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Gaseous nebulae and massive stars in the giant H I ring in Leo
Venturi, Giacomo; Cresci, Giovanni; Thilker, David +2 more
Context. Chemical abundances in the Leo ring, the largest H I cloud in the local Universe, have recently been determined to be close to or above Solar values. This is a finding that is incompatible with prior claims that the ring was primordial in origin. The gas, pre-enriched in a galactic disk and tidally stripped, did not manage to efficiently …
The fractions of post-binary-interaction stars and evolved blue straggler stars on the red giant branch of globular clusters
Wang, Hai-Feng; Jiang, Deng-Kai; Wang, Bo +4 more
The red giant branch (RGB) of globular clusters (GCs) is home to some exotic stars, which may provide clues on the formation of multiple stellar populations in GCs. It is well known that binary interactions are responsible for many exotic stars. Thus, it is important to understand what fraction of stars on the RGB of GCs is the result of binary in…
Fundamental parameters and non local thermodynamic equilibrium abundances of key light elements for nine bright and nearby K giants
Lee, Byeong-Cheol; Han, Inwoo; Lyubimkov, Leonid S. +4 more
For nine bright K giants within 100 pc of the sun, the fundamental parameters and the non local thermodynamic equilibrium (LTE) abundances of three key light elements (Li, C, and O) are accurately determined. These stars are of special interest due to the planets detected around them. Their fundamental parameters are found to be typical for K gian…
ASASSN-14lp: two possible solutions for the observed ultraviolet suppression
Foley, Ryan J.; Kerzendorf, Wolfgang; Kromer, Markus +10 more
We test the adequacy of ultraviolet (UV) spectra for characterizing the outer structure of Type Ia supernova (SN) ejecta. For this purpose, we perform spectroscopic analysis for ASASSN-14lp, a normal SN Ia showing low continuum in the mid-UV regime. To explain the strong UV suppression, two possible origins have been investigated by mapping the ch…
Symbiotic Stars in the Apache Point Observatory Galactic Evolution Experiment Survey: The Case of LIN 358 and SMC N73 (LIN 445a)
Pan, Kaike; Cunha, Katia; Smith, Verne V. +9 more
LIN 358 and SMC N73 are two symbiotic binaries in the halo of the Small Magellanic Cloud, each composed of a hot white dwarf accreting from a cool giant companion. In this work, we characterize these systems using a combination of spectral energy distribution (SED)-fitting to the extant photometric data spanning a broad wavelength range (X-ray/ult…
Ion acoustic waves near a comet nucleus: Rosetta observations at comet 67P/Churyumov-Gerasimenko
Henri, Pierre; Nilsson, Hans; Goetz, Charlotte +6 more
Ion acoustic waves were observed between 15 and 30 km from the centre of comet 67P/Churyumov-Gerasimenko by the Rosetta spacecraft during its close flyby on 28 March 2015. There are two electron populations: one cold at kBTe≈0.2 eV and one warm at kBTe≈2 eV. The ions are dominated by a cold (a few hundre…
Astrometric Mass Ratios of 248 Long-period Binary Stars Resolved in Hipparcos and Gaia EDR3
Makarov, Valeri V.; Fabricius, Claus
Using the absolute astrometric positions and proper motions for common stars in the Hipparcos and Gaia catalogs separated by 24.75 yr in the mean epoch, we compute mass ratios for long-period, resolved binary systems without any astrophysical assumptions or dependencies, except the presence of inner binary subsystems that may perturb the observed …
Solar activity classification based on Mg II spectra: Towards classification on compressed data
Ivanov, S.; Tsizh, M.; Ullmann, D. +2 more
Although large volumes of solar data are available for investigation and study, the vast majority of these data remain unlabeled and are therefore not amenable to modern supervised machine learning methods. Having a way to accurately and automatically classify spectra into categories related to the degree of solar activity is highly desirable and …
Chlorine-bearing species and the 37Cl/35Cl isotope ratio in the coma of comet 67P/Churyumov-Gerasimenko
De Keyser, Johan; Wurz, Peter; Altwegg, Kathrin +6 more
A full-mission analysis has been conducted of Cl-bearing species in the coma of comet 67P/Churyumov-Gerasimenko as detected by the Double Focusing Mass Spectrometer (DFMS) of Rosetta's ROSINA instrument. The isotope ratio of the two stable chlorine isotopes 37Cl/35Cl is found to be 0.336 ± 0.017, to be compared with the stand…
The onset of jets in classical novae
Blundell, Katherine M.; Lee, Steven; McLoughlin, Dominic +1 more
We present two further classical novae, V906 Car and V5668 Sgr, which show jets and accretion disc spectral signatures in their H α complexes throughout the first 1000 d following their eruptions. From extensive densely time-sampled spectroscopy, we measure the appearance of the first high-velocity absorption component in V906 Car, and the duratio…