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The episodic dust-making Wolf-Rayet star HD 38030 in the Large Magellanic Cloud
Massey, Philip; Boutsia, Konstantina; Williams, Peredur M. +1 more
Mid-infrared photometry of the Wolf-Rayet star HD 38030 in the Large Magellanic Cloud from the NEOWISE-R mission show it to have undergone a dust-formation episode in 2018 and the dust to have cooled in 2019-20. New spectroscopy with the MagE spectrograph on the Magellan I Baade Telescope in 2019 and 2020 show absorption lines attributable to a co…
Modeling of two CoRoT solar analogues constrained by seismic and spectroscopic analysis
Baudin, F.; Samadi, R.; Morel, T. +8 more
Solar analogues are important stars to study for understanding the properties of the Sun. Combined with seismic and spectroscopic analysis, evolutionary modelling becomes a powerful method to characterize stellar intrinsic parameters, such as mass, radius, metallicity and age. However, these characteristics, relevant for other aspects of astrophys…
Comptonization as an Origin of the Continuum in Intermediate Polars
Maiolino, T.; Titarchuk, L.; Wang, W. +2 more
In this paper we test if the ∼0.3-15 keV XMM-Newton EPIC pn spectral continuum of IPs can be described by the thermal Comptonization COMPTT model. We used publicly observations of 12 IPs (AE Aqr, EX Hya, V1025 Cen, V2731 Oph, RX J2133.7+5107, PQ Gem, NY Lup, V2400 Oph, IGR J00234+6141, IGR J17195-4100, V1223 Sgr, and XY Ari). We find that our mode…
Evolution of the Ultraviolet Upturn at 0.3 < z < 1: Exploring Helium-rich Stellar Populations
De Propris, Roberto; Ali, Sadman S.; Chung, Chul +2 more
We measure the near-UV (rest-frame ~2400 Å) to optical color for early-type galaxies in 12 clusters at 0.3 < z < 1.0. We show that this is a suitable proxy for the more common far-ultraviolet bandpass used to measure the ultraviolet upturn and find that the upturn is detected to z = 0.6 in these data, in agreement with previous work. We find…
Stellar Feedback on the Earliest Stage of Massive Star Formation
Chevance, M.; Stutzki, J.; Nayak, O. +7 more
We report SOFIA/GREAT observations of high-J CO lines and [C II] observations of the super star cluster candidate H72.97-69.39 in the Large Magellanic Cloud (LMC), which is in its very early formation stage. We use our observations to determine if shocks are heating the gas or if photon-dominated regions (PDRs) are being heated by local far-UV rad…
On ancient solar-type stars - II
Fuhrmann, Klaus; Chini, Rolf
We report on the progress of our survey on ancient solar-type stars down to main-sequence effective temperatures Teff ≥ 5300 K and within 42 pc of the Sun. High signal-to-noise, high-resolution spectroscopy is presented for a second major subset of the Population II (τ ≥ 12 Gyr) and the intermediate-disc stars (τ ≃ 10 Gyr) within that v…
Detection of volatiles undergoing sublimation from 67P/Churyumov-Gerasimenko coma particles using ROSINA/COPS. II. The nude gauge
Altwegg, K.; Balsiger, H.; Rubin, M. +5 more
Context. In an earlier study, we reported that the ram gauge of the COmet Pressure Sensor (COPS), one of the three instruments of the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA), could be used to obtain information about the sublimating content of icy particles, made up of volatiles and conceivably refractories coming from c…
Far-ultraviolet Variables in M31: Concentration in Spiral Arms and Association with Young Stars
Buick, Megan; Postma, Joseph E.; Leahy, Denis A.
The Andromeda galaxy (M31) is an object of ongoing study with the Ultraviolet Imaging Telescope (UVIT) on AstroSat. Field 2, which is 6.4 kpc in diameter at the distance of M31, includes a substantial part of the NE spiral arms of the galaxy. We have obtained a second observation of Field 2 with the far-ultraviolet (FUV) F148W (148 nm) filter, sep…
The Abundance of Lead in Four Metal-poor Stars
Peterson, Ruth C.
Cowan et al. review how roughly half the elements heavier than iron found in the Sun are produced by rapid neutron capture and half by slow neutron capture, the r- and s-processes. In the Sun, their relative contribution to individual elemental abundances is well understood, except for the lightest and heaviest elements beyond iron. Their contribu…
Detecting and Characterising Small-Scale Brightenings in Solar Imaging Data
Morgan, Huw; Humphries, Llŷr Dafydd; Kuridze, David
Observations of small-scale brightenings in the low solar atmosphere can provide valuable constraints on possible heating and heat transport mechanisms. We present a method for the detection and analysis of brightenings, and demonstrate its application to time-series imagery of the Interface Region Imaging Spectrograph (IRIS) in the extreme ultrav…