An international team of astronomers using the worlds biggest telescopes have directly measured the mass of an ultra-cool brown dwarf star and its companion dwarf star for the first time. Barely the size of the planet Jupiter, the dwarf star weighs in at just 8.5 percent of the mass of our Sun. This is the first ever mass measurement of a dwarf star belonging to a new stellar class of very low mass ultra-cool dwarf stars. The observation is a major step towards our understanding of the types of objects that occupy the gap between the lightest stars and the heaviest planets.
This image shows the orbit of the brown dwarf around the ultra-cool L-dwarf. Each red dot on the orbit (in blue) corresponds to one observation made with a ground- or space-based telescope. The observations cover 60% of the whole orbit. Credit: ESA/NASA and Herve Bouy (Max-Planck-Institut für Extraterrestrische Physik/ESO, Germany)
Image credit: ESA/NASA and Herve Bouy (Max-Planck-Institut für Extraterrestrische Physik/ESO, Germany)
In 2000 the NASA/ESA Hubble Space Telescope detected a brown dwarf companion around the star named 2MASSW J0746425+2000321. In the subsequent four years the system was tracked by the NASA/ESA Hubble Space Telescope, the European Southern Observatory’s Very Large Telescope (Chile), the Gemini North (Hawaii) and the Keck Telescopes (Hawaii). The masses of the stars could be measured from the orbital motions of the two objects. With a mass of 8.5% of our Suns mass, the primary star is precariously close to the theoretical minimal fusion limit, which is 7.5 percent of our Suns mass. Objects below this limit are called brown dwarfs, failed stars or even super-planets, as their properties are more similar to those of large Jupiter-type planets than stars. The brown dwarf is measured to be 6.6 percent of the Suns mass, and thereby too puny to shine by nuclear fusion.
The mass measurements were made by an international team of astronomers led by Hervé Bouy from the Max-Planck-Institut für Extraterrestrische Physik/ESO, Germany and the Observatoire de Grenoble, France; Eduardo Martin (Instituto de Astrofisica de Canarias, Spain); and Wolfgang Brandner (Max Planck Institut für Astronomie, Germany).
Lars Christensen | ESA
Prediction: More gas-giants will be found orbiting Sun-like stars
22.02.2017 | Carnegie Institution for Science
NASA's fermi finds possible dark matter ties in andromeda galaxy
22.02.2017 | NASA/Goddard Space Flight Center
In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
23.02.2017 | Health and Medicine
23.02.2017 | Life Sciences
23.02.2017 | Life Sciences