80
80
Sep 18, 2013
09/13
by
T. G. Müller; J. A. D. L. Blommaert
texts
eye 80
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We investigated the physical and thermal properties of 65 Cybele}, one of the largest main-belt asteroids. Based on published and recently obtained thermal infrared observations, including ISO measurements, we derived through thermophysical modelling (TPM) a size of 302x290x232 km (+/- 4 %) and an geometric visible albedo of 0.050+/-0.005. Our model of a regolith covered surface with low thermal inertia and "default" roughness describes the wavelengths and phase angle dependent...
Source: http://arxiv.org/abs/astro-ph/0401458v1
59
59
Sep 20, 2013
09/13
by
M. A. T. Groenewegen; J. A. D. L. Blommaert
texts
eye 59
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(abridged) The 222000 I-band light curves of variable stars detected by the OGLE-II survey in the direction of the Galactic Bulge have been fitted and have also been correlated with the DENIS and 2MASS databases. Results are presented for 2691 objects with I-band semi-amplitude larger than 0.45 magnitude, corresponding to classical Mira variables. The Mira period distribution of 6 fields at similar longitude but spanning latitudes from -1.2 to -5.8 degrees are statistically indistinguisable...
Source: http://arxiv.org/abs/astro-ph/0506338v1
148
148
Jul 20, 2013
07/13
by
E. Vanhollebeke; J. A. D. L. Blommaert; M. Schultheis; B. Aringer; A. Lancon
texts
eye 148
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Context. Galactic Centre (GC) OH/IR stars can be, based on the expansion velocities of their circumstellar shells, divided into two groups which are kinematically different and therefore are believed to have evolved from different stellar populations. Aims. To study the metallicity distribution of the OH/IR stars population in the GC on basis of a theoretical relation between EW(Na), EW(Ca) and EW(CO) and the metallicity. Methods. For 70 OH/IR stars in the GC, we obtained near-IR spectra. The...
Source: http://arxiv.org/abs/astro-ph/0604612v1
58
58
Sep 19, 2013
09/13
by
A. Moneti; S. Stolovy; J. A. D. L. Blommaert; D. F. Figer; F. Najarro
texts
eye 58
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In an attempt to determine the nature of the enigmatic cocoon stars in the Quintuplet Cluster, we have obtained mid-infrared imaging and spectrophotometry of the cluster, using the CAM and SWS instruments on ISO, using SpectroCam-10 on the Palomar 5m telescope, and NICMOS on HST. The spectra show smooth continua with various dust and ice absorption features. These features are all consistent with an interstellar origin, and there is no clear evidence for any circumstellar contribution to these...
Source: http://arxiv.org/abs/astro-ph/0010558v1
72
72
Sep 19, 2013
09/13
by
A. Moneti; J. A. D. L. Blommaert; F. Najarro; D. F. Figer; S. Stolovy
texts
eye 72
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We present initial results of a spectroscopic study of the Pistol and of the cocoon stars in the Quintuplet Cluster. From ISOCAM CVF 5--17 micron spectroscopy of the field of the Pistol Star, we have discovered a nearly spherical shell of hot dust surrounding this star, a probable LBV. This shell is most prominent at lambda > 12 micron, and its morphology clearly indicates that the shell is stellar ejecta. Emission line images show that most of the ionised material is along the northern...
Source: http://arxiv.org/abs/astro-ph/9812046v1
48
48
Sep 21, 2013
09/13
by
I. S. Glass; M. Schultheis; J. A. D. L. Blommaert; R. Sahai; M. Stute; S. Uttenthaler
texts
eye 48
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Asymptotic Giant Branch variables are found to obey period-luminosity relations in the mid-IR similar to those seen at K_S (2.14 microns), even at 24 microns where emission from circumstellar dust is expected to be dominant. Their loci in the M, logP diagrams are essentially the same for the LMC and for NGC6522 in spite of different ages and metallicities. There is no systematic trend of slope with wavelength. The offsets of the apparent magnitude vs. logP relations imply a difference between...
Source: http://arxiv.org/abs/0901.3032v1
45
45
Sep 22, 2013
09/13
by
S. Dehaes; M. A. T. Groenewegen; L. Decin; S. Hony; G. Raskin; J. A. D. L. Blommaert
texts
eye 45
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It is generally acknowledged that the mass loss of Asymptotic Giant Branch (AGB) stars undergoes variations on different time scales. We constructed models for the dust envelopes for a sample of AGB stars to assess whether mass-loss variations influence the spectral energy distribution (SED). To constrain the variability, extra observations at millimetre wavelengths (1.2 mm) were acquired. From the analysis of the dust models, two indications for the presence of mass-loss variations can be...
Source: http://arxiv.org/abs/astro-ph/0702628v1
4
4.0
Jun 28, 2018
06/18
by
P. Scicluna; R. Siebenmorgen; R. Wesson; J. A. D. L Blommaert; M. Kasper; N. V. Voshchinnikov; S. Wolf
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eye 4
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Massive stars live short lives, losing large amounts of mass through their stellar wind. Their mass is a key factor determining how and when they explode as supernovae, enriching the interstellar medium with heavy elements and dust. During the red supergiant phase, mass-loss rates increase prodigiously, but the driving mechanism has proven elusive. Here we present high-contrast optical polarimetric-imaging observations of the extreme red supergiant VY Canis Majoris and its clumpy, dusty,...
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1511.07624
60
60
Sep 22, 2013
09/13
by
D. Ladjal; K. Justtanont; M. A. T. Groenewegen; J. A. D. L. Blommaert; C. Waelkens; M. J. Barlow
texts
eye 60
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During their evolution, Asymptotic Giant Branch (AGB) stars experience a high mass-loss which leads to the formation of a Circumstellar Envelope (CSE) of dust and gas. The mass-loss process is the most important phenomenon during this evolutionary stage. In order to understand it, it is important to study the physical parameters of the CSE. The emission of the CSE in the (sub)millimetre range is dominated by the dust continuum. This means that (sub)millimetre observations are a key tool in...
Source: http://arxiv.org/abs/1001.2098v1
82
82
Sep 17, 2013
09/13
by
B. L. de Vries; M. Min; L. B. F. M. Waters; J. A. D. L. Blommaert; F. Kemper
texts
eye 82
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Aims. We present a diagnostic tool to determine the abundance of the crystalline silicate forsterite in AGB stars surrounded by a thick shell of silicate dust. Using six infrared spectra of high mass-loss oxygen rich AGB stars we obtain the forsterite abundance of their dust shells. Methods. We use a monte carlo radiative transfer code to calculate infrared spectra of dust enshrouded AGB stars. We vary the dust composition, mass-loss rate and outer radius. We focus on the strength of the 11.3...
Source: http://arxiv.org/abs/1003.3100v1
55
55
Sep 21, 2013
09/13
by
B. L. de Vries; M. Min; L. B. F. M. Waters; J. A. D. L. Blommaert; F. Kemper
texts
eye 55
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We present a diagnostic tool to determine the forsterite abundance of the dust ejected by AGB stars. Our method is based on a comparison between the observed strength of spectral bands of forsterite and model calculations. We show that the 11.3 {\mu}m forsterite band is a robust indicator of the forsterite abundance of the current mass-loss period for AGB stars with an optically thick dust shell. The 33.6 {\mu}m band of forsterite is sensitive to changes in the density and the geometry of the...
Source: http://arxiv.org/abs/1011.1123v1
25
25
Jun 27, 2018
06/18
by
S. Uttenthaler; J. A. D. L. Blommaert; P. R. Wood; T. Lebzelter; B. Aringer; M. Schultheis; N. Ryde
texts
eye 25
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An analysis of high-resolution near-infrared spectra of a sample of 45 asymptotic giant branch (AGB) stars towards the Galactic bulge is presented. The sample consists of two subsamples, a larger one in the inner and intermediate bulge, and a smaller one in the outer bulge. The data are analysed with the help of hydrostatic model atmospheres and spectral synthesis. We derive the radial velocity of all stars, and the atmospheric chemical mix ([Fe/H], C/O, $^{12}$C/$^{13}$C, Al, Si, Ti, and Y)...
Topics: Solar and Stellar Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1505.01425
57
57
Sep 18, 2013
09/13
by
Jacco Th. van Loon; A. A. Zijlstra; L. Kaper; G. F. Gilmore; C. Loup; J. A. D. L. Blommaert
texts
eye 57
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The obscured OH/IR star IRAS05298-6957 in the LMC was recently noticed to be member of the small double cluster HS 327 that also contains a carbon star (van Loon et al., 1998, A&A 329, 169). Hence they are coeval and have (nearly) the same progenitor mass, which can only be understood if Hot Bottom Burning (HBB) has prevented IRAS05298-6957 from being a carbon star. We present extensive visual and near-IR photometric data for >10^4 stars in and around HS 327, and spectroscopic data for...
Source: http://arxiv.org/abs/astro-ph/0101107v1
14
14
Jun 26, 2018
06/18
by
B. L. de Vries; K. M. Maaskant; M. Min; R. Lombaert; L. B. F. M. Waters; J. A. D. L. Blommaert
texts
eye 14
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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 the PPN. We use the best-fit model for IRAS 17150-3224 of Meixner et al. (2002) and add forsterite to this model. We investigate different spatial distributions and grain sizes of the forsterite crystals in the circumstellar environment. We compare the...
Topics: Solar and Stellar Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1502.06766
42
42
Sep 21, 2013
09/13
by
S. Dehaes; E. Bauwens; L. Decin; K. Eriksson; G. Raskin; B. Butler; C. D. Dowell; B. Ali; J. A. D. L. Blommaert
texts
eye 42
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Context: Among late-type red giants, an interesting change occurs in the structure of the outer atmospheric layers as one moves to later spectral types in the Hertzsprung-Russell diagram: a chromosphere is always present, but the coronal emission diminishes and a cool massive wind steps in. Aims: Where most studies have focussed on short-wavelength observations, this article explores the influence of the chromosphere and the wind on long-wavelength photometric measurements. Methods: The...
Source: http://arxiv.org/abs/0905.1240v1
56
56
Sep 23, 2013
09/13
by
I. S Glass; S. Ganesh; C. Alard; J. A. D. L. Blommaert; G. Gilmore; T. Lloyd Evans; A. Omont; M. Schultheis; G. Simon
texts
eye 56
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The ISOGAL mid-infrared survey of areas close to the Galactic Plane aims to determine their stellar content and its possible bearing on the history of the Galaxy. The NGC6522 and Sgr I Baade's Windows of low obscuration towards the inner parts of the Bulge represent ideal places in which to calibrate and understand the ISOGAL colour-magnitude diagrams. The survey observations were made with the ISOCAM instrument of the ISO satellite. The filter bands chosen were LW2(~7 microns) and LW3(~15...
Source: http://arxiv.org/abs/astro-ph/9904010v1
13
13
Jun 27, 2018
06/18
by
R. Lombaert; L. Decin; A. de Koter; J. A. D. L. Blommaert; P. Royer; E. De Beck; B. L. de Vries; T. Khouri; M. Min
texts
eye 13
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Context: AGB stars lose a large percentage of their mass in a dust-driven wind. This creates a circumstellar envelope, which can be studied through thermal dust emission and molecular emission lines. In the case of high mass-loss rates, this study is complicated by the high optical depths and the intricate coupling between gas and dust radiative transfer characteristics. An important aspect of the physics of gas-dust interactions is the strong influence of dust on the excitation of several...
Topics: Solar and Stellar Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1505.07696
51
51
Sep 21, 2013
09/13
by
R. Lombaert; B. L. de Vries; L. Decin; J. A. D. L. Blommaert; P. Royer; E. De Beck; A. de Koter; L. B. F. M. Waters
texts
eye 51
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Observations of high-excitation molecular emission lines can greatly increase our understanding of AGB winds, as they trace the innermost regions of the circumstellar envelope. The PACS spectrometer on-board the Herschel Space Telescope, provides for the first time the spectral resolution and sensitivity necessary to trace these lines. We report on the first modelling efforts of a PACS spectral scan for the OH/IR star V669 Cas. Central to our methodology is the consistent treatment of both dust...
Source: http://arxiv.org/abs/1011.4475v1
4
4.0
Jun 30, 2018
06/18
by
M. Mecina; F. Kerschbaum; M. A. T. Groenewegen; R. Ottensamer; J. A. D. L. Blommaert; A. Mayer; L. Decin; A. Luntzer; B. Vandenbussche; Th. Posch; C. Waelkens
texts
eye 4
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For the Mass-loss of Evolved StarS (MESS) programme, the unprecedented spatial resolution of the PACS photometer on board the Herschel space observatory was employed to map the dusty environments of asymptotic giant branch (AGB) and red supergiant (RSG) stars. Among the morphologically heterogeneous sample, a small fraction of targets is enclosed by spherically symmetric detached envelopes. Based on observations in the 70 {\mu}m and 160 {\mu}m wavelength bands, we investigated the surroundings...
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1405.2769
66
66
Sep 18, 2013
09/13
by
Jacco Th. van Loon; G. F. Gilmore; A. Omont; J. A. D. L. Blommaert; I. S. Glass; M. Messineo; F. Schuller; M. Schultheis; I. Yamamura; H. S. Zhao
texts
eye 66
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Near- and mid-IR survey data from DENIS and ISOGAL are used to investigate the structure and formation history of the inner 10 degree (1.4 kpc) of the Milky Way galaxy. Synthetic bolometric corrections and extinction coefficients in the near- and mid-IR are derived for stars of different spectral types, to allow the transformation of theoretical isochrones into observable colour-magnitude diagrams. The observed IR colour-magnitude diagrams are used to derive the extinction, metallicity and age...
Source: http://arxiv.org/abs/astro-ph/0210073v1
52
52
Sep 22, 2013
09/13
by
K. Smolders; B. Acke; T. Verhoelst; J. A. D. L. Blommaert; L. Decin; S. Hony; G. C. Sloan; P. Neyskens; S. Van Eck; A. A. Zijlstra; H. Van Winckel
texts
eye 52
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Polycyclic aromatic hydrocarbons (PAHs) produce characteristic infrared emission bands that have been observed in a wide range of astrophysical environments, where carbonaceous material is subjected to ultraviolet (UV) radiation. Although PAHs are expected to form in carbon-rich AGB stars, they have up to now only been observed in binary systems where a hot companion provides a hard radiation field. In this letter, we present low-resolution infrared spectra of four S-type AGB stars, selected...
Source: http://arxiv.org/abs/1004.1967v1
52
52
Sep 21, 2013
09/13
by
A. Mayer; A. Jorissen; F. Kerschbaum; S. Mohamed; S. Van Eck; R. Ottensamer; J. A. D. L. Blommaert; L. Decin; M. A. T. Groenewegen; Th. Posch; B. Vandenbussche; C. Waelkens
texts
eye 52
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Herschel's PACS instrument observed the environment of the binary system Mira Ceti in the 70 and 160 micron bands. These images reveal bright structures shaped as five broken arcs and fainter filaments in the ejected material of Mira's primary star. The overall shape of the IR emission around Mira deviates significantly from the expected alignment with Mira's exceptionally high space velocity. The observed broken arcs are neither connected to each other nor are they of a circular shape; they...
Source: http://arxiv.org/abs/1106.3643v1
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53
Sep 19, 2013
09/13
by
F. Schuller; S. Ganesh; M. Messineo; A. Moneti; J. A. D. L. Blommaert; C. Alard; B. Aracil; M. -A. Miville-Deschenes; A. Omont; M. Schultheis; G. Simon; A. Soive; L. Testi
texts
eye 53
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We present version 1.0 of the ISOGAL-DENIS Point Source Catalogue (PSC), containing more than 100,000 point sources detected at 7 and/or 15 micron in the ISOGAL survey of the inner Galaxy with the ISOCAM instrument on board the Infrared Space Observatory (ISO). These sources are cross-identified, wherever possible, with near-infrared (0.8-2.2 micron) data from the DENIS survey. The overall surface covered by the ISOGAL survey is about 16 square degrees, mostly (95%) distributed near the...
Source: http://arxiv.org/abs/astro-ph/0304309v1
42
42
Sep 22, 2013
09/13
by
L. Decin; P. Royer; N. L. J. Cox; B. Vandenbussche; R. Ottensamer; J. A. D. L. Blommaert; M. A. T. Groenewegen; M. J. Barlow; T. Lim; F. Kerschbaum; T. Posch; C. Waelkens
texts
eye 42
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We present new Herschel/PACS images at 70, 100, and 160 micron of the well-known, nearby, carbon-rich asymptotic giant branch star IRC+10216 revealing multiple dust shells in its circumstellar envelope. For the first time, dust shells (or arcs) are detected until 320 arcsec. The almost spherical shells are non-concentric and have an angular extent between 40 deg and 200 deg. The shells have a typical width of 5 arcsec - 8 arcsec, and the shell separation varies in the range of 10 arcsec - 35...
Source: http://arxiv.org/abs/1210.3483v1
71
71
Jul 20, 2013
07/13
by
Norman R. Trams; Jacco Th. van Loon; Albert A. Zijlstra; Cecile Loup; M. A. T. Groenewegen; L. B. F. M. Waters; Patricia A. Whitelock; J. A. D. L. Blommaert; Ralf Siebenmorgen; Astrid Heske
texts
eye 71
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We describe ISO observations of the obscured Asymptotic Giant Branch (AGB) star IRAS04496-6958 in the Large Magellanic Cloud (LMC). This star has been classified as a carbon star. Our new ISOCAM CVF spectra show that it is the first carbon star with silicate dust known outside of the Milky Way. The existence of this object, and the fact that it is one of the highest luminosity AGB stars in the LMC, provide important information for theoretical models of AGB evolution and understanding the...
Source: http://arxiv.org/abs/astro-ph/9902323v1
38
38
Sep 19, 2013
09/13
by
M. -R. L. Cioni; J. A. D. L. Blommaert; M. A. T. Groenewegen; H. J. Habing; J. Hron; F. Kerschbaum; C. Loup; A. Omont; J. Th. van Loon; P. A. Whitelock; A. A. Zijlstra
texts
eye 38
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This article presents the study of the light-curves extracted from the MACHO database of a sample of stars observed by the ISO in the SMC. These stars belong to the ISO-Mini-Survey catalogue of the Magellanic Clouds (ISO-MCMS, Loup et al. in preparation). Most of them are in the AGB and supergiant phases. The dominant period and amplitude of pulsation have been derived and the stars have been classified as Mira or Semi-Regular pulsators. Furthermore, the cross-identification with near-infrared...
Source: http://arxiv.org/abs/astro-ph/0304143v1
127
127
Jul 19, 2013
07/13
by
F. Kerschbaum; D. Ladjal; R. Ottensamer; M. A. T. Groenewegen; M. Mecina; J. A. D. L. Blommaert; B. Baumann; L. Decin; B. Vandenbussche; C. Waelkens; T. Posch; E. Huygen; W. De Meester; S. Regibo; P. Royer; K. Exter; C. Jean
texts
eye 127
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Detached circumstellar dust shells are detected around three carbon variables using Herschel-PACS. Two of them are already known on the basis of their thermal CO emission and two are visible as extensions in IRAS imaging data. By model fits to the new data sets, physical sizes, expansion timescales, dust temperatures, and more are deduced. A comparison with existing molecular CO material shows a high degree of correlation for TT Cyg and U Ant but a few distinct differences with other...
Source: http://arxiv.org/abs/1005.2689v1
73
73
Sep 21, 2013
09/13
by
A. Jorissen; A. Mayer; S. Van Eck; R. Ottensamer; F. Kerschbaum; T. Ueta; P. Bergman; J. A. D. L. Blommaert; L. Decin; M. A. T. Groenewegen; J. Hron; W. Nowotny; H. Olofsson; Th. Posch; L. O. Sjouwerman; B. Vandenbussche; C. Waelkens
texts
eye 73
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The asymptotic giant branch (AGB) stars X Her and TX Psc have been imaged at 70 and 160 microns with the PACS instrument onboard the Herschel satellite, as part of the large MESS (Mass loss of Evolved StarS) Guaranteed Time Key Program. The images reveal an axisymmetric extended structure with its axis oriented along the space motion of the stars. This extended structure is very likely to be shaped by the interaction of the wind ejected by the AGB star with the surrounding interstellar medium...
Source: http://arxiv.org/abs/1106.3645v1
52
52
Sep 18, 2013
09/13
by
A. Mayer; A. Jorissen; F. Kerschbaum; R. Ottensamer; W. Nowotny; N. L. J. Cox; B. Aringer; J. A. D. L. Blommaert; L. Decin; S. van Eck; H. -P. Gail; M. A. T. Groenewegen; K. Kornfeld; M. Mecina; Th. Posch; B. Vandenbussche; C. Waelkens
texts
eye 52
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The Mass loss of Evolved StarS (MESS) sample offers a selection of 78 Asymptotic Giant Branch (AGB) stars and Red Supergiants (RSGs) observed with the PACS photometer on-board Herschel at 70 and 160 {\mu}m. For most of these objects, the dusty AGB wind differs from spherical symmetry and the wind shape can be subdivided into four classes. In the present paper we concentrate on the influence of a companion on the morphology of the stellar wind. Literature was searched to find binaries in the...
Source: http://arxiv.org/abs/1211.3595v2
4
4.0
Jun 29, 2018
06/18
by
R. Lombaert; L. Decin; P. Royer; A. de Koter; N. L. J. Cox; E. González-Alfonso; D. Neufeld; J. De Ridder; M. Agúndez; J. A. D. L. Blommaert; T. Khouri; M. A. T. Groenewegen; F. Kerschbaum; J. Cernicharo; B. Vandenbussche; C. Waelkens
texts
eye 4
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Context. The recent detection of warm H$_2$O 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 H$_2$O vapor formation. In the first, periodic shocks passing through the medium immediately above the stellar surface lead to H$_2$O formation. In the second, penetration of ultraviolet interstellar radiation through a clumpy circumstellar medium leads to...
Topics: Astrophysics, Solar and Stellar Astrophysics, Astrophysics of Galaxies
Source: http://arxiv.org/abs/1601.07017
60
60
Sep 21, 2013
09/13
by
B. L. de Vries; D. Klotz; R. Lombaert; A. Baier; J. A. D. L. Blommaert; L. Decin; F. Kerschbaum; W. Nowotny; T. Posch; H. Van Winckel; M. A. T. Groenewegen; T. Ueta; G. Van de Steene; B. Vandenbussche; P. Royer; C. Waelkens
texts
eye 60
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In this article we present the detection of the 69 {\mu}m band of the crystalline olivine forsterite within the MESS key program of Herschel. We determine the temperature of the forsterite grains by fitting the 69 {\mu}m band.
Source: http://arxiv.org/abs/1011.1126v1
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42
Sep 18, 2013
09/13
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Jacco Th. van Loon; J. M. Oliveira; P. R. Wood; A. A. Zijlstra; G. C. Sloan; M. Matsuura; P. A. Whitelock; M. A. T. Groenewegen; J. A. D. L. Blommaert; M. -R. L. Cioni; S. Hony; C. Loup; L. B. F. M. Waters
texts
eye 42
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We present the first thermal-infrared spectra of an extra-galactic Young Stellar Object (YSO), IRAS05328-6827 in the HII region LHA 120-N148 in the Large Magellanic Cloud. The observed and modelled spectral energy distribution reveals a massive YSO, M=20 Msun, which is heavily-embedded and probably still accreting. The reduced dust content as a consequence of the lower metallicity of the LMC allows a unique view into this object, and together with a high C/O ratio may be responsible for the...
Source: http://arxiv.org/abs/astro-ph/0509695v1
118
118
Sep 23, 2013
09/13
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Eric Lagadec; Albert A. Zijlstra; G. C. Sloan; Peter R. Wood; Mikako Matsuura; Jeronimo Bernard-Salas; J. A. D. L. Blommaert; M. -R. L. Cioni; M. W. Feast; M. A. T. Groenewegen; Sacha Hony; J. W. Menzies; J. Th. van Loon; P. A. Whitelock
texts
eye 118
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We present spectroscopic observations from the {\it Spitzer Space Telescope} of six carbon-rich AGB stars in the Sagittarius Dwarf Spheroidal Galaxy (Sgr dSph) and two foreground Galactic carbon stars. The band strengths of the observed C$_2$H$_2$ and SiC features are very similar to those observed in Galactic AGB stars. The metallicities are estimated from an empirical relation between the acetylene optical depth and the strength of the SiC feature. The metallicities are higher than those of...
Source: http://arxiv.org/abs/0903.1045v1
50
50
Sep 23, 2013
09/13
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L. Decin; N. L. J. Cox; P. Royer; A. J. Van Marle; B. Vandenbussche; D. Ladjal; F. Kerschbaum; R. Ottensamer; M. J. Barlow; J. A. D. L. Blommaert; H. L. Gomez; M. A. T. Groenewegen; T. Lim; B. M. Swinyard; C. Waelkens; A. G. G. M. Tielens
texts
eye 50
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Context. The interaction between stellar winds and the interstellar medium (ISM) can create complex bow shocks. The photometers on board the Herschel Space Observatory are ideally suited to studying the morphologies of these bow shocks. Aims. We aim to study the circumstellar environment and wind-ISM interaction of the nearest red supergiant, Betelgeuse. Methods. Herschel PACS images at 70, 100, and 160 micron and SPIRE images at 250, 350, and 500 micron were obtained by scanning the region...
Source: http://arxiv.org/abs/1212.4870v1
68
68
Sep 18, 2013
09/13
by
Eric Lagadec; Albert A. Zijlstra; G. C. Sloan; Mikako Matsuura; Peter Wood; G. J. Harris; Jacco Th. van Loon; J. A. D. L. Blommaert; S. Hony; M. A. T. Groenewegen; M. W. Feast; P. A. Whitelock; J. W. Menzies; M. -R. Cioni; L. B. F. M. Waters
texts
eye 68
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We present Spitzer Space telescope spectroscopic observations of 14 carbon-rich AGB stars in the Small Magellanic Cloud. SiC dust is seen in most of the carbon-rich stars but it is weak compared to LMC stars. The SiC feature is strong only for stars with significant dust excess, opposite to what is observed for Galactic stars. We argue that in the SMC, SiC forms at lower temperature than graphite dust, whereas the reverse situation occurs in the Galaxy where SiC condenses at higher temperatures...
Source: http://arxiv.org/abs/astro-ph/0611071v1
58
58
Sep 23, 2013
09/13
by
N. L. J. Cox; F. Kerschbaum; A. -J. van Marle; L. Decin; D. Ladjal; A. Mayer; M. A. T. Groenewegen; S. van Eck; P. Royer; R. Ottensamer; T. Ueta; A. Jorissen; M. Mecina; Z. Meliani; A. Luntzer; J. A. D. L. Blommaert; Th. Posch; B. Vandenbussche; C. Waelkens
texts
eye 58
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Far-infrared Herschel/PACS images at 70 and 160 micron of a sample of 78 Galactic evolved stars are used to study the (dust) emission structures, originating from stellar wind-ISM interaction. In addition, two-fluid hydrodynamical simulations of the coupled gas and dust in wind-ISM interactions are used to compare with the observations. Four distinct classes of wind-ISM interaction (i.e. "fermata", "eyes", "irregular", and "rings") are identified and...
Source: http://arxiv.org/abs/1110.5486v1
6
6.0
Jun 29, 2018
06/18
by
S. Viaene; M. Baes; A. Tamm; E. Tempel; G. Bendo; J. A. D. L. Blommaert; M. Boquien; A. Boselli; P. Camps; A. Cooray; I. De Looze; P. De Vis; J. A. Fernandez-Ontiveros; J. Fritz; M. Galametz; G. Gentile; S. Madden; M. W. L. Smith; L. Spinoglio; S. Verstocken
texts
eye 6
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The radiation of stars heats dust grains in the diffuse interstellar medium and in star-forming regions in galaxies. Modelling this interaction provides information on dust in galaxies, a vital ingredient for their evolution. It is not straightforward to identify the stellar populations heating the dust, and to link attenuation to emission on a sub-galactic scale. Radiative transfer models are able to simulate this dust-starlight interaction in a realistic, three-dimensional setting. We...
Topics: Astrophysics, Astrophysics of Galaxies
Source: http://arxiv.org/abs/1609.08643
12
12
Jun 30, 2018
06/18
by
J. A. D. L. Blommaert; B. L. de Vries; L. B. F. M. Waters; C. Waelkens; M. Min; H. Van Winckel; F. Molster; L. Decin; M. A. T. Groenewegen; M. Barlow; P. García-Lario; F. Kerschbaum; Th. Posch; P. Royer; T. Ueta; B. Vandenbussche; G. Van de Steene; P. van Hoof
texts
eye 12
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We present 48 Herschel/PACS spectra of evolved stars in the wavelength range of 67-72 $\mu$m. This wavelength range covers the 69 $\mu$m band of crystalline olivine ($\text{Mg}_{2-2x}\text{Fe}_{(2x)}\text{SiO}_{4}$). The width and wavelength position of this band are sensitive to the temperature and composition of the crystalline olivine. Our sample covers a wide range of objects: from high mass-loss rate AGB stars (OH/IR stars, $\dot M \ge 10^{-5}$ M$_\odot$/yr), through post-AGB stars with...
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1403.6335
54
54
Sep 18, 2013
09/13
by
M. Matsuura; P. R. Wood; G. C. Sloan; A. A. Zijlstra; J. Th. van Loon; M. A. T. Groenewegen; J. A. D. L. Blommaert; M. -R. L. Cioni; M. W. Feast; H. J. Habing; S. Hony; E. Lagadec; C. Loup; J. W. Menzies; L. B. F. M. Waters; P. A. Whitelock
texts
eye 54
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We investigate the molecular bands in carbon-rich AGB stars in the Large Magellanic Cloud (LMC), using the InfraRed Spectrograph (IRS) on board the Spitzer Space Telescope (SST) over the 5--38 micron range. All 26 low-resolution spectra show acetylene (C2H2) bands at 7 and 14 micron. The hydrogen cyanide (HCN) bands at these wavelengths are very weak or absent. This is consistent with low nitrogen abundances in the LMC. The observed 14 micron C2H2 band is reasonably reproduced by an excitation...
Source: http://arxiv.org/abs/astro-ph/0606296v1
3
3.0
Jun 30, 2018
06/18
by
S. M. Lawler; J. Di Francesco; G. M. Kennedy; B. Sibthorpe; M. Booth; B. Vandenbussche; B. C. Matthews; W. S. Holland; J. Greaves; D. J. Wilner; M. Tuomi; J. A. D. L. Blommaert; B. L. de Vries; C. Dominik; M. Fridlund; W. Gear; A. M. Heras; R. Ivison; G. Olofsson
texts
eye 3
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$\tau$ Ceti is a nearby, mature G-type star very similar to our Sun, with a massive Kuiper Belt analogue (Greaves et al. 2004) and possible multiplanet system (Tuomi et al. 2013) that has been compared to our Solar System. We present Herschel Space Observatory images of the debris disk, finding the disk is resolved at 70 and 160 microns, and marginally resolved at 250 microns. The Herschel images and infrared photometry from the literature are best modelled using a wide dust annulus with an...
Topics: Earth and Planetary Astrophysics, Astrophysics
Source: http://arxiv.org/abs/1408.2791
57
57
Sep 21, 2013
09/13
by
Albert A. Zijlstra; Mikako Matsuura; Peter R. Wood; G. C. Sloan; Eric Lagadec; Jacco Th. van Loon; M. A. T. Groenewegen; M. W. Feast; J. W. Menzies; P. A. Whitelock; J. A. D. L. Blommaert; M. -RL. Cioni; H. J. Habing; S. Hony; C. Loup; L. B. F. M. Waters
texts
eye 57
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We present a Spitzer Space Telescope spectroscopic survey of mass-losing carbon stars (and one oxygen-rich star) in the Large Magellanic Cloud. The spectra cover the wavelength range 5--38 micron. They show varying combinations of dust continuum, dust emission features (SiC, MgS) and molecular absorption bands (C2H2, HCN). A set of four narrow bands, dubbed the Manchester system, is used to define the infrared continuum for dusty carbon stars. The relations between the continuum colours and the...
Source: http://arxiv.org/abs/astro-ph/0602531v1
9
9.0
Jun 30, 2018
06/18
by
T. Khouri; A. de Koter; L. Decin; L. B. F. M. Waters; M. Maercker; R. Lombaert; J. Alcolea; J. A. D. L. Blommaert; V. Bujarrabal; M. A. T. Groenewegen; K. Justtanont; F. Kerschbaum; M. Matsuura; K. M. Menten; H. Olofsson; P. Planesas; P. Royer; M. R. Schmidt; R. Szczerba; D. Teyssier; J. Yates
texts
eye 9
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The evolution of low- and intermediate-mass stars on the asymptotic giant branch (AGB) is mainly controlled by the rate at which these stars lose mass in a stellar wind. Understanding the driving mechanism and strength of the stellar winds of AGB stars and the processes enriching their surfaces with products of nucleosynthesis are paramount to constraining AGB evolution and predicting the chemical evolution of galaxies. In a previous paper we have constrained the structure of the outflowing...
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1409.0396
4
4.0
Jun 30, 2018
06/18
by
S. Viaene; J. Fritz; M. Baes; G. J. Bendo; J. A. D. L. Blommaert; M. Boquien; A. Boselli; L. Ciesla; L. Cortese; I. De Looze; W. K. Gear; G. Gentile; T. M. Hughes; T. Jarrett; O. Ł. Karczewski; M. W. L. Smith; L. Spinoglio; A. Tamm; E. Tempel; D. Thilker; J. Verstappen
texts
eye 4
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The imprints of dust-starlight interactions are visible in scaling relations between stellar characteristics, star formation parameters and dust properties. We aim to examine dust scaling relations on a sub-kpc resolution in the Andromeda galaxy (M31) by comparing the properties on a local and global scale to other galaxies of the local universe. New Herschel observations are combined with available data from GALEX, SDSS, WISE and Spitzer to construct a dataset covering UV to submm wavelengths....
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1403.4272
48
48
Jul 20, 2013
07/13
by
A. Omont; S. Ganesh; C. Alard; J. A. D. L. Blommaert; B. Caillaud; E. Copet; P. Fouque; G. Gilmore; D. Ojha; M. Schultheis; G. Simon; X. Bertou; J. Borsenberger; N. Epchtein; I. Glass; F. Guglielmo; M. A. T. Groenewegen; H. J. Habing; S. Kimeswenger; M. Morris; S. D. Price; A. Robin; M. Unavane; R. Wyse
texts
eye 48
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The ISOGAL project is a survey of the stellar populations, structure, and recent star formation history of the inner disk and bulge of the Galaxy. ISOGAL combines 15 and 7micron ISOCAM observations with DENIS IJKs data to determine the nature of a source and the interstellar extinction. In this paper we report an ISOGAL study of a small field in the inner Galactic Bulge (l=0deg, b=1.0deg, area=0.035 sq. deg) as a prototype of the larger area ISOGAL survey of the inner Galaxy. The five...
Source: http://arxiv.org/abs/astro-ph/9906489v1
5
5.0
Jun 30, 2018
06/18
by
T. Khouri; A. de Koter; L. Decin; L. B. F. M. Waters; R. Lombaert; P. Royer; B. Swinyard; M. J. Barlow; J. Alcolea; J. A. D. L. Blommaert; V. Bujarrabal; J. Cernicharo; M. A. T. Groenewegen; K. Justtanont; F. Kerschbaum; M. Maercker; A. Marston; M. Matsuura; G. Melnick; K. M. Menten; H. Olofsson; P. Planesas; E. Polehampton; Th. Posch; M. Schmidt; R. Szczerba; B. Vandenbussche; J. Yates
texts
eye 5
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Asymptotic giant branch (AGB) stars lose their envelopes by means of a stellar wind whose driving mechanism is not understood well. Characterizing the composition and thermal and dynamical structure of the outflow provides constraints that are essential for understanding AGB evolution, including the rate of mass loss and isotopic ratios. We modeled the CO emission from the wind of the low mass-loss rate oxygen-rich AGB star W Hya using data obtained by the HIFI, PACS, and SPIRE instruments...
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1403.2892
56
56
Jul 19, 2013
07/13
by
D. Ladjal; M. J. Barlow; M. A. T. Groenewegen; T. Ueta; J. A. D. L. Blommaert; M. Cohen; L. Decin; W. De Meester; K. Exter; W. K. Gear; H. L. Gomez; P. C. Hargrave; R. Huygen; R. J. Ivison; C. Jean; F. Kerschbaum; S. J. Leeks; T. L. Lim; G. Olofsson; E. Polehampton; T. Posch; S. Regibo; P. Royer; B. Sibthorpe; B. M. Swinyard; B. Vandenbussche; C. Waelkens; R. Wesson
texts
eye 56
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Herschel PACS and SPIRE images have been obtained over a 30'x30' area around the well-known carbon star CW Leo (IRC +10 216). An extended structure is found in an incomplete arc of ~22' diameter, which is cospatial with the termination shock due to interaction with the interstellar medium (ISM) as defined by Sahai & Chronopoulos from ultraviolet GALEX images. Fluxes are derived in the 70, 160, 250, 350, and 550 um bands in the region where the interaction with the ISM takes place, and this...
Source: http://arxiv.org/abs/1005.1433v2
41
41
Sep 23, 2013
09/13
by
K. Smolders; P. Neyskens; J. A. D. L. Blommaert; S. Hony; H. Van Winckel; L. Decin; S. Van Eck; G. C. Sloan; J. Cami; S. Uttenthaler; P. Degroote; D. Barry; M. Feast; M. A. T. Groenewegen; M. Matsuura; J. Menzies; R. Sahai; J. Th. van Loon; A. A. Zijlstra; B. Acke; S. Bloemen; N. Cox; P. de Cat; M. Desmet; K. Exter; D. Ladjal; R. Ostensen; S. Saesen; F. van Wyk; T. Verhoelst; W. Zima
texts
eye 41
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S-type AGB stars are thought to be in the transitional phase between M-type and C-type AGB stars. Because of their peculiar chemical composition, one may expect a strong influence of the stellar C/O ratio on the molecular chemistry and the mineralogy of the circumstellar dust. In this paper, we present a large sample of 87 intrinsic galactic S-type AGB stars, observed at infrared wavelengths with the Spitzer Space Telescope, and supplemented with ground-based optical data. On the one hand, we...
Source: http://arxiv.org/abs/1202.2290v2
42
42
Sep 21, 2013
09/13
by
M. W. L. Smith; S. A. Eales; H. L. Gomez; J. Roman Duval; J. Fritz; R. Braun; M. Baes; G. J. Bendo; J. A. D. L Blommaert; M. Boquien; A. Boselli; D. L. Clements; A. R. Cooray; L. Cortese; I. de Looze; G. P. Ford; W. K. Gear; G. Gentile; K. D. Gordon; J. Kirk; V. Lebouteiller; S. Madden; E. Mentuch; B. O'Halloran; M. J. Page; B. Schulz; L. Spinoglio; J. Verstappen; C. D. Wilson
texts
eye 42
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We present an analysis of the dust and gas in Andromeda, using Herschel images sampling the entire far-infrared peak. We fit a modified-blackbody model to ~4000 quasi-independent pixels with spatial resolution of ~140pc and find that a variable dust-emissivity index (beta) is required to fit the data. We find no significant long-wavelength excess above this model suggesting there is no cold dust component. We show that the gas-to-dust ratio varies radially, increasing from ~20 in the center to...
Source: http://arxiv.org/abs/1204.0785v2
45
45
Sep 19, 2013
09/13
by
P. A. M. van Hoof; K. M. Exter; G. C. Van de Steene; M. J. Barlow; T. L. Lim; B. Sibthorpe; M. A. T. Groenewegen; T. Ueta; M. Matsuura; J. A. D. L. Blommaert; M. Cohen; W. De Meester; W. K. Gear; H. L. Gomez; P. C. Hargrave; E. Huygen; R. J. Ivison; C. Jean; S. J. Leeks; G. Olofsson; E. T. Polehampton; S. Regibo; P. Royer; B. M. Swinyard; B. Vandenbussche; H. Van Winckel; C. Waelkens; R. Wesson
texts
eye 45
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In this paper we will discuss the images of Planetary Nebulae that have recently been obtained with PACS and SPIRE on board the Herschel satellite. This comprises results for NGC 650 (the little Dumbbell nebula), NGC 6853 (the Dumbbell nebula), and NGC 7293 (the Helix nebula).
Source: http://arxiv.org/abs/1009.5258v1
5
5.0
Jun 29, 2018
06/18
by
A. Brandeker; G. Cataldi; G. Olofsson; B. Vandenbussche; B. Acke; M. J. Barlow; J. A. D. L. Blommaert; M. Cohen; W. R. F. Dent; C. Dominik; J. Di Francesco; M. Fridlund; W. K. Gear; A. M. Glauser; J. S. Greaves; P. M. Harvey; A. M. Heras; M. R. Hogerheijde; W. S. Holland; R. Huygen; R. J. Ivison; S. J. Leeks; T. L. Lim; R. Liseau; B. C. Matthews; E. Pantin; G. L. Pilbratt; P. Royer; B. Sibthorpe; C. Waelkens; H. J. Walker
texts
eye 5
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The young star beta Pictoris is well known for its dusty debris disk, produced through the grinding down by collisions of planetesimals, kilometre-sized bodies in orbit around the star. In addition to dust, small amounts of gas are also known to orbit the star, likely the result from vaporisation of violently colliding dust grains. The disk is seen edge on and from previous absorption spectroscopy we know that the gas is very rich in carbon relative to other elements. The oxygen content has...
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1604.07418
