A new population of Darwin's fox (Lycalopex fulvipes) in the Valdivian Coastal Range

Indexación: Web of Science; Scielo.Darwin's fox (Lycalopex fulvipes Martin, 1837) is an endemic of the temperate forests of the Coastal Range of southern Chile, that was reported by Charles Darwin in 1834 in southern Chiloé Island (42° S, 74° W; Martin 1837). Initially known exclusively from that island, it was considered both an insular subspecies of the chilla fox (Lycalopex griseus Gray, 1837) (Housse 1953; Clutton-Brock et al. 1976) and a valid species (Martin 1837; Gay 1947; Osgood 1943). In 1990, a mainland population was reported at Nahuelbuta National Park (ca. 450 km north of Chiloé Island, 37° 47′ S, 72° 59′ W; Figure 1a) in sympatry with the chilla and culpeo foxes (Lycalopex culpaeus Molina, 1782) (Jaksic et al. 1990; Medel et al. 1990; Jiménez et al. 1991). This supported its status as a valid species, later confirmed through genetic studies (Yahnke et al. 1996).http://ref.scielo.org/z7mmt

Primer registro de Vespula vulgaris (Linnaeus 1758) (Hymenoptera: Vespidae) en la isla Navarino, Chile

The common wasp Vespula vulgaris (Linnaeus 1758) is an introduced species in the Southern Hemisphere that has been reported in Australia, New Zealand, Tasmania, Argentina and South-central Chile. This report documents the presence of V. vulgaris on Navarino Island, Cape Horn Biosphere Reserve, Southern Chile.La avispa común Vespula vulgaris (Linnaeus 1758) es una especie introducida en el Hemisferio Sur que ha sido registrada en Australia, Nueva Zelanda, Tasmania, Argentina y Chile central. Este trabajo documenta la presencia de V. vulgaris en la isla Navarino, Reserva de la Biósfera Cabo de Hornos, sur de Chile

TESS spots a mini-neptune interior to a hot saturn in the TOI-2000 system

Hot jupiters (P 60 $\mathrm{M}_\oplus$) are almost always found alone around their stars, but four out of hundreds known have inner companion planets. These rare companions allow us to constrain the hot jupiter's formation history by ruling out high-eccentricity tidal migration. Less is known about inner companions to hot Saturn-mass planets. We report here the discovery of the TOI-2000 system, which features a hot Saturn-mass planet with a smaller inner companion. The mini-neptune TOI-2000 b ($2.70 \pm 0.15 \,\mathrm{R}_\oplus$, $11.0 \pm 2.4 \,\mathrm{M}_\oplus$) is in a 3.10-day orbit, and the hot saturn TOI-2000 c ($8.14^{+0.31}_{-0.30} \,\mathrm{R}_\oplus$, $81.7^{+4.7}_{-4.6} \,\mathrm{M}_\oplus$) is in a 9.13-day orbit. Both planets transit their host star TOI-2000 (TIC 371188886, V = 10.98, TESS magnitude = 10.36), a metal-rich ([Fe/H] = $0.439^{+0.041}_{-0.043}$) G dwarf 174 pc away. TESS observed the two planets in sectors 9-11 and 36-38, and we followed up with ground-based photometry, spectroscopy, and speckle imaging. Radial velocities from CHIRON, FEROS, and HARPS allowed us to confirm both planets by direct mass measurement. In addition, we demonstrate constraining planetary and stellar parameters with MIST stellar evolutionary tracks through Hamiltonian Monte Carlo under the PyMC framework, achieving higher sampling efficiency and shorter run time compared to traditional Markov chain Monte Carlo. Having the brightest host star in the V band among similar systems, TOI-2000 b and c are superb candidates for atmospheric characterization by the JWST, which can potentially distinguish whether they formed together or TOI-2000 c swept along material during migration to form TOI-2000 b.Comment: v3 adds RV frequency analysis; 25 pages, 11 figures, 14 tables; revision submitted to MNRAS; machine-readable tables available as ancillary files; posterior samples available from Zenodo at https://doi.org/10.5281/zenodo.7683293 and source code at https://doi.org/10.5281/zenodo.798826

The Multiplanet System TOI-421: A Warm Neptune and a Super Puffy Mini-Neptune Transiting a G9 V Star in a Visual Binary

We report the discovery of a warm Neptune and a hot sub-Neptune transiting TOI-421 (BD-14 1137, TIC 94986319), a bright (V = 9.9) G9 dwarf star in a visual binary system observed by the Transiting Exoplanet Survey Satellite (TESS) space mission in Sectors 5 and 6. We performed ground-based follow-up observations—comprised of Las Cumbres Observatory Global Telescope transit photometry, NIRC2 adaptive optics imaging, and FIbre-fed Echellé Spectrograph, CORALIE, High Accuracy Radial velocity Planet Searcher, High Resolution Échelle Spectrometer, and Planet Finder Spectrograph high-precision Doppler measurements—and confirmed the planetary nature of the 16 day transiting candidate announced by the TESS team. We discovered an additional radial velocity signal with a period of five days induced by the presence of a second planet in the system, which we also found to transit its host star. We found that the inner mini-Neptune, TOI-421 b, has an orbital period of P_b = 5.19672 ± 0.00049 days, a mass of M_b = 7.17 ± 0.66 M⊕, and a radius of R_b = 2.68^(+0.19)_(-0.18) R⊕, whereas the outer warm Neptune, TOI-421 c, has a period of Pc = 16.06819 ± 0.00035 days, a mass of M_c = 16.42^(+1.06)_(-1.04) M⊕, a radius of R_c = 5.09^(+0.16)_(-0.15) R⊕ and a density of ρ_c = 0.685^(+0.080)_(-0.072) g cm⁻³. With its characteristics, the outer planet (ρ_c = 0.685^(+0.080)_(-0.072) g cm⁻³) is placed in the intriguing class of the super-puffy mini-Neptunes. TOI-421 b and TOI-421 c are found to be well-suited for atmospheric characterization. Our atmospheric simulations predict significant Lyα transit absorption, due to strong hydrogen escape in both planets, as well as the presence of detectable CH4 in the atmosphere of TOI-421 c if equilibrium chemistry is assumed

TOI-677 b: A Warm Jupiter (P=11.2d) on an eccentric orbit transiting a late F-type star

We report the discovery of TOI-677 b, first identified as a candidate in light curves obtained within Sectors 9 and 10 of the Transiting Exoplanet Survey Satellite (TESS) mission and confirmed with radial velocities. TOI-677 b has a mass of M_p = 1.236$^{+0.069}_{-0.067}$ M_J, a radius of R_p = 1.170 +- 0.03 R_J,and orbits its bright host star (V=9.8 mag) with an orbital period of 11.23660 +- 0.00011 d, on an eccentric orbit with e = 0.435 +- 0.024. The host star has a mass of M_* = 1.181 +- 0.058 M_sun, a radius of R_* = 1.28 +- 0.03 R_sun, an age of 2.92$^{+0.80}_{-0.73}$ Gyr and solar metallicity, properties consistent with a main sequence late F star with T_eff = 6295 +- 77 K. We find evidence in the radial velocity measurements of a secondary long term signal which could be due to an outer companion. The TOI-677 b system is a well suited target for Rossiter-Mclaughlin observations that can constrain migration mechanisms of close-in giant planets.Comment: Submitted to AAS journals, 15 pages, 8 figure

Inhibition of light emission from the metastable tetragonal phase at low temperatures in island-like films of lead iodide perovskites

Photonic applications based on halide perovskites, namely CH3NH3PbI3 (MAPbI3), have recently attracted remarkable attention due to the high efficiencies reported for photovoltaic and light emitting devices. Despite these outstanding results, there are many temperature-, laser excitation power-, and morphology-dependent phenomena that require further research to be completely understood. In this work, we have investigated in detail the nature of exciton optical transitions and recombination dynamics below and above the orthorhombic/tetragonal (‘O’-/‘T’-) temperature phase transition (∼150 K) depending on the material continuity (continuous-like) or discontinuity (island-like) in MAPbI3 films. At low temperatures, continuous thin films of the perovskite can exhibit strain inhomogeneities associated with the formation of different ‘T’-defective domains leading to an energy spread of states over more than 200 meV. On the other hand, a single photoluminescence line peak related to the perovskite ‘O’-phase (associated with the distortion of the [PbI3] − anion) is observed in the island-like sample that we attribute to strain relaxation for this morphology. Moreover, the predominantly radiative recombination dynamics of the continuouslike sample mainly originates from nongeminate electron–hole formation of excitons in the ‘O’-phase and the internal dynamics with carrier trapping levels. This observation is in strong contrast to the free exciton recombination dominantly found in the island-like sample

First record of Vespula vulgaris (Linnaeus 1758) (Hymenoptera: Vespidae); on Navarino Island, Chile

This article documents the presence of the common wasp V. vulgaris on Navarino Island, Cape Horn Biosphere Reserve, Southern Chile