NASA’S KEPLER SPACECRAFT TAKES PULSE OF DISTANT STARS

An international cadre of scientists that used data from NASA's Kepler spacecraft announced Tuesday the detection of stellar oscillations, or "starquakes," that yield new insights about the size, age and evolution of stars.

The results were presented at a news conference at Aarhus University in Denmark by scientists representing the Kepler Asteroseismic Science Consortium (KASC). The team studied thousands of stars observed by Kepler, releasing what amounts to a roster of some of humanity's most well-characterized stars.

Analysis of stellar oscillations is similar to how seismologists study earthquakes to probe the Earth's interior. This branch of science, called asteroseismology, produces measurements of stars the Kepler science team is anxious to have.

"Using the unparalleled data provided by Kepler, KASC scientists are quite literally revolutionizing our understanding of stars and their structures," said Douglas Hudgins, Kepler Program Scientist at NASA Headquarters in Washington. "What's more, they are doing so at no cost to the American taxpayer. All the KASC scientists are supported by research funding from their home countries. It is a perfect illustration of the tremendous value that our international partners bring to NASA missions."

In the results presented Tuesday, one oscillating star took center stage: KIC 11026764 has the most accurately known properties of any star in the Kepler field. In fact, few stars in the universe are known to similar accuracy. At an age of 5.94 billion years, it has grown to a little over twice the diameter of the Sun and will continue to do so as it transforms into a red giant. The oscillations reveal that this star is powered by hydrogen fusion in a thin shell around a helium-rich core.

"We are just about to enter a new area in stellar astrophysics," said Thomas Kallinger, lead author on a study of red giant stars and postdoctoral fellow at the Universities of British Columbia and Vienna. "Kepler provides us with data of such good quality that they will change our view of how stars work in detail."

KASC scientists also reported on the star RR Lyrae. It has been studied for more than 100 years as the first member of an important class of stars used to measure cosmological distances. The brightness, or light wave amplitude, of the star oscillates within a well-known period of about 13.5 hours. Yet during that period, other small cyclic changes in amplitude occur -- behavior known as the Blazhko effect.

The effect has puzzled astronomers for decades, but thanks to Kepler data, scientists may have a clue as to its origin. Kepler observations revealed an additional oscillation period that had never been previously detected. The oscillation occurs with a time scale twice as long as the 13.5-hour period. The Kepler data indicates the doubling is linked to the Blazhko effect.

"Kepler data ultimately will give us a better understanding of the future of our Sun and the evolution of our galaxy as a whole," said Daniel Huber, lead author on one of the KASC studies.

Launched in March 2009, Kepler was designed to discover Earth-size planets orbiting other stars. The spacecraft uses a huge digital camera, known as a photometer, to continuously monitor the brightness of more than 150,000 stars in its field of view as it orbits around the Sun. Kepler searches for distant worlds by looking for "transits," when a planet passes in front of a star, briefly causing it to dim. The amount of dimming reveals the size of the planet compared to the size of the star.

More information about the findings by the KASC scientists: http://astro.phys.au.dk/KASC/

More information about the Kepler mission: http://www.nasa.gov/kepler
http://www.nasa.gov/kepler

Astronomers Discover Most Massive Neutron Star Yet Known

Pulses from neutron star (rear) are slowed as they pass near foreground white dwarf.
This effect allowed astronomers to measure masses of the system.

Source: The National Radio Astronomy Observatory

Astronomers using the National Science Foundation’s Green Bank Telescope (GBT) have discovered the most massive neutron star yet found, a discovery with strong and wide-ranging impacts across several fields of physics and astrophysics.

“This neutron star is twice as massive as our Sun. This is surprising, and that much mass means that several theoretical models for the internal composition of neutron stars now are ruled out,” said Paul Demorest, of the National Radio Astronomy Observatory (NRAO). “This mass measurement also has implications for our understanding of all matter at extremely high densities and many details of nuclear physics,” he added.

Neutron stars are the superdense “corpses” of massive stars that have exploded as supernovae. With all their mass packed into a sphere the size of a small city, their protons and electrons are crushed together into neutrons. A neutron star can be several times more dense than an atomic nucleus, and a thimbleful of neutron-star material would weigh more than 500 million tons. This tremendous density makes neutron stars an ideal natural “laboratory” for studying the most dense and exotic states of matter known to physics.

The scientists used an effect of Albert Einstein’s theory of General Relativity to measure the mass of the neutron star and its orbiting companion, a white dwarf star. The neutron star is a pulsar, emitting lighthouse-like beams of radio waves that sweep through space as it rotates. This pulsar, called PSR J1614-2230, spins 317 times per second, and the companion completes an orbit in just under nine days.

The pair, some 3,000 light-years distant, are in an orbit seen almost exactly edge-on from Earth. That orientation was the key to making the mass measurement.

As the orbit carries the white dwarf directly in front of the pulsar, the radio waves from the pulsar that reach Earth must travel very close to the white dwarf. This close passage causes them to be delayed in their arrival by the distortion of space-time produced by the white dwarf’s gravitation. This effect, called the Shapiro Delay, allowed the scientists to precisely measure the masses of both stars.

“We got very lucky with this system. The rapidly-rotating pulsar gives us a signal to follow throughout the orbit, and the orbit is almost perfectly edge-on. In addition, the white dwarf is particularly massive for a star of that type. This unique combination made the Shapiro Delay much stronger and thus easier to measure,” said Scott Ransom, also of NRAO.

The astronomers used a newly-built digital instrument called the Green Bank Ultimate Pulsar Processing Instrument (GUPPI), attached to the GBT, to follow the binary stars through one complete orbit earlier this year. Using GUPPI improved the astronomers’ ability to time signals from the pulsar severalfold.

The researchers expected the neutron star to have roughly one and a half times the mass of the Sun. Instead, their observations revealed it to be twice as massive as the Sun. That much mass, they say, changes their understanding of a neutron star’s composition. Some theoretical models postulated that, in addition to neutrons, such stars also would contain certain other exotic subatomic particles called hyperons or condensates of kaons.

“Our results rule out those ideas,” Ransom said.

Demorest and Ransom, along with Tim Pennucci of the University of Virginia, Mallory Roberts of Eureka Scientific, and Jason Hessels of the Netherlands Institute for Radio Astronomy and the University of Amsterdam, reported their results in the October 28 issue of the scientific journal Nature.

Their result has further implications, outlined in a companion paper, scheduled for publication in the Astrophysical Journal Letters. “This measurement tells us that if any quarks are present in a neutron star core, they cannot be ‘free,’ but rather must be strongly interacting with each other as they do in normal atomic nuclei,” said Feryal Ozel of the University of Arizona, lead author of the second paper.

There remain several viable hypotheses for the internal composition of neutron stars, but the new results put limits on those, as well as on the maximum possible density of cold matter.

The scientific impact of the new GBT observations also extends to other fields beyond characterizing matter at extreme densities. A leading explanation for the cause of one type of gamma-ray burst -- the “short-duration” bursts -- is that they are caused by colliding neutron stars. The fact that neutron stars can be as massive as PSR J1614-2230 makes this a viable mechanism for these gamma-ray bursts.

Such neutron-star collisions also are expected to produce gravitational waves that are the targets of a number of observatories operating in the United States and Europe. These waves, the scientists say, will carry additional valuable information about the composition of neutron stars.

“Pulsars in general give us a great opportunity to study exotic physics, and this system is a fantastic laboratory sitting out there, giving us valuable information with wide-ranging implications,” Ransom explained. “It is amazing to me that one simple number -- the mass of this neutron star -- can tell us so much about so many different aspects of physics and astronomy,” he added.

A lot more information, videos and images...

Stunning Spacecraft Photos Show Moon Eclipsing the Sun

Click on image to enlarge

On Oct. 7, 2010, NASA's Solar Dynamics Observatory, or SDO, observed its first lunar transit when the new moon passed directly between the spacecraft (in its geosynchronous orbit) and the sun. With SDO watching the sun in a wavelength of extreme ultraviolet light, the dark moon created a partial eclipse of the sun. Credit: NASA

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NASA Readies Shuttle Discovery for Final Mission

by Staff WritersKSC FL (SPX) Oct 25, 2010

Source: www.space-travel.com

The countdown is on: NASA has only two shuttle launches left. The U.S. space agency is retiring its shuttle fleet next year and encouraging the development of commercial human spaceflight vehicles. Space shuttle Discovery is set to launch November 1
Last week, engineers found that Discovery had developed a fuel leak.
John Shannon, the space shuttle program manager at NASA's Johnson Space Flight Center in Houston, Texas, says engineers have the situation under control.
"We had a very small leak in the plumbing at a flange fitting, and the team has been working that very hard over the last week," Shannon told reporters Thursday.
"We did some troubleshooting on it, and it looked like the leak stopped."

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Group 1117, only one of the three big sunspots visible now

Visit Spaceweather.com for more information!

Runway opens at world's first spaceport

Virgin Galactic's VSS Enterprise made a celebratory flight over the runway

Commercial space travel took a step closer with the opening of the runway at the world's first spaceport in the US state of New Mexico.

The event was marked with a flypast of an aircraft carrying SpaceShip Two.

The vehicle has been designed to take fee-paying tourists on trips to the edge of space and back.

British billionaire Sir Richard Branson - whose Virgin group has backed the venture - said the first passenger trip should take place within 18 months.

• Read more and watch the video

Nikon Small World Competition

Image of Distinction, 2010

Dr. Marie Andersson

UCMR/Dep. Molecular Biology
Umeå Universitet
Umeå, Sweden

Drosophila sp. (fruit fly) eye, direct mount (20x)

•  More amzing images

University of Texas Students, Telescopes Help Discover Planets Around Elderly Binary Star

 

 The 2.1-meter (82-inch) Otto Struve Telescope at the University of Texas McDonald Observatory. Photo by Marty Harris/McDonald Observatory.

News Release: McDonald Observatory, The University of Texas, 21 October 2010

An international consortium of astronomers, including undergraduate and graduate
students at The University of Texas at Austin, have discovered a planetary system
consisting of at least two massive Jupiter-like planets orbiting the extremely close
binary star system NN Serpentis. The team used a wide variety of observations
taken over two decades from many telescopes, including two at The University of
Texas at Austin’s McDonald Observatory in West Texas.
|
The results are published
online in the current edition of the journal Astronomy & Astrophysics.

Because of the disturbing effects of a binary star system’s gravity, astronomers
normally do not expect to find planets in such systems, but the research team was
able to use the eclipses of the stars as a precise clock whose irregularities could be
used to detect planets in orbit around the binary.

Publish Post

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Multi-University Project to Study 'Dark Energy' Receives $8 Million from National Science Foundation

Video to watch
 

News Release: McDonald Observatory, The University of Texas, 20 October 2010

A project to discover the nature of dark energy, a mysterious force causing the expansion of the universe to speed up, has received an $8 million grant from the National Science Foundation (NSF).

The funds will be split among The University of Texas at Austin ($3.6 million), Texas A&M University ($3.9 million) and Penn State University ($.5 million), to support their respective roles in the Hobby-Eberly Telescope Dark Energy Experiment, or HETDEX. The project will be carried out at The University of Texas at Austin’s McDonald Observatory in west Texas.

“HETDEX is one of our gems within the university,” said William Powers Jr., president of The University of Texas at Austin. “It’s one of the projects being done here today that will still be talked about in a hundred years, the way we now read about discoveries by Newton and Einstein. This NSF grant is strong confirmation of the project’s importance and our commitment to it.”

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Feedback after Laser Workshop during ASSA Symposium in Pretoria

Pretoria Centre of the Astronomical Society of Southern Africa

Laser Safety

PROPOSED FEEDBACK TO ASSA NATIONAL BODY REGARDING LASER WORKSHOP DURING 2010 ASSA SYMPOSIUM

Background:

Regulation 1302 identifies visible lasers with an output power over 0.30µW as 'dangerous goods' under the HAZARDOUS SUBSTANCES ACT NO. 15 OF 1973

1. Importers who import these devices must license the product at the Department of Health.
2. Any person using a laser device with an output power of more than 5 mW has to register as a Laser Safety Officer (LSO) at the Department of Health.
3. There is a general concern that laser pointers are used irresponsibly. This may increase the risk that green laser pointers be 'overregulated' by the Dept. of Health.

Delegates agree to the following:

1. ASSA members are encouraged to register their unregistered laser pointers (It is currently free to do so)
2. The organisers of events such as star parties, ScopeX, viewing evenings, etc, will be liable in accordance with the Occupational Health and Safety Act (Act 85 of 1993) for any incident during the event. The organisers therefore have to define the 'laser rules' for the event and act accordingly.
3. The organisers have the right to confiscate (store in safe position) any non-compliant laser pointer used at the event.
4. There is no requirement for anyone (except presenting astronomers) to use a laser pointer with an output of more than 5mW for astronomy purposes.
5. Presenting astronomers (those who do astronomy presentations to groups of people) may justify the use of stronger laser pointers. Suggested laser output ranged from 10mW to 50mW. The delegates agree that 20mW should be suitable for most applications, but foresee applications for up to 50mW.
6. Approved organisations should be identified (eg: ASSA branches; Universities; SAAO; SANParks; etc) These organisations should recommend applications for LSO's.
7. The following 'safe practices' is a good starting point when presentations to groups are done:
   • Lasers should be used by knowledgeable astronomers under controlled circumstances:
   • Do not point at people, aircraft or animals
   • Keep suitable distance from audience
   • Warn the audience
   • Area should be clean of obstacles
   • Avoid pointing to surfaces that can give specular reflections
   • Minimise use (do not play)
   • Keep away from children
   • Do not use mechanisms that keeps the pointer switched on.
8. The outcome should be posted on the website and comments requested.

Additional comments from discussions after the workshop:

1. There was a notion that 'approved organisations' (ASSA; SAAO; Universities; etc) appoint personnel to train users of green laser pointers in the safe practices.
2. Aspiring LSO's has to pass a laser safety test.
3. ASSA should have a LASER safety section (to communicate with the DoH)
   
   

Go to Pretoria Centre for more information about:

• Example of a very comprehensive Laser Safety Manual.
• Give feedback or leave a comment about the Green laser isssue
• Read some of the feedback and comments.