Search Publications
The COS Legacy Archive Spectroscopy Survey (CLASSY) Treasury Atlas
Ouchi, Masami; Kewley, Lisa J.; Ravindranath, Swara +46 more
Far-ultraviolet (FUV; ~1200-2000 Å) spectra are fundamental to our understanding of star-forming galaxies, providing a unique window on massive stellar populations, chemical evolution, feedback processes, and reionization. The launch of the James Webb Space Telescope will soon usher in a new era, pushing the UV spectroscopic frontier to higher red…
Identifying quiescent compact objects in massive Galactic single-lined spectroscopic binaries
Shenar, T.; Sana, H.; Hawcroft, C. +13 more
Context. The quest to detect dormant stellar-mass black holes (BHs) in massive binaries (i.e. OB+BH systems) is challenging; only a few candidates have been claimed to date, all of which must still be confirmed.
Aims: To search for these rare objects, we study 32 Galactic O-type stars that were reported as single-lined spectroscopic binaries …
AU Microscopii in the Far-UV: Observations in Quiescence, during Flares, and Implications for AU Mic b and c
France, Kevin; Youngblood, Allison; Gaidos, Eric +13 more
High-energy X-ray and ultraviolet (UV) radiation from young stars impacts planetary atmospheric chemistry and mass loss. The active ~22 Myr M dwarf AU Mic hosts two exoplanets orbiting interior to its debris disk. Therefore, this system provides a unique opportunity to quantify the effects of stellar X-ray and UV irradiation on planetary atmospher…
A dynamically discovered and characterized non-accreting neutron star-M dwarf binary candidate
Huang, Yang; Liu, Jifeng; Bai, Yu +26 more
Typically, neutron stars are discovered by observations at radio, X-ray or gamma-ray wavelengths. Unlike radio pulsar surveys and X-ray observations, optical time-domain surveys can unveil and characterize exciting but less explored non-accreting and/or non-beaming neutron stars in binaries. Here we report the discovery of such a neutron star cand…
CRIRES high-resolution near-infrared spectroscopy of diffuse interstellar band profiles. Detection of 12 new DIBs in the YJ band and the introduction of a combined ISM sight line and stellar analysis approach
Butler, K.; Weßmayer, D.; Przybilla, N. +7 more
Aims: A high spectral resolution investigation of diffuse interstellar bands (DIBs) in the near-infrared (YJ band) is conducted to test new methods, to confirm and improve existing parameters, and to search for new DIBs.
Methods: The CRyogenic high-resolution InfraRed Echelle Spectrograph (CRIRES) on the European Southern Observatory's V…
Dynamical Masses of the Primary Be Star and Secondary sdB Star in the Single-lined Binary κ Dra (B6 IIIe)
Gies, Douglas R.; Wang, Luqian; Klement, Robert +16 more
Because many classical Be stars may owe their nature to mass and angular-momentum transfer in a close binary, the present masses, temperatures, and radii of their components are of high interest for comparison to stellar evolution models. Object κ Dra is a 61.5 day single-lined binary with a B6 IIIe primary. With the CHARA Array instruments MIRC/M…
γ Columbae as a recently stripped pulsating core of a massive star
Meynet, Georges; Przybilla, Norbert; Irrgang, Andreas
Stellar cores, that is, the central regions where densities and temperatures are high enough for nuclear fusion processes to take place, are usually covered by an opaque envelope. Only in very rare cases, stars may expose their cores, for example, when a tiny fraction of them evolve into Wolf-Rayet or helium hot subdwarf stars. However, for the va…
The Role of Disk Tearing and Precession in the Observed Variability of Pleione
Carciofi, A. C.; Tycner, C.; Jones, C. E. +2 more
We acquired Hα spectroscopic observations from 2005 to 2019 showing Pleione has transitioned from a Be phase to a Be-shell phase during this period. Using the radiative transfer code HDUST, we created a grid of ~100,000 disk models for Pleione. We successfully reproduced the observed transition with a disk model that varies in inclination while ma…
Quantitative spectroscopy of B-type supergiants
Butler, K.; Weßmayer, D.; Przybilla, N.
Context. B-type supergiants are versatile tools to address a number of highly-relevant astrophysical topics, ranging from stellar atmospheres over stellar and galactic evolution to the characterisation of interstellar sightlines and to the cosmic distance scale.
Aims: A hybrid non-local thermodynamic equilibrium (LTE) approach, involving line…
Near-Ultraviolet Continuum Modeling of the 1985 April 12 Great Flare of AD Leo
Kowalski, Adam F.
White-light stellar flares are now reported by the thousands in long-baseline, high-precision, broad-band photometry from missions like \emph{Kepler}, K2, and TESS. These observations are crucial inputs for assessments of biosignatures in exoplanetary atmospheres and surface ultraviolet radiation dosages for habitable zone planets around low-mass …