Abstract
We present and analyze 58 transit light curves of TrES-3b and 98 transit light curves of Qatar-1b, observed by the Transiting Exoplanet Survey Satellite, plus two transit light curves of ...Qatar-1b, observed by us, using a ground-based 1.23 m telescope. These light curves are combined with the best-quality light curves taken from the Exoplanet Transit Database and the literature. The precisely determined midtransit times from these light curves enable us to obtain the refined orbital ephemerides, with improved precision, for both hot Jupiters. From the timing analysis, we find indications of the presence of transit timing variations (TTVs) in both systems. Since the observed TTVs are unlikely to be short-term and periodic, the possibility of additional planets in orbits close to TrES-3b and Qatar-1b is ruled out. The possible causes of long-term TTVs, such as orbital decay, apsidal precession, the Applegate mechanism, and line-of-sight acceleration, are also examined. However, none of these possibilities are found to explain the observed TTV of TrES-3b. In contrast to this, line-of-sight acceleration appears to be a plausible explanation for the observed TTV of Qatar-1b. In order to confirm these findings, further high-precision transit and radial velocity observations of both systems would be worthwhile.
ABSTRACT
We present broad-band photometry of 30 planetary transits of the ultra-hot-Jupiter KELT-16 b, using five medium-class telescopes. The transits were monitored through standard $B,\, V,\, R,\, ...I$ filters and four were simultaneously observed from different places, for a total of 36 new light curves. We used these new photometric data and those from the TESS space telescope to review the main physical properties of the KELT-16 planetary system. Our results agree with previous measurements but are more precise. We estimated the mid-transit times for each of these transits and combined them with others from the literature to obtain 69 epochs, with a time baseline extending over more than 4 yr, and searched for transit time variations. We found no evidence for a period change, suggesting a lower limit for orbital decay at 8 Myr, with a lower limit on the reduced tidal quality factor of $Q^{\prime }_{\star }\gt (1.9 \pm 0.8) \times 10^5$ with $95{{\rm {per\ cent}}}$ confidence. We built up an observational, low-resolution transmission spectrum of the planet, finding evidence of the presence of optical absorbers, although with a low significance. Using TESS data, we reconstructed the phase curve finding that KELT-16 b has a phase offset of 25.25 ± 14.03 °E, a day- and night-side brightness temperature of 3190 ± 61 K and 2668 ± 56 K, respectively. Finally, we compared the flux ratio of the planet over its star at the TESS and Spitzer wavelengths with theoretical emission spectra, finding evidence of a temperature inversion in the planet’s atmosphere, the chemical composition of which is preferably oxygen-rich rather than carbon-rich.
Abstract
We present broad-band photometry of 11 planetary transits of the hot Jupiter WASP-74 b, using three medium-class telescopes and employing the telescope-defocusing technique. Most of the ...transits were monitored through I filters and one was simultaneously observed in five optical (U, g′, r′, i′, z′) and three near-infrared (J, H, K) passbands, for a total of 18 light curves. We also obtained new high-resolution spectra of the host star. We used these new data to review the orbital and physical properties of the WASP-74 planetary system. We were able to better constrain the main system characteristics, measuring smaller radius and mass for both the hot Jupiter and its host star than previously reported in the literature. Joining our optical data with those taken with the HST in the near infrared, we built up an observational transmission spectrum of the planet, which suggests the presence of strong optical absorbers, as TiO and VO gases, in its atmosphere.
In the texture analysis of volcanic rocks, the preferred orientation of the constituents can provide useful information for the interpretation of the processes involved in the rock formation. We ...present here a new data analysis technique, based on X-ray microtomography measurements and on shape preferred orientation analysis, to obtain the orientation distribution functions of the constituents of volcanic rocks. This procedure proved to be very suitable for volcanic samples, where diffraction-based techniques, developed for crystallographic preferred orientation studies, are of limited utilization, in addition to the fact that they cannot provide any information about vesicles or bubbles. Moreover the analysis performed directly in three dimensions (3D) overcomes the problems that usually occur when employing stereological methods for the analysis of the images obtained via microscopy-based techniques. In this study, two scoriae (from Stromboli and Etna) and a tube pumice (from Campi Flegrei) were measured via X-ray microtomography and then the resulting volumes were analyzed following the proposed procedure. Results highlight little preferred orientation for the vesicles in the two scoria samples, whereas the pumice shows a marked preferred orientation. Crystals (also divided by mineral species) were taken into account as well and in the two scoria samples there is no crystal preferred orientation, in contrast with the pumice, where crystal preferred orientation features are very similar to the ones found for the vesicles. Overall we found strong differences in preferred orientation: weak for vesicles in scoriae, showing an axial symmetry with the axis parallel to the elongation axis of the sample, and a stronger and more complex orientation texture in the pumice sample for both crystals and vesicles. The promising results obtained suggest that this procedure is potentially very useful for the analysis of preferred orientation in volcanic rocks and geomaterials in general.
► Shape preferred orientation analysis. ► Synchrotron X-ray computed microtomography. ► Preferred orientation in scoriae and pumices.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Context. Thanks to the improved angular resolution of modern telescopes and kinematic models, the existence of supermassive black holes (SMBHs) in the inner part of galaxies, regardless their ...morphology and nuclear activity, has been established on quite solid grounds. A possible correlation between the mass of SMBHs (M•) and the evolutionary state of their host galaxies is expected and is currently under a heated debate. Aims. Based on the recent 2D decomposition of 3.6 μm Spitzer/IRAC images of local late- and early-type galaxies with M• measurements, we investigated various scaling laws, studying what is the best predictor of the mass of the central black holes, that is the one with the lowest value of intrinsic scatter. In particular, we focused on the M• − MGσ2 law, that is the relation between the mass of SMBHs and the kinetic energy of random motions of the corresponding host galaxies, MG is the mass and σ the velocity dispersion of the host galaxy (bulge). Methods. In order to find the best fit for each of the scaling laws examined, we performed a least-squares regression of M• on x for the considered sample of galaxies, x being a whatever known parameter of the galaxy bulge. For this purpose, we made use of both the linear regression LINMIX_ERR and FITEXY methods. Results. Our analysis shows that M• − MGσ2 law fits the examined experimental data successfully as much as the other known scaling laws (all correlations have similar intrinsic scatters within the errors) and shows a value of χ2 (estimated by FITEXY) better than the others, a result which is consistent with previous determinations at shorter wavelengths. This means that a combination of σ and MG (or Re) could be necessary to drive the correlations between M• and other bulge properties. This issue has been investigated by a careful, although not fully conclusive, analysis of the residuals of the various relations. Conclusions. In order to avoid rushed conclusions on galaxy activity and evolution, the indirect inferring of the masses of the supermassive black holes from the kinetic energy of random motions via the M• − MGσ2 relation should be considered, especially when applied to higher redshift galaxies (z > 0.01). This statement is suggested by a reanalysis of Sloan Digital Sky Survey (SDSS) data used to study the black hole growth in the nearby Universe. By adopting the M• − MGσ2 relation instead of the M• − σ relation, a radio-quiet/radio-loud dichotomy appears in the SMBH mass distribution of the corresponding SDSS early-type AGN galaxies.
Full text
Available for:
FMFMET, NUK, UL, UM, UPUK
ABSTRACT
We investigate whether there is a variation in the orbital period of the short-period brown dwarf-mass KELT-1 b, which is one of the best candidates to observe orbital decay. We obtain 19 ...high-precision transit light curves of the target using six different telescopes. We add all precise and complete transit light curves from open databases and the literature, as well as the available Transiting Exoplanet Survey Satellite (TESS) observations from sectors 17 and 57, to form a transit timing variation (TTV) diagram spanning more than 10 yr of observations. The analysis of the TTV diagram, however, is inconclusive in terms of a secular or periodic variation, hinting that the system might have synchronized. We update the transit ephemeris and determine an informative lower limit for the reduced tidal quality parameter of its host star of Q$_{\star }^{\prime } \gt (8.5 \pm 3.9) \times 10^{6}$ assuming that the stellar rotation is not yet synchronized. Using our new photometric observations, published light curves, the TESS data, archival radial velocities, and broadband magnitudes, we also update the measured parameters of the system. Our results are in good agreement with those found in previous analyses.
We report 13 high-precision light curves of eight transits of the exoplanet WASP-52 b, obtained by using four medium-class telescopes, through different filters, and adopting the defocussing ...technique. One transit was recorded simultaneously from two different observatories and another one from the same site but with two different instruments, including a multiband camera. Anomalies were clearly detected in five light curves and modelled as star-spots occulted by the planet during the transit events. We fitted the clean light curves with the JKTEBOP code, and those with the anomalies with the PRISM+GEMC codes in order to simultaneously model the photometric parameters of the transits and the position, size and contrast of each star-spot. We used these new light curves and some from the literature to revise the physical properties of the WASP-52 system. Star-spots with similar characteristics were detected in four transits over a period of 43 d. In the hypothesis that we are dealing with the same star-spot, periodically occulted by the transiting planet, we estimated the projected orbital obliquity of WASP-52 b to be ... = 3 Math Processing Error...8 plus or minus 8 Math Processing Error...4. We also determined the true orbital obliquity, ... = 20... plus or minus 50..., which is, although very uncertain, the first measurement of ... purely from star-spot crossings. We finally assembled an optical transmission spectrum of the planet and searched for variations of its radius as a function of wavelength. Our analysis suggests a flat transmission spectrum within the experimental uncertainties. (ProQuest: ... denotes formulae/symbols omitted.)
Multi-planet systems exhibit remarkable architectural diversity. However, short-period giant planets are typically isolated. Compact systems like TOI-5398, with an outer close-orbit giant and an ...inner small-size planet, are rare among systems containing short-period giants. TOI-5398’s unusual architecture coupled with its young age (650 ± 150 Myr) make it a promising system for measuring the original obliquity between the orbital axis of the giant and the stellar spin axis in order to gain insight into its formation and orbital migration. We collected in-transit (plus suitable off-transit) observations of TOI-5398 b with HARPS-N at TNG on March 25, 2023, obtaining high-precision radial velocity time series that allowed us to measure the Rossiter-McLaughlin (RM) effect. By modelling the RM effect, we obtained a sky-projected obliquity of λ = 3.0 −4.2 +6.8 deg for TOI-5398 b, consistent with the planet being aligned. With knowledge of the stellar rotation period, we estimated the true 3D obliquity, finding ψ = (13.2 ± 8.2) deg. Based on theoretical considerations, the orientation we measure is unaffected by tidal effects, offering a direct diagnostic for understanding the formation path of this planetary system. The orbital characteristics of TOI-5398, with its compact architecture, eccentricity consistent with circular orbits, and hints of orbital alignment, appear more compatible with the disc-driven migration scenario. TOI-5398, with its relative youth (compared with similar compact systems) and exceptional suitability for transmission spectroscopy studies, presents an outstanding opportunity to establish a benchmark for exploring the disc-driven migration model.
Full text
Available for:
FMFMET, NUK, UL, UM, UPUK
Aim
To evaluate the ability of ProGlider instruments, PathFiles and K‐files to maintain canal anatomy during glide path preparation using X‐ray computed micro‐tomography (micro‐CT).
Methodology
...Forty‐five extracted maxillary first permanent molars were selected. Mesio‐buccal canals were randomly assigned (n = 15) to manual K‐file, PathFile or ProGlider groups for glide path preparation. Irrigation was achieved with 5% NaOCl and 10% EDTA. After glide path preparation, each canal was shaped with ProTaper Next X1 and X2 to working length. Specimens were scanned (isotropic voxel size 9.1 μm) for matching volumes and surface areas and post‐treatment analyses. Canal volume, surface area, centroid shift, canal geometry variation through ratio of diameter ratios and ratio of cross‐sectional areas were assessed in the apical and coronal levels and at the point of maximum canal curvature. One‐way factorial anovas were used to evaluate the significance of instrument in the various canal regions.
Results
Post‐glide path analysis revealed that instrument factor was significant at the apical level for both the ratio of diameter ratios and the ratio of cross‐sectional areas (P < 0.001), with an improved maintenance of root canal geometry by ProGlider and PathFile. At the coronal level and point of maximum canal curvature, ProGlider demonstrated a tendency to pre‐flare the root canal compared with K‐file and PathFile. PathFile and ProGlider demonstrated a significantly lower centroid shift compared with K‐file at the apical level (P = 0.023). Post‐shaping analysis demonstrated a more centred preparation of ProGlider, compared with PathFile and K‐files, with no significant differences for other parameters.
Conclusions
Use of ProGlider instruments led to less canal transportation than PathFiles and K‐files.
Full text
Available for:
BFBNIB, CMK, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
We report the discovery by the HATSouth network of HATS-7b, a transiting Super-Neptune with a mass of 0.120 + or - 0.012 MsubJ, a radius of 0.563 + 0.046 - 0.034 RsubJ, and an orbital period of ...3.1853 days. The host star is a moderately bright K dwarf star with a mass of 0.849 + or - 0.027 MsubS, a radius of 0.815 + 0.049 - 0.035 RsubS, and a metallicity of Fe/H= +0.250 + or - 0.080. HATS-7b, which, together with the recently discovered HATS-8b, is one of the first two transiting Neptunes discovered in the Southern sky, is a prime target for additional follow-up observations with southern hemisphere facilities to characterize the atmospheres of super-Neptunes.
PDF
