Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Double sun sunset no longer science fiction

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:

More articles from Physics and Astronomy:

nachricht First results of NSTX-U research operations
26.10.2016 | DOE/Princeton Plasma Physics Laboratory

nachricht Scientists discover particles similar to Majorana fermions
25.10.2016 | Chinese Academy of Sciences Headquarters

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: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Greater Range and Longer Lifetime

26.10.2016 | Power and Electrical Engineering

VDI presents International Bionic Award of the Schauenburg Foundation

26.10.2016 | Awards Funding

3-D-printed magnets

26.10.2016 | Power and Electrical Engineering

More VideoLinks >>>