Jupiter-like Planets Could Form Around Twin Suns

January 06, 2009

Life on a planet ruled by two suns might be a little complicated. Two sunrises, two sunsets. Twice the radiation field.

In a paper published in the December 2008 issue of Astronomy and Astrophysics, astronomer Joel Kastner and his team suggest that planets may easily form around certain types of twin (or "binary") star systems. A disk of molecules discovered orbiting a pair of twin young suns in the constellation Sagittarius strongly suggests that many such binary systems also host planets.

"We think the molecular gas orbiting these two stars almost literally represents 'smoking gun' evidence of recent or possibly ongoing 'giant' (Jupiter-like) planet formation around the binary star system," says Kastner, professor at Rochester Institute of Technology's Chester F. Carlson Center for Imaging Science.

Kastner used the 30-meter radiotelescope operated by the Institut de Radio Astronomie Millimetrique (IRAM) to study radio molecular spectra emitted from the vicinity of the two stars in a binary system called V4046 Sgr, which lies about 210 light-years away from our solar system. (V4046 Sgr is the 4046th brightest variable-brightness star in the constellation Sagittarius.) The scientists found "in large abundance" raw materials for planet formation around the nearby stars, including circumstellar carbon monoxide and hydrogen cyanide, in the noxious molecular gas cloud.

The young stars, approximately 10 million years old, are close in proximity to each other-only 10 solar diameters apart-and orbit each other once every 2.5 days.

"In this case the stars are so close together, and the profile of the gas in terms of the types of molecules that are there is so much like the types of gaseous disks that we see around single stars, that it's a real link between planets forming around single stars and planets forming around double stars," Kastner says.

Planets that have just formed around young stars like the V4046 Sgr twins might leave leftover gas, a potential clue for astronomers who hunt planets.

Recently, direct imaging of planets orbiting the single stars Fomalhaut and HR 8799 irrefutably confirmed the existence of exosolar planets-those that orbit stars other than our Sun. In the spring, Kastner hopes to use IRAM to look for gas left over from the formation of the planets orbiting HR 8799.

Kastner hopes to compare the molecular profile in the gas remnants surrounding the single star (HR 8799) with the gas composition surrounding the dual star-system (V4046 Sgr).

Not a planet hunter himself, Kastner encourages other scientists to look closely at V4046 Sgr to see if planets are forming around them.

"We really don't have any idea right now about what kinds of planets form around double stars or even if planets can form around double stars," Kastner says. "It's not something that's established. It's theoretically possible, but I'm not aware of a single observation yet of a planet orbiting a double star. I hope someone will go looking soon, if they haven't already, around V4046 Sagittarius."

Rochester Institute of Technology

---

---

	Astrophysics of Planet Formation by Philip J. Armitage (Author) The study of planet formation has been revolutionized by recent observational breakthroughs, which have allowed the detection and characterization of extrasolar planets, the imaging of protoplanetary disks, and the discovery of the Solar System's Kuiper Belt. Written for beginning graduate students, this textbook provides a basic understanding of the astrophysical processes that shape the formation of planetary systems. It begins by describing the structure and evolution of protoplanetary disks, moves on to the formation of planetesimals, terrestrial and gas giant planets, and concludes by surveying new theoretical ideas for the early evolution of planetary systems. Covering all phases of planet formation - from protoplanetary disks to the dynamical evolution of planetary systems - this...
	Planet Formation: Theory, Observations, and Experiments (Cambridge Astrobiology) by Wolfgang Brandner (Author), Hubert Klahr (Editor) When this book was published in 2006, it had been just over ten years since the first planet outside our solar system was detected. Since then, much work has focused on understanding how extrasolar planets may form, and discovering the frequency of potentially habitable Earth-like planets. This volume addresses fundamental questions concerning the formation of planetary systems in general, and of our solar system in particular. Drawing from advances in observational, experimental and theoretical research, it summarises our understanding of the planet formation processes, and addresses major open questions and research issues. Chapters are written by leading experts in the field of planet formation and extrasolar planet studies. The book is based on a meeting held at Ringberg Castle in...
	The Formation and Early Evolution of Stars: From Dust to Stars and Planets (Astronomy and Astrophysics Library) by Norbert S. Schulz (Author) Starburst regions in nearby and distant galaxies have a profound impact on our understanding of the early universe. This new, substantially updated and extended edition of Norbert Schulz’s unique book "From Dust to Stars" describes complex physical processes involved in the creation and early evolution of stars. It illustrates how these processes reveal themselves from radio wavelengths to high energy X-rays and gamma–rays, with special reference towards high energy signatures. Several sections devoted to key analysis techniques demonstrate how modern research in this field is pursued and new chapters are introduced on massive star formation, proto-planetary disks and observations of young exoplanets. Recent advances and contemporary research on the theory of star formation are...
	Lonely Planet 1000 Ultimate Sights by Lonely Planet (Author) Where do you start? Iconic buildings, awesome canyons, weird monuments, vast animal migrations, spooky dungeons and romantic vistas are just some of the man-made marvels and natural wonders in 1000 Ultimate Sights. Make your own list, hit the road, and start exploring the world's most breathtaking sights. Natural phenomena, including the bubbling Pitch Lake of Trinidad. Architectural masterpieces, including the ground-breaking Sagrada Familia in Spain. Wildlife spectacles, including the Elephant Gathering of Sri Lanka. Historic sights, such as the magnificent ruins at Volubilis, Morocco. Cultural icons, including the Giant Buddha of Leshan, China.
	Origins: How the Planets, Stars, Galaxies, and the Universe Began (Astronomers' Universe) by Steve Eales (Author) This book looks at answers to the biggest questions in astronomy – the questions of how the planets, stars, galaxies and the universe were formed. Over the last decade, a revolution in observational astronomy has produced possible answers to three of these questions. This book describes this revolution. The one question for which we still do not have an answer is the question of the origin of the universe. In the final chapter, the author looks at the connection between science and philosophy and shows how new scientific results have laid the groundwork for the first serious scientific studies of the origin of the universe.
	Physics, Formation and Evolution of Rotating Stars (Astronomy and Astrophysics Library) by Andre Maeder (Author) Rotation is ubiquitous at each step of stellar evolution, from star formation to the final stages, and it affects the course of evolution, the timescales and nucleosynthesis. Stellar rotation is also an essential prerequisite for the occurrence of Gamma-Ray Bursts. In this book the author thoroughly examines the basic mechanical and thermal effects of rotation, their influence on mass loss by stellar winds, the effects of differential rotation and its associated instabilities, the relation with magnetic fields and the evolution of the internal and surface rotation. Further, he discusses the numerous observational signatures of rotational effects obtained from spectroscopy and interferometric observations, as well as from chemical abundance determinations, helioseismology and...
	Extra-Solar Planets: The Detection, Formation, Evolution and Dynamics of Planetary Systems (Scottish Graduate Series) by Bonnie Steves (Editor), Martin Hendry (Editor), Andrew C. Cameron (Editor) Since the discovery of the first exoplanet orbiting a main sequence star in 1995, nearly 500 planets have been detected, with this number expected to increase dramatically as new ground-based planetary searches begin to report their results. Emerging techniques offer the tantalizing possibility of detecting an Earth-mass planet in the habitable zone of a solar-type star as well as the exciting prospect of studying exoplanetary atmospheres that could reveal the presence of biomarkers, such as water vapor, oxygen, and carbon dioxide. Can we find the "Holy Grail" of exoplanets? Cutting-edge research may reveal the answer Written by internationally renowned scientists at the forefront of the field, Extra-Solar Planets: The Detection, Formation, Evolution and Dynamics of Planetary Systems...
	Planetary Systems: Detection, Formation and Habitability of Extrasolar Planets (Astronomy and Astrophysics Library) by Marc Ollivier (Author), Thérèse Encrenaz (Author), Francoise Roques (Author), Franck Selsis (Author), Fabienne Casoli (Author) Over the past ten years, the discovery of extrasolar planets has opened a new field of astronomy, and this area of research is rapidly growing, from both the observational and theoretical point of view. The presence of many giant exoplanets in the close vicinity of their star shows that these newly discovered planetary systems are very different from the solar system. New theoretical models are being developed in order to understand their formation scenarios, and new observational methods are being implemented to increase the sensitivity of exoplanet detections. In the present book, the authors address the question of planetary systems from all aspects. Starting from the facts (the detection of more than 300 extraterrestrial planets), they first describe the various methods used for...
	Planetary Formation and Biogenesis (Elements of Theory) by Ian Miller Why is our solar system different from most of the others we see? How common are planets like Earth that have life on them? Is there life under the ice of Europa? Why will alien life have similar systems to ours? How did we get homochirality, and more to the point, why? Planetary Formation and Biogenesis is the second ebook in my series Elements of Theory, which is designed to illustrate how to form a theory by inducing from the set of observations. There is a review of the literature with over 700 references, most presenting different aspects. This review shows there are significant problems with standard theory, including: there is no known mechanism to form the required planetesimals, there are no explanations for the fact that all the planets in our system are different from each...
	Formation and Evolution of Exoplanets by Rory Barnes (Editor) This single, coherent review of the theory behind extrasolar planet formation and interaction systematically covers all aspects of the topic, including different formation processes, planet-planet scattering, giant planets and brown dwarfs. With a chapter on observation, careful referencing and an elaborate bibliography at the end of each chapter, this is indispensable reading for researchers, theorists and observers alike.