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The Transiting Exoplanet Survey Satellite (TESS) space telescope is collecting continuous, high-precision optical photometry of stars throughout the sky, including thousands of RR Lyrae stars. In this paper, we present results for an initial sample of 118 nearby RR Lyrae stars observed in TESS Sectors 1 and 2. We use differential image photometry to generate light curves and analyze their mode content and modulation properties. We combine accurate light-curve parameters from TESS with parallax and color information from the Gaia mission to create a comprehensive classification scheme. We build a clean sample, preserving RR Lyrae stars with unusual light-curve shapes, while separating other types of pulsating stars. We find that a large fraction of RR Lyrae stars exhibit various low-amplitude modes, but the distribution of those modes is markedly different from those of the bulge stars. This suggests that differences in physical parameters have an observable effect on the excitation of extra modes, potentially offering a way to uncover the origins of these signals. However, mode identification is hindered by uncertainties when identifying the true pulsation frequencies of the extra modes. We compare mode amplitude ratios in classical double-mode stars to stars with extra modes at low amplitudes and find that they separate into two distinct groups. Finally, we find a high percentage of modulated stars among the fundamental mode pulsators, but also find that at least 28% of them do not exhibit modulation, confirming that a significant fraction of stars lack the Blazhko effect.

Rhegmatogenous retinal detachment (RRD) is a major cause of visual loss in developed countries. Proliferative vitreoretinopathy (PVR), an eye-sight threatening complication of RRD surgery, resembles a wound-healing process with inflammation, scar tissue formation, and membrane contraction. This study was performed to determine the possible involvement of a wide range of cytokines in the future development of PVR, and to identify predictors of PVR and visual outcome. A multiplex immunoassay was used for the simultaneous detection of 29 different cytokines in subretinal fluid samples from patients with primary RRD. Of 306 samples that were collected and stored in our BioBank between 2001 and 2008, 21 samples from patients who developed postoperative PVR were compared with 54 age-, sex-, and storage-time-matched RRD control patients who had an uncomplicated postoperative course during the overall follow-up period. Levels of IL-1α, IL-2, IL-3, IL-6, VEGF, and ICAM-1 were significantly higher (P<0.05) in patients who developed postoperative PVR after reattachment surgery than in patients with an uncomplicated postoperative course, whereas levels of IL-1β, IL-4, IL-5, IL-7, IL-9, IL-10, IL-11, IL-12p70, IL-13, IL-15, IL-17, IL-18, IL-21, IL-22, IL-23, IL-25, IL-33, TNF-α, IFN-γ, IGF-1, bFGF, HGF, and NGF were not (P>0.05). Multivariate logistic regression analysis revealed that IL-3 (P = 0.001), IL-6 (P = 0.047), ICAM-1 (P = 0.010), and preoperative visual acuity (P = 0.026) were independent predictors of postoperative PVR. Linear regression analysis showed that ICAM-1 (P = 0.005) and preoperative logMAR visual acuity (P = 0.001) were predictive of final visual outcome after primary RRD repair. Our findings indicate that after RRD onset an exaggerated response of certain cytokines may predispose to PVR. Sampling at a time close to the onset of primary RRD may thus provide clues as to which biological events may initiate the development of PVR and, most importantly, may provide a means for therapeutic control.

Short gamma-ray bursts Gamma-ray bursts (GRBs) are either ‘long and soft’, or ‘short and hard’. The long-duration type leave a strong afterglow and have been extensively studied. So we have a good idea of what causes them: explosions of massive stars in distant star-forming galaxies. Short GRBs, with no strong afterglow, were harder to pin down. The Swift satellite, launched last November, is designed to study bursts as soon as they happen. Having shown its worth with long GRBs (reported in the 18 August issue of Nature ), Swift has now bagged a short burst, GRB 050509B, precisely measured its location and detected the X-ray afterglow. Four papers this week report on this and another recent short burst. Now, over 20 years after they were first recognized, the likely origin of the short GRBs is revealed as a merger between neutron stars of a binary system and the instantaneous production of a black hole. Gamma-ray bursts (GRBs) fall into two classes: short-hard and long-soft bursts 1 , 2 , 3 . The latter are now known to have X-ray 4 and optical 5 afterglows, to occur at cosmological distances 6 in star-forming galaxies 7 , and to be associated with the explosion of massive stars 8 , 9 . In contrast, the distance scale, the energy scale and the progenitors of the short bursts have remained a mystery. Here we report the discovery of a short-hard burst whose accurate localization has led to follow-up observations that have identified the X-ray afterglow 10 and (for the first time) the optical afterglow 10 , 11 of a short-hard burst; this in turn led to the identification of the host galaxy of the burst as a late-type galaxy at z = 0.16 (ref. 10 ). These results show that at least some short-hard bursts occur at cosmological distances in the outskirts of galaxies, and are likely to be caused by the merging of compact binaries.

The nuclei of most galaxies are now believed to harbour supermassive black holes 1 . The motions of stars in the central few light years of our Milky Way Galaxy indicate the presence of a dark object with a mass of about 2.6 × 10 6  solar masses (refs 2 , 3 ). This object is spatially coincident with the compact radio source Sagittarius A* (Sgr A*) at the dynamical centre of the Galaxy, and the radio emission is thought to be powered by the gravitational potential energy released by matter as it accretes onto a supermassive black hole 4 , 5 . Sgr A* is, however, much fainter than expected at all wavelengths, especially in X-rays, which has cast some doubt on this model. The first strong evidence for X-ray emission was found only recently 6 . Here we report the discovery of rapid X-ray flaring from the direction of Sgr A*, which, together with the previously reported steady X-ray emission, provides compelling evidence that the emission is coming from the accretion of gas onto a supermassive black hole at the Galactic Centre.

Doppler and transit surveys are finding extrasolar planets of ever smaller mass and radius, and are now sampling the domain of super Earths (1–3R ⊕ 1 – 3 R ⊕ ). Recent results from the Doppler surveys suggest that discovery of a transiting super Earth in the habitable zone of a lower main sequence star may be possible. We evaluate the prospects for an all-sky transit survey targeted to the brightest stars, that would find the most favorable cases for photometric and spectroscopic characterization using theJames Webb Space Telescope(JWST). We use the proposedTransiting Exoplanet Survey Satellite(TESS) as representative of an all-sky survey. We couple the simulated TESS yield to a sensitivity model for the MIRI and NIRSpec instruments onJWST. Our sensitivity model includes all currently known and anticipated sources of random and systematic error for these instruments. We focus on the TESS planets with radii between those of Earth and Neptune. Our simulations consider secondary eclipse filter photometry usingJWST/MIRI, comparing the 11 and 15 μm bands to measureCO2 CO 2 absorption in super Earths, as well asJWST/NIRSpec spectroscopy of water absorption from 1.7–3.0 μm, andCO2 CO 2 absorption at 4.3 μm. We find thatJWSTwill be capable of characterizing dozens of TESS super Earths with temperatures above the habitable range, using both MIRI and NIRspec. We project that TESS will discover about eight nearby habitable transiting super Earths, all orbiting lower–main-sequence stars. The principal sources of uncertainty in the prospectiveJWSTcharacterization of habitable super Earths are super-Earth frequency and the nature of super-Earth atmospheres. Based on our estimates of these uncertainties, we project thatJWSTwill be able to measure the temperature and identify molecular absorptions (water,CO2 CO 2 ) in one to four nearby habitable TESS super Earths orbiting lower–main-sequence stars.

Since 2018, the ESPRESSO spectrograph at the VLT has been hunting for planets in the Southern skies via the RV method. One of its goals is to follow up candidate planets from transit surveys such as the TESS mission, particularly small planets. We analyzed photometry from TESS and ground-based facilities, high-resolution imaging, and RVs from ESPRESSO, HARPS, and HIRES, to confirm and characterize three new planets: TOI-260 b, transiting a late K-dwarf, and TOI-286 b and c, orbiting an early K-dwarf. We also update parameters for the known super-Earth TOI-134 b , hosted by an M-dwarf. TOI-260 b has a \\(13.475853^+0.000013_-0.000011\\) d period, \\(4.23 1.60 M_\\) mass and \\(1.710.08R_\\) radius. For TOI-286 b we find a \\(4.5117244^+0.0000031_-0.0000027\\) d period, \\(4.530.78M_\\) mass and \\(1.420.10R_\\) radius; for TOI-286 c, a \\(39.361826^+0.000070_-0.000081\\) d period, \\(3.722.22M_\\) mass and \\(1.88 0.12R_\\) radius. For TOI-134 b we obtain a \\(1.40152604^+0.00000074_-0.00000082\\) d period, \\(4.070.45M_\\) mass, and \\(1.630.14R_\\) radius. Circular models are preferred for all, although for TOI-260 b the eccentricity is not well-constrained. We compute bulk densities and place the planets in the context of composition models. TOI-260 b lies within the radius valley, and is most likely a rocky planet. However, the uncertainty on the eccentricity and thus on the mass renders its composition hard to determine. TOI-286 b and c span the radius valley, with TOI-286 b lying below it and having a likely rocky composition, while TOI-286 c is within the valley, close to the upper border, and probably has a significant water fraction. With our updated parameters for TOI-134 b, we obtain a lower density than previous findings, giving a rocky or Earth-like composition.

We report the discovery and characterisation of the transiting mini-Neptune HD~207496~b (TOI-1099) as part of a large programme that aims to characterise naked core planets. We obtained HARPS spectroscopic observations, one ground-based transit, and high-resolution imaging which we combined with the TESS photometry to confirm and characterise the TESS candidate and its host star. The host star is an active early K dwarf with a mass of \\(0.80 0.04\\,\\)M\\(_\\), a radius of \\(0.769 0.026\\,\\)R\\(_\\), and a G magnitude of 8. We found that the host star is young, \\( 0.52\\,\\) Myr, allowing us to gain insight into planetary evolution. We derived a planetary mass of \\(6.1 1.6\\,M_E\\),\\, a planetary radius of \\(2.25 0.12\\,R_E\\),\\ and a planetary density of \\(_p = 3.27_-0.91^+0.97\\,g.cm^-3\\). From internal structure modelling of the planet, we conclude that the planet has either a water-rich envelope, a gas-rich envelope, or a mixture of both. We have performed evaporation modelling of the planet. If we assume the planet has a gas-rich envelope, we find that the planet has lost a significant fraction of its envelope and its radius has shrunk. Furthermore, we estimate it will lose all its remaining gaseous envelope in \\( 0.52\\,\\) Gyr. Otherwise, the planet could have already lost all its primordial gas and is now a bare ocean planet. Further observations of its possible atmosphere and/or mass-loss rate would allow us to distinguish between these two hypotheses. Such observations would determine if the planet remains above the radius gap or if it will shrink and be below the gap.

Tidal orbital decay is suspected to occur especially for hot Jupiters, with the only observationally confirmed case of this being WASP-12 b. By examining this effect, information on the properties of the host star can be obtained using the so-called stellar modified tidal quality factor \\(Q_*'\\), which describes the efficiency with which kinetic energy of the planet is dissipated within the star. This can help to get information about the interior of the star. In this study, we aim to improve constraints on the tidal decay of the KELT-9, KELT-16 and WASP-4 systems, to find evidence for or against the presence of this particular effect. With this, we want to constrain each star's respective \\(Q_*'\\) value. In addition to that, we also aim to test the existence of the transit timing variations (TTVs) in the HD 97658 system, which previously favoured a quadratic trend with increasing orbital period. Making use of newly acquired photometric observations from CHEOPS and TESS, combined with archival transit and occultation data, we use Markov chain Monte Carlo (MCMC) algorithms to fit three models, a constant period model, an orbital decay model, and an apsidal precession model, to the data. We find that the KELT-9 system is best described by an apsidal precession model for now, with an orbital decay trend at over 2 \\(\\) being a possible solution as well. A Keplerian orbit model with a constant orbital period fits the transit timings of KELT-16 b the best due to the scatter and scale of their error bars. The WASP-4 system is represented the best by an orbital decay model at a 5 \\(\\) significance, although apsidal precession cannot be ruled out with the present data. For HD 97658 b, using recently acquired transit observations, we find no conclusive evidence for a previously suspected strong quadratic trend in the data.

We report the confirmation and characterisation of TOI-1820~b, TOI-2025~b, and TOI-2158~b, three Jupiter-sized planets on short-period orbits around G-type stars detected by TESS. Through our ground-based efforts using the FIES and Tull spectrographs, we have confirmed these planets and characterised their orbits, and find periods of around \\(4.9\\)~d, \\(8.9\\)~d, and \\(8.6\\)~d for TOI-1820~b, TOI-2025~b, and TOI-2158~b, respectively. The sizes of the planets range from 0.96 to 1.14 Jupiter radii, and their masses are in the range from 0.8 to 4.4 Jupiter masses. For two of the systems, namely TOI-2025 and TOI-2158, we see a long-term trend in the radial velocities, indicating the presence of an outer companion in each of the two systems. For TOI-2025 we furthermore find the star to be well-aligned with the orbit, with a projected obliquity of \\(9^+33_-31\\)~\\(^\\). As these planets are all found in relatively bright systems (V\\(\\)10.9-11.6 mag), they are well-suited for further studies, which could help shed light on the formation and migration of hot and warm Jupiters.