Search Publications
Herschel discovery of a new class of cold, faint debris discs
Heras, A. M.; Fridlund, M.; Krivov, A. V. +25 more
We present Herschel PACS 100 and 160 µm observations of the solar-type stars α Men, HD 88230 and HD 210277, which form part of the FGK stars sample of the Herschel open time key programme (OTKP) DUNES (DUst around NEarby Stars). Our observations show small infrared excesses at 160 µm for all three stars. HD 210277 also shows a small ex…
Herschel's view into Mira's head
Blommaert, J. A. D. L.; Jorissen, A.; Ottensamer, R. +9 more
Herschel's PACS instrument observed the environment of the binary system Mira Ceti in the 70 and 160 µm bands. These images reveal bright structures shaped as five broken arcs and fainter filaments in the ejected material of Mira's primary star, the famous AGB star o Ceti. The overall shape of the IR emission around Mira deviates significant…
Can coronal hole spicules reach coronal temperatures?
Doyle, J. G.; Madjarska, M. S.; Vanninathan, K.
Aims: The present study aims to provide observational evidence of whether coronal hole spicules reach coronal temperatures.
Methods: We combine multi-instrument co-observations obtained with the SUMER/SoHO and with the EIS/SOT/XRT/Hinode.
Results: The analysed three large spicules were found to be comprised of numerous thin spicules…
A mid-IR study of Hickson compact groups. II. Multiwavelength analysis of the complete GALEX-Spitzer sample
Le Floc'h, E.; Magdis, G.; da Cunha, E. +3 more
We present a comprehensive study of the impact of the environment of compact galaxy groups on the evolution of their members using a multiwavelength analysis from the ultraviolet to the infrared, for a sample of 32 Hickson compact groups (HCGs) containing 135 galaxies. Fitting the spectral energy distributions (SEDs) of all galaxies with the state…
Evolution of sunspot properties during solar cycle 23
Fletcher, L.; Marshall, S.; Watson, F. T.
Context. The long term study of the Sun is necessary if we are to determine the evolution of sunspot properties and thereby inform modeling of the solar dynamo, particularly on scales of a solar cycle.
Aims: We aim to determine a number of sunspot properties over cycle 23 using the uniform database provided by the SOHO Michelson Doppler Image…
HST/STIS Lyman-α observations of the quiet M dwarf GJ 436 . Predictions for the exospheric transit signature of the hot Neptune GJ 436b
Ehrenreich, D.; Delfosse, X.; Lecavelier Des Etangs, A.
Lyman-α (Lyα) emission of neutral hydrogen (λ1215.67 Å) is the main contributor to the ultraviolet flux of low-mass stars such as M dwarfs. It is also the main light source used in studies of the evaporating upper atmospheres of transiting extrasolar planets with ultraviolet transmission spectroscopy. However, there are very few observations of th…
Multiwavelength campaign on Mrk 509. II. Analysis of high-quality Reflection Grating Spectrometer spectra
Kaastra, J. S.; Kriss, G. A.; Bianchi, S. +11 more
Aims: We study the bright Seyfert 1 galaxy Mrk 509 with the Reflection Grating Spectrometers (RGS) of XMM-Newton, using for the first time the RGS multi-pointing mode of XMM-Newton to constrain the properties of the outflow in this object. We obtain very accurate spectral properties from a 600 ks spectrogram of Mrk 509 with excellent quality.…
Abundances of the elements He to Ni in the atmosphere of Sirius A
Landstreet, J. D.
Context. The abundances of elements in the atmosphere of an individual star provide a very broad range of extremely important information about the formation and evolution history of that star. Specifically, during the main sequence phase, the abundance pattern observed can provide valuable constraints on a range of hydrodynamical processes occurr…
The diameter of the CoRoT target HD 49933. Combining the 3D limb darkening, asteroseismology, and interferometry
Morel, P.; Berio, P.; Kervella, P. +21 more
Context. The interpretation of stellar pulsations in terms of internal structure depends on the knowledge of the fundamental stellar parameters. Long-base interferometers permit us to determine very accurate stellar radii, which are independent constraints for stellar models that help us to locate the star in the HR diagram.
Aims: Using a dir…
The Herschel M 33 extended survey (HerM33es): PACS spectroscopy of the star-forming region BCLMP 302
Boquien, M.; Braine, J.; Calzetti, D. +19 more
Context. The emission line of [C ii] at 158 µm is one of the strongest cooling lines of the interstellar medium (ISM) in galaxies.
Aims: Distinguishing the relative contributions of the different ISM phases to [C ii] emission is a major objective of the HerM33es program, a Herschel key project to study the ISM in the nearby spiral galax…