This spectacular image of the star cluster Messier 47 was taken using the Wide Field Imager camera, installed on the MPG/ESO 2.2-meter telescope at ESO’s La Silla Observatory in Chile. This young open cluster is dominated by a sprinkling of brilliant blue stars but also contains a few contrasting red giant stars.
The MPG/ESO 2.2-meter telescope at ESO’s La Silla Observatory in Chile captured this richly colorful view of the bright star cluster NGC 3532. Some of the stars still shine with a hot bluish color, but many of the more massive ones have become red giants and glow with a rich orange hue.
The largest interstellar dust track found in the Stardust aerogel collectors was this 35 micron-long hole produced by a 3 picogram speck of dust that was probably traveling so fast that it vaporized upon impact. The other two likely interstellar dust grains were traveling more slowly and remained intact after a soft landing in the aerogel.
Seven rare, microscopic interstellar dust particles that date to the beginnings of the solar system are among the samples collected by scientists who have been studying the payload from NASA's Stardust spacecraft since its return to Earth in 2006. If confirmed, these particles would be the first samples of contemporary interstellar dust.
A team of scientists has been combing through the spacecraft's aerogel and aluminum foil dust collectors since Stardust returned in 2006.The seven particles probably came from outside our solar system, perhaps created in a supernova explosion millions of years ago and altered by exposure to the extreme space environment. The particles would be the first confirmed samples of contemporary interstellar dust.
The research report appears in the August 15 issue of the journal Science. Twelve other papers about the particles will appear next week in the journal Meteoritics & Planetary Science.
"These are the most challenging objects we will ever have in the lab for study, and it is a triumph that we have made as much progress in their analysis as we have," said Michael Zolensky, curator of the Stardust laboratory at NASA's Johnson Space Center in Houston and coauthor of the Science paper.
Stardust was launched in 1999 and returned to Earth on January 15, 2006, at the Utah Test and Training Range, 80 miles west of Salt Lake City. The Stardust Sample Return Canister was transported to a curatorial facility at Johnson where the Stardust collectors remain preserved and protected for scientific study.
Inside the canister, a tennis racket-like sample collector tray captured the particles in silica aerogel as the spacecraft flew within 149 miles (about 240 kilometers) of a comet in January 2004. An opposite side of the tray holds interstellar dust particles captured by the spacecraft during its seven-year, three-billion-mile journey.
Scientists caution that additional tests must be done before they can say definitively that these are pieces of debris from interstellar space. But if they are, the particles could help explain the origin and evolution of interstellar dust.
The particles are much more diverse in terms of chemical composition and structure than scientists expected. The smaller particles differ greatly from the larger ones and appear to have varying histories. Many of the larger particles have been described as having a fluffy structure, similar to a snowflake.
Two particles, each only about two microns (thousandths of a millimeter) in diameter, were isolated after their tracks were discovered by a group of citizen scientists. These volunteers, who call themselves "Dusters," scanned more than a million images as part of a University of California, Berkeley, citizen-science project, which proved critical to finding these needles in a haystack.
A third track, following the direction of the wind during flight, was left by a particle that apparently was moving so fast -- more than 10 miles per second (15 kilometers per second) -- that it vaporized. Volunteers identified tracks left by another 29 particles that were determined to have been kicked out of the spacecraft into the collectors.
Four of the particles reported in Science were found in aluminum foils between tiles on the collector tray. Although the foils were not originally planned as dust collection surfaces, an international team led by physicist Rhonda Stroud of the Naval Research Laboratory searched the foils and identified four pits lined with material composed of elements that fit the profile of interstellar dust particles.
Three of these four particles, just a few tenths of a micron across, contained sulfur compounds, which some astronomers have argued do not occur in interstellar dust. A preliminary examination team plans to continue analysis of the remaining 95 percent of the foils to possibly find enough particles to understand the variety and origins of interstellar dust.
Supernovas, red giants and other evolved stars produce interstellar dust and generate heavy elements like carbon, nitrogen and oxygen necessary for life. Two particles, dubbed Orion and Hylabrook, will undergo further tests to determine their oxygen isotope quantities, which could provide even stronger evidence for their extrasolar origin.
Scientists at Johnson have scanned half the panels at various depths and turned these scans into movies, which were then posted online, where the Dusters could access the footage to search for particle tracks.
Once several Dusters tag a likely track, Andrew Westphal, lead author of the Science article, and his team verify the identifications. In the one million frames scanned so far, each a half-millimeter square, Dusters have found 69 tracks, while Westphal has found two. Thirty-one of these were extracted along with surrounding aerogel by scientists at Johnson and shipped to UC Berkeley to be analyzed.
This image tracks the life of a Sun-like star, from its birth on the left side of the frame to its evolution into a red giant star on the right. On the left the star is seen as a protostar, embedded within a dusty disc of material as it forms. It later becomes a star like our Sun. After spending the majority of its life in this stage, the star's core begins to gradually heat up, the star expands and becomes redder until it transforms into a red giant.
Following this stage, the star will push its outer layers into the surrounding space to form an object known as a planetary nebula, while the core of the star itself will cool into a small, dense remnant called a white dwarf star.
Marked on the lower timeline are where our Sun and solar twins 18 Sco and HIP 102152 are in this life cycle. The Sun is 4.6 billion years old and 18 Sco is 2.9 billion years old, while the oldest solar twin is some 8.2 billion years old — the oldest solar twin ever identified. By studying HIP 102152, we can get a glimpse of what the future holds for our Sun.
This image is illustrative; the ages, sizes, and colors are approximate (not to scale). The protostar stage, on the far left of this image, can be some 2000 times larger than our Sun. The red giant stage, on the far right of this image, can be some 100 times larger than the Sun.
Kepler's Supernova Remnant: The remains of a stellar explosion that appear in Earth's sky in 1604.
Over 400 years ago, Johannes Kepler and many others witnessed the appearance of a new "star" in the sky. Today, this object is known as the Kepler supernova remnant. Previously, astronomers have deduced that the Kepler remnant comes from a so-called Type Ia supernova, which is the result of a thermonuclear explosion of a white dwarf. New data from Chandra suggest that this white dwarf exploded after pulling material from a companion red giant star, and not from the merger with another white dwarf. In this image, data from Chandra are colored red, green, and blue to show low, medium, and high-energy X-rays that have been combined with an optical image of the field.
Scale: Image is 12 arcmin across (45 light years)
Observations using the Atacama Large Millimeter/submillimeter Array (ALMA) have revealed an unexpected spiral structure in the material around the old star R Sculptoris. This feature has never been seen before and is probably caused by a hidden companion star orbiting the star. This slice through the new ALMA data reveals the shell around the star, which shows up as the outer circular ring, as well as a very clear spiral structure in the inner material.
It's a dust bunny of cosmic proportions. Astronomers used images from NASA's Wide-field Infrared Survey Explorer, or WISE, to locate an aging star shedding loads of dust (orange dot at upper left). Only one other star, called Sakurai's Object, has been caught erupting with such large amounts of dust. The process is a natural part of aging for stars like our Sun. As they puff up into red giants, they shed dust that is later recycled back into other stars, planets, and in the case of our solar system, living creatures.
In this image, infrared data from WISE and a past all-sky survey mission, the Infrared Astronomical Satellite (IRAS), have been combined. Color is used to show similar observations taken almost thirty years apart; the recent WISE data are color-coded green and red, while the older IRAS data are blue.
The picture reveals that the newfound dusty star, called WISE J180956.27-330500.2, was not seen at all by IRAS, which surveyed the sky in 1983 (it is the only bright star in this field that does not have a corresponding blue halo). Astronomers say the star has brightened by a factor of 100. This appears to have been caused by a sudden eruption in the star around 15 years ago. Dust freshly created in this event is heated by starlight and glows at infrared wavelengths.
The image also demonstrates that WISE and its state-of-the-art technology produced, as expected, much crisper images than its predecessors. The blue IRAS data show both stars, and, higher up in the picture, interstellar dust.
Data from IRAS show 12-micron infrared light (blue); data from WISE show 12- and 22-micron infrared light (green and red, respectively).
