Science Current Events | Science News | Brightsurf.com
 

Some Stars Capture Rogue Planets

April 18, 2012
Cambridge, MA - New research suggests that billions of stars in our galaxy have captured rogue planets that once roamed interstellar space. The nomad worlds, which were kicked out of the star systems in which they formed, occasionally find a new home with a different sun. This finding could explain the existence of some planets that orbit surprisingly far from their stars, and even the existence of a double-planet system.

"Stars trade planets just like baseball teams trade players," said Hagai Perets of the Harvard-Smithsonian Center for Astrophysics.

The study, co-authored by Perets and Thijs Kouwenhoven of Peking University, China, will appear in the April 20th issue of The Astrophysical Journal.

To reach their conclusion, Perets and Kouwenhoven simulated young star clusters containing free-floating planets. They found that if the number of rogue planets equaled the number of stars, then 3 to 6 percent of the stars would grab a planet over time. The more massive a star, the more likely it is to snag a planet drifting by.

They studied young star clusters because capture is more likely when stars and free-floating planets are crowded together in a small space. Over time, the clusters disperse due to close interactions between their stars, so any planet-star encounters have to happen early in the cluster's history.

Rogue planets are a natural consequence of star formation. Newborn star systems often contain multiple planets. If two planets interact, one can be ejected and become an interstellar traveler. If it later encounters a different star moving in the same direction at the same speed, it can hitch a ride.

A captured planet tends to end up hundreds or thousands of times farther from its star than Earth is from the Sun. It's also likely to have a orbit that's tilted relative to any native planets, and may even revolve around its star backward.

Astronomers haven't detected any clear-cut cases of captured planets yet. Imposters can be difficult to rule out. Gravitational interactions within a planetary system can throw a planet into a wide, tilted orbit that mimics the signature of a captured world.

Finding a planet in a distant orbit around a low-mass star would be a good sign of capture, because the star's disk wouldn't have had enough material to form the planet so far out.

The best evidence to date in support of planetary capture comes from the European Southern Observatory, which announced in 2006 the discovery of two planets (weighing 14 and 7 times Jupiter) orbiting each other without a star.

"The rogue double-planet system is the closest thing we have to a 'smoking gun' right now," said Perets. "To get more proof, we'll have to build up statistics by studying a lot of planetary systems."

Could our solar system harbor an alien world far beyond Pluto? Astronomers have looked, and haven't found anything yet.

"There's no evidence that the Sun captured a planet," said Perets. "We can rule out large planets. But there's a non-zero chance that a small world might lurk on the fringes of our solar system."

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.

Harvard-Smithsonian Center for Astrophysics


Related Astrophysics Current Events and Astrophysics News Articles


Astronomers discover likely precursors of galaxy clusters we see today
By combining observations of the distant Universe made with ESA's Herschel and Planck space observatories, cosmologists have discovered what could be the precursors of the vast clusters of galaxies that we see today.

Planck: An 'unfocused' eye that sees the big picture
"Planck detects, then Herschel analyzes". That's how Gianfranco De Zotti, professor at the International School for Advanced Studies (SISSA) in Trieste and at INAF-Astronomical Observatory of Padova, summarizes the rationale of the study just published in Astronomy & Astrophysics.

As stars form, magnetic fields influence regions big and small
Stars form when gravity pulls together material within giant clouds of gas and dust. But gravity isn't the only force at work.

Extent of moon's giant volcanic eruption is revealed
Scientists have produced a new map of the Moon's most unusual volcano showing that its explosive eruption spread debris over an area much greater than previously thought.

Iron rain fell on early Earth, new Z machine data supports
Researchers at Sandia National Laboratories' Z machine have helped untangle a long-standing mystery of astrophysics: why iron is found spattered throughout Earth's mantle, the roughly 2,000-mile thick region between Earth's core and its crust.

More than a million stars are forming in a mysterious dusty gas cloud in a nearby galaxy
More than a million young stars are forming in a hot, dusty cloud of molecular gases in a tiny galaxy near our own, an international team of astronomers has discovered.

Planets in the habitable zone around most stars, calculate researchers
Astronomers have discovered thousands of exoplanets in our galaxy, the Milky Way, using the Kepler satellite and many of them have multiple planets orbiting the host star.

Frozen highly charged ions for highest precision spectroscopy
A team of researchers from the Max Planck Institute for Nuclear Physics in Heidelberg, the Physikalisch-Technische Bundesanstalt in Braunschweig and the University of Aarhus in Denmark demonstrated for the first time Coulomb crystallization of highly-charged ions (HCIs).

Particle jets reveal the secrets of the most exotic state of matter
Shortly following the Big Bang, the Universe was filled with a chaotic primordial soup of quarks and gluons, particles which are now trapped inside of protons and neutrons.

Queen's astronomers discover fastest ever unbound star in our galaxy
A fast-moving unbound star discovered by astronomers at Queen's University Belfast has broken the galactic speed record.
More Astrophysics Current Events and Astrophysics News Articles

Death by Black Hole: And Other Cosmic Quandaries

Death by Black Hole: And Other Cosmic Quandaries
by Neil deGrasse Tyson (Author)


“[Tyson] tackles a great range of subjects . . . with great humor, humility, and—most important— humanity.” —Entertainment Weekly Loyal readers of the monthly "Universe" essays in Natural History magazine have long recognized Neil deGrasse Tyson's talent for guiding them through the mysteries of the cosmos with clarity and enthusiasm. Bringing together more than forty of Tyson's favorite essays, ?Death by Black Hole? explores a myriad of cosmic topics, from what it would be like to be inside a black hole to the movie industry's feeble efforts to get its night skies right. One of America's best-known astrophysicists, Tyson is a natural teacher who simplifies the complexities of astrophysics while sharing his infectious fascination for our...

Introduction to Astrophysics: The Stars (Dover Books on Physics)

Introduction to Astrophysics: The Stars (Dover Books on Physics)
by Jean Dufay (Author), Owen Gingerich (Translator)


A bridge between introductory and advanced technical treatments, this readable and authoritative translation from the French provides an excellent guide to observational astrophysics. Physics students and professionals will appreciate the text's mid-level approach, in which methods of research and observation receive as much attention as results.
Confining his discussion to normal stars, the author examines current methods of stellar photometry and spectroscopy and the main results of research involving star classification and properties. Additional topics include construction of Hertzsprung-Russell diagrams, Yerkes two-dimensional classification, masses and densities of stars, general theories about the constitution of stellar atmospheres and the evolution of stars, and much more....

The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory

The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory
by Brian Greene (Author)


The international bestseller that inspired a major Nova special and sparked a new understanding of the universe, now with a new preface and epilogue. Brian Greene, one of the world's leading string theorists, peels away layers of mystery to reveal a universe that consists of eleven dimensions, where the fabric of space tears and repairs itself, and all matter—from the smallest quarks to the most gargantuan supernovas—is generated by the vibrations of microscopically tiny loops of energy. The Elegant Universe makes some of the most sophisticated concepts ever contemplated accessible and thoroughly entertaining, bringing us closer than ever to understanding how the universe works.

A Brief History of Time

A Brief History of Time
by Stephen Hawking (Author)


#1 NEW YORK TIMES BESTSELLER

A landmark volume in science writing by one of the great minds of our time, Stephen Hawking’s book explores such profound questions as: How did the universe begin—and what made its start possible? Does time always flow forward? Is the universe unending—or are there boundaries? Are there other dimensions in space? What will happen when it all ends?

Told in language we all can understand, A Brief History of Time plunges into the exotic realms of black holes and quarks, of antimatter and “arrows of time,” of the big bang and a bigger God—where the possibilities are wondrous and unexpected. With exciting images and profound imagination, Stephen Hawking brings us closer to the ultimate secrets at the very heart of...

An Introduction to Modern Astrophysics (2nd Edition)

An Introduction to Modern Astrophysics (2nd Edition)
by Bradley W. Carroll (Author), Dale A. Ostlie (Author)


An Introduction to Modern Astrophysics, Second Edition has been thoroughly revised to reflect the dramatic changes and advancements in astrophysics that have occurred over the past decade. The Second Edition of this market-leading book has been updated to include the latest results from relevant fields of astrophysics and advances in our theoretical understanding of astrophysical phenomena. The Tools of Astronomy: The Celestial Sphere, Celestial Mechanics, The Continuous Spectrum of Light, The Theory of Special Relativity, The Interaction of Light and Matter, Telescopes; The Nature of Stars: Binary Systems and Stellar Parameters, The Classification of Stellar Spectra, Stellar Atmospheres, The Interiors of Stars, The Sun, The Process of Star Formation, Post-Main-Sequence Stellar...

Astrophysics is Easy!: An Introduction for the Amateur Astronomer (The Patrick Moore Practical Astronomy Series)

Astrophysics is Easy!: An Introduction for the Amateur Astronomer (The Patrick Moore Practical Astronomy Series)
by Michael Inglis (Author)


Astrophysics is often - with some justification - regarded as incomprehensible without at least degree-level mathematics. Consequently, many amateur astronomers skip the math, and miss out on the fascinating fundamentals of the subject. In Astrophysics Is Easy! Mike Inglis takes a quantitative approach to astrophysics that cuts through the incomprehensible mathematics, and explains the basics of astrophysics in accessible terms. The reader can view objects under discussion with commercial amateur equipment.

The Science of Interstellar

The Science of Interstellar
by Kip Thorne (Author), Christopher Nolan (Foreword)


A journey through the otherworldly science behind Christopher Nolan’s highly anticipated film, Interstellar, from executive producer and theoretical physicist Kip Thorne.Interstellar, from acclaimed filmmaker Christopher Nolan, takes us on a fantastic voyage far beyond our solar system. Yet in The Science of Interstellar, Kip Thorne, the physicist who assisted Nolan on the scientific aspects of Interstellar, shows us that the movie’s jaw-dropping events and stunning, never-before-attempted visuals are grounded in real science. Thorne shares his experiences working as the science adviser on the film and then moves on to the science itself. In chapters on wormholes, black holes, interstellar travel, and much more, Thorne’s scientific insights—many of them triggered during the actual...

Astrophysics and the Evolution of the Universe

Astrophysics and the Evolution of the Universe
by Leonard S Kisslinger (Author)


The aim of this book is to teach undergraduate college or university students the basic physics concepts needed to understand the mathematics which describes the evolution of the universe, and based on this to teach the astrophysical theories behind evolution from very early times to the present. The book does not require students to have extensive knowledge of mathematics, like calculus, and includes material that explains concepts such as velocity, acceleration, and force. Based on this, fascinating topics such as Dark Matter, measuring Dark Energy via supernovae velocities, and the creation of mass via the Higgs mechanism are explained. All college students with an interest in science, especially astronomy, without extensive mathematical backgrounds should be able to use and learn from...

Astrophysics for Physicists

Astrophysics for Physicists
by Arnab Rai Choudhuri (Author)


Designed for teaching astrophysics to physics students at advanced undergraduate or beginning graduate level, this textbook also provides an overview of astrophysics for astrophysics graduate students, before they delve into more specialized volumes. Assuming background knowledge at the level of a physics major, the textbook develops astrophysics from the basics without requiring any previous study in astronomy or astrophysics. Physical concepts, mathematical derivations and observational data are combined in a balanced way to provide a unified treatment. Topics such as general relativity and plasma physics, which are not usually covered in physics courses but used extensively in astrophysics, are developed from first principles. While the emphasis is on developing the fundamentals...

The Fabric of the Cosmos: Space, Time, and the Texture of Reality

The Fabric of the Cosmos: Space, Time, and the Texture of Reality
by Brian Greene (Author)


From Brian Greene, one of the world’s leading physicists and author the Pulitzer Prize finalist The Elegant Universe, comes a grand tour of the universe that makes us look at reality in a completely different way.

Space and time form the very fabric of the cosmos. Yet they remain among the most mysterious of concepts. Is space an entity? Why does time have a direction? Could the universe exist without space and time? Can we travel to the past? Greene has set himself a daunting task: to explain non-intuitive, mathematical concepts like String Theory, the Heisenberg Uncertainty Principle, and Inflationary Cosmology with analogies drawn from common experience. From Newton’s unchanging realm in which space and time are absolute, to Einstein’s fluid conception of...

© 2015 BrightSurf.com