Search Publications
Li-rich K giants, dust excess, and binarity
Jorissen, A.; Pourbaix, D.; Escorza, A. +3 more
The origin of the Li-rich K giants is still highly debated. Here, we investigate the incidence of binarity among this family from a nine-year radial-velocity monitoring of a sample of 11 Li-rich K giants using the HERMES spectrograph attached to the 1.2 m Mercator Telescope. A sample of 13 non-Li-rich giants (8 of them being surrounded by dust acc…
The 21 µm and 30 µm emission features in carbon-rich objects
Volk, Kevin; Sloan, G. C.; Kraemer, Kathleen E.
We review the observational properties and possible carriers of the 21 and 30 µm features seen in the spectra of evolved carbon-rich objects. The 30 µm feature is generally taken to be due to MgS, possibly in combination with other sulfides. It is commonly assumed that the sulfides coat grains of SiC or amorphous carbon, but it remains…
Analysis of the TiO isotopologues in stellar optical spectra
Yurchenko, Sergei N.; Pavlenko, Ya. V.; Tennyson, Jonathan +1 more
Context. We used the new ExoMol TiO rovibronic line lists to identify and model TiO isotopologue features in spectra of M dwarfs.
Aims: We investigate problems involving the computation of electronic bands for different isotopologues of TiO by modelling optical spectra of late-type stars. Based on this, we determine their Ti isotopic abundanc…
A Wide Planetary-mass Companion to a Young Low-mass Brown Dwarf in Ophiuchus
Albert, Loïc; Liu, Michael C.; Zhang, Zhoujian +6 more
We present the discovery of a planetary-mass companion to CFHTWIR-Oph 98, a low-mass brown dwarf member of the young Ophiuchus star-forming region, with a wide 200 au separation (1"46). The companion was identified using Hubble Space Telescope images, and confirmed to share common proper motion with the primary using archival and new ground-based …
An Analysis of the Statistics and Systematics of Limb Anomaly Detections in HST/STIS Transit Images of Europa
Strobel, Darrell; Saur, Joachim; Giono, Gabriel +5 more
Several recent studies derived the existence of plumes on Jupiter's moon Europa. The only technique that provided multiple detections is the far-ultraviolet imaging observations of Europa in transit of Jupiter taken by the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST). In this study, we reanalyze the three HST/STI…
Multiwavelength Absolute Magnitudes and Colors of Red Clump Stars in the Gaia Era
Bilir, Selçuk; Plevne, Olcay; Seabroke, George M. +1 more
This study presents the multiwavelength investigation of the absolute magnitudes and colors of the red clump (RC) stars selected from APOGEE and GALAH DR2 combined catalog which is complemented with Gaia DR2 astrometric data and multiwavelength photometric data of GALEX GR6/7, SDSS DR7, Gaia DR2, 2MASS, and WISE sky surveys. The analyses are cente…
Kinematics of the Magellanic Stream and Implications for Its Ionization
Richter, Philipp; Bland-Hawthorn, Joss; Fox, Andrew J. +3 more
The Magellanic Stream and the Leading Arm form a massive, filamentary system of gas clouds surrounding the Large and Small Magellanic Clouds. Here we present a new component-level analysis of their ultraviolet (UV) kinematic properties using a sample of 31 sightlines through the Magellanic System observed with the Hubble Space Telescope/Cosmic Ori…
5D memberships and fundamental properties of the old open cluster NGC 6791 based on Gaia
Gao, Xinhua
This paper investigates reliable memberships and fundamental astrophysical properties of the old (∼8 Gyr) open cluster NGC 6791 using the astrometric and photometric data of the Gaia data release 2 (
The WAGGS project-III. Discrepant mass-to-light ratios of Galactic globular clusters at high metallicity
Martocchia, S.; Da Costa, G. S.; Usher, C. +10 more
Observed mass-to-light ratios (M/L) of metal-rich globular clusters (GCs) disagree with theoretical predictions. This discrepancy is of fundamental importance since stellar population models provide the stellar masses that underpin most of extragalactic astronomy, near and far. We have derived radial velocities for 1622 stars located in the centre…
High-resolution X-ray spectroscopy of the stellar wind in Vela X-1 during a flare
Bianchi, S.; Guainazzi, M.; Grinberg, V. +8 more
Context. We present a ~130 ks observation of the prototypical wind-accreting, high-mass X-ray binary Vela X-1 collected with XMM-Newton at orbital phases between 0.12 and 0.28. A strong flare took place during the observation that allows us to investigate the reaction of the clumpy stellar wind to the increased X-ray irradiation.
Aims: To exa…