We know of just over 50 close double white dwarfs but this was only the second ever eclipsing close white dwarf pair to be found. The University of Warwick astronomers Steven Parsons and Professor Tom Marsh were able to use the fact that the stars eclipse each other when seen from Earth to make particularly detailed observations of the system.
These observations revealed that uniquely both the white dwarf stars in this pairing are composed largely of helium. Most white dwarfs tend to have largely inert cores of carbon and oxygen that have formed over the star’s long life when it has used up most of its hydrogen and helium. Helium white dwarfs are a sure sign that the star has undergone some extreme mass loss at some point. To find two such helium white dwarfs stars is a clear sign to astronomers that both stars have had an exotic and mutually destructive past.
What was originally the most massive star of the pair had once actually began to expand to become a red giant but its outer hydrogen envelope was ripped off by its companion. This meant the star never got an opportunity to start fusing its helium and it was left as a helium white dwarf. When the companion star then began expanded it also had its expanding layer torn off by the first star - but as the first star was already reduced to a white dwarf it could not use that new material. That hydrogen was therefore simply lost to the star system leaving behind helium white dwarfs.
In just over 1 billion years, the two stars feud will end as they will spiral together and merge, finally igniting each other’s helium to become an object known as a hot subdwarf which should last for 100 million years
The University of Warwick researchers found this star system CSS 41177 (which is over 351 parsecs , or 1140 light years, away - in the constellation Leo) using a combination of data from the robotic 2m Liverpool Telescope in the Canary Islands and the 8m Gemini Telescope on Hawaii.
The full paper has been accepted for publication in the Astrophysical Journal and is entitled A deeply eclipsing detached double helium white dwarf binary Authors: S. G. Parsons, T. R. Marsh, B. T. Gänsicke, A. J. Drake, D. Koester
For further details please contact:Professor Tom Marsh
Professor Tom Marsh | EurekAlert!
'Frequency combs' ID chemicals within the mid-infrared spectral region
16.03.2018 | American Institute of Physics
Fraunhofer HHI have developed a novel single-polarization Kramers-Kronig receiver scheme
16.03.2018 | Fraunhofer-Institut für Nachrichtentechnik, Heinrich-Hertz-Institut, HHI
For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.
In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...
Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...
On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...
The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...
At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.
When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...
19.03.2018 | Event News
16.03.2018 | Event News
13.03.2018 | Event News
19.03.2018 | Event News
19.03.2018 | Information Technology
19.03.2018 | Interdisciplinary Research