Search Publications
Spectral library of age-benchmark low-mass stars and brown dwmarfs
Béjar, V. J. S.; Boudreault, S.; Bonnefoy, M. +3 more
In recent years, some extremely red brown dwarfs have been discovered. They were believed to have a low surface gravity, but many of their spectral characteristics are similar to those of high-surface-gravity brown dwarfs, showing that the spectral characteristics of young brown dwarfs are poorly understood. We aim to test surface-gravity indicato…
Power-law energy distributions of small-scale impulsive events on the active Sun: results from IRIS
Ramsay, Gavin; Mathioudakis, Mihalis; Doyle, J. Gerry +2 more
Numerous studies have analysed inferred power-law distributions between frequency and energy of impulsive events in the outer solar atmosphere in an attempt to understand the predominant energy supply mechanism in the corona. Here, we apply a burst detection algorithm to high-resolution imaging data obtained by the Interface Region Imaging Spectro…
Evidence of spectral evolution on the white dwarf sample from the Gaia mission
Kepler, S. O.; Koester, D.; Ourique, G. +2 more
Since the Gaia data release 2, several works have been published describing a bifurcation in the observed white dwarf colour-magnitude diagram for ${G_{\mathrm{BP}}}{}-{G_{\mathrm{RP}}}{} \gt 0$ . Some possible explanations in the literature include the existence of a double population with different initial mass functions or two distinct populati…
Candidate LBV stars in galaxy NGC 7793 found via HST photometry + MUSE spectroscopy
Della Bruna, Lorenza; Gouliermis, Dimitrios A.; Van Dyk, Schuyler D. +21 more
Only about 19 Galactic and 25 extragalactic bonafide luminous blue variables (LBVs) are known to date. This incomplete census prevents our understanding of this crucial phase of massive star evolution which leads to the formation of heavy binary black holes via the classical channel. With large samples of LBVs one could better determine the durati…
TYC 8327-1678-1: a new super lithium-rich K giant
Pereira, C. B.; Holanda, N.; Drake, N. A.
In this work, we show that TYC 8327-1678-1 is a low-mass red giant star with a super lithium abundance in its atmosphere. For this, we used high-resolution spectroscopy to determine atmospheric parameters, the chemical abundances of the light elements and the isotopic ratio 12C/13C using the spectral synthesis techniques and …
THOR 42: A touchstone ∼24 Myr-old eclipsing binary spanning the fully convective boundary
Zhou, George; Murphy, Simon J.; Feinstein, Adina D. +7 more
We present the characterization of CRTS J055255.7-004426 (=THOR 42), a young eclipsing binary comprising two pre-main sequence M dwarfs (combined spectral type M3.5). This nearby (103 pc), short-period (0.859 d) system was recently proposed as a member of the ∼24 Myr-old 32 Orionis Moving Group. Using ground- and space-based photometry in combinat…
Mutual inclinations between giant planets and their debris discs in HD 113337 and HD 38529
Wyatt, Mark C.; Kennedy, Grant M.; Xuan, Jerry W. +1 more
HD 113337 and HD 38529 host pairs of giant planets, a debris disc, and wide M-type stellar companions. We measure the disc orientation with resolved images from Herschel and constrain the three-dimensional orbits of the outer planets with Gaia DR2 and Hipparcos astrometry. Resolved disc modelling leaves degeneracy in the disc orientation, so we de…
A new white dwarf companion around the Δµ star GJ 3346
Sozzetti, A.; D'Orazi, V.; Zurlo, A. +7 more
We present the discovery of a white dwarf companion at ∼3.6 arcsec from GJ 3346, a nearby (π ∼ 42 mas) K star observed with SPHERE@VLT as part of an open time survey for faint companions to objects with significant proper motion discrepancies (Δµ) between Gaia DR1 and Tycho-2. Syrius-like systems like GJ 3346 AB, which include a main-sequenc…
Discovery of a pre-cataclysmic binary with unusual chromaticity of the eclipsed white dwarf by the GPX survey
Barkaoui, Khalid; Gillon, Michaël; Jehin, Emmanuël +14 more
We report the discovery of a relatively bright eclipsing binary system, which consists of a white dwarf (WD) and a main-sequence K7 star with clear signs of chromospheric and spot activity. The light curve of this system shows ∼0.2 mag ellipsoidal variability with a period of 0.297549 d and a short total eclipse of the WD. Based on our analysis of…
BRITE-Constellation photometry of π5 Orionis, an ellipsoidal SPB variable
Handler, G.; Wade, G. A.; Pigulski, A. +5 more
Results of an analysis of the BRITE-Constellation photometry of the SB1 system and ellipsoidal variable π5 Ori (B2 III) are presented. In addition to the orbital light-variation, which can be represented as a five-term Fourier cosine series with the frequencies forb, 2forb, 3forb, 4forb, and 6…