.5 \ub1 0.7 d using archival photometry and RVs. Transiting Exoplanet Survey Satellite (TESS) objects of Interest (TOI)-431 b is\ua0a\ua0super-Earth with\ua0a\ua0period of 0.49 d,\ua0a\ua0radius of 1.28 \ub1 0.04 R,\ua0a\ua0mass of 3.07 \ub1 0.35 M, and\ua0a\ua0density of 8.0 \ub1 1.0 g cm-3; TOI-431 d is\ua0a\ua0sub-Neptune with\ua0a\ua0period of 12.46 d,\ua0a\ua0radius of 3.29 \ub1 0.09 R,\ua0a\ua0mass of 9.90+1.53-1.49 M, and\ua0a\ua0density of 1.36 \ub1 0.25 g cm-3. We find\ua0a\ua0third planet, TOI-431 c,\ua0in\ua0the High Accuracy Radial velocity Planet Searcher RV data, but it is not seen to transit\ua0in\ua0the TESS light curves. It has an Msin i of 2.83+0.41-0.34 M, and\ua0a\ua0period of 4.85 d. TOI-431 d likely has an extended atmosphere and is one of the most well-suited TESS discoveries for atmospheric characterization, while the super-Earth TOI-431 b may be\ua0a\ua0stripped core. These planets straddle the radius gap, presenting an interesting case-study for atmospheric evolution, and TOI-431 b is\ua0a\ua0prime TESS discovery for the study of rocky planet phase curves

Orbital alignment of the eccentric warm Jupiter TOI-677 b

Warm Jupiters lay out an excellent laboratory for testing models of planet formation and migration. Their separation from the host star makes tidal reprocessing of their orbits ineffective, which preserves the orbital architectures that result from the planet-forming process. Among the measurable properties, the orbital inclination with respect to the stellar rotational axis, stands out as a crucial diagnostic for understanding the migration mechanisms behind the origin of close-in planets. Observational limitations have made the procurement of spin-orbit measurements heavily biased toward hot Jupiter systems. In recent years, however, high-precision spectroscopy has begun to provide obliquity measurements for planets well into the warm Jupiter regime. In this study, we present Rossiter-McLaughlin (RM) measurements of the projected obliquity angle for the warm Jupiter TOI-677 b using ESPRESSO at the VLT. TOI-677 b exhibits an extreme degree of alignment ($\lambda = 0.3 \pm 1.3$ deg), which is particularly puzzling given its significant eccentricity ($e \approx 0.45$). TOI-677 b thus joins a growing class of close-in giants that exhibit large eccentricities and low spin-orbit angles, which is a configuration not predicted by existing models. We also present the detection of a candidate outer brown dwarf companion on an eccentric, wide orbit ($e \approx 0.4$ and $P \approx 13$ yr). Using simple estimates, we show that this companion is unlikely to be the cause of the unusual orbit of TOI-677 b. Therefore, it is essential that future efforts prioritize the acquisition of RM measurements for warm Jupiters.Comment: 15 pages, 6 figures, 5 tables. Accepted for publication in the Astronomical Journa

EPIC247098361b: a transiting warm Saturn on an eccentric P=11.2P=11.2 days orbit around a V=9.9V=9.9 star

We report the discovery of EPIC247098361b using photometric data of the Kepler K2 satellite coupled with ground-based spectroscopic observations. EPIC247098361b has a mass of M$_{P}=0.397\pm 0.037$ M$_J$, a radius of R$_{P}=1.00 \pm 0.020$ R$_J$, and a moderately low equilibrium temperature of $T_{eq}=1030 \pm 15$ K due to its relatively large star-planet separation of $a=0.1036$ AU. EPIC247098361b orbits its bright ($V=9.9$) late F-type host star in an eccentric orbit ($e=0.258 \pm 0.025$) every 11.2 days, and is one of only four well characterized warm Jupiters having hosts stars brighter than $V=10$. We estimate a heavy element content of 20 $\pm$ 7 M$_{\oplus}$ for EPIC247098361b, which is consistent with standard models of giant planet formation. The bright host star of EPIC247098361b makes this system a well suited target for detailed follow-up observations that will aid in the study of the atmospheres and orbital evolution of giant planets at moderate separations from their host stars.Comment: 11 pages, 10 figures, submitted to MNRA

Discovery and Validation of a High-Density sub-Neptune from the K2 Mission

We report the discovery of BD+20594b, a high density sub-Neptune exoplanet, made using photometry from Campaign 4 of the two-wheeled Kepler (K2) mission, ground-based radial velocity follow-up from HARPS and high resolution lucky and adaptive optics imaging obtained using AstraLux and MagAO, respectively. The host star is a bright ($V=11.04$, $K_s = 9.37$), slightly metal poor ([Fe/H]$=-0.15\pm 0.05$ dex) solar analogue located at $152.1^{+9.7}_{-7.4}$ pc from Earth, for which we find a radius of $R_*=0.928^{+0.055}_{-0.040}R_\odot$ and a mass of $M_* = 0.961^{+0.032}_{-0.029}M_\odot$. A joint analysis of the K2 photometry and HARPS radial velocities reveal that the planet is in a $\approx 42$ day orbit around its host star, has a radius of $2.23^{+0.14}_{-0.11}R_\oplus$, and a mass of $16.3^{+6.0}_{-6.1}M_\oplus$. Although the data at hand puts the planet in the region of the mass-radius diagram where we could expect planets with a pure rock (i.e. magnesium silicate) composition using two-layer models (i.e., between rock/iron and rock/ice compositions), we discuss more realistic three-layer composition models which can explain the high density of the discovered exoplanet. The fact that the planet lies in the boundary between "possibly rocky" and "non-rocky" exoplanets, makes it an interesting planet for future RV follow-up.Comment: 12 pages, 11 figures. Accepted for publication in Ap