R. Lombaert
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View article: MELCHIORS: The Mercator Library of High Resolution Stellar Spectroscopy
MELCHIORS: The Mercator Library of High Resolution Stellar Spectroscopy Open
Over the past decades, libraries of stellar spectra have been used in a large variety of science cases, including as sources of reference spectra for a given object or a given spectral type. Despite the existence of large libraries and the…
View article: MELCHIORS
MELCHIORS Open
Aims . Over the past decades, libraries of stellar spectra have been used in a large variety of science cases, including as sources of reference spectra for a given object or a given spectral type. Despite the existence of large libraries …
View article: PACS and SPIRE range spectroscopy of cool, evolved stars
PACS and SPIRE range spectroscopy of cool, evolved stars Open
Context . At the end of their lives AGB stars are prolific producers of dust and gas. The details of this mass-loss process are still not understood very well. Herschel PACS and SPIRE spectra which cover the wavelength range from ∼55 to 67…
View article: Chemical content of the circumstellar envelope of the oxygen-rich AGB star R Doradus
Chemical content of the circumstellar envelope of the oxygen-rich AGB star R Doradus Open
Context. The stellar outflows of low- to intermediate-mass stars are characterised by a rich chemistry. Condensation of molecular gas species into dust grains is a key component in a chain of physical processes that leads to the onset of a…
View article: The discovery of a planetary candidate around the evolved low-mass<i>Kepler</i>giant star HD 175370
The discovery of a planetary candidate around the evolved low-mass<i>Kepler</i>giant star HD 175370 Open
We report on the discovery of a planetary companion candidate with a minimum mass M sin i = 4.6 +/- 1.0 M-Jupiter orbiting the K2 III giant star HD 175370 (KIC 007940959). This star was a target in our programme to search for planets aroun…
View article: Probing The Abundance Of Sio And Hcn Throughout The Stellar Wind Of R Dor
Probing The Abundance Of Sio And Hcn Throughout The Stellar Wind Of R Dor Open
R Dor is an oxygen-rich AGB star characterised by a low mass-loss rate. Using retrieval methods, we found abundance profiles for SiO and HCN, two chemically important molecules. By comparing these results to those of forward chemistry mode…
View article: Determining The Stellar Initial Mass By Means Of The 17O/18O Ratio On The Agb
Determining The Stellar Initial Mass By Means Of The 17O/18O Ratio On The Agb Open
This poster presents newly obtained circumstellar 12C17O and 12C18O line observations, from which the line intensity are then related directly to the 17O/18O surface abundance ratio for a sample of nine AGB stars covering the three spectra…
View article: ALMA observations of the vibrationally excited rotational CO transition <i>v</i> = 1, <i>J</i> = 3 − 2 towards five AGB stars
ALMA observations of the vibrationally excited rotational CO transition <i>v</i> = 1, <i>J</i> = 3 − 2 towards five AGB stars Open
We report the serendipitous detection with the Atacama Large Millimeter/submillimeter Array (ALMA) of the vibrationally excited pure-rotational CO transition v = 1, J = 3 − 2 towards five asymptotic giant branch (AGB) stars, o Cet, R Aqr, …
View article: Mineralogy of an OH/IR superwind
Mineralogy of an OH/IR superwind Open
The mineralogy of the dense, dusty superwind of OH/IR stars can provide important constraints for understanding the dust formation process as well as the acceleration of the wind. We aim to model the ISO-SWS spectrum of the OH/IR star OH 3…
View article: Nucleosynthesis in AGB stars traced by oxygen isotopic ratios. I - Determining the stellar initial mass by means of the $^{17}$O/$^{18}$O ratio
Nucleosynthesis in AGB stars traced by oxygen isotopic ratios. I - Determining the stellar initial mass by means of the $^{17}$O/$^{18}$O ratio Open
The aim of this paper is to investigate the $^{17}$O/$^{18}$O ratio for a sample of AGB stars, containing M-, S- and C-type stars. These ratios are evaluated in relation to fundamental stellar evolution parameters: the stellar initial mass…
View article: Study of the inner dust envelope and stellar photosphere of the AGB star R Doradus using SPHERE/ZIMPOL
Study of the inner dust envelope and stellar photosphere of the AGB star R Doradus using SPHERE/ZIMPOL Open
Context. On the asymptotic giant branch (AGB) low-and intermediate-mass stars eject a large fraction of their envelope, but the mechanism driving these outflows is still poorly understood. For oxygen-rich AGB stars, the wind is thought to …
View article: A HIFI view on circumstellar H<sub>2</sub>O in M-type AGB stars: radiative transfer, velocity profiles, and H<sub>2</sub>O line cooling
A HIFI view on circumstellar H<sub>2</sub>O in M-type AGB stars: radiative transfer, velocity profiles, and H<sub>2</sub>O line cooling Open
We aim to constrain the temperature and velocity structures, and H2O\nabundances in the winds of a sample of M-type AGB stars. We further aim to\ndetermine the effect of H2O line cooling on the energy balance in the inner\ncircumstellar en…
View article: Constraints on the H<sub>2</sub>O formation mechanism in the wind of carbon-rich AGB stars
Constraints on the H<sub>2</sub>O formation mechanism in the wind of carbon-rich AGB stars Open
Context. The recent detection of warm H2O vapor emission from the outflows of carbon-rich asymptotic giant branch (AGB) stars challenges the current understanding of circumstellar chemistry. Two mechanisms have been invoked to explain warm…
View article: KIC 10080943: An eccentric binary system containing two pressure- and gravity-mode hybrid pulsators
KIC 10080943: An eccentric binary system containing two pressure- and gravity-mode hybrid pulsators Open
Context. γ Doradus and δ Scuti pulsators cover the transition region between low mass and massive main-sequence stars, and as such, are critical for testing stellar models. When they reside in binary systems, we can combine two independent…
View article: GRAVITY-MODE PERIOD SPACINGS AS A SEISMIC DIAGNOSTIC FOR A SAMPLE OF <i>γ</i> DORADUS STARS FROM <i>KEPLER</i> SPACE PHOTOMETRY AND HIGH-RESOLUTION GROUND-BASED SPECTROSCOPY
GRAVITY-MODE PERIOD SPACINGS AS A SEISMIC DIAGNOSTIC FOR A SAMPLE OF <i>γ</i> DORADUS STARS FROM <i>KEPLER</i> SPACE PHOTOMETRY AND HIGH-RESOLUTION GROUND-BASED SPECTROSCOPY Open
Gamma Doradus stars (hereafter γ Dor stars) are gravity-mode pulsators of spectral type A or F. Such modes probe the deep stellar interior, offering a detailed fingerprint of their structure. Four-year high-precision space-based Kepler pho…
View article: Simplified models of stellar wind anatomy for interpreting high-resolution data
Simplified models of stellar wind anatomy for interpreting high-resolution data Open
\n Context. Recent high-resolution observations have shown that stellar winds harbour complexities that strongly deviate from spherical symmetry, which generally is assumed as standard wind model. One such morphology is the Archimedean spi…
View article: Dusty wind of W Hydrae: Multi-wavelength modelling of the present-day and recent mass loss
Dusty wind of W Hydrae: Multi-wavelength modelling of the present-day and recent mass loss Open
Context. Low- and intermediate-mass stars go through a period of intense mass-loss at the end of their lives, during the asymptotic giant branch (AGB) phase. While on the AGB a significant part, or even most, of their initial mass is expel…
View article: Simplified models of stellar wind anatomy for interpreting high-resolution data: Analytical approach to embedded spiral geometries
Simplified models of stellar wind anatomy for interpreting high-resolution data: Analytical approach to embedded spiral geometries Open
Recent high-resolution observations have shown stellar winds to harbour complexities which strongly deviate from spherical symmetry, generally assumed as standard wind model. One such morphology is the archimedean spiral, generally believe…
View article: Gravity-mode period spacings as seismic diagnostic for a sample of gamma Doradus stars from Kepler space photometry and high-resolution ground-based spectroscopy
Gravity-mode period spacings as seismic diagnostic for a sample of gamma Doradus stars from Kepler space photometry and high-resolution ground-based spectroscopy Open
Gamma Doradus stars (hereafter gamma Dor stars) are gravity-mode pulsators of spectral type A or F. Such modes probe the deep stellar interior, offering a detailed fingerprint of their structure. Four-year high-precision space-based Kepler…
View article: Dusty wind of W Hya. Multi-wavelength modelling of the present-day and recent mass-loss
Dusty wind of W Hya. Multi-wavelength modelling of the present-day and recent mass-loss Open
Low- and intermediate-mass stars go through a period of intense mass-loss at the end of their lives in a phase known as the asymptotic giant branch (AGB). During the AGB a significant fraction of their initial mass is expelled in a stellar…
View article: Micron-sized forsterite grains in the pre-planetary nebula of IRAS 17150−3224
Micron-sized forsterite grains in the pre-planetary nebula of IRAS 17150−3224 Open
\n Aims. We study the grain properties and location of the forsterite crystals in the circumstellar environment of the pre-planetary nebula (PPN) IRAS 17150−3224 in order to learn more about the as yet poorly understood evolutionary phase …
View article: Micron-sized forsterite grains in the pre-planetary nebula of IRAS 17150-3224 - Searching for clues on the mysterious evolution of massive AGB stars
Micron-sized forsterite grains in the pre-planetary nebula of IRAS 17150-3224 - Searching for clues on the mysterious evolution of massive AGB stars Open
We study the grain properties and location of the forsterite crystals in the circumstellar environment of the pre-planetary nebula (PPN) IRAS 17150-3224 in order to learn more about the as yet poorly understood evolutionary phase prior to …
View article: Investigation of the binary fraction among candidate A-F type hybrid stars detected by<i>Kepler</i>
Investigation of the binary fraction among candidate A-F type hybrid stars detected by<i>Kepler</i> Open
We are currently monitoring up to 40 Kepler candidate δ Scuti-γ Doradus (resp. γ Doradus-δ Scuti) hybrid stars in radial velocity in order to identify the physical cause behind the low frequencies observed in the periodograms based on the …