Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Double sun sunset no longer science fiction

24.01.2007
During the last decade, the discovery of planets around stars other than the Sun has revealed a variety of kinds of planets, orbits, and systems, often very different to our Solar System.

One of the most interesting examples are those of stars accompanied not only by planets, but also by other stars, making double "Sun" sunsets, and sunrises, no longer science fiction. A research team from the University of Jena (Germany) has recently made interesting discoveries at Calar Alto by performing a systematic search for such systems.

Since the discovery in 1995 of the first extrasolar planet around a normal star (51 Pegasi), it has become evident that there exists an unexpected diversity of planetary systems, most of them very different to our Solar System. First, it was found that there are many massive planets placed extremely close to their parent stars: the so-called "hot Jupiters". This is very different from what we observe in the Solar System, where massive planets are located far away from the Sun, and this finding required a revision of the theories of planetary formation. Second, it was shown that the process of planetary formation is not restricted to single stars as our Sun: indeed, under certain circumstances, it is possible to form planets around binary stars, which are a much more dynamically complex environment than our own Solar System.

A binary star is a physical system formed by two stars circling around their common center of mass. There is a wide diversity of such couples, often formed by stars of similar mass, but there are also may examples of binary systems with components of very different masses. The Star and Planet Formation subgroup of the Astrophysical Institute of the University of Jena (AIU) has recently been looking hard into candidate systems that might allow the existence of planets surrounding binary stars. Their search, carried out by Ralph Neuhäuser and Markus Mugrauer, makes use of the sharpest possible images of these stars and their immediate surroundings in order to identify faint neighbors (that could be potentially associated with the system). To get images of extreme sharpness it is necessary to compensate the blurring effect of the atmosphere (which make stars twinkle) and this can be achieved thanks to adaptive optics, or other techniques such as speckle imaging, both available at Calar Alto. The potential companions detected this way are later studied in detail to confirm their true physical association to the planet-hosting star, by discarding the possibility that they are simple chance alignments of unrelated objects at different distances.

Infrared images of the gamma Cephei system obtained from Calar alto on September the 11th (left) and 12th (right) 2006. The bright, A component would be located at the center of both images, but it has been digitally subtracted to reveal the position of the faint, B component, marked with an arrow.

One of their recent findings refers to a quite bright star, gamma Cephei (gamma Cephei), a star with a planet (gamma Cephei Ab) with a minimum mass 1.7 times that of planet Jupiter and with a period of around 3 years. From previous spectroscopic studies this star is known to also have a low-mass stellar companion (gamma Cephei B) orbiting the brighter component. This team has now been able to get the first direct images of the secondary star which allow to significantly improve the determination of physical parameters of the gamma Cephei system. The observations were obtained both with the Japanese telescope Subaru (placed at Mauna Kea, Hawaii), and with the instrument Omega-Cass attached to the 3.5 m telescope of Calar Alto (Spain). The observations at Mauna Kea were obtained by Misato Fukagawa (Nagoya University) in June 2006, and at Calar Alto by Markus Mugrauer and Tobias Schmidt (both AIU Jena) in September 2006.

The two stars in the gamma Cephei system are separated by an average distance only 20 times the distance from the Earth to the Sun making this system one of the closest planet hosting binary systems presently known. It is composed of the central bright subgiant star gamma Cephei A, which is more massive than our Sun (1.4 solar masses), the secondary star gamma Cephei B which is smaller than half the mass of the Sun (0.4 solar masses) and a planetary companion, circling the primary star.

Imagine a "Sun" and a failed "Sun" sunset

Another outstanding discovery by the same team using Calar Alto telescopes, is that of the companion to the star HD 3651. HD 3651 is a nearby faint, red star, known to have a sub-Saturn-mass planet. This team discovered that the very faint companion is in fact a cool brown dwarf, the first brown dwarf directly imaged as companion to an exoplanet host star. Observations performed with the instrument Omega-Cass at the 3.5 m telescope of Calar Alto in September 2006, helped to demonstrate the link between HD 3651 and this small substellar object (now called HD 3651 B), and to determine its physical characteristics. The faint companion of the planet host star HD 3651 is one of the coolest brown dwarfs presently known (effective temperature ranging between 500o and 600o C).

The same research team has used several instruments and telescopes to find faint companions to planet host stars. In the course of their campaigns, they have found secondary objects with masses from 0.5 to 0.075 the mass of the Sun, in the substellar-stellar mass border. Two companions turned out to be white dwarf stars, an evolved kind of object whose existence in planet-harboring systems implies new restrictions to the theories that explain the formation of planets.

Science fiction needs to catch up!

Joao Alves | alfa
Further information:
http://www.caha.es

More articles from Physics and Astronomy:

nachricht Engineering team images tiny quasicrystals as they form
18.08.2017 | Cornell University

nachricht Astrophysicists explain the mysterious behavior of cosmic rays
18.08.2017 | Moscow Institute of Physics and Technology

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Nagoya physicists resolve long-standing mystery of structure-less transition

21.08.2017 | Materials Sciences

Chronic stress induces fatal organ dysfunctions via a new neural circuit

21.08.2017 | Health and Medicine

Scientists from the MSU studied new liquid-crystalline photochrom

21.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>