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The Advanced Spectral Library (ASTRAL): Abundance Analysis of the Chemically Peculiar Star HR 465
Carpenter, Kenneth G.; Nielsen, Krister E.; Wahlgren, Glenn M. +1 more
This paper presents the results of the spectrum analysis of the B-type magnetic chemically peculiar star HR 465. HR 465 shows unusual abundance patterns that vary with a period of 21.5 yr. Our observations are recorded at φ = 0.45, 0.68, and 0.85 of the spectroscopic period, where φ = 0 represents the phase of maximum flux in the photometric y-ban…
Fragmentation and isomerization of polycyclic aromatic hydrocarbons in the interstellar medium: Coronene as a case study
Chen, Tao; Li, Aigen; Luo, Yi
Aims: Due to the limitations of current computational technology, the fragmentation and isomerization products of vibrationally-excited polycyclic aromatic hydrocarbon (PAH) molecules and their derivatives have been poorly studied. In this work, we investigate the intermediate products of PAHs and their derivatives as well as the gas-phase re…
Optical spectroscopy of type 2 LINERs
Hermosa Muñoz, L.; Márquez, I.; Masegosa, J. +1 more
Context. Type 2 Low-ionization Nuclear Emission-line Regions (LINERs) have been optically classified with the Palomar data as not presenting a broad component in the Balmer emission lines that are associated with the broad-line region (BLR) of the active galactic nuclei (AGN).
Aims: We aim to unveil the presence of different kinematic compone…
A Mechanistic Study on the Formation of Acetic Acid (CH3COOH) in Polar Interstellar Analog Ices Exploiting Photoionization Reflectron Time-of-flight Mass Spectrometry
Kleimeier, N. Fabian; Eckhardt, André K.; Kaiser, Ralf I.
Acetic acid (CH3COOH) is considered a key molecule in the formation of the simplest amino acid, glycine, and consequently peptides. It is ubiquitous in the interstellar medium and has been detected toward hot cores, in the coma of comets, and on the surface of the comet 67P/Churyumov-Gerasimenko by the Rosetta mission. Here we present t…
Panchromatic calibration of Ca II triplet luminosity dependence
Dias, B.; Parisi, M. C.
Context. The line strength of the near-infrared Ca II triplet (CaT) lines are a proxy for measuring metallicity from integrated and individual stellar spectra of bright red giant stars. In the latter case it is a mandatory step to remove the magnitude (proxy for gravity, temperature, and luminosity) dependence from the equivalent width (EW) of the…
Did Martian valley networks substantially modify the landscape?
Grau Galofre, Anna; Jellinek, A. Mark; Bahia, Rickbir Singh +2 more
Valley networks are ancient drainage systems incised on the southern hemisphere of Mars, and stand as evidence that liquid water once sculpted its surface. The duration of valley network activity and the sources of water are key questions in deciphering the timing of water stability on early Mars, but remain poorly constrained. In this study we ad…
A search for young exoplanets in Sectors 1-5 of the TESS full-frame images
Armstrong, David J.; Pollacco, Don; Battley, Matthew P.
Young (<1 Gyr) exoplanets represent a critically important area of exoplanet research, as they offer the opportunity to learn about the formation and early dynamic history of exoplanetary systems. However, finding young exoplanets is significantly complicated by the fast rotation and complex activity of their young host stars, which are often n…
Optical spectra of FO Aquarii during low and high accretion rates
Garnavich, P. M.; Marsh, T. R.; Breton, R. P. +7 more
Between 2016 May and 2018 September, the intermediate polar (IP) FO Aquarii exhibited two distinct low states and one failed low state. We present optical spectroscopy of FO Aquarii throughout this period, making this the first detailed study of an accretion disc during a low state in any IP. Analysis of these data confirm that the low states are …
High-resolution spectroscopy of red giants and 'yellow stragglers' in the southern open cluster NGC 2539
Pereira, C. B.; Holanda, N.; Drake, N. A. +1 more
We present a detailed high-resolution spectroscopic analysis of 12 red giant stars, in single and binaries or multiples systems, classified as members of the intermediate-age (631 Myr) open cluster NGC 2539. We used FEROS echelle spectra and the standard LTE analysis to derive the atmospheric parameters for the stars and the abundance ratios of li…
Towards studying hierarchical assembly in real time: a Milky Way progenitor galaxy at z = 2.36 under the microscope
Johnson, Benjamin D.; Bouwens, Rychard; Weisz, Daniel R. +4 more
We use Hubble Space Telescope (HST) imaging and near-infrared spectroscopy from Keck/Multi-Object Spectrometer For Infra-Red Exploration (MOSFIRE) to study the substructure around the progenitor of a Milky Way-mass galaxy in the Hubble Frontier Fields (HFF). Specifically, we study an $r_\mathrm{ e} = 40^{+70}_{-30}$ pc, $M_{\star } \sim 10^{8.2} \…