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
First evidence on the source of extragalactic particles
13.07.2018 | Technische Universität München
Simpler interferometer can fine tune even the quickest pulses of light
12.07.2018 | University of Rochester
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
13.07.2018 | Event News
13.07.2018 | Materials Sciences
13.07.2018 | Life Sciences