Context.
The Multi-site All-Sky CAmeRA (MASCARA) and bRing are both photometric ground-based instruments with multiple stations that rely on interline charge-coupled devices with wide-field lenses to ...monitor bright stars in the local sky for variability. MASCARA has already discovered several planets in the northern sky, which are among the brightest known transiting hot Jupiter systems.
Aims.
In this paper, we aim to characterize a transiting planetary candidate in the southern skies found in the combined MASCARA and bRing data sets of HD 85628, an A7V star of
V
= 8.2 mag at a distance 172 pc, to establish its planetary nature.
Methods.
The candidate was originally detected in data obtained jointly with the MASCARA and bRing instruments using a Box Least-Square search for transit events. Further photometry was taken by the 0.7 m Chilean-Hungarian Automated Telescope (CHAT), and radial velocity measurements with the Fiber Dual Echelle Optical Spectrograph on the European Southern Observatory 1.0 m Telescope. High-resolution spectra during a transit were taken with the CTIO high-resolution spectrometer (CHIRON) on the Small and Moderate Aperture Research Telescope System 1.5 m telescope to target the Doppler shadow of the candidate.
Results.
We confirm the existence of a hot Jupiter transiting the bright A7V star HD 85628, which we co-designate as MASCARA-4b and bRing-1b. It is in an orbit of 2.824 days, with an estimated planet radius of 1.53
−0.04
+0.07
R
Jup
and an estimated planet mass of 3.1 ± 0.9
M
Jup
, putting it well within the planetary regime. The CHAT observations show a partial transit, reducing the probability that the transit was around a faint background star. The CHIRON observations show a clear Doppler shadow, implying that the transiting object is in a retrograde orbit with |
λ
| =244.9
−3.6
+2.7
°. The planet orbits at a distance of 0.047 ± 0.004 AU from the star and has a zero-albedo equilibrium temperature of 2100 ± 100 K. In addition, we find that HD 85628 has a previously unreported stellar companion star in the
Gaia
DR2 data demonstrating common proper motion and parallax at 4.3′′ separation (projected separation ~740 AU), and with absolute magnitude consistent with being a K/M dwarf.
Conclusions.
MASCARA-4 b/bRing-1 b is the brightest transiting hot Jupiter known to date in a retrograde orbit. It further confirms that planets in near-polar and retrograde orbits are more common around early-type stars. Due to its high apparent brightness and short orbital period, the system is particularly well suited for further atmospheric characterization.
Aims. We describe the design and first light observations from the β Pictoris b Ring (“bRing”) project. The primary goal is to detect photometric variability from the young star β Pictoris due to ...circumplanetary material surrounding the directly imaged young extrasolar gas giant planet β Pictoris b. Methods. Over a nine month period centred on September 2017, the Hill sphere of the planet will cross in front of the star, providing a unique opportunity to directly probe the circumplanetary environment of a directly imaged planet through photometric and spectroscopic variations. We have built and installed the first of two bRing monitoring stations (one in South Africa and the other in Australia) that will measure the flux of β Pictoris, with a photometric precision of 0.5% over 5 min. Each station uses two wide field cameras to cover the declination of the star at all elevations. Detection of photometric fluctuations will trigger spectroscopic observations with large aperture telescopes in order to determine the gas and dust composition in a system at the end of the planet-forming era. Results. The first three months of operation demonstrate that bRing can obtain better than 0.5% photometry on β Pictoris in five minutes and is sensitive to nightly trends enabling the detection of any transiting material within the Hill sphere of the exoplanet.
The kinetics of high-temperature nitriding and changes in the structure and properties of heat-resistant Ni – Co – Cr – W – Ti nickel alloy VZh171 depending on its duration were studied. Short-term ...pulling and long-term strength tests were carried out. An analysis of the microstructure of a nitrided case is presented along with a mathematical description of the process. Recommendations are given for determining the optimal nitriding conditions of the VZh171 alloy in order to achieve the highest short-term and long-term strength. The established dependencies allow the nitriding time during the course of manufacturing items of various thicknesses from the VZh171 alloy to be determined.
Stages of superalloy production development at the Electrostal Metallurgical Plant are reviewed. Dynamics of the increase in stress-rupture strength indices, and also areas for improvement of ...manufacturing technology providing the requirements for superalloys are reviewed.
The features of deformation of high-alloy heat-resistant nickel alloys for disks of gas turbine engines of the Ni–Co–Cr–W–Al–Nb–Ti–Mo system (EP962, EK151, and EP975 type) have been studied near the ...temperature of complete dissolution of the strengthening γ' phase. Analysis of the deformation curves has shown that the softening processes are controlled by dynamic recrystallization, and the greatest decrease in the flow stress in the two-phase region is observed at a temperature of ~20°C below the complete dissolution of the γ' phase, which is associated with the presence of ~10% of γ' particles larger than 1.5 μm.
In this paper, we study the welded joints of cast intermetallic single-crystal rhenium-containing alloy VKNA-25 with crystallographic orientation 001 and deformable disk heat-resistant nickel alloy ...EP975 depending on the parameters (temperature and degree of deformation) of pressure welding under superplasticity conditions. The samples before and after heat treatment (annealing at 1210°C for 5 h) are compared. The results of X-ray spectral microanalysis of a solid-phase joint in the welding zone and at distances of up to 140 μm are presented in comparison with the initial chemical composition of the alloys, indicating an intense course of diffusion processes. The obtained results are analyzed from the point of view of maintaining the balance of alloying that is calculated by the method of G.I. Morozova (calculating the number of valence electrons per unit atomic mass of the composition). The change in the atomic mass and average electron concentration of solid-phase compounds before and after heat treatment in the welded joint zone and at distances of up to 140 μm is calculated. Calculated with allowance for the alloying balance, the alloy compositions are shown to allow obtaining a high-quality one-piece connection of a disk and a blade for blisk-type structures that is performed under superplasticity conditions using a setup for high-temperature pressure welding.
—The results of development of new nickel-base superalloy having an operating temperature up to 800°C for gas turbine disks have been presented. Structures, mechanical properties, and phase ...transformations of six experimental compositions have been researched. Physical and chemical modeling has been used to make a right choice of an alloy; with parameters as composition equivalents (they were based on equations of nonpolarizing ionic radii). The highest level of strength, ductility, toughness, and heat resistance was exhibited at 750°C by the Ni–Co–Cr–W–Mo–Ta–Al–Ti–Nb experimental composition with the total of aluminum, titanium, and niobium equal to 10 wt % and containing 4 wt % of tantalum.
The state of stress in the welded joints of new nickel and titanium alloys in a high-pressure compressor during heat treatment is simulated. The QForm software package is used to simulate the results ...of heat treatment and to find heat-treatment conditions. The designed thermal locks made of nickel and titanium alloys are shown to minimize the technological risks of cracking and to retain the geometric sizes of the welded joints during heat treatment.
Results are given for a study of the effect of quenching temperature on macro- and microstructure, and mechanical properties of nickel-based superalloy EI437B-VD. It is shown that in order to improve ...structure stability and mechanical properties of rolled bar and stamped GTE blades made of alloy EI437B-VD, and also to avoid a different grain size, it is necessary to reduce quenching temperature in performing heat treatment from 1080 ± 5°C to 1020 ± 5°C.
The bRing robotic observatory network was built to search for circumplanetary material within the transiting Hill sphere of the exoplanet β Pic b across its bright host star β Pic. During the bRing ...survey of β Pic, it simultaneously monitored the brightnesses of thousands of bright stars in the southern sky (V 4-8, δ −30°). In this work, we announce the discovery of δ Scuti pulsations in the A-type star HD 156623 using bRing data. HD 156623 is notable as it is a well-studied young star with a dusty and gas-rich debris disk, previously detected using ALMA. We present the observational results on the pulsation periods and amplitudes for HD 156623, discuss its evolutionary status, and provide further constraints on its nature and age. We find strong evidence of frequency regularity and grouping. We do not find evidence of frequency, amplitude, or phase modulation for any of the frequencies over the course of the observations. We show that HD 156623 is consistent with other hot and high-frequency pre-main sequence and early zero-age main sequence (ZAMS) δ Scutis as predicted by theoretical models and corresponding evolutionary tracks, although we observe that HD 156623 lies hotter than the theoretical blue edge of the classical instability strip. This, coupled with our characterization and Sco-Cen membership analyses, suggests that the star is most likely an outlying ZAMS member of the ∼16 Myr Upper Centaurus-Lupus subgroup of the Sco-Cen association.
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