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Massive colliding-wind binaries that host a Wolf–Rayet (WR) star present a potentially important source of dust and chemical enrichment in the interstellar medium. However, the chemical composition and survival of dust formed from such systems is not well understood. The carbon-rich Wolf–Rayet binary WR 140 presents an ideal astrophysical laboratory for investigating these questions, given its well-defined orbital period and predictable dust-formation episodes every 7.93 years around periastron passage. We present observations from our Early Release Science programme (ERS 1349) with the James Webb Space Telescope Mid-Infrared Instrument (MIRI) Medium-Resolution Spectrometer and Imager that reveal the spectral and spatial signatures of nested circumstellar dust shells around WR 140. MIRI medium-resolution spectroscopy of the second dust shell and Imager detections of over 17 shells formed throughout approximately the past 130 years confirm the survival of carbonaceous dust grains from WR 140 that are probably carriers of ‘unidentified infrared’-band features at 6.4 and 7.7 μm. The observations indicate that dust-forming carbon-rich Wolf–Rayet binaries can enrich the interstellar medium with organic compounds and carbonaceous dust.

The Heliospheric Imager (HI) instruments on board the two STEREO (Solar TErrestrial RElations Observatory) spacecraft provides an excellent opportunity for space based stellar photometry. The HI instruments provide a wide area coverage (20° × 20° for the two HI-1 instruments and 70° × 70° for the two HI-2 instruments) and long continuous periods of observations (20 days and 70 days respectively). Using HI-1A which has a pass band of 6500Å to 7500Å and a cadence of 40 minutes, we have gathered photometric information for more than a million stars brighter than 12th magnitude for a period of two years. Here we present some early results from this study on a range of variable stars and the future prospects for the data.

This paper proposes that pulsars can serve as beacons for the discovery of and communication with extraterrestrials. The motivation for the communication strategy proposed is discussed in detail, along with relevant astrophysical considerations. It is shown that millisecond pulsars have characteristics and a distribution in space that make it possible to envisage communication being targeted towards and away from habstars (as defined by Turnbull & Tarter) aligned with pulsars in a specified way. Lists of candidate habstars and their pulsar alignments are included for those wishing to conduct searches using the strategy described.

In this paper, the period evolution of the rotating chemically peculiar star V473\\,Tau is investigated. Even though the star has been observed for more than fifty years, for the first time four consecutive years of space-based data covering between 2007 and 2010 are presented. The data are from the {\\sl STEREO} satellite, and are combined with the archival results. The analysis shows that the rotation period of V473\\,Tau is \\(1.406829(10)\\) days, and has slightly decreased with the variation rate of 0.11(3)~s~yr\\(^{-1}\\) over time. Also, the acceleration timescale of the star is found to be shorter than its main sequence lifetime. This indicates that the process of decrease in period might be reversible. On this basis, it can be suggested that V473\\,Tau has a possible magnetic acceleration and a differential rotation, which cause a variation in the movement of inertia, and hence the observed period change. Additionally, the evolution path of V473\\,Tau on the H-R diagram is evaluated. Accordingly, the position of the star on the diagram suggests that its magnetic properties develop before it reaches the main sequence or in the beginning of its main sequence lifetime.

In this paper, the period evolution of the rotating chemically peculiar star V473\\,Tau (A0Si, V = 7.26 mag) is investigated. Even though the star has been observed for more than fifty years, for the first time four consecutive years of space-based data covering between 2007 and 2010 is presented. The data is from the {\\sl STEREO} satellite, and is combined with the archival results. The analysis shows that the rotation period of V473\\,Tau is \\(1.406829(10)\\) days, and has slightly decreased with the variation rate of -0.11(3)~s~yr\\(^{-1}\\) over time. Also, the acceleration timescale of the star is found to be around \\(-1.11(63) \\times 10^6\\)~yr, shorter than its main sequence lifetime (\\(9.26(1.25) \\times 10^8\\)~yr). This indicates that the process of decrease in period might be reversible. On this basis, it can be suggested that V473\\,Tau has a possible magnetic breaking and a differential rotation, which cause a variation in the movement of inertia, and hence the observed period change.

Hot Jupiter (HJ) type exoplanets are expected to produce strong radio emission in the MHz range via the Electron Cyclotron Maser Instability (ECMI). To date, no repeatable detections have been made. To explain the absence of observational results, we conduct 3D adaptive mess refinement (AMR) magnetohydrodynamic (MHD) simulations of the magnetic interactions between a solar type star and HJ using the publicly available code PLUTO. The results are used to calculate the efficiency of the ECMI at producing detectable radio emission from the planets magnetosphere. We also calculate the frequency of the ECMI emission, providing an upper and lower bounds, placing it at the limits of detectability due to Earth's ionospheric cutoff of \\(\\sim 10 \\ \\mathrm{MHz}\\). The incident kinetic and magnetic power available to the ECMI is also determined and a flux of \\(0.069 \\ \\mathrm{mJy}\\) for an observer at \\(10 \\ \\mathrm{pc}\\) is calculated. The magnetosphere is also characterized and an analysis of the bow shock which forms upstream of the planet is conducted. This shock corresponds to the thin shell model for a colliding wind system. A result consistent with a colliding wind system. The simulation results show that the ECMI process is completely inhibited by the planets expanding atmosphere, due to absorption of UV radiation form the host star. The density, velocity, temperature and magnetic field of the planetary wind are found to result in a magnetosphere where the plasma frequency is raised above that due to the ECMI process making the planet undetectable at radio MHz frequencies.

We have performed 3D isothermal MHD simulation of a magnetic rotating massive star with a non-zero dipole obliquity and predicted the radio/sub-mm observable lightcurves and continuum spectra for a frequency range compatible with ALMA. From these results we also compare the model input mass-loss to that calculated from the synthetic thermal emission. Spherical and cylindrical symmetry is broken due to the obliquity of the stellar magnetic dipole resulting in an inclination and phase dependence of both the spectral flux and inferred mass-loss rate, providing testable predictions of variability for oblique rotator. Both quantities vary by factors between 2 and 3 over a full rotational period of the star, demonstrating that the role of rotation as critical in understanding the emission. This illustrates the divergence from a symmetric wind, resulting in a two armed spiral structure indicative of a oblique magnetic rotator. We show that a constant spectral index, \\(\\alpha\\), model agrees well with our numerical prediction for a spherical wind for \\(\\nu~<~10^{3} \\ \\mathrm{GHz}\\), however it is unable to capture the behavior of emission at \\(\\nu~>~10^{3} \\ \\mathrm{GHz}\\). As such we caution the use of such constant \\(\\alpha\\) models for predicting emission from non-spherical winds such as those which form around magnetic massive stars.

We present results from a 30 ksec Chandra observation of the important starburst galaxy NGC 2782, covering the 0.3-10keV energy band. We find evidence of a superwind of small extent, that is likely in an early stage of development. We find a total of 27 X-ray point sources within a region of radius 2\\(D_{25}\\) of the galaxy centre and which are likely associated with the galaxy. Of these, 13 are ULXs (\\(L_{X}\\geq 10^{39}~ erg s ^{-1}\\)) and a number have likely counterparts. The X-ray luminosities of the ULX candidates are \\(1.2-3.9\\times10^{39}~ erg s ^{-1}\\). NGC2782 seems to have an unusually large number of ULXs. Central diffuse X-ray emission extending to ~ 3kpc from the nuclear region has been detected. We also find an X-ray structure to the south of the nucleus, coincident with H{\\alpha} filaments and with a 5 GHz radio source. We interpret this as a blow-out region of a forming superwind. This X-ray bubble has a total luminosity (0.3-10 keV) of \\(5\\times10^{39}erg s ^{-1}\\) (around \\(15\\%\\) of the total luminosity of the extended emission), and an inferred wind mass of \\(1.5\\times10^{6}\\) M\\(_\\odot\\). We also discuss the nature of the central X-ray source in NGC2782, and conclude that it is likely a low-luminosity AGN (LLAGN), with a total X-ray luminosity of \\(L_{X}=6\\times10^{40}~erg s ^{-1}\\) with strong Fe line emission at 6.4 keV.

The binary eta Carinae is the closest example of a very massive star, which may have formed through a merger during its Great Eruption in the mid-nineteenth century. We aimed to confirm and improve the kinematics using a spectroscopic data set taken with the CTIO 1.5 m telescope over the time period of 2008-2020, covering three periastron passages of the highly eccentric orbit. We measure line variability of H-alpha and H-beta, where the radial velocity and orbital kinematics of the primary star were measured from the H-beta emission line using a bisector method. At phases away from periastron, we observed the He II 4686 emission moving opposite the primary star, consistent with a possible Wolf-Rayet companion, although with a seemingly narrow emission line. This could represent the first detection of emission from the companion.

We report high-precision X-ray monitoring observations in the 0.4-10 keV band of the luminous, long-period colliding-wind binary Eta Carinae up to and through its most recent X-ray minimum/periastron passage in February 2020. Eta Carinae reached its observed maximum X-ray flux on 7 January 2020, at a flux level of \\(3.30 \\times 10^{-10}\\) ergs s\\(^{-1}\\) cm\\(^{-2}\\), followed by a rapid plunge to its observed minimum flux, \\(0.03 \\times 10^{-10}\\) ergs s\\(^{-1}\\) cm\\(^{-2}\\) near 17 February 2020. The NICER observations show an X-ray recovery from minimum of only \\(\\sim\\)16 days, the shortest X-ray minimum observed so far. We provide new constraints of the \"deep\" and \"shallow\" minimum intervals. Variations in the characteristic X-ray temperature of the hottest observed X-ray emission indicate that the apex of the wind-wind \"bow shock\" enters the companion's wind acceleration zone about 81 days before the start of the X-ray minimum. There is a step-like increase in column density just before the X-ray minimum, probably associated with the presence of dense clumps near the shock apex. During recovery and after, the column density shows a smooth decline, which agrees with previous \\(N_{H}\\) measurements made by SWIFT at the same orbital phase, indicating that changes in mass-loss rate are only a few percent over the two cycles. Finally, we use the variations in the X-ray flux of the outer ejecta seen by NICER to derive a kinetic X-ray luminosity of the ejecta of \\(\\sim 10^{41}\\) ergs s\\(^{-1}\\) near the time of the \"Great Eruption'.