An international team of astronomers, led by Hervé Bouy from the Max Planck Institute, Garching, Germany and the Observatoire de Grenoble, France, have for the first time measured the mass of an ultra-cool brown dwarf star. The team performed the measurements using four of the most powerful telescopes available. This is the first-ever mass measurement of an L-type star belonging to the new stellar class of very low-mass stars, discovered a few years ago. With a mass of 6.6% of the solar mass, this celestial object is a "failed" star, lying between stars and planets in the evolutionary scheme.
Making use of four of the most famous telescopes worldwide, an international team of astronomers made the first-ever direct measurement of the mass of a so-called L-type star. The star, named 2MASSW J0746425+2000321, is a binary star that was observed for four years with the ESO Very Large Telescope (Chile), the Keck and Gemini Telescopes (Hawaii), and the Hubble Space Telescope.
Precise observations of each component of the binary system were required to be able to compute their masses. As both stars are very close to each other, telescopes providing high-resolution images were needed. Additionally, observations had to be performed over a long period of time (four years) to follow the motion of both stars around each other. Very accurate measurements of the relative position of the individual components were made, so that the full orbit of the binary system could be reconstructed, as illustrated in the following picture. Once the orbit was known, the astronomers were able to compute the total mass of the system using Keplers laws. In addition, very precise measurements of the brightness of each star were needed to be able to compute the individual mass of each component of the system. The astronomers calculated the mass ratio of the system from these brightness measurements, using the theoretical models by G. Chabrier and collaborators (Centre de Recherche Astronomique de Lyon, France). Finally, the mass of each component could be determined.
Jennifer Martin | alfa
A new force for optical tweezers awakens
19.06.2019 | University of Gothenburg
View of the Earth in front of the Sun
19.06.2019 | Georg-August-Universität Göttingen
The quality of additively manufactured components depends not only on the manufacturing process, but also on the inline process control. The process control ensures a reliable coating process because it detects deviations from the target geometry immediately. At LASER World of PHOTONICS 2019, the Fraunhofer Institute for Laser Technology ILT will be demonstrating how well bi-directional sensor technology can already be used for Laser Material Deposition (LMD) in combination with commercial optics at booth A2.431.
Fraunhofer ILT has been developing optical sensor technology specifically for production measurement technology for around 10 years. In particular, its »bd-1«...
The well-known representation of chemical elements is just one example of how objects can be arranged and classified
The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...
Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.
Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...
Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.
The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...
Discovery by Brazilian and US researchers could change the classification of two species, which appear more akin to jellyfish than was thought.
The tube anemone Isarachnanthus nocturnus is only 15 cm long but has the largest mitochondrial genome of any animal sequenced to date, with 80,923 base pairs....
29.04.2019 | Event News
17.04.2019 | Event News
15.04.2019 | Event News
19.06.2019 | Materials Sciences
19.06.2019 | Health and Medicine
19.06.2019 | Materials Sciences