Posted on by Ken Kremer

Era of Space Shuttle Endeavour Ends with June 1 landing at the Kennedy Space Center

Space Shuttle Endeavour landed safely at the Kennedy Space Center on June 1, 2011 at 2:35 a.m. EDT. During the 16 day STS-134 mission, Endeavour delivered the $2 Billion Alpha Magnetic Spectrometer to the International Space Station and journeyed more than sixteen million miles. Endeavour was towed back to the Orbiter Processing Facility in preparation for display at her new retirement home at the California Science Center. Credit: Ken Kremer

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KENNEDY SPACE CENTER – Space Shuttle Endeavour and her six man crew landed safely today at the Kennedy Space Center in Florida at 2:35 a.m. EDT following a 16 day journey of more than sixteen million miles.

The STS-134 mission marked the end of Endeavour’s space exploration career. It was the 25th and last space mission by NASA’s youngest orbiter. Altogether, Endeavour has logged 299 days in space, orbited Earth 4,671 times and traveled 122,883,151 miles.

The crew was led by Shuttle Commander Mark Kelly. Also aboard were Pilot Greg H. Johnson and Mission Specialists Mike Fincke, Drew Feustel, Greg Chamitoff and the European Space Agency’s Roberto Vittori. Vittori is the last non NASA astronaut to fly on a shuttle mission.

The night landing capped a highly productive flight highlighted by the delivery of the $2 Billion Alpha Magnetic Spectrometer (AMS) to the International Space Station. AMS is a cosmic ray detector that seeks to unveil the invisible universe and search for evidence of dark matter, strange matter and antimatter.

5 of 6 crew members of STS-134 mission of Space Shuttle Endeavour at post landing press briefing. Credit: Ken Kremer

“What a great ending to this really wonderful mission,” said Bill Gerstenmaier, associate administrator for Space Operation at a briefing today for reporters “They’re getting great data from their instrument on board the space station. It couldn’t have gone any better for this mission.”

Mike Leinbach, the Space Shuttle Launch Director, said, “It’s been a great morning at the Kennedy Space Center. Commander Kelly and his crew are in great spirits.”

Four members of the crew conducted 4 spacewalks during the flight, which were the last by shuttle crew members during the space shuttle era. Simultaneously they completed the construction of the US portion of the ISS.

During the flight, Mike Fincke established a new record of 382 days for time a U.S. astronaut has spent in space. He broke the record on May 27, his 377th day on May 27, by surpassing previous record holder Peggy Whitson.

STS-134 was the 134th space shuttle mission and the 36th shuttle mission dedicated to ISS assembly and maintenance.

“You know, the space shuttle is an amazing vehicle, to fly through the atmosphere, hit it at Mach 25, steer through the atmosphere like an airplane, land on a runway, it is really, really an incredible ship,” said Kelly.

“On behalf of my entire crew, I want to thank every person who’s worked to get this mission going and every person who’s worked on Endeavour. It’s sad to see her land for the last time, but she really has a great legacy.”

After the landing at the Shuttle Landing Facility (SLF) , Endeavour was towed back into the Orbiter Processing Facility (OPF) where she will be cleaned and “safed” in preparation for her final resting place – Retirement and public display at the California Science Center in Los Angelos, California.

With the successful conclusion of Endeavour’s mission, the stage is now set for blastoff of the STS-135 mission on July 8, the very final flight of the three decade long shuttle Era.

“We’ve had a lot going on here,” said Mike Moses, space shuttle launch integration manager, “Being able to send Atlantis out to the pad and then go out and land Endeavour was really a combination I never expected to have.

It’s been a heck of a month in the last 4 hours !”

Shuttle Endeavour Landing Photos by Mike Deep for Universe Today

STS-134 Space Shuttle Commander Mark Kelly. Credit: Ken Kremer
STS-134 Endeavour Post Landing Press Briefing.
Bill Gerstenmaier, NASA Associate Administrator for Space Operations, Mike Moses, Space Shuttle launch integration manager at NASA KSC, Mike Leinbach, Space Shuttle Launch Director at NASA KSC, laud the hard work and dedication of everyone working on the Space Shuttle program. Credit: Ken Kremer

Read my related stories about the STS-134 mission here:

Amazing Photos and Milestone Tributes Mark Last Space Shuttle Spacewalk
Awesome Hi Def Launch Videos from Endeavour
Spectacular Soyuz Photo Gallery shows Unprecedented View Of Shuttle Docked at Station
Ultimate ISS + Shuttle + Earth Photo Op Coming on May 23 from Soyuz and Paolo Nespoli
Endeavour Blasts Off on Her 25th and Final Mission
Endeavour Unveiled for Historic Final Blastoff
Looking to the Heavens with Endeavour; Launch Pad Photo Special
Endeavour Astronauts Arrive at Cape for May 16 Launch
NASA Sets May 16 for Last Launch of Endeavour; Atlantis Slips to July
Endeavour’s Final Launch further delayed another Week or more
On the Cusp of Endeavour’s Final Flight
Brush Fires Erupt at Kennedy Space Center during Endeavour’s Last Countdown
Commander Mark Kelly and STS-134 Crew Arrive at Kennedy for Endeavour’s Final Flight
President Obama to Attend Endeavour’s Last Launch on April 29
Shuttle Endeavour Photo Special: On Top of Pad 39A for Final Flight
Endeavour Mated to Rockets for Last Flight Photo Album
Endeavour Rolls to Vehicle Assembly Building for Final Flight

Posted on by Jason Major

Bringing the Solar System Down to Earth

As a part of NASA’s ongoing Year of the Solar System – which is actually a single Martian year long, or 23 months – the excitement of planetary exploration is being brought to people around the world through a enthusiastic science outreach program called From Earth to the Solar System (FETTSS). A continuation of the well-received International Year of Astronomy 2009 From Earth to the Universe program, FETTSS provides over 90 beautiful high-resolution images of fascinating locations around our solar system; from the ice geysers of Enceladus to the plasma arcs of solar prominences, the cold dunes of Mars to the hot springs of Yellowstone, the FETTSS collection showcases many wonders of many worlds – and helps bring them within view of as many people as possible.

The images are displayed in public locations, hosted by organizations that raise all the necessary funding to have them printed and installed. The FETTSS site exists to provide the high-resolution print images as well as offer guidance as to how to best plan, market and set up an installation.

What’s wonderful about From Earth to the Solar System – as well as its predecessor From Earth to the Universe – is how it brings the fascination of science and astronomy to people who may not have previously given it much thought. By presenting large-format images with descriptive captions in common places – such as in an airport or outside in a public park – FETTSS hosts are actively capturing the interest of viewers and engaging them in astronomy – many undoubtedly for the first time.

People around the world are being connected with the most recent work of scientists and researchers in a way that’s attractive, informative and yet accessible. This is the key to any successful outreach program.

The images are at once artistic and informative, weaving together themes in astrobiology, planetary science, and astronomy. Including contributions from backyard astronomers, large telescopes in space, and even point-and-shoot cameras of field researchers, the collection represents the current state of exploration as seen through the eyes of the scientific community.

Currently an exhibit is just wrapping up in Corpus Christi, Texas, at the Museum of Science and History and was very well-received by both people and the press! The next scheduled event will take place in June at the National Air and Space Museum in Washington, DC.

A FETTU outdoor installation in Geneva

FETTSS looks to build on the success of the 2009 FETTU program.

“We are hoping to replicate some of FETTU’s success and bring a measure of sustainability to the FETTU concept. ‘From Earth to the Solar System’ is taking a similar grassroots-type of approach to exhibit creation, and will hopefully help remove the barrier to ‘seeking science out’ for some visitors and help make setting up an exhibit more efficient for organizers,” said Kimberly Kowal Arcand, Media Production Coordinator for the Harvard-Smithsonian Center for Astrophysics and FETTSS principal investigator.

“With FETTU – and what we hope to find with FETTSS – there was a wonderful response from both visitors and organizers,” said Arcand. “We found, unexpectedly, a sort of emotional and personal connection to the images in the FETTU project and I’m interested to see if we find that again with FETTSS. I was personally overwhelmed with the response to FETTU… it was the most inspiring thing I have ever worked on!”

Already, exhibitors worldwide have expressed interest in hosting FETTSS installations… from Argentina, Serbia, China, Colombia, Canada, UK, Ireland, Egypt, Spain, Armenia, as well as from numerous locations in the US – many of whom had previously hosted FETTU events.

So with such a great program and strong response, the question remains: what’s next?

“From Earth to the Sun? From Earth to the Galaxies?” suggested Arcand.

With all that’s being discovered, whatever it is it’s sure to be another success!

 

For more information about FETTSS or to host an FETTSS event in your area, visit the main site here.

Posted on by Tammy Plotner

MOST… Cutting To The Heart Of A Wolf-Rayet Star

M1-67 is the youngest wind-nebula around a Wolf-Rayet star, called WR124, in our Galaxy. Credit: ESO

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In 1867, astronomers using the 40 cm Foucault telescope at the Paris Observatory, discovered three stars in the constellation Cygnus (now designated HD191765, HD192103 and HD192641), that displayed broad emission bands on an otherwise continuous spectrum. The astronomers’ names were Charles Wolf and Georges Rayet, and thus this category of stars became named Wolf–Rayet (WR) stars. Now using the Canadian MOST microsatellite, a team of researchers from the Universite de Montreal and the Centre de Recherche en Astrophysique du Quebec have made a stunning observation. They probed into the depth of the atmospheric eclipses in the Wolf-Rayet star, CV Serpentis, and observed a never before seen change of mass-loss rate.

Thanks to the service of MOST – Canada’s first space telescope and its high precision photometry – the team has observed significant changes in the depth of the atmospheric eclipses in the 30-day binary WR+O system. The equipment is aboard a suitcase-sized microsatellite (65 x 65 x 30 cm) which was launched in 2003 from a former ICBM in northern Russia. It is on a low-Earth polar orbit and has long outlived its original estimated life expectancy, offering Canadian astronomers almost eight years (and still counting) of ultra-high quality space-based data. Now this data gives us a huge insight into the heart of Wolf-Rayet stars.

Intrinsically luminous, WR stars can be massive or mid-sized, but the most interesting stage is arguably the last 10% in the lifetime of the star, when hydrogen fuel is used up and the star survives by much hotter He-burning. Towards the end of this phase, the copious supply of carbon atoms head for the stellar surface and are ejected in the form of stellar winds. WR stars in this stage are known as WC stars… and their production of carbon dust is one of the greatest mysteries of the Cosmos. These amorphous dust grains range in size from a few to millions of atoms and astronomers hypothesize their formation may requires high pressure and less than high temperatures.

“One key case is undoubtedly the sporadic dust-producing WC star in CV Ser. MOST was recently used to monitor CV Ser twice (2009 and 2010), revealing remarkable changes in the depths of the atmospheric eclipse that occurs every time the hot companion’s light is absorbed as it passes through the inner dense WC wind.” says the researchers. “The remarkable, unprecedented 70% change in the WC mass-loss rate might be connected to dust formation.”

And all thanks to the MOST tiny little satellite imaginable…

Original Story Source: AstroNews and excerpt from Wikipedia.

Posted on by Tammy Plotner

Coming To A Theatre Near You… Extreme Neutron Stars!

Artist's Conception of a Neutron Star Courtesy of NASA

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They came into existence violently… Born at the death of a massive star. They are composed almost entirely of neutrons, barren of electrical charge and with a slightly larger mass than protons. They are quantum degenerates with an average density typically more than one billion tons per teaspoonful – a state which can never be created here on Earth. And they are absolutely perfect for study of how matter and exotic particles behave under extreme conditions. We welcome the extreme neutron star…

In 1934 Walter Baade and Fritz Zwicky proposed the existence of the neutron star, only a year after the discovery of the neutron by Sir James Chadwick. But it took another 30 years before the first neutron star was actually observed. Up until now, neutron stars have had their mass accurately measured to about 1.4 times that of Sol. Now a group of astronomers using the Green Bank Radio Telescope found a neutron star that has a mass of nearly twice that of the Sun. How can they make estimates so precise? Because the extreme neutron star in question is actually a pulsar – PSR J1614-2230. With heartbeat-like precision, PSR J1614-2230 sends out a radio signal each time it spins on its axis at 317 times per second.

According to the team; “What makes this discovery so remarkable is that the existence of a very massive neutron star allows astrophysicists to rule out a wide variety of theoretical models that claim that the neutron star could be composed of exotic subatomic particles such as hyperons or condensates of kaons.”

The presence of this extreme star poses new questions about its origin… and its nearby white dwarf companion. Did it become so extreme from pulling material from its binary neighbor – or did it simply become that way through natural causes? According to Professor Lorne Nelson (Bishop’s University) and his colleagues at MIT, Oxford, and UCSB, the neutron star was likely spun up to become a fast-rotating (millisecond) pulsar as a result of the neutron star having cannibalized its stellar companion many millions of years ago, leaving behind a dead core composed mostly of carbon and oxygen. According to Nelson, “Although it is common to find a high fraction of stars in binary systems, it is rare for them to be close enough so that one star can strip off mass from its companion star. But when this happens, it is spectacular.”

Through the use of theoretical models, the team hopes to gain insight as to how binary systems evolve over the entire lifetime of the Universe. With today’s extreme super-computing powers, Nelson and his team members were able to calculate the evolution of more than 40,000 plausible starting cases for the binary and determine which ones were relevant. As they describe at this week’s CASCA meeting in Ontario, Canada, they found many instances where the neutron star could evolve higher in mass at the expense of its companion, but as Nelson says, “It isn’t easy for Nature to make such high-mass neutron stars, and this probably explains why they are so rare.”

Original story source at Physorg.com.

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Posted on by Ken Kremer

Atlantis Goes Vertical for the Last Time

Credit: Ken Kremer

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KENNEDY SPACE CENTER – For the last time in history, Atlantis and the shuttle program have literally gone vertical. Following the rollover of Atlantis into the Vehicle Assembly Building (VAB), the orbiter was attached to a massive crane and then hoisted and mated to the External Tank and twin Solid Rocket boosters that will power her 25th and last climb to orbit.

Myself and a small band of lucky photo journalists were privileged to witness this milestone on the way to blastoff of the STS-135 mission, the last one of the three decade long shuttle era. Check out a selection of my images in this photo album for Universe Today readers. I’ll post a few now and more later as Atlantis prepares to rollout to Launch Pad 39 A.

The STS-135 mission remains on target for liftoff on July 8 at about 11:40 a.m. EDT on a 12 day flight to deliver critical parts, science experiments, gear, crew supplies and provisions to the International Space Station (ISS).

Credit: Ken Kremer
Credit: Ken Kremer
Credit: Ken Kremer
Credit: Ken Kremer
Credit: Ken Kremer
Credit: Ken Kremer
Credit: Ken Kremer

Read my prior story about the Final Shuttle mission, STS-135, here:
Atlantis Rolls to Vehicle Assembly Building with Final Space Shuttle Crew for July 8 Blastoff

Posted on by Tammy Plotner

Voyager 1 Measures Magnetic Mayhem

Artist's Conception of Voyager - Credit: NASA

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When Voyager 1 passed into the heliosheath in 2004, it became the first man-made object to explore the remote edge of the Sun’s magnetic influence. Launched by NASA on September 5, 1977, the probe was designed to study the outer Solar System and eventually interstellar space. One of its missions was to look for the heliopause – the boundary at which the solar wind transitions into the interstellar medium. What it found was mayhem…

According to NASA, Voyager 1 has crossed into an area where the velocity of the hot ionized gas, or plasma, emanating directly outward from the sun has slowed to zero. Scientists suspect the solar wind has been turned sideways by the pressure from the interstellar wind in the region between stars. “The solar wind has turned the corner,” said Ed Stone, Voyager project scientist based at the California Institute of Technology in Pasadena, Calif. “Voyager 1 is getting close to interstellar space.”

Now it has entered the heliosheath, an area ranging from 1.5 to 15 billion kilometers thick (930 million to 9.3 billion miles) and starting roughly 14 billion km (8.7 billion mi) from the Sun. But there’s nothing quiet here. This is the area where outgoing flows of solar wind begin to be repelled by interstellar particles and magnetic fields pushing towards the solar system. While passing through the heliosheath, Voyager 1 experienced many sudden and drastic changes in the surrounding magnetic field driven by structures called current sheets.

Illustration Courtesy of NASA

The team of L. F. Burlaga: Geospace Physics Laboratory, NASA Goddard Space Flight Center and N. F. Ness of the Institute for Astrophysics and Computational Sciences have been studying the ongoing results sent back by Voyager and have come to a new conclusion – there are three distinct types of current sheets.

“The structures, appearing as proton boundary layers (PBLs), magnetic holes or humps, or sector boundaries, were identified by characteristic fluctuations in either magnetic field strength or direction as the spacecraft crossed nearly 500 million km (310 million mi) of heliosheath in 2009. PBLs are defined by a rapid jump in magnetic field strength, with one observed event resulting in a doubling of the field strength in just half an hour.” said the team. “Passing through a sector boundary led to a sudden change in direction of the magnetic field. Magnetic holes saw the field strength drop to near zero before returning to the original background strength. Magnetic humps consisted of a sudden spike in strength and then a return to initial levels.”

But this isn’t the first time the Voyager has returned zero readings. In December 2004 the intrepid probe broke the barrier of the termination shock and data from Voyager 1’s Low-Energy Charged Particle Instrument was used to deduce the solar wind’s velocity. When the speed of the particles matched the speed of the spacecraft, scientists knew they had a null number on their records. “When I realized that we were getting solid zeroes, I was amazed,” said Rob Decker, a Voyager Low-Energy Charged Particle Instrument co-investigator and senior staff scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. “Here was Voyager, a spacecraft that has been a workhorse for 33 years, showing us something completely new again.”

And new is what we need to continue our understanding of what lay at the furthest reaches of our now explorable space. Says Burlaga, “The firsthand detections made by Voyager 1 are likely to be extremely important for researchers trying to decide between current leading theories for the source and structure of current sheets.”

Story source: Journal of Geophysical Research – Space Physics.

Posted on by Jason Major

And The Moon Is Eclipsed By The Earth

Total lunar eclipse on December 21, 2010/ Credit: Jason Major

 

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On June 15 there will be a total lunar eclipse visible from Australia, Indonesia, southern Japan, India, a large area of Asia, Africa, Europe and the eastern part of South America. This is expected to be one of the darkest eclipses ever (with a magnitude of 1.7), second only to the July 2000 eclipse.

Sadly it won’t be visible to viewers in North America, but much of the rest of the world should be treated to a wonderful show as the Moon slips into Earth’s shadow. Gradually growing darker from its western limb inwards, the Moon then gains a bluish cast which transitions to orange then deep red as it moves into light passing through the edge of Earth’s atmosphere (the same as what makes the colors of a sunset) and then eventually going almost completely dark before the process then reverses itself from the opposite side.

 

Visibility map for June 15 lunar eclipse

The entire eclipse will last 5 hours and 39 minutes, with a totality duration of 1 hour and 40 minutes. It will begin at 17:23 UT.

Viewers in Australia and eastern Asia will see the eclipse begin as the Moon is setting while those in Europe and South America will see it as the Moon is rising. Only locations in India, eastern Africa, the Middle East and western Asia will experience the entire eclipse.

This is the first of two total lunar eclipses in 2011; the next will take place on December 10.

I saw my first total lunar eclipse last December, which took place on the night of the winter solstice (December 21). It really was an amazing event to watch… in totality the Moon was colored a deep coppery red and really just seemed to be suspended among the stars – it felt like you could just reach up and pluck it from the sky! If you are in any of the areas where this next one is visible I encourage you to check it out for yourself!

Read more about lunar eclipses on MrEclipse.com.

Image: Jason Major

Posted on by Steve Nerlich

Twisted Ring Of Gas Orbits Galactic Center

A Herschel PACS (Photodetector Array Camera and Spectrometer) image of the center of the Milky Way. The dark line of cool gas is thought to be an elliptical ring surrounding the galactic center. The galaxy’s central supermassive black hole Sagittarius A* (Sgr A*) is labelled. The differential velocity of clouds in the ring may result from interaction with Sgr A*. Credit: ESA/Herschel/NASA/Molinari et al.

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The Herschel Space Observatory scanned the center of the galaxy in far-infrared and found a cool (in all senses of the word) twisting ring of rapidly orbiting gas clouds. The ring is estimated to have dimensions of 100 parsecs by 60 parsecs (or 326 by 196 light years) – with a composite mass of 30 million solar masses.

The ring is proposed to oscillate twice about the galactic mid-plane for each orbit it makes of the galactic center – giving it the apparent shape of an infinite symbol when viewed from the side.

The research team speculate that the ring may be conforming to the shape of a standing wave – perhaps caused by the spin of the central galactic bulge and the lateral movement of gas across the galaxy’s large central bar. The researchers suggest that the combination of these forces may produce some kind of gravitational ‘sloshing’ effect, which would account for the unusual movement of the ring.

The estimated shape of the 100 by 60 parsec ring. Note the oscillating shape from a lateral perspective – and from above, note the ring encircles the supermassive black hole Sagittarius A*, but the black hole is not at its center. Credit: Molinari et al.

Although the ring is estimated to have an average orbital velocity of 10 to 20 kilometers a second, an area of dense cloud coming in close to the galaxy’s central supermassive black hole, Sagittarius A*, was clocked at 50 kilometers a second – perhaps due to its close proximity to Sagittarius A*.

However, the researchers also estimate that Sagittarius A* is well off-centre of the gas ring. Thus, the movement of the ring is dominated by the dynamics of the galactic bulge – rather than Sagittarius A*, which would only exert a significant gravitational influence within a few parsecs of itself.

Further reading: Molinari et al A 100 parsec elliptical and twisted ring of cold and dense molecular clouds revealed by Herschel around the galactic center.

Posted on by Nancy Atkinson

Copenhagen Suborbitals Upcoming Launch Attempt in June

Kristian Von Bengtson checks the cockpit before the launch dummy is loaded. Photo credit: Bo Tornvig, Copenhagen Suborbitals.

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Copenhagen Suborbitals hopes to launch the world’s first amateur-built rocket for human space travel and have announced an upcoming launch window for their Tycho Brahe capsule. The window extends from June 1-14, 2011 and they are currently shooting for Thursday, June 2 for an unmanned suborbital test flight, according the their website. The group is headed by Kristian von Bengtson and Peter Madsen, and their HEAT 1-X rocket is being prepared for launch from a steel catamaran in the Baltic Sea off the coast of Denmark.

If all goes well with this test flight, Madsen hopes to be inside the capsule himself for a manned flight in the near future.

The company, which is funded by donations, is working towards launching tourists on suborbital flights in the single-seat capsule to altitudes above 100 kilometers (62.5 miles).

And talk about a wild ride : the Tycho Brahe capsule will provide a single passenger capsule with a full view through a polymer plexiglas-dome so that the person can see and experience the entire ballistic ride. It has a pressurized volume providing support for one upright standing/half-sitting person. It will also have additional pressurized space, around and behind the astronaut, available for several other systems necessary for the flight procedure, and to support additional scientific and commercial project.

The flight trajectory for the HEAT rocket. Credit: Copenhagen Suborbitals.

No specific launch time has been announced, so check their website for more updated information. There will also be live coverage and launch parties in Denmark.

Check these links for possible online coverage:

Live internet coverage: www.ing.dk/live
and http://maylaunch.dotsquare.dk/

Copenhagen Suborbitals were hoping to launch their first test flight last summer, but ran into problems with their rocket.

Posted on by Tammy Plotner

Globular Clusters Are Real Oddballs

M80 Image Credit: NASA, The Hubble Heritage Team, STScI, AURA

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Hanging onto the outskirts of our Milky Way galaxy like cockle burs on a shaggy dog’s coat, globular clusters contain over hundreds of thousands of stars. Estimated to be up to ten billion years old, these spherical stellar seed pods are gravitationally bound together and tend to be more dense towards their cores. We’ve long known all the stars contained within a globular cluster to be about the same age and the individual members most likely formed at the same time as the parent galaxy – but what we weren’t expecting was change.

“We thought we understood these clusters very well”, says Dr. Alison Sills, Associate Professor of Physics & Astronomy. She is presenting new findings at this week’s CASCA 2011 meeting in Ontario, Canada. “We taught our students that all the stars in these clusters were formed at the same time, from one giant cloud of gas. And since that time, the individual stars may have evolved and died, but no new stars were born in the cluster.”

In 1953, astronomer Allan Sandage was performing photometry of the stars in the globular cluster M3 when he made an incredible discovery – blue stragglers. No, it’s not a down-his-luck musician waiting for a coin in his instrument case… but a main sequence star more luminous and more blue than stars at the main sequence turn-off point for the cluster. They shouldn’t belong where they are, but with masses two to three times that of the rest of the main sequence cluster stars, blue stragglers seem to be exceptions to the rule. Maybe they are a product of interaction… grappling together… pulling material from one another… and eventually merging.

Image of NGC 6397 taken by the Hubble Space Telescope, with evidence of a number of blue stragglers.

“Astronomers expect that the stars get too close to each other because of the complicated dance that stars perform in these dense clusters, where thousands of stars are packed into a relatively small space, and each star is moving through this cluster under the influence of the gravity of all the other stars. Somewhat like a traffic system with no stop lights, there are a lot of close encounters and collisions,” explains Sills.

By taking a closer look at globular clusters, the Hubble Space Telescope has given us evidence for two generations of star formation. The first is our accepted rule, but the second generation isn’t like anything else found in our Galaxy. Instead of being created from an earlier generation of expended stars, the second generation in globular clusters appears to have formed from material sloughed off by the first generation of stars. An enigma? You bet.

“Studying the normal stars in clusters was instrumental in allowing astronomers to figure out how stars lived and died”, says Dr. Sills, “but now we can look even further back, to when they were born, by using the oddballs. It pays off to pay attention to the unusual individuals in any population. You never know what they’ll be able to tell you.”

At the CASCA conference, Dr. Sills is presenting her work – a link between these two unusual forms of globular clusters. Blue stragglers and the second generation of stars would appear to have identical properties, including where they are concentrated in the cluster, and that both are.. well.. a little more “blue” than we would expect. She is investigating how the close encounters and collisions could affect the formation of this strange second generation and link the two phenomena we see in these complicated systems.

Real oddballs…

Original story soucre at Physorg.com.