Vietnam National Satellite Center

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Vietnam, Vietnam
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News Article | November 18, 2016
Site: www.eurekalert.org

A major step forward in establishing an unprecedented regional regime to develop microsatellite technologies and share and use collected data. The memorandum of understanding to create the Asian Micro-satellite Consortium (AMC) will come into effect on November 18, marking a major step forward in establishing an unprecedented regional regime to develop microsatellite technologies and share and use collected data relating to the environment and natural disasters, etc. The consortium will comprise 16 space agencies and universities from nine Asian nations, including Japan. Microsatellites have rapidly become a major factor in space exploitation, and their advent could spur a revolution comparable to that which followed the launch of humankind's first satellite, Sputnik-1, in 1957. The advantages of microsatellites are multifold: In general, they can be developed within a few years, which is much faster than the 10 years required for some larger satellites; they generally weigh 100 kilograms or less; and they are cheaper to build, costing about one-hundredth the price of large satellites. It is essential for Japan and other Asian nations to create an effective international framework toward the goal of obtaining state-of-the-art satellite bus and sensing technologies and the sharing and use of satellite-collected data, thereby maintaining a global presence in the field--this is the notion that has driven the formation of the AMC. The 16 participating institutions are space agencies, governmental institutes or top-class universities from Bangladesh, Indonesia, Japan, Malaysia, Mongolia, Myanmar, Philippines, Thailand and Vietnam (see list below). Data relating to such fields as natural disasters and the environment are of great value to these disaster-prone nations. They also help tackle the issue of environmental destruction. The AMC is also expected to make it much easier to share and standardize satellite bus and sensing technologies, observational data, and data application methodologies. In the future, the consortium is expected to share and utilize data collected by about 50 microsatellites that the participating nations are planning to launch. These microsatellites will allow the AMC to monitor any given location on the Earth around the clock, therefore making it possible to grasp a variety of situations, including major disasters if one should occur. The standardization of advanced optical sensors and other devices is essential in order to effectively make use of satellite-gathered data. By using drones mounted with such sensors for ground observation in international joint undertakings, it will drastically increase the volume of data gathered and the precision of ground verification. Data verified on the ground would also help researchers make far more accurate satellite-data-based estimates. The resultant effects could be enormous in such areas as disaster preparedness/mitigation, global environment change, promotion of agriculture, forestry, fisheries and mining, and countermeasures against air and marine pollution. The signing ceremony for the consortium will be held on November 18th at Hotel Jen in Manila, Philippines. Yukihiro Takahashi, the professor at Hokkaido University who led the formation of the AMC says "I believe that the consortium will trigger the advanced space utilization with microsatellites not only in Asia but also all over the world including Africa and South America". Indonesian National Institute of Aeronautics and Space (LAPAN) Agency for the Assessment and Application of Technology (BPPT) National University of Mongolia (NUM) New Mongol Institute of Technology (NMIT) German-Mongolian Institute for Resources and Technology (GMIT) Philippine Council for Industry, Energy and Emerging Technology Research and Development (DOST-PCIEERD) Vietnam National Satellite Center (VAST-VNSC) University of Science and Technology of Hanoi (VAST-USTH)


Nhung P.T.,Paris Observatory | Nhung P.T.,Vietnam National Satellite Center | Hoai D.T.,Paris Observatory | Hoai D.T.,Vietnam National Satellite Center | And 7 more authors.
Astronomy and Astrophysics | Year: 2015

The CO(1-0) and (2-1) emission of the circumstellar envelope of the asymptotic giant branch (AGB) star EP Aqr has been observed in 2003 using the IRAM Plateau-de-Bure Interferometer and in 2004 with the IRAM 30-m telescope at Pico Veleta. The line profiles reveal the presence of two distinct components centred on the star velocity, a broad component extending up to ∼10 km s-1 and a narrow component indicating an expansion velocity of only ∼2 km s-1. An early analysis of these data was performed under the assumption of isotropic winds. The present study revisits this interpretation, instead assuming a bipolar outflow nearly aligned with the line of sight. A satisfactory description of the observed flux densities is obtained with a radial expansion velocity increasing from ∼2 km s-1 at the equator to ∼10 km s-1 near the poles. The mass-loss rate is ∼1.2 × 10-7 M yr-1. The angular aperture of the bipolar outflow is ∼ 45° with respect to the star axis, which makes an angle of ∼ 13° with the line of sight. A detailed study of the CO(1-0) to CO(2-1) flux ratio reveals a significant dependence of the temperature on the stellar latitude, smaller and steeper at the poles than at the equator at large distances from the star (>2′′ 1.0 × 10-3 pc). Under the hypothesis of radial expansion of the gas and of rotation invariance about the star axis, the effective density was evaluated in space as a function of star coordinates (longitude, latitude, and distance from the star). Evidence is found for an enhancement of the effective density in the northern hemisphere of the star at angular distances in excess of ∼ 3′′ and covering the whole longitudinal range. The peak velocity of the narrow component is observed to vary slightly with position on the sky, a variation consistent with the model and understood as the effect of the inclination of the star axis with respect to the line of sight. This variation is inconsistent with the assumption of a spherical wind and strengthens our interpretation in terms of an axisymmetric outflow. While the phenomenological model presented here reproduces well the general features of the observations, not only qualitatively but also quantitatively, significant differences are also revealed, which would require a better spatial resolution to be properly described and understood. © ESO, 2015.


Tuan P.A.,Vietnam National Satellite Center | Phuong V.V.,Vietnam National Satellite Center
Proceedings of the International Astronautical Congress, IAC | Year: 2013

The Vietnam National Satellite Center (VNSC), a national research agency under Vietnam Academy of Science and Technology (VAST), was established in 2011 by the Decision of the Prime Minister. Its tasks are to research and develop earth observation satellites and to apply, especially in remote sensing, GIS and GPS; to establish infrastructure for space technology; to promote education and training activities; and to explore international cooperation. VNSC is also an executing organization involved in implementation and management of Vietnam Space Center Project. ©2013 by the International Astronautical Federation. All rights reserved.


Anh P.T.,Vietnam National Satellite Center | Diep P.N.,Vietnam National Satellite Center | Hoai D.T.,Vietnam National Satellite Center | Nhung P.T.,Vietnam National Satellite Center | And 3 more authors.
Research in Astronomy and Astrophysics | Year: 2015

Observations of an unprecedented quality made by ALMA on the Red Rectangle of CO(3-2) and CO(6-5) emissions are analysed jointly with the aim of obtaining as simple as possible a description of the gas morphology and kinematics. Evidence is found for polar conical outflows and for a broad equatorial torus in rotation and expansion. Simple models of both are proposed. Comparing CO(6-5) and CO(3-2) emissions provides evidence for a strong temperature enhancement over the polar outflows. Continuum emission (dust) is seen to be enhanced in the equatorial region. Observed asymmetries are briefly discussed. © 2015 National Astronomical Observatories, Chinese Academy of Sciences and IOP Publishing Ltd.


Nhung P.T.,Vietnam National Satellite Center | Hoai D.T.,Vietnam National Satellite Center | Diep P.N.,Vietnam National Satellite Center | Phuong N.T.,Vietnam National Satellite Center | And 3 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2016

Observations of 12CO(3-2) emission of the circumbinary envelope of Mira Ceti, made by Atacama Large Millimetre/sub-millimetre Array, are analysed. The observed Doppler velocity distribution is made of three components: a blueshifted south-eastern arc, which can be described as a ring in slow radial expansion, ∼1.7 km s-1, making an angle of ∼50° with the plane of the sky and born some 2000 years ago; a few arcs, probably born at the same epoch as the blueshifted arc, all sharing Doppler velocities redshifted by approximately 3±2 km s-1 with respect to the main star; thirdly, a central region dominated by the circumbinary envelope, displaying two outflows in the south-western and north-eastern hemispheres. At short distances from the star, up to ∼1.5 arcsec, these hemispheres display very different morphologies: the south-western outflow covers a broad solid angle, expands radially at a rate between 5 and 10 km s-1 and is slightly redshifted; the north-eastern outflow consists of two arms, both blueshifted, bracketing a broad dark regionwhere emission is suppressed. At distances between ∼1.5 and ∼2.5 arcsec the asymmetry between the two hemispheres is significantly smaller and detached arcs, particularly spectacular in the north-eastern hemisphere are present. Close to the stars, we observe a mass of gas surrounding Mira B, with a size of a few tens of au, and having Doppler velocities with respect to Mira B reaching ±1.5 km s-1, which we interpret as gas flowing from Mira A towards Mira B. © 2016 The Authors. Published by Oxford University Press on behalf of The Royal Astronomical Society.


Hoai D.T.,Vietnam National Satellite Center | Nhung P.T.,Vietnam National Satellite Center | Diep P.N.,Vietnam National Satellite Center | Phuong N.T.,Vietnam National Satellite Center | And 3 more authors.
Research in Astronomy and Astrophysics | Year: 2016

We analyse ALMA observations of the 12CO(3-2) emission of the circumstellar envelope (CSE) of the Mira variable binary star W Aql. These provide, for the first time, spatially resolved Doppler velocity spectra of the CSE up to angular distances to the central star of ∼ 5″ (meaning some 2000 AU). The exploratory nature of the observations (only five minutes in each of two different configurations) does not allow for a detailed modelling of the properties of the CSE but provides important qualitative information on its morphology and kinematics. Emission is found to be enhanced along an axis moving from east/west to north-east/south-west when the angular distance from the central star projected on the plane of the sky increases from zero to four arcseconds. In parallel, the Doppler velocity distribution displays asymmetry along an axis moving from east/west to north-west/south-east. The results are discussed in the context of earlier observations, in particular of the dust morphology. © 2016 National Astronomical Observatories, Chinese Academy of Sciences and IOP Publishing Ltd.


Nhung P.T.,Vietnam National Satellite Center | Hoai D.T.,Vietnam National Satellite Center | Diep P.N.,Vietnam National Satellite Center | Phuong N.T.,Vietnam National Satellite Center | And 3 more authors.
Research in Astronomy and Astrophysics | Year: 2016

Observations of the 12CO(3-2) emission from the circumstellar envelope (CSE) of the variable star π1 Gru using the compact array of the ALMA observatory have been recently made accessible to the public. An analysis of the morphology and kinematics of the CSE is presented with a result very similar to that obtained earlier for 12CO(2-1) emission using the Submillimeter Array. A quantitative comparison is made using their flared disk model. A new model is presented that provides a significantly better description of the data, using radial winds and smooth evolutions of the radio emission and wind velocity from the stellar equator to the poles. © 2016 National Astronomical Observatories, Chinese Academy of Sciences and IOP Publishing Ltd.

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