Our stellar neighbourhood expands
Astronomers from the Observatory of the University of Hamburg were involved in the discovery of a new planet. As part of an international research team led by the Institut de Ciències de l'Espai (ICE, CSIC), they have found a planet in orbit of Barnard's star.
Barnard's star is a so-called red dwarf and after the Alpha-Centauri triple stellar system the second closest star to the Sun. As scientists reported in the current issue of Nature, they used astronomical observational data from about 20 years ago and combined it with new measurement data taken with the CARMENES planet-hunter spectrograph at Calar Alto/Spain among others.
The astronomers found significant evidence for a super-Earth with the size of 3.2 Earth masses, orbiting the red dwarf every 233 days. The new planet is at the so-called snowline of the star and is likely to be a frozen world.
Barnard's star is only six light-years from us and its velocity on Earth's night sky is the fastest of all stars which makes it noticeable also by hobby watchers. It is one of the least active red dwarfs known, smaller and with 7-10 billion years older than our Sun (about 4.6 billion years), and represents an ideal target to search for exoplanets.
Since 1997, several instruments gathered a large amount of measurements on the star’s subtle back and forth wobble. An analysis of the data collected up to 2015 suggested the wobble might be caused by a planet with an orbital period of about 230 days.
To confirm this theory, astronomers regularly monitored Barnard’s star using high-precision spectrometer such as the CARMENES planet-hunter spectrograph at the Calar Alto Observatory in Spain. The re-analysis of all 771 measurements detected a clear signal over a period of 233 days. This signal shows that Barnard's star is approaching and descending at about 1.2 meters per second in its shaking motion – which is about the speed of a person's gait. This was the first time that this type of exoplanet could be discovered with the so-called radial velocity method.
This discovery brought in the work of many scientists worldwide. "In Hamburg, we helped to redefine the mass of Barnard's star. Only then the measured speed of 1.2 meters per second can be used to determine the mass of the newly discovered planet," Andreas Schweitzer adds, co-author of the Hamburg Observatory of the University of Hamburg.
The newly discovered planet is called Barnard's star b (or GJ 699 b). It is a super-Earth, a large extrasolar planet with more than three times the mass of the Earth. He orbits his cool red home star near the so-called snow line – an orbit where water remains frozen. Therefore, in the absence of an atmosphere, the temperature is about -150 ° C, making the presence of liquid water on its surface unlikely.
"The discovery of a planet in our immediate neighborhood is a great motivation to continue to search for exoplanets surrounding neighboring stars and one day actually find a planet on which life would be possible," explains Andreas Schweitzer.
I. Ribas, M. Tuomi, A. Reiners, R. P. Butler, J. C. Morales, M. Perger, S. Dreizler, C. Rodríguez-López, J. I. González Hernández, A. Rosich, F. Feng, T. Trifonov, S. S. Vogt, J. A. Caballero, A. Hatzes, E. Herrero, S. V. Jeffers, M. Lafarga, F. Murgas, R. P. Nelson, E. Rodríguez, J. B. P. Strachan, L. Tal-Or, J. Teske, B. Toledo-Padrón, M. Zechmeister, A. Quirrenbach, P. J. Amado, M. Azzaro, V. J. S. Béjar, J. R. Barnes, Z. M. Berdiñas, J. Burt, G. Coleman, M. Cortés-Contreras, J. Crane, S. G. Engle, E. F. Guinan, C. A. Haswell, Th. Henning, B. Holden, J. Jenkins, H. R. A. Jones, A. Kaminski, M. Kiraga, M. Kürster, M. H. Lee, M. J. López-González, D. Montes, J. Morin, A. Ofir, E. Pallé, R. Rebolo, S. Reffert, A. Schweitzer, W. Seifert, S. A. Shectman, D. Staab, R. A. Street, A. Suárez Mascareño, Y. Tsapras, S. X. Wang, G. Anglada-Escudé, A super-Earth planet candidate orbiting at the snow-line of Barnard’s star, Nature (2018).
The radial velocity method
Precision spectrometers measuring the Doppler effect were used for the researches. The Doppler effect is a temporal compression or elongation of a signal with changes in the distance between transmitter and receiver. In everyday life, one knows the phenomenon that an approaching car sounds different than a departing vehicle. Now, if a stellar object moves away from the earth, the observed light becomes slightly less energetic and therefore redder. The light becomes energy-rich and blue as the star moves towards the Earth.
For more information
Hamburg Observatory of the University of Hamburg: https://www.hs.uni-hamburg.de
University of Hamburg
Phone: +49 40 42838-8416
University of Hamburg
Faculty of Mathematics, Informatics and Natural Sciences
Office of the dean
Phone: +49 40 42838-7193
University of Hamburg
Phone: +49 40 42838-8416
A super-Earth planet candidate orbiting at the snow-line of Barnard’s star, Nature (2018).
Birgit Kruse | idw - Informationsdienst Wissenschaft
Exotic spiraling electrons discovered by physicists
19.02.2019 | Rutgers University
Astronomers publish new sky map detecting hundreds of thousands of previously unknown galaxies
19.02.2019 | Universität Bielefeld
Up to now, OLEDs have been used exclusively as a novel lighting technology for use in luminaires and lamps. However, flexible organic technology can offer much more: as an active lighting surface, it can be combined with a wide variety of materials, not just to modify but to revolutionize the functionality and design of countless existing products. To exemplify this, the Fraunhofer FEP together with the company EMDE development of light GmbH will be presenting hybrid flexible OLEDs integrated into textile designs within the EU-funded project PI-SCALE for the first time at LOPEC (March 19-21, 2019 in Munich, Germany) as examples of some of the many possible applications.
The Fraunhofer FEP, a provider of research and development services in the field of organic electronics, has long been involved in the development of...
For the first time, an international team of scientists based in Regensburg, Germany, has recorded the orbitals of single molecules in different charge states in a novel type of microscopy. The research findings are published under the title “Mapping orbital changes upon electron transfer with tunneling microscopy on insulators” in the prestigious journal “Nature”.
The building blocks of matter surrounding us are atoms and molecules. The properties of that matter, however, are often not set by these building blocks...
Scientists at the University of Konstanz identify fierce competition between the human immune system and bacterial pathogens
Cell biologists from the University of Konstanz shed light on a recent evolutionary process in the human immune system and publish their findings in the...
Laser physicists have taken snapshots of carbon molecules C₆₀ showing how they transform in intense infrared light
When carbon molecules C₆₀ are exposed to an intense infrared light, they change their ball-like structure to a more elongated version. This has now been...
The so-called Abelian sandpile model has been studied by scientists for more than 30 years to better understand a physical phenomenon called self-organized...
11.02.2019 | Event News
30.01.2019 | Event News
16.01.2019 | Event News
20.02.2019 | Life Sciences
20.02.2019 | Medical Engineering
20.02.2019 | Power and Electrical Engineering