Hyades Member K2-136c:The Smallest Planet in an Open Cluster with a Precisely Measured Mass

International audienceK2-136 is a late-K dwarf (0.742 ± 0.039 M ⊙) in the Hyades open cluster with three known, transiting planets and an age of 650 ± 70 Myr. Analyzing K2 photometry, we found that planets K2-136b, c, and d have periods of 8.0, 17.3, and 25.6 days and radii of 1.014 ± 0.050 R ⊕, 3.00 ± 0.13 R ⊕, and 1.565 ± 0.077 R ⊕, respectively. We collected 93 radial velocity (RV) measurements with the High-Accuracy Radial-velocity Planet Searcher for the Northern hemisphere (HARPS-N) spectrograph (Telescopio Nazionale Galileo) and 22 RVs with the Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO) spectrograph (Very Large Telescope). Analyzing HARPS-N and ESPRESSO data jointly, we found that K2-136c induced a semi-amplitude of 5.49 ± 0.53 m s-1, corresponding to a mass of 18.1 ± 1.9 M ⊕. We also placed 95% upper mass limits on K2-136b and d of 4.3 and 3.0 M ⊕, respectively. Further, we analyzed Hubble Space Telescope and XMM-Newton observations to establish the planetary high-energy environment and investigate possible atmospheric loss. K2-136c is now the smallest planet to have a measured mass in an open cluster and one of the youngest planets ever with a mass measurement. K2-136c has ~75% the radius of Neptune but is similar in mass, yielding a density of ${3.69}_{-0.56}^{+0.67}$ g cm-3 (~2-3 times denser than Neptune). Mass estimates for K2-136b (and possibly d) may be feasible with more RV observations, and insights into all three planets' atmospheres through transmission spectroscopy would be challenging but potentially fruitful. This research and future mass measurements of young planets are critical for investigating the compositions and characteristics of small exoplanets at very early stages of their lives and providing insights into how exoplanets evolve with time

PESQUISAS DESENVOLVIDAS NO PROGRAMA DE PÓS-GRADUAÇÃO EM GERONTOLOGIA DA UNIVERSIDADE FEDERAL DE SÃO CARLOS E SUA IMPORTÂNCIA NO CONTEXTO DO ENVELHECIMENTO

Esta revisão narrativa tem como objetivo apresentar e discutir a relevância dos estudos desenvolvidos no Programa de Pós-Graduação em Gerontologia da Universidade Federal de São Carlos (PPGGero/UFSCar). Os dados foram coletados na disciplina “Seminários Avançados em Gerontologia”, em que os docentes autores apresentaram suas linhas de pesquisa, as quais foram compiladas pelos discentes autores. Os resultados desta revisão apresentam os estudos realizados em um programa interdisciplinar de mestrado acadêmico que possui duas linhas de pesquisa denominadas: 1) Saúde, Biologia e Envelhecimento; e 2) Gestão, Tecnologia e Inovação em Gerontologia. Os estudos se inserem em diversas temáticas da área do envelhecimento, que se articulam entre ambas as linhas de pesquisa do programa. Na linha 1 destacam-se estudos relacionados à cognição, à demência e suas consequências aos pacientes e cuidadores, bem como a pesquisas relacionadas ao seu diagnóstico e cuidado. Destacam-se também pesquisas epidemiológicas e aquelas relacionadas a condições ou doenças comuns no envelhecimento, como dor crônica, osteoartrite e, mais recentemente, a infecções em idosos, incluindo a COVID-19. Na linha 2 destacam-se pesquisas relacionadas a tecnologias assistivas voltadas aos idosos, bem como estratégias de marketing e políticas de atenção para esse público. É notório que a multidimensionalidade de abordagens das questões do envelhecimento exige enfoque multidisciplinar sobre um contexto de excelência acadêmica. Assim, conclui-se que as pesquisas do PPGGero/UFSCar, ao abrangerem várias áreas do conhecimento – as quais permeiam as ciências humanas, biológicas, sociais e exatas no contexto de tecnologia e inovação –, promovem a formação de mestres e pesquisadores que contribuem para a produção de conhecimento em Gerontologia no país

Precise Masses in the WASP-47 System

We present precise radial velocity observations of WASP-47, a star known to host a hot Jupiter, a distant Jovian companion, and, uniquely, two additional transiting planets in short-period orbits: a super-Earth in a ~19 hour orbit, and a Neptune in a ~9 day orbit. We analyze our observations from the HARPS-N spectrograph along with previously published data to measure the most precise planet masses yet for this system. When combined with new stellar parameters and reanalyzed transit photometry, our mass measurements place strong constraints on the compositions of the two small planets. We find unlike most other ultra-short-period planets, the inner planet, WASP-47 e, has a mass (6.83 +/- 0.66 Me) and radius (1.810 +/- 0.027 Re) inconsistent with an Earth-like composition. Instead, WASP-47 e likely has a volatile-rich envelope surrounding an Earth-like core and mantle. We also perform a dynamical analysis to constrain the orbital inclination of WASP-47 c, the outer Jovian planet. This planet likely orbits close to the plane of the inner three planets, suggesting a quiet dynamical history for the system. Our dynamical constraints also imply that WASP-47 c is much more likely to transit than a geometric calculation would suggest. We calculate a transit probability for WASP-47 c of about 10%, more than an order of magnitude larger than the geometric transit probability of 0.6%.Comment: 15 pages, 3 figures, 3 tables. Accepted in A

A New Investigation Of Hydration In The M-Type Asteroids

We obtained 2-4. μm spectra of six M-type asteroids using the SpeX spectrograph at NASA\u27s Infrared Telescope Facility. We find evidence for hydrated minerals on all six asteroids, including two that were previously thought to be dry. One of our targets, (216) Kleopatra, shows rotational variability in the depth of its 3-μm feature. We also studied three of these asteroids in the 0.8-2.4. μm range using the NICS instrument at the Telescopio Nazionale Galileo (TNG) in La Palma, Spain. The discovery of spectral signatures of hydrated minerals on so many M-types is difficult to reconcile with a highly thermally evolved composition. It has been suggested that the hydrated minerals could have been delivered to M-types via impacts with primitive objects, or that the M-types may actually have primitive compositions that are not represented in meteorite collections. Understanding the origin and type of hydration on these asteroids will help determine which of these interpretations is correct

Hungaria Asteroid Region Telescopic Spectral Survey (Hartss) I: Stony Asteroids Abundant In The Hungaria Background Population

The Hungaria asteroids remain as survivors of late giant planet migration that destabilized a now extinct inner portion of the primordial asteroid belt and left in its wake the current resonance structure of the Main Belt. In this scenario, the Hungaria region represents a “purgatory” for the closest, preserved samples of the asteroidal material from which the terrestrial planets accreted. Deciphering the surface composition of these unique samples may provide constraints on the nature of the primordial building blocks of the terrestrial planets. We have undertaken an observational campaign entitled the Hungaria Asteroid Region Telescopic Spectral Survey (HARTSS) to record near-infrared (NIR) reflectance spectra in order to characterize their taxonomy, surface mineralogy, and potential meteorite analogs. The overall objective of HARTSS is to evaluate the compositional diversity of asteroids located throughout the Hungaria region. This region harbors a collisional family of Xe-type asteroids, which are situated among a background (i.e., non-family) of predominantly S-complex asteroids. In order to assess the compositional diversity of the Hungaria region, we have targeted background objects during Phase I of HARTSS. Collisional family members likely reflect the composition of one original homogeneous parent body, so we have largely avoided them in this phase. We have employed NIR instruments at two ground-based telescope facilities: the NASA Infrared Telescope Facility (IRTF), and the Telescopio Nazionale Galileo (TNG). Our data set includes the NIR spectra of 42 Hungaria asteroids (36 background; 6 family). We find that stony S-complex asteroids dominate the Hungaria background population (29/36 objects; ∼80%). C-complex asteroids are uncommon (2/42; ∼5%) within the Hungaria region. Background S-complex objects exhibit considerable spectral diversity as band parameter measurements of diagnostic absorption features near 1- and 2-µm indicate that several different S-subtypes are represented therein, which translates to a variety of surface compositions. We identify the Gaffey S-subtype (Gaffey et al. [1993]. Icarus 106, 573–602) and potential meteorite analogs for 24 of these S-complex background asteroids. Additionally, we estimate the olivine and orthopyroxene mineralogy for 18 of these objects using spectral band parameter analysis established from laboratory-based studies of ordinary chondrite meteorites. Nine of the asteroids have band parameters that are not consistent with ordinary chondrites. We compared these to the band parameters measured from laboratory VIS+NIR spectra of six primitive achondrite (acapulcoite-lodranite) meteorites. These comparisons suggest that two main meteorite groups are represented among the Hungaria background asteroids: unmelted, nebular L- (and possibly LL-ordinary chondrites), and partially-melted primitive achondrites of the acapulcoite-lodranite meteorite clan. Our results suggest a source region for L chondrite like material from within the Hungarias, with delivery to Earth via leakage from the inner boundary of the Hungaria region. H chondrite like mineralogies appear to be absent from the Hungaria background asteroids. We therefore conclude that the Hungaria region is not a source for H chondrite meteorites. Seven Hungaria background asteroids have spectral band parameters consistent with partially-melted primitive achondrites, but the probable source region of the acapulcoite-lodranite parent body remains inconclusive. If the proposed connection with the Hungaria family to fully-melted enstatite achondrite meteorites (i.e., aubrites) is accurate (Gaffey et al. [1992]. Icarus 100, 95–109; Kelley and Gaffey [2002]. Meteorit. Planet. Sci. 37, 1815–1827), then asteroids in the Hungaria region exhibit a full range of petrologic evolution: from nebular, unmelted ordinary chondrites, through partially-melted primitive achondrites, to fully-melted igneous aubrite meteorites

The Changing Rotational Light-curve Amplitude of Varuna and Evidence for a Close-in Satellite

International audienc

A polarimetric unit for HARPS-North at the Telescopio Nazionale Galileo: HANPO

Usually observational astronomy is based on direction and intensity of radiation considered as a function of wavelength and time. Despite the polarisation degree of radiation provides information about asymmetry, anisotropy and magnetic fields within the radiative source or in the medium along the line of sight, it is commonly ignored. Because of the importance of high resolution spectropolarimetry to study a large series of phenomena related to the interaction of radiation with matter, as in stellar atmospheres or more generally stellar envelopes, we designed and built a dual beam polarimeter for HARPS-N that is in operation at the Telescopio Nazionale Galileo. Since the polarisation degree is measured from the combination of a series of measurements and accuracy is limited by the instrumental stability, just the great stability (0.6 m/s) and spectral resolution (R=115000) of the HARPS-N spectrograph should result in an accuracy in the measurements of Stokes parameters as small as 0.01%. Here we report on the design, realization, assembling, aligning and testing of the polarimetric unit whose first light is planned in August 2014