Cornell-led team detects dust around a primitive star, shedding new light on universe's origins

January 16, 2009

ITHACA, N.Y. - A Cornell-led team of astronomers has observed dust forming around a dying star in a nearby galaxy, giving a glimpse into the early universe and enlivening a debate about the origins of all cosmic dust.

The findings are reported in the Jan. 16 issue of the journal Science (Vol. 323, No. 5912). Cornell research associate Greg Sloan led the study, which was based on observations with NASA's Spitzer Space Telescope. The researchers used Spitzer's Infrared Spectrograph, which was developed at Cornell.

Dust plays a key role in the evolution of such galaxies as our Milky Way. Stars produce dust - rich with carbon or oxygen - as they die. But less is known about how and what kind of dust was created in galaxies as they formed soon after the big bang.

Sloan and his colleagues observed dust forming around the carbon star MAG 29, located 280,000 light years away in a smaller nearby galaxy called the Sculptor Dwarf. Stars more massive than the sun end their lives as carbon stars, which in our galaxy are a rich source of dust.

The Sculptor Dwarf contains only 4 percent of the carbon and other heavy elements in our own galaxy, making it similar to primitive galaxies seen at the edge of the universe. Those galaxies emitted the light we now see soon after they and the universe formed.

"What this tells us is that carbon stars could have been pumping dust soon after the first galaxies were born," Sloan said.

Scientists have debated where the dust in the early universe comes from. Supernovae have been a favorite suspect, but they may destroy more dust than they create.

"While everyone is focused on the questions of how much and what kind of dust supernovae make, they may not have appreciated that carbon stars can make at least some of the dust we are seeing," Sloan said. "The more we can understand the quantity and composition of the dust, the better we can understand how stars and galaxies evolve, both in the early universe and right next door."

Observing such stars as MAG 29 is not unlike using a time machine, Sloan said, in which astronomers can catch glimpses of what the universe looked like billions of years ago.

"We haven't seen carbon-rich dust in this primitive of an environment before," Sloan said.

Cornell University Communications

---

---

	Galaxies by Seymour Simon (Author) This close-up look at our own Milky Way and other enormous clusters of stars describes the many different types of galaxies, how they were formed, and how they got their different shapes. "A dazzling photo-essay."--School Library Journal.
	Galaxies, Galaxies! by Gail Gibbons (Author) Planet Earth is in the Milky Way Galaxy, the cloudy band of light that stretches clear across the night sky. How many galaxies are there in the universe? For years astronomers thought that the Milky Way was the universe. Now we know that there are billions of them. Gail Gibbons takes the reader on a journey light-years away.
	Galaxies by Timothy Ferris (Author) Beyond the Milky Way and toward infinity, Timothy Ferris navigates an exploration of the universe, guided by stars and galaxies that have been photographed through telescopes at the greatest observatories in the world. The book celebrates the wonder and the power of the cosmos in these photographs, which take you through silvery star clusters and vast red, exploding nebulae toward blue quasars 15 billion light years away. Revealing not only the ingredients of our own galaxy, the Milky Way, Ferris' vivid text also visits local galaxies, such as the Magellanic Clouds, the Andromeda, and the Sculptor and Fornax dwarves. The author then proceeds to discuss the elliptical, spiral and even violent aspects of galaxies, concluding with an examination of cosmology, which adresses such subjects as...
	Galaxy Formation and Evolution by Houjun Mo (Author), Frank van den Bosch (Author), Simon White (Author) The rapidly expanding field of galaxy formation lies at the interface between astronomy, particle physics, and cosmology. Covering diverse topics from these disciplines, all of which are needed to understand how galaxies form and evolve, this book is ideal for researchers entering the field. Individual chapters explore the evolution of the Universe as a whole and its particle and radiation content; linear and nonlinear growth of cosmic structure; processes affecting the gaseous and dark matter components of galaxies and their stellar populations; the formation of spiral and elliptical galaxies; central supermassive black holes and the activity associated with them; galaxy interactions; and the intergalactic medium. Emphasizing both observational and theoretical aspects, this book provides...
	Cosmic Collisions: The Hubble Atlas of Merging Galaxies by Lars Lindberg Christensen (Author), Davide de Martin (Author), Raquel Yumi Shida (Author) Like no other telescope ever invented, the NASA/ESA Hubble Space Telescope has given us magnificent high resolution views of the gigantic cosmic collisions between galaxies. Hubble's images are snapshots in time and catch the colliding galaxies in different stages of collision. Thanks to a new and amazing set of 60 Hubble images, for the first time these different stages can be put together to form a still-frame movielike montage showing the incredible processes taking place as galaxies collide and merge. The significance of these cosmic encounters reaches far beyond aesthetics. Galaxy mergers may, in fact, be some of the most important processes that shape our universe. Colliding galaxies very likely, hold some of the most important clues to our cosmic past and to our destiny. It now...
	Universe: Stars and Galaxies by Roger A. Freedman (Author), William J. Kaufmann (Author) What astronomers know about our universe changes every day. For the past twenty years, Universe has been the most thrilling way to communicate the excitement of discovery in astronomy, to students of all scientific backgrounds. This edition of Universe which contains the full text of chapters 1-8 and 18-30 gives students the means to explore the stars and galaxies like never before. In addition to covering all the top discoveries, the text and accompanying CD contains spectacular images, captivating writing, and guides students on a fascinating journey around the cosmos and back again.
	Galaxies: A Very Short Introduction by John Gribbin (Author) In this fascinating Very Short Introduction, popular science writer John Gribben tells the story of our growing understanding of galaxies, from the days before Galileo to our present-day observations of our many hundreds of millions of galactic neighbors. Not only are galaxies fascinating astronomical structures in themselves, but their study has revealed much of what we know today about the cosmos, providing a window on the Big Bang and the origins of the Universe. Gribben looks at our own "Milky Way" Galaxy in detail, from the different kinds of stars that are born within it, to the origins of its magnificent spiral structure. Perhaps most interesting, Gribben describes the many exciting discoveries have been made about our own galaxy and about those beyond: how a supermassive black...
	Galaxies in the Universe: An Introduction by Linda S. Sparke (Author), John S. Gallagher III (Author) This extensively illustrated book presents the astrophysics of galaxies since their beginnings in the early Universe. It has been thoroughly revised to take into account the most recent observational data, and recent discoveries such as dark energy. There are new sections on galaxy clusters, gamma ray bursts and supermassive black holes. The authors explore the basic properties of stars and the Milky Way before working out towards nearby galaxies and the distant Universe. They discuss the structures of galaxies and how galaxies have developed, and relate this to the evolution of the Universe. The book also examines ways of observing galaxies across the whole electromagnetic spectrum, and explores dark matter and its gravitational pull on matter and light. This book is self-contained and...
	Stars and Galaxies by Michael A. Seeds (Author), Dana Backman (Author) With this newly revised Eighth Edition of STARS AND GALAXIES, the authors' goals are to help you use astronomy to understand science--and use science to understand what we are. Fascinating, engaging, and visually vibrant, this text will help you answer two fundamental questions: What are we? And how do we know?
	The Ultimate Hitchhiker's Guide to the Galaxy by Douglas Adams (Author), Neil Gaiman (Introduction) At last in paperback in one complete volume, here are the five classic novels from Douglas Adams’s beloved Hitchiker series. The Hitchhiker’s Guide to the Galaxy Seconds before the Earth is demolished for a galactic freeway, Arthur Dent is saved by Ford Prefect, a researcher for the revised Guide. Together they stick out their thumbs to the stars and begin a wild journey through time and space. The Restaurant at the End of the Universe Facing annihilation at the hands of warmongers is a curious time to crave tea. It could only happen to the cosmically displaced Arthur Dent and his comrades as they hurtle across the galaxy in a desperate search for a place to eat. Life, the Universe and Everything The unhappy inhabitants of planet Krikkit are sick of...