Calculating the dust properties of the class I source Elias29

2020 ◽  
Author(s):  
Maria Koutoulaki ◽  
Leonardo Testi ◽  
Anna Miotello ◽  
László Szűcs ◽  
Satoshi Yamamoto ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Optical Depth ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Band 3 ◽  
Early History ◽  
Class I ◽  
Planetary Formation ◽  
Disk System ◽  
History Of

<p>A first step towards understanding planetary formation is the characterisation of the structure and evolution of protoplanetary discs. A variety of planetary systems has been discovered in recent years and it likely depends on the early history of their formation. Thus understanding the chemical composition of early solar-like protostars is crucial. To be able to study the lines in detail though, a good knowledge of the dust properties and in particular the optical depth is needed in order to interpreted the lines correctly.</p> <p> </p> <p>In this talk I want to present our results of the class I source Elias29 as part of the FAUST (fifty au study of the chemistry in the disk/envelope system of solar-like protostars) collaboration. The goal of FAUST is to quantify the chemical composition of the envelope/disk system of solar-lie class 0 and I protostars. With the high spatial resolution of 50 au in band 3 and band 6 ALMA data we can spatially resolve the envelope and the disk on this source and calculate the dust properties of the two components.</p>

scholarly journals Enlightening the Chemistry of Infalling Envelopes and Accretion Disks Around Sun-Like Protostars: The ALMA FAUST Project

2021 ◽  
Vol 8 ◽  
Author(s):  
C. Codella ◽  
C. Ceccarelli ◽  
C. Chandler ◽  
N. Sakai ◽  
S. Yamamoto ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Accretion Disks ◽  
Early History ◽  
Chemical Diversity ◽  
Disk System ◽  
Large Program ◽  
Ionization Structure ◽  
History Of ◽  
System 2 ◽  
Huge Variety

The huge variety of planetary systems discovered in recent decades likely depends on the early history of their formation. In this contribution, we introduce the FAUST Large Program which focuses specifically on the early history of solar-like protostars and their chemical diversity at scales of ∼ 50 au, where planets are expected to form. In particular, the goal of the project is to reveal and quantify the variety of chemical composition of the envelope/disk system at scales of 50 au in a sample of Class 0 and I protostars representative of the chemical diversity observed at larger scales. For each source, we propose a set of molecules able to (1) disentangle the components of the 50–2000 au envelope/disk system, (2) characterize the organic complexity in each of them, (3) probe their ionization structure, and (4) measure their molecular deuteration. The output will be a homogeneous database of thousands of images from different lines and species, i.e., an unprecedented source survey of the chemical diversity of solar-like protostars. FAUST will provide the community with a legacy dataset that will be a milestone for astrochemistry and star formation studies.

scholarly journals Old Structure – Young Stars The Stellar Content of the Centre of the LMC Bar

1999 ◽  
Vol 192 ◽  
pp. 108-111
Author(s):  
P. Linde ◽  
A. Ardeberg ◽  
B. Gustafsson
Keyword(s):  
Image Processing ◽  
Star Formation ◽  
Spatial Resolution ◽  
Chemical Evolution ◽  
High Spatial Resolution ◽  
Young Stars ◽  
Stellar Content ◽  
History Of ◽  
Older Populations

The history of star formation and chemical evolution are studied in the LMC Bar centre with the HST PC and WFC and uvby photometry. Using dedicated image processing, we secured high spatial resolution and photometric quality. We present colour magnitude diagrams (CMDs) from PC and WFC y and b data. The PC provides a CMD close to complete to V = 23.5, the WFC contributes favourable statistics on brighter stars. We find a population of stars seemingly around or younger than 0.2 Gyr comprising around 30% of the total amount of stars. Star formation seems to have decreased 3-0.2 Gyr ago. Older populations are aged 3–9 Gyr. Stars older than 10 Gyr seem rare if not absent. Our CMD morphology and, especially, our uvby metallicity index give [Me/H] close to −0.4, with older stars more and younger stars less metal poor.

scholarly journals Development and Assessment of a High Spatial Resolution (4.4 km) MISR Aerosol Product Using AERONET-DRAGON Data

2016 ◽  
Author(s):  
Michael J. Garay ◽  
Olga V. Kalashnikova ◽  
Michael A. Bull
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Validation Data ◽  
Particle Property ◽  
Terra Satellite

Abstract. Since early 2000, the Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA’s Terra satellite has been acquiring data that has been used to produce aerosol optical depth (AOD) and particle property retrievals at 17.6 km spatial resolution. Capitalizing on the capabilities provided by multiangle viewing, the current operational (Version 22) MISR algorithm performs well with about 75 % of MISR AOD retrievals globally falling within 0.05 or 20 % × AOD of paired validation data from the ground-based Aerosol Robotic Network (AERONET). This paper describes the development and assessment of a prototype version of a higher spatial resolution, 4.4 km MISR aerosol product compared against multiple AERONET Distributed Regional Aerosol Gridded Observations Network (DRAGON) deployments around the globe.

Retrieval of High Spatial Resolution Aerosol Optical Depth from Chinese gAofen Data for Australian bushfire

2020 ◽  
Author(s):  
Yong Xue
Keyword(s):  
High Resolution ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Spatial Resolution ◽  
Satellite Data ◽  
High Spatial Resolution ◽  
Experimental Results ◽  
Observation System ◽  
Observation Data ◽  
Surface Reflectance

<p>Aerosol optical depth (AOD) is an important factor to estimate the effect of aerosol on light, and an accurate retrieval of it can make great contribution to monitor atmosphere. Therefore, retrieval of AOD has been a frontier topic and attracted much attention from researchers at home and abroad. However, the spatial resolution of AOD, based on Moderate-resolution Imaging Spectroradiometer (MODIS), is low, and hard to meet the needs of regional air quality fine monitoring. In 2018, China launched Gaofen-6 satellite, which set up a network with Gaofen-1 enabling two-day revisited observations in China's land area, improving the scale and timeliness of remote sensing data acquisition and making up for the shortcomings of lacking multi-spectral satellite with medium and high spatial resolution. Along with advancement of the Earth Observation System and the launch of high-resolution satellites, it is of profound significance to give full play to the active role of high-scoring satellites, in monitoring atmospheric environmental elements such as atmospheric aerosols and particulate matter concentrations, and achieve high-resolution retrieval of AOD through Gaofen satellites.</p><p>In this paper the data of Gaofen-6 and Gaofen-1 was used to retrieve the AOD. based on the Synergetic Retrieval of Aerosol Properties (SRAP) algorithm. This algorithm can retrieve the surface reflectance and AOD synchronously through constructing a closed equation based on double star observations. It can be applied to various types of surface reflectance which extends the coverage of the retrieval of AOD inversion effectively. Experimental data includes the satellite data of New South Wales and eastern Queensland on November 21, 2019, which have been suffered from unprecedented large-scale forest fires for over 2 months. The retrieval of AOD during the time with the satellite data is benefit for the prevention and monitoring of forest fire. The experimental results are compared with the AERONET ground observation data for preliminary validation. The correlation coefficient is about 0.7. The experimental results show that the method have higher accuracy, and further validation work is continuing.</p>

scholarly journals Retrieval of High Spatial Resolution Aerosol Optical Depth from HJ-1 A/B CCD Data

2019 ◽  
Vol 11 (7) ◽  
pp. 832 ◽  
Author(s):  
Xianlei Fan ◽  
Ying Qu
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Estimation Method ◽  
Absolute Error ◽  
Lookup Table ◽  
Visual Interpretation ◽  
Infrared Band ◽  
Moderate Resolution Imaging Spectroradiometer

A high-spatial resolution aerosol optical depth (AOD) dataset is critically important for regional meteorology and climate studies. Chinese Huanjing-1 (HJ-1) A/B charge-coupled diode (CCD) data are a suitable data source for retrieving AODs. However, AOD cannot be retrieved based on the dark target method due to the absence of a shortwave infrared band. In this study, an AOD estimation method based on the relationships between visible bands of HJ-1 A/B CCDs is proposed. The Polarization and Directionality of the Earth's Reflectances (POLDER) Bidirectional Reflectance Distribution Function (BRDF) dataset was used to construct a lookup table for interband regression coefficients that varied by solar/view angle and land cover type. Finally, high-spatial resolution AODs could be retrieved with the aerosol lookup table and constraints. The results showed that the AODs retrieved from the HJ-1 A/B CCD data had the same range of distribution and trends as a visual interpretation of the images and Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol products did. The validation results using four sites of the Aerosol Robotic Network (AERONET) in Beijing showed that the value of the correlation coefficient R was 0.866, the root mean square error (RMSE) was 0.167, the mean absolute error (MAE) was 0.131, and the expected error (EE) was 53.9%. If the measurements of an AERONET site were used as prior knowledge, AOD retrieval results could be much more accurately obtained by this method (R is 0.989, RMSE is 0.052, MAE is 0.042, and EE is 96.7%).

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