Search Publications
The Supernova Legacy Survey 3-year sample: Type Ia supernovae photometric distances and cosmological constraints
Sullivan, M.; Lidman, C.; González-Gaitán, S. +31 more
Aims: We present photometric properties and distance measurements of 252 high redshift Type Ia supernovae (0.15 < z < 1.1) discovered during the first three years of the Supernova Legacy Survey (SNLS). These events were detected and their multi-colour light curves measured using the MegaPrime/MegaCam instrument at the Canada-France-Hawa…
Chemical composition of A and F dwarfs members of the Hyades open cluster
Fossati, L.; Gebran, M.; Monier, R. +1 more
Aims: Abundances of 15 chemical elements have been derived for 28 F and 16 A stars members of the Hyades open cluster in order to set constraints on self-consistent evolutionary models that include radiative and turbulent diffusion.
Methods: A spectral synthesis, iterative procedure was applied to derive the abundances from selected high…
Signature of wide-spread clumping in B supergiant winds
Prinja, R. K.; Massa, D. L.
Aims: We seek to establish additional observational signatures of the effects of clumping in OB star winds. The action of clumping on strategic wind-formed spectral lines is tested to steer the development of models for clumped winds and thus improve the reliability of mass-loss determinations for massive stars.
Methods: The Siiv λλ1400 …
The extrasolar planet Gliese 581d: a potentially habitable planet?
Rauer, H.; von Paris, P.; Grenfell, J. L. +6 more
Aims: The planetary system around the M star Gliese 581 contains at least three close-in potentially low-mass planets, Gl 581c, d, and e. In order to address the question of the habitability of Gl 581d, we performed detailed atmospheric modeling studies for several planetary scenarios.
Methods: A 1D radiative-convective model was used to…
Gas in the protoplanetary disc of HD 169142: Herschel's view
Pinte, C.; Ménard, F.; Duchêne, G. +49 more
In an effort to simultaneously study the gas and dust components of the disc surrounding the young Herbig Ae star HD 169142, we present far-IR observations obtained with the PACS instrument onboard the Herschel Space Observatory. This work is part of the open time key program GASPS, which is aimed at studying the evolution of protoplanetary discs.…
Realistic model atmosphere and revised abundances of the coolest Ap star HD 101065
Shulyak, D.; Ryabchikova, T.; Kochukhov, O. +1 more
Aims: Among the known Ap stars, HD 101065 is probably one of the most interesting objects, demonstrating very rich spectra of rare-earth elements (REE). Strongly peculiar photometric parameters of this star can not be fully reproduced by any modern theoretical calculations, even those accounting for realistic chemistry of its atmosphere. In t…
The central star of the planetary nebula PB 8: a Wolf-Rayet-type wind of an unusual WN/WC chemical composition
Hamann, W. -R.; Todt, H.; Gräfener, G. +1 more
A considerable fraction of the central stars of planetary nebulæ (CSPNe) are hydrogen-deficient. As a rule, these CSPNe exhibit a chemical composition of helium, carbon, and oxygen with the majority showing Wolf-Rayet-like emission line spectra. These stars are classified as CSPNe of a spectral type [WC]. We perform a spectral analysis of CSPN PB …
Modelling the light variability of the Ap star ɛ Ursae Majoris
Shulyak, D.; Kochukhov, O.; Krtička, J. +2 more
Aims: We simulate the light variability of the Ap star ɛ UMa using the observed surface distributions of Fe, Cr, Ca, Mn, Mg, Sr, and Ti obtained with the help of the Doppler imaging technique.
Methods: Using all photometric data available, we specified light variations of ɛ UMa modulated by its rotation from far UV to IR. We employed the…
Resolving the dusty circumstellar environment of the A[e] supergiant HD 62623 with the VLTI/MIDI
Lopez, B.; Meilland, A.; Millour, F. +4 more
Context. B[e] stars are hot stars surrounded by circumstellar gas and dust which is responsible for the presence of emission lines and IR-excess in their spectra. How dust can be formed in this highly illuminated and diluted environment remains an open issue.
Aims: HD 62623 is one of the very few A-type supergiants showing the B[e] phenomenon…
The radius and effective temperature of the binary Ap star β CrB from CHARA/FLUOR and VLT/NACO observations
Kervella, P.; Kiss, L. L.; Tuthill, P. G. +14 more
Context. The prospects for using the asteroseismology of rapidly oscillating Ap (roAp) stars are hampered by the large uncertainty in fundamental stellar parameters. Results in the literature for the effective temperature (Teff) often span a range of 1000 K.
Aims: Our goal is to reduce systematic errors and improve the Teff