scholarly journals Spatially resolved spectroscopy of the debris disk HD 32297

2019 ◽  
Vol 630 ◽  
pp. A85 ◽  
Author(s):  
T. Bhowmik ◽  
A. Boccaletti ◽  
P. Thébault ◽  
Q. Kral ◽  
J. Mazoyer ◽  
...  
Keyword(s):  
Size Distribution ◽  
Debris Disks ◽  
Blue Color ◽  
Back Side ◽  
Spatially Resolved ◽  
Debris Disk ◽  
Spatially Resolved Spectroscopy ◽  
Photometric Measurements ◽  
Disk Image ◽  
First Time

Context. Spectro-photometry of debris disks in total intensity and polarimetry can provide new insight into the properties of the dust grains therein (size distribution and optical properties). Aims. We aim to constrain the morphology of the highly inclined debris disk HD 32297. We also intend to obtain spectroscopic and polarimetric measurements to retrieve information on the particle size distribution within the disk for certain grain compositions. Methods. We observed HD 32297 with SPHERE in Y, J, and H bands in total intensity and in J band in polarimetry. The observations are compared to synthetic models of debris disks and we developed methods to extract the photometry in total intensity overcoming the data-reduction artifacts, namely the self-subtraction. The spectro-photometric measurements averaged along the disk mid-plane are then compared to model spectra of various grain compositions. Results. These new images reveal the very inner part of the system as close as 0.15″. The disk image is mostly dominated by the forward scattering making one side (half-ellipse) of the disk more visible, but observations in total intensity are deep enough to also detect the back side for the very first time. The images as well as the surface brightness profiles of the disk rule out the presence of a gap as previously proposed. We do not detect any significant asymmetry between the northeast and southwest sides of the disk. The spectral reflectance features a “gray to blue” color which is interpreted as the presence of grains far below the blowout size. Conclusions. The presence of sub-micron grains in the disk is suspected to be the result of gas drag and/or “avalanche mechanisms”. The blue color of the disk could be further investigated with additional total intensity and polarimetric observations in K and H bands respectively to confirm the spectral slope and the fraction of polarization.

scholarly journals Constraining the detectability of water ice in debris disks

2019 ◽  
Vol 629 ◽  
pp. A141
Author(s):  
M. Kim ◽  
S. Wolf ◽  
A. Potapov ◽  
H. Mutschke ◽  
C. Jäger
Keyword(s):  
Scattered Light ◽  
Spectral Energy ◽  
Debris Disks ◽  
Water Ice ◽  
Spatially Resolved ◽  
Infrared Telescope ◽  
Effective Medium Theories ◽  
Debris Disk ◽  
Highly Porous ◽  
Entire Planet

Context. Water ice is important for the evolution and preservation of life. Identifying the distribution of water ice in debris disks is therefore of great interest in the field of astrobiology. Furthermore, icy dust grains are expected to play important roles throughout the entire planet formation process. However, currently available observations only allow deriving weak conclusions about the existence of water ice in debris disks. Aims. We investigate whether it is feasible to detect water ice in typical debris disk systems. We take the following ice destruction mechanisms into account: sublimation of ice, dust production through planetesimal collisions, and photosputtering by UV-bright central stars. We consider icy dust mixture particles with various shapes consisting of amorphous ice, crystalline ice, astrosilicate, and vacuum inclusions (i.e., porous ice grains). Methods. We calculated optical properties of inhomogeneous icy dust mixtures using effective medium theories, that is, Maxwell-Garnett rules. Subsequently, we generated synthetic debris disk observables, such as spectral energy distributions and spatially resolved thermal reemission and scattered light intensity and polarization maps with our code DMS. Results. We find that the prominent ~3 and 44 μm water ice features can be potentially detected in future observations of debris disks with the James Webb Space Telescope (JWST) and the Space Infrared telescope for Cosmology and Astrophysics (SPICA). We show that the sublimation of ice, collisions between planetesimals, and photosputtering caused by UV sources clearly affect the observational appearance of debris disk systems. In addition, highly porous ice (or ice-rich aggregates) tends to produce highly polarized radiation at around 3 μm. Finally, the location of the ice survival line is determined by various dust properties such as a fractional ratio of ice versus dust, physical states of ice (amorphous or crystalline), and the porosity of icy grains.

scholarly journals Lucky Spectroscopy, an equivalent technique to Lucky Imaging

2018 ◽  
Vol 615 ◽  
pp. A161 ◽  
Author(s):  
J. Maíz Apellániz ◽  
R. H. Barbá ◽  
S. Simón-Díaz ◽  
A. Sota ◽  
E. Trigueros Páez ◽  
...  
Keyword(s):  
Star Formation ◽  
Massive Star ◽  
Massive Stars ◽  
Close Binaries ◽  
Massive Star Formation ◽  
Visual Component ◽  
Spatially Resolved ◽  
Profile Fitting ◽  
Spatially Resolved Spectroscopy ◽  
First Time

Context. Many massive stars have nearby companions whose presence hamper their characterization through spectroscopy. Aims. We want to obtain spatially resolved spectroscopy of close massive visual binaries to derive their spectral types. Methods. We obtained a large number of short long-slit spectroscopic exposures of five close binaries under good seeing conditions. We selected those with the best characteristics, extracted the spectra using multiple-profile fitting, and combined the results to derive spatially separated spectra. Results. We demonstrate the usefulness of Lucky Spectroscopy by presenting the spatially resolved spectra of the components of each system, in two cases with separations of only ~0.′′3. Those are δ Ori Aa+Ab (resolved in the optical for the first time) and σ Ori AaAb+B (first time ever resolved). We also spatially resolve 15 Mon AaAb+B, ζ Ori AaAb+B (both previously resolved with GOSSS, the Galactic O-Star Spectroscopic Survey), and η Ori AaAb+B, a system with two spectroscopic B+B binaries and a fifth visual component. The systems have in common that they are composed of an inner pair of slow rotators orbited by one or more fast rotators, a characteristic that could have consequences for the theories of massive star formation.

scholarly journals Spatially resolved spectroscopy of close massive visual binaries with HST/STIS

2020 ◽  
Vol 636 ◽  
pp. A28 ◽  
Author(s):  
J. Maíz Apellániz ◽  
R. H. Barbá
Keyword(s):  
Spectroscopic Characterization ◽  
Space Telescope ◽  
Multiple Systems ◽  
Spatially Resolved ◽  
Profile Fitting ◽  
Spatially Resolved Spectroscopy ◽  
First Time ◽  
Magnitude Difference ◽  
Visual Binaries

Context. The spectroscopic characterization of many O-type stars is hampered by a nearby companion. Aims. We want to obtain spatially resolved spectroscopy of close O-type visual binaries to derive their spectral types. Methods. We used the Space Telescope Imaging Spectrograph (STIS) of the Hubble Space Telescope (HST) to obtain long-slit blue-violet spectroscopy of eight Galactic O-type stars with nearby visual companions and used spatial-profile fitting to extract the separate spectra. We also used the ground-based Galactic O-Star Spectroscopic Survey to study more distant visual components. Results. We spatially resolve seven of the eight systems, present spectra for their components, and obtain their spectral types. Those seven multiple systems are ι Ori Aa,Ab,B; 15 Mon Aa,Ab,C; τ CMa Aa,Ab,B,C,D,E; HD 206 267 Aa,Ab,C,D; HD 193 443 A,B; HD 16 429 Aa,Ab; and IU Aur A,B. This is the first time that spatially resolved spectroscopy of the close visual binaries of those systems is obtained. We establish the applicability of the technique as a function of the separation and magnitude difference of the binary.

scholarly journals Diva - A Small Satellite for Global Astrometry and Photometry

1998 ◽  
Vol 11 (1) ◽  
pp. 583-583
Author(s):  
S. Röser ◽  
U. Bastian ◽  
K.S. de Boer ◽  
E. Høg ◽  
E. Schilbach ◽  
...  
Keyword(s):  
High Precision ◽  
Wavelength Range ◽  
Fizeau Interferometer ◽  
Proper Motions ◽  
Small Satellite ◽  
Short Overview ◽  
Photometric Observations ◽  
Photometric Measurements ◽  
First Time ◽  
Astronomy And Astrophysics

DIVA (Double Interferometer for Visual Astrometry) is a Fizeau interferometer on a small satellite. It will perform astrometric and photometric observations of at least 4 million stars. A launch in 2002 and a minimum mission length of 24 months are aimed at. A detailed description of the experiment can be obtained from the DIVA homepage at http://www.aip.de:8080/᷉dso/diva. An overview is given by Röser et al., 1997. The limiting magnitude of DIVA is about V = 15 for spectral types earlier than M0, but drops to about V = 17.5 for stars later than M5. Table 1 gives a short overview on DIVA’s performance. DIVA will carry out a skysurvey complete to V = 12.5. For the first time this survey will comprise precise photometry in at least 8 bands in the wavelength range from 400 to 1000 nm. DIVA will improve parallaxes by a factor of 3 compared to Hipparcos; proper motions by at least a factor of 2 and, in combination with the Hipparcos observations, by a factor of 10 for Hipparcos stars. At least 30 times asmany stars as Hipparcos will be observed, and doing this DIVA will fill the gap in observations between Hipparcos and GAIA. DIVA’s combined astrometric and photometric measurements of high precision will have important impacts on astronomy and astrophysics in the next decade.

scholarly journals XMM–Newtonlarge program on SN1006 – I. Methods and initial results of spatially resolved spectroscopy

2015 ◽  
Vol 453 (4) ◽  
pp. 3954-3975 ◽  
Author(s):  
Jiang-Tao Li ◽  
Anne Decourchelle ◽  
Marco Miceli ◽  
Jacco Vink ◽  
Fabrizio Bocchino
Keyword(s):  
Spatially Resolved ◽  
Spatially Resolved Spectroscopy ◽  
Initial Results

scholarly journals Reconstruction of an Accretion Disk Image in AU Mon from CoRoT Photometry

2011 ◽  
Vol 7 (S282) ◽  
pp. 63-64
Author(s):  
P. Mimica ◽  
K. Pavlovski
Keyword(s):  
Binary System ◽  
Accretion Disk ◽  
Hot Spots ◽  
Disk Surface ◽  
Precise Location ◽  
Active Mass ◽  
Disk Structure ◽  
Surface Time ◽  
Photometric Measurements ◽  
Disk Image

AbstractThe long-period binary system AU Mon was photometrically observed on-board the CoRoT satellite in a continuous run of almost 60 days long which has covered almost 5 complete cycles. Unprecedented sub milimag precision of CoRoT photometry reveals all complexity of its light variations in this, still active mass-transfer binary system. We present images of an accretion disk reconstructed by eclipse mapping, and an optimization of intensity distribution along disk surface. Time resolution and accurate CoRoT photometric measurements allow precise location of spatial distribution of ‘hot’ spots on the disk, and tracing temporal changes in their activity. Clumpy disk structure is similar to those we detected early for another W Serpentis binary W Cru (Pavlovski, Burki & Mimica, 2006, A&A, 454, 855).

Measuring The Tensile Strain of Wood By Visible And Near-Infrared Spatially Resolved Spectroscopy

2021 ◽  
Author(s):  
Ma Te ◽  
Tetsuya Inagaki ◽  
Masato Yoshida ◽  
Mayumi Ichino ◽  
Satoru Tsuchikawa
Keyword(s):  
Light Scattering ◽  
Prediction Accuracy ◽  
Tensile Strain ◽  
Near Infrared ◽  
Mean Squared Error ◽  
Calibration Model ◽  
Spatially Resolved ◽  
Squared Error ◽  
Stiffness Evaluation ◽  
Spatially Resolved Spectroscopy

Abstract Wood has various mechanical properties, so stiffness evaluation is critical for quality management. Using conventional strain gauges constantly is high cost, also challenging to measure precious wood materials due to the use of strong adhesive. This study demonstrates the correlation between light scattering changes inside the wood cell walls and tensile strain. A multifiber-based visible-near-infrared (Vis–NIR) spatially resolved spectroscopy (SRS) system was designed to rapidly and conventiently acquire such light scattering changes. For the preliminary experiment, samples with different thicknesses were measured to evaluate the influence of thickness. The differences in Vis–NIR SRS spectral data diminish with an increase in sample thickness, which suggests that the SRS method can successfully measure the whole strain (i.e., surface and inside) of wood samples. Then, for the primary experiment, 18 wood samples with the same thickness (2 mm) were tested to construct a strain calibration model. The prediction accuracy was characterized by a determination coefficient (R2) of 0.86 with a root mean squared error (RMSE) of 297.89 με for five-fold cross-validation; for test validation, The prediction accuracy was characterized by an R2 of 0.82 and an RMSE of 345.44 με.

scholarly journals Spatially Resolved Spectroscopy of Starburst and Post-Starburst Galaxies in the Rich z ∼0.55 Cluster CL 0016+16

2010 ◽  
Vol 27 (3) ◽  
pp. 360-373 ◽  
Author(s):  
Michael B. Pracy ◽  
Warrick J. Couch ◽  
Harald Kuntschner
Keyword(s):  
Age Distribution ◽  
Starburst Galaxies ◽  
Small Sample ◽  
Spectral Signature ◽  
Rich Cluster ◽  
Spatially Resolved ◽  
Radial Profiles ◽  
Field Samples ◽  
The Rich ◽  
Spatially Resolved Spectroscopy

AbstractWe have used the Low Resolution Imaging Spectrograph on the W. M. Keck I telescope to obtain spatially resolved spectroscopy of a small sample of six ‘post-starburst’ and three ‘dusty-starburst’ galaxies in the rich cluster CL 0016+16 at z=0.55. We use this to measure radial profiles of the Hδ and [OII]λ3727 lines which are diagnostic probes of the mechanisms that give rise to the abrupt changes in star formation rates in these galaxies. In the post-starburst sample we are unable to detect any radial gradients in the Hδ line equivalent width — although one galaxy exhibits a gradient from one side of the galaxy to the other. The absence of Hδ gradients in these galaxies is consistent with their production via interaction with the intracluster medium; however, our limited spatial sampling prevents us from drawing robust conclusions. All members of the sample have early-type morphologies, typical of post-starburst galaxies in general, but lack the high incidence of tidal tails and disturbances seen in local field samples. This argues against a merger origin and adds weight to a scenario where truncation by the intra-cluster medium is at work. The post-starburst spectral signature is consistent over the radial extent probed with no evidence of [OII]λ3727 emission and strong Hδ absorption at all radii, i.e. the post-starburst classification is not an aperture effect. In contrast the ‘dusty-starburst’ sample shows a tendency for a central concentration of [OII]λ3727 emission. This is most straightforwardly interpreted as the consequence of a central starburst. However, other possibilities exist such as a non-uniform dust distribution (which is expected in such galaxies) and/or a non-uniform starburst age distribution. The members of the sample exhibit late-type and irregular morphologies.

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