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The B & V light curves for recurrent nova T CrB from 1842-2022, the unique pre- and post-eruption high-states, the complex period changes, and the upcoming eruption in 2025.5 ± 1.3
Schaefer, Bradley E.
T CrB is one of the most-famous and brightest novae known, and is a recurrent nova with prior eruptions in 1866 and 1946 that peak at V = 2.0. I have constructed light curves spanning 1842-2022 with 213 730 magnitudes, where the B and V magnitudes are fully corrected to the Johnson system. These light curves first reveal a unique complex high-stat…
Line luminosities of Galactic and Magellanic Cloud Wolf-Rayet stars
Crowther, Paul A.; Bestenlehner, Joachim M.; Rate, G.
We provide line luminosities and spectroscopic templates of prominent optical emission lines of 133 Galactic Wolf-Rayet (WR) stars by exploiting Gaia DR3 parallaxes and optical spectrophotometry, and provide comparisons with 112 counterparts in the Magellanic Clouds. Average line luminosities of the broad blue (He II λ4686, C III λλ4647,51, N III …
An HST COS ultraviolet spectroscopic survey of 311 DA white dwarfs - I. Fundamental parameters and comparative studies
Hermes, J. J.; Redfield, Seth; Sahu, Snehalata +8 more
White dwarf studies carry significant implications across multiple fields of astrophysics, including exoplanets, supernova explosions, and cosmological investigations. Thus, accurate determinations of their fundamental parameters (Teff and log g) are of utmost importance. While optical surveys have provided measurements for many white d…
Bayesian sampling with BeAtlas, a grid of synthetic Be star spectra I. Recovering the fundamental parameters of α Eri and β CMi
Carciofi, A. C.; de Amorim, T. H.; Vieira, R. G. +14 more
Classical B emission (Be) stars are fast rotating, near-main-sequence B-type stars. The rotation and the presence of circumstellar discs profoundly modify the observables of active Be stars. Our goal is to infer stellar and disc parameters, as well as distance and interstellar extinction, using the currently most favoured physical models for these…
Non-LTE abundance analysis of A-B stars with low rotational velocities - II. Do A-B stars with normal abundances exist?
Sitnova, T. M.; Korotin, S. A.; Romanovskaya, A. M. +2 more
We present chemical composition and fundamental parameters (the effective temperature, surface gravity, and radius) for four sharp-lined A-type stars γ Gem (HD 41705), o Peg (HD 214994), θ Vir (HD 114330), and ν Cap (HD 193432). Our analysis is based on a self-consistent model fitting of high-resolution spectra and spectrophotometric observations …
A study of the rapid rotator ζ Aql: differential surface rotation?
Bailey, Jeremy; Cotton, Daniel V.; Howarth, Ian D. +1 more
We report new, extremely precise photopolarimetry of the rapidly-rotating A0 main-sequence star ζ Aql, covering the wavelength range ~400-900 nm, which reveals a rotationally-induced signal. We model the polarimetry, together with the flux distribution and line profiles, in the framework of Roche geometry with ω-model gravity darkening, to establi…
Ups!... I did it again: unveiling the hidden companion in Upsilon Sagittarii, a unique binary system at a second mass transfer stage
Shenar, Tomer; Gilkis, Avishai
Upsilon Sagittarii is a hydrogen-deficient binary that has been suggested to be in its second stage of mass transfer, after the primary has expanded to become a helium supergiant following core helium exhaustion. A tentative identification of the faint companion in the ultraviolet led to mass estimates of both components that made the helium star …
Extreme mass ratios and fast rotation in three massive binaries
Nazé, Yaël; Labadie-Bartz, Jonathan; Rauw, Gregor +2 more
The origin of rapid rotation in massive stars remains debated, although binary interactions are now often advocated as a cause. However, the broad and shallow lines in the spectra of fast rotators make direct detection of binarity difficult. In this paper, we report on the discovery and analysis of multiplicity for three fast-rotating massive star…
The 2175 Å interstellar extinction bump: is the wavelength variable?
Li, Aigen; Yang, X. J.; Wang, Qian
The most striking characteristics of the mysterious 2175$\mathring{\rm A}$ extinction bump, the strongest spectroscopic absorption feature seen on the interstellar extinction curve, are the invariant central wavelength and variable bandwidth: its peak position at 2175$\mathring{\rm A}$ is remarkably constant, while its bandwidth varies from one li…
Analysis of integral field spectroscopy observations of the planetary nebula Hen 2-108 and its central star
Corradi, Romano L. M.; Akras, Stavros; Todt, Helge +3 more
The study of planetary nebulae provides important constraints for many aspects of stellar and Galactic evolution. Hen 2-108 is a poorly known planetary nebula with a slight elliptical morphology and a peculiar central star (CS), which has defied classification. In this work, we present the first detailed integral field spectroscopic study of the p…