all astrophysics stories

Building a stellar time machine

50443248 — Mon, 06 Jul 2009 13:47:38 -0400

Harvard researchers are building a celestial time machine that lets astronomers look back at hundreds of thousands of objects in the Earth’s skies over the past century.

The effort aims to digitize 525,000 glass photographic plates taken at observing sites around the world between the 1880s and the 1980s. The collection, the largest such in the world, contains a treasure trove of largely unexamined data, according to Paine Professor of Practical Astronomy Jonathan Grindlay, who is leading the digitizing effort.

Visitors will gravitate to 'Black Holes' exhibit

50443248 — Thu, 18 Jun 2009 09:27:12 -0400

On Sunday, June 21, a new exhibit developed by educators and scientists at the Harvard-Smithsonian Center for Astrophysics (CfA) will open at the Boston Museum of Science.

Peculiar, junior-sized supernova discovered by New York teen

50443248 — Mon, 15 Jun 2009 15:20:44 -0400

In November 2008, Caroline Moore, a 14-year-old student from upstate New York, discovered a supernova in a nearby galaxy, making her the youngest person ever to do so. Additional observations determined that the object, called SN 2008ha, is a new type of stellar explosion, 1,000 times more powerful than a nova but 1,000 times less powerful than a supernova. Astronomers say that it may be the weakest supernova ever seen.

Kepler starts search for other Earths

50443248 — Wed, 13 May 2009 15:04:05 -0400

As NASA’s Kepler space telescope this week begins scanning the Milky Way for planets that might harbor life, scientists at the Harvard-Smithsonian Center for Astrophysics (CfA) are keeping their fingers crossed and waiting for the data to start flowing.

Life in the universe? Almost certainly. Intelligence? Maybe not

50443248 — Tue, 12 May 2009 13:56:00 -0400

We are likely not alone in the universe, though it may feel like it, since life on other planets is probably dominated by microbes or other nonspeaking creatures, according to scientists who gave their take on extraterrestrial life at Harvard recently.

Speakers reviewed how life on Earth arose and the many, sometimes improbable steps it took to create intelligence here. Radio astronomer Gerrit Verschuur said he believes that though there is very likely life out there — perhaps a lot of it — it is very unlikely to be both intelligent and able to communicate with us.

Charbonneau gets prestigious ‘young researcher’ award

50443248 — Wed, 04 Mar 2009 12:59:36 -0500

David Charbonneau, the 34-year-old Thomas D. Cabot Associate Professor of Astronomy, has been named the recipient of the National Science Foundation’s 2009 Alan T. Waterman Award, and will receive $500,000 over a three-year period for scientific research or advanced study in his field.

Strong evidence brown dwarfs form like stars

404132862 — Wed, 03 Dec 2008 10:12:32 -0500

Astronomers have uncovered strong evidence that brown dwarfs form like stars. Using the Smithsonian's Submillimeter Array (SMA), they detected molecules of carbon monoxide shooting outward from the object known as ISO-Oph 102. Such molecular outflows typically are seen coming from young stars or protostars. However, this object has an estimated mass of 60 Jupiters, meaning it is too small to be a star. Astronomers have classified it as a brown dwarf.

Solar system’s young twin has two asteroid belts

404132862 — Mon, 27 Oct 2008 14:35:03 -0400

Astronomers have discovered that the nearby star Epsilon Eridani has two rocky asteroid belts and an outer icy ring, making it a triple-ring system. The inner asteroid belt is a virtual twin of the belt in our solar system, while the outer asteroid belt holds 20 times more material. Moreover, the presence of these three rings of material implies that unseen planets confine and shape them.

White dwarf "sibling rivalry" explodes

404132862 — Thu, 01 Nov 2007 15:57:02 -0400

Astronomers at the Harvard-Smithsonian Center for Astrophysics (CfA) have found that a supernova discovered last year was caused by two colliding white dwarf stars. The white dwarfs were siblings orbiting each other. They slowly spiraled inward until they merged, touching off a titanic explosion. CfA observations show the strongest evidence yet of what was, until now, a purely theoretical mechanism for creating a supernova.

CfA reveals Magellanic Clouds are first-time visitors

50443248 — Mon, 01 Oct 2007 13:36:07 -0400

The Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) are two of the Milky Way’s closest neighboring galaxies. A stunning sight in the southern hemisphere, they were named after the Portuguese explorer Ferdinand Magellan, who explored those waters in the 16th century. For hundreds of years, these galaxies were considered satellites of the Milky Way, gravitationally bound to our home galaxy. But new research by Gurtina Besla of the Harvard-Smithsonian Center for Astrophysics (CfA) and her colleagues shows that the Magellanic Clouds are recent arrivals — on their first visit to the Milky Way’s neighborhood.

Negative vibes from space

70652986 — Mon, 26 Mar 2007 06:28:27 -0400

Astronomers have discovered the first negatively charged molecule in space, identifying it from radio signals that were a mystery until now. While about 130 neutral and 14 positively charged molecules are known to exist in interstellar space, this is the first negative molecule, or anion, to be found.

"We've spotted a rare and exotic species, like the white tiger of space," said astronomer Michael McCarthy of the Harvard- Smithsonian Center for Astrophysics.

By learning more about the rich broth of chemicals found in interstellar space, astronomers hope to explain how the young Earth converted these basic ingredients into the essential chemicals for life.

Astronomers nab culprit in galactic hit-and-run

70652986 — Mon, 26 Mar 2007 05:46:46 -0400

The Andromeda galaxy, the closest large spiral to the Milky Way, appears calm and tranquil as it wheels through space. But appearances can be deceiving. Astronomers have new evidence that Andromeda was involved in a violent head-on collision with the neighboring dwarf galaxy Messier 32 (M32) more than 200 million years ago.

"Like a CSI team, we gathered clues and reconstructed the scene of the crime," said Pauline Barmby (Harvard-Smithsonian Center for Astrophysics), a member of the research group that made the discovery. "The evidence clearly shows that M32 is guilty of committing a hit-and-run."

This discovery was reported in the Oct. 19, 2006, issue of the journal Nature.

Dramatic proof of the galactic smash-up came from images taken by the Infrared Array Camera (IRAC) on NASA's Spitzer Space Telescope. Those images revealed a never-before-seen dust ring deep within the Andromeda galaxy. When combined with a previously observed outer ring, the presence of both dust rings suggests a long-ago disturbance whose effects are still expanding outward through Andromeda.

Cosmic blast announces a future supernova

Thu, 12 Jul 2007 16:07:54 -0400

It's one thing to theorize about an exploding star the size of our sun, it's another to look up in the sky and watch one getting ready to blow.

Astronomers are now doing this.

On Feb. 12, a star known as RS Ophiuchi, some 8,000 trillion miles away, erupted in an explosion so bright it could be seen on Earth without a telescope. It was the star's sixth attention-getting blowout since 1898.

Using satellites and ground-based telescopes, observers from the Harvard-Smithsonian Center for Astrophysics (CfA) and their colleagues from other institutions caught the eruption near its maximum brightness. They measured high-energy X-rays, low-energy radio waves, and heat coming from the outburst.

Jupiter's 'big brother' has moon-forming dust disk

70652986 — Mon, 26 Mar 2007 06:27:45 -0400

Earth's moon was created by an early collision with another large planetary body. It was a "chip off the old block." Mars captured its asteroidal moons as they passed by. But Jupiter made its own moons out of dust and gas remaining from its formation. Now, observations by astronomer Subhanjoy Mohanty of the Harvard- Smithsonian Center for Astrophysics and his colleagues provide the first direct evidence for a dusty disk around a distant planet that in mass would be Jupiter's "big brother."

"It is quite possible that moons or moonlets could form out of this disk, just as they have around the giant planets in our own solar system," said Mohanty.

Mohanty presented the discovery June 5, 2006, in a press conference at the 208th meeting of the American Astronomical Society. Other members of the team are Ray Jayawardhana (University of Toronto), Nuria Huélamo (ESO) and Eric Mamajek (CfA).

The team studied a planetary mass object known as 2MASS1207-3932B, which is located about 170 light-years from Earth in the direction of the constellation Centaurus. 2M1207B, as it is abbreviated, orbits a tiny brown dwarf star at a separation of about 40 astronomical units, or 3.7 billion miles - comparable to the size of Pluto's orbit. That separation is much larger than typical for binary brown dwarf systems. The wide separation may indicate that the duo formed in relative isolation, far from passing stars that could have pulled them apart.

Neutron star swaps lead to short gamma-ray bursts

70652986 — Mon, 26 Mar 2007 06:24:31 -0400

Gamma-ray bursts are the most powerful explosions in the universe, emitting huge amounts of high-energy radiation. For decades their origin was a mystery. Scientists now believe they understand the processes that produce gamma-ray bursts. However, a new study by Jonathan Grindlay of the Harvard- Smithsonian Center for Astrophysics (CfA) and his colleagues, Simon Portegies Zwart (Astronomical Institute, The Netherlands) and Stephen McMillan (Drexel University), suggests a previously overlooked source for some gamma-ray bursts: stellar encounters within globular clusters.

"As many as one-third of all short gamma-ray bursts that we observe may come from merging neutron stars in globular clusters," said Grindlay.

Gamma-ray bursts (GRBs) come in two distinct "flavors." Some last up to a minute, or even longer. Astronomers believe those long GRBs are generated when a massive star explodes in a hypernova. Other bursts last for only a fraction of a second. Astronomers theorize that short GRBs originate from the collision of two neutrons stars, or a neutron star and a black hole.

Most double neutron star systems result from the evolution of two massive stars already orbiting each other. The natural aging process will cause both to become neutron stars (if they start with a given mass), which then spiral together over millions or billions of years until they merge and release a gamma-ray burst.

Grindlay's research points to another potential source of short GRBs - globular clusters. Globular clusters contain some of the oldest stars in the universe crammed into a tight space only a few light-years across. Such tight quarters provoke many close stellar encounters, some of which lead to star swaps. If a neutron star with a stellar companion (such as a white dwarf or main-sequence star) exchanges its partner with another neutron star, the resulting pair of neutron stars will eventually spiral together and collide explosively, creating a gamma-ray burst.

The paper announcing this finding was published in the Jan. 29, 2006 online issue of Nature Physics. It is available online at http: //www.nature.com/nphys/index.html and in preprint form at http://arxiv.org/abs/astro-ph/0512654.