Abstract
We present the results of the analysis of the photometric data collected in long- and short-cadence mode by the Transiting Exoplanet Survey Satellite for GJ 504, a well-studied ...planet-hosting solar-like star, whose fundamental parameters have been largely debated during the last decade. Several attempts have been made by the present authors to isolate the oscillatory properties expected on this main-sequence star, but we did not find any presence of solar-like pulsations. The suppression of the amplitude of the acoustic modes can be explained by the high level of magnetic activity revealed for this target, not only by the study of the photometric light curve but also by the analysis of three decades of available Mount Wilson spectroscopic data. In particular, our measurements of the stellar rotational period
P
rot
≃ 3.4 days and of the main principal magnetic cycle of ≃12 yr confirm previous findings and allow us to locate this star in the early main-sequence phase of its evolution during which the chromospheric activity is dominated by the superposition of several cycles before the transition to the phase of the magnetic-braking shutdown with the subsequent decrease of the magnetic activity.
The prevalent pathogens associated with bovine uterine infections are bacteria that appear to increase the host's susceptibility to secondary infections with other bacteria or viruses, among which ...BoGHV4 is the most frequently found. In this work, the study of the pathways of apoptosis induction was carried out on an experimental model of primary culture of endometrial cells, in order to know the implication of BoGHV4 and the presence of bacterial LPS in the pathogenesis of the bovine reproductive tract. For this, different staining techniques and molecular analysis by RT-PCR were used. The results obtained allowed us to conclude that the level of cell death observed in the proposed primary culture is directly related to the time of viral infection and the presence of LPS in BoGHV4 infection. The apoptosis indices in cells infected with BoGHV4 and BoGHV4 + LPS revealed a maximum that correlated with the appearance of cytopathic effects and the maximum viral titers in the model studied. However, morphological, biochemical, and molecular changes were evident during both early and late stages of apoptosis. These findings provide information on the factors that may influence the pathogenesis of BoGHV4 and help to better understand the mechanisms involved in virus infection.
Most previous efforts to calibrate how rotation and magnetic activity depend on stellar age and mass have relied on observations of clusters, where isochrones from stellar evolution models are used ...to determine the properties of the ensemble. Asteroseismology employs similar models to measure the properties of an individual star by matching its normal modes of oscillation, yielding the stellar age and mass with high precision. We use 27 days of photometry from the Transiting Exoplanet Survey Satellite to characterize solar-like oscillations in the G8 subgiant of the 94 Aqr triple system. The resulting stellar properties, when combined with a reanalysis of 35 yr of activity measurements from the Mount Wilson HK project, allow us to probe the evolution of rotation and magnetic activity in the system. The asteroseismic age of the subgiant agrees with a stellar isochrone fit, but the rotation period is much shorter than expected from standard models of angular momentum evolution. We conclude that weakened magnetic braking may be needed to reproduce the stellar properties, and that evolved subgiants in the hydrogen shell-burning phase can reinvigorate large-scale dynamo action and briefly sustain magnetic activity cycles before ascending the red giant branch.
ABSTRACT
We present the confirmation and characterization of three hot Jupiters, TOI-1181b, TOI-1516b, and TOI-2046b, discovered by the TESS space mission. The reported hot Jupiters have orbital ...periods between 1.4 and 2.05 d. The masses of the three planets are 1.18 ± 0.14 MJ, 3.16 ± 0.12 MJ, and 2.30 ± 0.28 MJ, for TOI-1181b, TOI-1516b, and TOI-2046b, respectively. The stellar host of TOI-1181b is a F9IV star, whereas TOI-1516b and TOI-2046b orbit F main sequence host stars. The ages of the first two systems are in the range of 2–5 Gyrs. However, TOI-2046 is among the few youngest known planetary systems hosting a hot Jupiter, with an age estimate of 100–400 Myrs. The main instruments used for the radial velocity follow-up of these three planets are located at Ondřejov, Tautenburg, and McDonald Observatory, and all three are mounted on 2–3 m aperture telescopes, demonstrating that mid-aperture telescope networks can play a substantial role in the follow-up of gas giants discovered by TESS and in the future by PLATO.
Abstract
π
Men hosts a transiting planet detected by the Transiting Exoplanet Survey Satellite space mission and an outer planet in a 5.7 yr orbit discovered by radial velocity (RV) surveys. We ...studied this system using new RV measurements taken with the HARPS spectrograph on ESO’s 3.6 m telescope, as well as archival data. We constrain the stellar RV semiamplitude due to the transiting planet,
π
Men c, as
K
c
= 1.21 ± 0.12 m s
−1
, resulting in a planet mass of
M
c
= 3.63 ± 0.38
M
⊕
. A planet radius of
R
c
= 2.145 ± 0.015
R
⊕
yields a bulk density of
ρ
c
= 2.03 ± 0.22 g cm
−3
. The precisely determined density of this planet and the brightness of the host star make
π
Men c an excellent laboratory for internal structure and atmospheric characterization studies. Our HARPS RV measurements also reveal compelling evidence for a third body,
π
Men d, with a minimum mass
M
d
sin
i
d
= 13.38 ± 1.35
M
⊕
orbiting with a period of
P
orb,d
= 125 days on an eccentric orbit (
e
d
= 0.22). A simple dynamical analysis indicates that the orbit of
π
Men d is stable on timescales of at least 20 Myr. Given the mutual inclination between the outer gaseous giant and the inner rocky planet and the presence of a third body at 125 days,
π
Men is an important planetary system for dynamical and formation studies.
We report the discovery of an intermediate-mass transiting brown dwarf (BD), TOI-503b, from the TESS mission. TOI-503b is the first BD discovered by TESS, and it has circular orbit around a ...metallic-line A-type star with a period of P=3.6772±0.0001 days. The light curve from TESS indicates that TOI-503b transits its host star in a grazing manner, which limits the precision with which we measure the BD’s radius R(b) = 1.34(+0.26, -0.15)R(J). We obtained high resolution spectroscopic observations with the FIES, Ondrejov, PARAS, Tautenburg, and TRES spectrographs, and measured the mass of TOI-503b to be M(b)=53.7±1.2 M(J). The host star has a mass of M(*)=1.80±0.06M(ʘ), a radius of R(*)=1.70±0.05R(ʘ), an effective temperature of T(eff)=7650±160 K, and a relatively high metallicity of 0.61±0.07 dex. We used stellar isochrones to derive the age of the system to be ∼180 Myr, which places its age between that of RIK 72b (a ∼10 Myr old BD in the Upper Scorpius stellar association) and AD 3116b (a ∼600 Myr old BD in the Praesepe cluster). Given the difficulty in measuring the tidal interactions between BDs and their host stars, we cannot precisely say whether this BD formed in situ or has had its orbit circularized by its host star over the relatively short age of the system. Instead, we offer an examination of plausible values for the tidal quality factor for the star and BD. TOI-503b joins a growing number of known short-period, intermediate-mass BDs orbiting main sequence stars, and is the second such BD known to transit an A star, after HATS-70b. With the growth in the population in this regime, the driest region in the BD desert (35–55M(J) sin i) is reforesting.
Bovine gammaherpesvirus type 4 (BoHV-4) shows tropism for the endometrium, in which it causes the death of epithelial and stroma cells. Despite having anti-apoptotic genes in its genome, experiments ...based on immortalized cell lines have shown that BoHV-4 induces cell death by apoptosis. In the present study, we evaluated BoHV-4 replication, pro-apoptotic (Bax) and anti-apoptotic (Bcl-2) mitochondrial genes expression and chromatin condensation in bovine endometrium primary culture cells (BEC) and in the Madin Darby bovine kidney (MDBK) cell line. Results showed that BoHV-4 has a preference for replication in BEC cells over the MDBK cell line, demonstrated by the high viral titer that is consistent with the tropism of the virus. In BEC cells, chromatin condensation was consistent with the values of viral kinetics at the late stage of infection, accompanied with a balance in the mRNA levels of apoptotic mitochondrial proteins. As a consequence, in those cells viral transmission would be enhanced by inhibiting apoptosis in the early stage of virus proliferation, allowing the complete production of viral progeny, and then, the induction of apoptosis in late stages would allow neighboring cells infection. In MDBK cells replication kinetics was coincident with the up-regulation of Bcl-2, which suggests that the productive infection in MDBK is associated with a lytic phase of the virus or another cell death pathway (probably autophagy mechanism) at the late stage of infection. The results agree with the study of nuclear morphology, where a constant chromatin condensation was observed over time. It is clear that the documented BoHV-4 apoptotic responses observed in the cell lines studied above are not valid in cells from primary cultures. The data presented in this study suggest that BoHV-4 could induce apoptosis in BEC cells without a leading role of the mitochondria pathway. Further studies will be necessary to characterize in detail the programmed cell death pathways involved in BoHV-4 infection in the primary cell cultures evaluated.
•BoHV-4 shows tropism for bovine endometrial primary culture cells (BEC).•High viral titers of BoHV-4 are associated with apoptosis in BEC cells.•The mitochondrial pathway of apoptosis is not relevant in BEC cells infected with BoHV-4.•bax and bcl-2 gene expression differs between BEC and MDBK cells infected with BoHV-4.
ABSTRACT
Binary stars in which oscillations can be studied in either or both components can provide powerful constraints on our understanding of stellar physics. The bright binary 12 Boötis (12 Boo) ...is a particularly promising system because the primary is roughly 60 per cent brighter than the secondary despite being only a few per cent more massive. Both stars have substantial surface convection zones and are therefore, presumably, solar-like oscillators. We report here the first detection of solar-like oscillations and ellipsoidal variations in the TESS light curve of 12 Boo. Though the solar-like oscillations are not clear enough to unambiguously measure individual mode frequencies, we combine global asteroseismic parameters and a precise fit to the spectral energy distribution (SED) to provide new constraints on the properties of the system that are several times more precise than values in the literature. The SED fit alone provides new effective temperatures, luminosities, and radii of $6115\pm 45\, \mathrm{K}$, $7.531\pm 0.110\, \mathrm{L}_\odot$, and $2.450\pm 0.045\, \mathrm{R}_\odot$ for 12 Boo A and $6200\pm 60\, \mathrm{K}$, $4.692\pm 0.095\, \mathrm{L}_\odot$, and $1.901\pm 0.045\, \mathrm{R}_\odot$ for 12 Boo B. When combined with our asteroseismic constraints on 12 Boo A, we obtain an age of $2.67^{+0.12}_{-0.16}\, \mathrm{Gyr}$, which is consistent with that of 12 Boo B.
ABSTRACT
The Transiting Exoplanet Survey Satellite (TESS) is recording short-cadence, high duty-cycle timeseries across most of the sky, which presents the opportunity to detect and study ...oscillations in interesting stars, in particular planet hosts. We have detected and analysed solar-like oscillations in the bright G4 subgiant HD 38529, which hosts an inner, roughly Jupiter-mass planet on a $14.3\, \mathrm{d}$ orbit and an outer, low-mass brown dwarf on a $2136\, \mathrm{d}$ orbit. We combine results from multiple stellar modelling teams to produce robust asteroseismic estimates of the star’s properties, including its mass $M=1.48\pm 0.04\, \mathrm{M}_\odot {}$, radius $R=2.68\pm 0.03\, \mathrm{R}_\odot {}$, and age $t=3.07\pm 0.39\, \mathrm{Gyr}{}$. Our results confirm that HD 38529 has a mass near the higher end of the range that can be found in the literature and also demonstrate that precise stellar properties can be measured given shorter timeseries than produced by CoRoT, Kepler, or K2.
ABSTRACT
The Neptune desert is a feature seen in the radius-period plane, whereby a notable dearth of short period, Neptune-like planets is found. Here, we report the Transiting Exoplanet Survey ...Satellite (TESS) discovery of a new short-period planet in the Neptune desert, orbiting the G-type dwarf TYC 8003-1117-1 (TOI-132). TESS photometry shows transit-like dips at the level of ∼1400 ppm occurring every ∼2.11 d. High-precision radial velocity follow-up with High Accuracy Radial Velocity Planet Searcher confirmed the planetary nature of the transit signal and provided a semi-amplitude radial velocity variation of 11.38 $^{+0.84}_{-0.85}$ m s−1, which, when combined with the stellar mass of 0.97 ± 0.06 M⊙, provides a planetary mass of 22.40$^{+1.90}_{-1.92}$ M⊕. Modelling the TESS light curve returns a planet radius of 3.42$^{+0.13}_{-0.14}$ R⊕, and therefore the planet bulk density is found to be 3.08$^{+0.44}_{-0.46}$ g cm−3. Planet structure models suggest that the bulk of the planet mass is in the form of a rocky core, with an atmospheric mass fraction of 4.3$^{+1.2}_{-2.3}$ per cent. TOI-132 b is a TESS Level 1 Science Requirement candidate, and therefore priority follow-up will allow the search for additional planets in the system, whilst helping to constrain low-mass planet formation and evolution models, particularly valuable for better understanding of the Neptune desert.
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