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Barium and related stars, and their white-dwarf companions. III. The masses of the white dwarfs
Escorza, A.; De Rosa, R. J.
Context. Masses are one of the most difficult stellar properties to measure. In the case of the white-dwarf (WD) companions of Barium (Ba) stars, the situation is worse. These stars are dim, cool, and difficult to observe via direct methods. However, Ba stars were polluted by the asymptotic giant branch (AGB) progenitors of these WDs with matter r…
Polarimetry of hydrogen-poor superluminous supernovae
Sollerman, J.; Gal-Yam, A.; Wheeler, J. C. +11 more
We present linear polarimetry for seven hydrogen-poor superluminous supernovae (SLSNe-I) of which only one has previously published polarimetric data. The best-studied event is SN 2017gci, for which we present two epochs of spectropolarimetry at +3 d and +29 d post-peak in rest frame, accompanied by four epochs of imaging polarimetry up to +108 d.…
Panchromatic HST/WFC3 Imaging Studies of Young, Rapidly Evolving Planetary Nebulae. II. NGC 7027
Montez, Rodolfo; Balick, Bruce; Kastner, Joel H. +2 more
The iconic planetary nebula (PN) NGC 7027 is bright, nearby (D ~ 1 kpc), highly ionized, intricately structured, and well observed. This nebula is hence an ideal case study for understanding PN shaping and evolution processes. Accordingly, we have conducted a comprehensive imaging survey of NGC 7027 comprised of 12 HST Wide Field Camera 3 images i…
JWST/NIRCam detections of dusty subsolar-mass young stellar objects in the Small Magellanic Cloud
Hirschauer, Alec S.; Fahrion, Katja; Lenkić, Laura +23 more
Low-mass stars are the most numerous stellar objects in the Universe. Before the James Webb Space Telescope (JWST), we had limited knowledge of how planetary systems around low-mass stars could form at subsolar metallicities. Here we present JWST observations of NGC 346, a star-forming region in the metal-poor Small Magellanic Cloud, revealing a s…
Hot Subdwarf Stars Identified in LAMOST DR8 with Single-lined and Composite Spectra
Németh, Péter; Zhao, Jingkun; Hu, Ke +6 more
A total of 222 hot subdwarf stars were identified with LAMOST DR8 spectra, among which 131 stars show composite spectra and have been decomposed, while 91 stars present single-lined spectra. Atmospheric parameters of all sample stars were obtained by fitting hydrogen (H) and helium (He) line profiles with synthetic spectra. Two long-period composi…
Flashlights: an off-caustic lensed star at redshift z = 1.26 in Abell 370
Broadhurst, Tom; Filippenko, Alexei V.; Kelly, Patrick L. +11 more
We report the discovery of a transient seen in a strongly lensed arc at redshift zs = 1.2567 in Hubble Space Telescope imaging of the Abell 370 galaxy cluster. The transient is detected at 29.51 ± 0.14 AB mag in a WFC3/UVIS F200LP difference image made using observations from two different epochs, obtained in the framework of the Flashl…
Examining the orbital decay targets KELT-9 b, KELT-16 b, and WASP-4b, and the transit-timing variations of HD 97658 b
Alonso, R.; Deleuil, M.; Erikson, A. +87 more
Context. Tidal orbital decay is suspected to occur for hot Jupiters in particular, with the only observationally confirmed case of this being WASP-12b. 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 eff…
Polarisation of decayless kink oscillations of solar coronal loops
Antolin, Patrick; Berghmans, David; Chitta, Lakshmi Pradeep +4 more
Decayless kink oscillations of plasma loops in the solar corona may contain an answer to the enigmatic problem of solar and stellar coronal heating. The polarisation of the oscillations gives us a unique information about their excitation mechanisms and energy supply. However, unambiguous determination of the polarisation has remained elusive. Her…
TOI-836: A super-Earth and mini-Neptune transiting a nearby K-dwarf
Barclay, Thomas; Hellier, Coel; Triaud, Amaury H. M. J. +137 more
We present the discovery of two exoplanets transiting TOI-836 (TIC 440887364) using data from TESS Sector 11 and Sector 38. TOI-836 is a bright (T = 8.5 mag), high proper motion (~200 mas yr-1), low metallicity ([Fe/H]≈-0.28) K-dwarf with a mass of 0.68 ± 0.05 M⊙ and a radius of 0.67 ± 0.01 R⊙. We obtain photometri…
Digging into the Galactic Bulge: Stellar Population and Structure of the Poorly Studied Cluster NGC 6316
Cadelano, Mario; Pallanca, Cristina; Ferraro, Francesco R. +2 more
High-resolution Hubble Space Telescope optical observations have been used to analyze the stellar population and the structure of the poorly investigated bulge globular cluster NGC 6316. We constructed the first high-resolution reddening map in the cluster direction, which allowed us to correct the evolutionary sequences in the color-magnitude dia…