Stanford Lockheed Institute for Scientific Research (SLISR)
Palo Alto, Calif.
June 8, 1998
"TRACE is demonstrating that large scale events can happen very rapidly on the Sun," said Dr. Alan Title, the TRACE Principal Investigator from the Stanford Lockheed Institute for Scientific Research (SLISR) in Palo Alto, Calif. "Although less than 200 miles wide, the flare was about 55,000 miles long. It appeared and vanished in just a few minutes. TRACE was able to detect this explosion because it can maintain high cadence, high resolution imagings for long durations. At the time of the explosion, TRACE was taking images at a cadence of a frame every 86 seconds and an exposure time of 28 seconds."
High resolution movies of this explosion will be presented at a press conference Monday, June 8, 1998 at 2:30 A.M. PDT during the spring meeting of the American Astronomical Society in San Diego, Calif.
"TRACE is operated in conjunction with the ESA/NASA Solar and Heliospheric Observatory (SOHO) spacecraft. The Michelson Doppler Imager (MDI) on SOHO was producing magnetic and velocity maps at the time. These tell us where the flare occurred with respect to the Sun's magnetic field, and further analysis may reveal evidence for Sun quakes. The SOHO Extreme-Ultraviolet Imaging Telescope (EIT) was taking full disk images during the same interval at a 17 minute cadence. About an hour before the flare, the EIT movie shows that a coronal mass ejection (eruption of hot gas from the Sun, abbreviated CME) occurred on the edge of the Sun. It is well known that such events trigger waves that can travel across the entire Sun. It may be that the trigger for the flare came from the blast wave associated with the CME. We are now studying the EIT data and will be on the look out for similar events in future data," said Title.
"The TRACE spacecraft had been following an active region's (NOAA 8227) passage across the solar disk since May 26, 1998. Suddenly, at 3:56:18 UTC on May 31, the region brightened in an area that was approximately 'T' shaped. The top and length of the 'T' were each about 55,000 miles (90,000 km) long and less than 200 miles (350 km) wide. At the same time, the X-ray detectors on the National Oceanic and Atmospheric Administration's (NOAA) GOES satellite recorded a doubling of their signals. The explosion is not visible in the frame taken a couple of minutes earlier at 3:54:52 UTC. This means that the event trigger, if it started from a point, had to travel at least 55,000 miles in a time period between 58 and 86 seconds long. This corresponds to a velocity of between 640 and 2,000 miles/second (2.3 to 7.1 million miles/hour)." said Title.
"The intensity in the exploding region increases by a factor of at least 220 between frames. We don't know exactly how much the increase is because we don't know when in the exposure the increase occurred. Almost as fast as the increase is the cooling. A frame 149 seconds later shows almost no evidence of the event," added Title.
"The TRACE spacecraft is unique in that it has both high spatial and temporal resolution in the extreme ultraviolet, a wavelength of light that reveals the multimillion degree Sun. We can image solar activity in finer detail than existing spacecraft, and we can take a new image once every few seconds. For example, there are 25 TRACE pixels for each one of SOHO EIT. Both high temporal and spatial resolution are necessary for our mission, which is to understand in great detail how energy is transported from the solar surface into the outer atmosphere. In the past, spacecraft of lower resolution were forced to average over much larger areas and periods of time. This made it difficult to get at the fundamental physics," said Title.
The TRACE spacecraft, launched from Vandenberg Air Force Base in Calif., Apr. 1, 1998, joins a multinational fleet of International Solar Terrestrial Physics project spacecraft studying the Sun during a critical period when solar activity is beginning its rise to a peak early in the new millennium. The Sun goes through an 11-year cycle from a period of numerous intense storms and sunspots to a period of relative calm and then back again. The coming months in the Sun's cycle will provide solar scientists with periods of intense solar activity interspersed with periods when the Sun is relatively passive and quiet. This will give TRACE the chance to study the full range of solar conditions, even in its relatively short planned lifetime.
TRACE is training it's powerful telescope on the so-called "transition region" of the Sun's atmosphere, a dynamic region between the relatively cool surface and lower atmosphere regions of the Sun (about 6,000 degrees Fahrenheit) and the extremely hot upper atmosphere called the corona (up to 3 million degrees Fahrenheit). Using portions of the telescope sensitive to extreme-ultraviolet and ultraviolet wavelengths of light, TRACE is studying the detailed connections between the fine scale surface features and the overlying, changing atmospheric structures of hot, electrically charged gas called plasma. The surface features and atmospheric structures are linked by fine-scale solar magnetic fields. The solar atmosphere is constantly evolving because the magnetic fields that dominate the corona are continuously displaced by the convective motions in the outer layers of the Sun just below the photosphere.
The TRACE science team will also study the evolution of events, such as massive flarings and huge eruptions, in the Sun's atmosphere. These events originate at the Sun's visible surface, the photosphere, and travel upward through it's atmosphere (chromosphere and transition region), and then into its super-hot corona before speeding out into space, sometimes towards Earth.
The power of the TRACE telescope to do detailed studies of the solar atmosphere makes this observatory unique among the current group of spacecraft studying the Sun. The spacecraft has roughly 10 times the temporal resolution and 5 times the spatial resolution of previously launched solar spacecraft. These advances are possible because of the near Earth "Sun-synchronous" orbit and significant advances in optical coatings developed at the Lawrence Livermore National Laboratory, Livermore, Calif., and an optical system developed at the Smithsonian Astrophysical Observatory, Cambridge, Mass. A Sun-synchronous orbit is uninterrupted by Earth's shadow for eight months at a time, allowing the mission the greatest chance to observe the random processes which lead to flares and massive eruptions in the Sun's atmosphere.
PHOTO CAPTION:
RAPID SOLAR FLARE IMAGE: This image was taken using the extreme ultraviolet light telescope on board NASA's Transition Region and Coronal Explorer (TRACE) spacecraft on May 31, 1998. The bright, roughly "T" shaped region is a solar flare, an explosion in the Sun's atmosphere caused by the tearing and reconnection of strong magnetic fields. The top and length of the 'T' are each about 55,000 miles (90,000 kilometers) long and less than 200 miles (350 kilometers) wide. Although very large, the flare appeared and vanished in just a few minutes. TRACE was able to detect this explosion because it can maintain high cadence, high resolution imagings for long durations. At the time of the explosion, TRACE was taking images at a cadence of a frame every 86 seconds and an exposure time of 28 seconds.
(Photo Credit: Dr. Alan Title, Stanford Lockheed Institute for Scientific Research and NASA Goddard)
NASA Headquarters, Washington, DC
Goddard Space Flight Center, Greenbelt, MD
May 29, 1998
The magnetic reconnection was observed on May 8, 1998, in a region of the solar atmosphere where two sets of perpendicular magnetic loops expanded into each other. Magnetic reconnection occurs when magnetic fields "snap" to a new, lower energy configuration, much like when a twisted rubber band unwinds or breaks. A magnetic reconnection can release vast amounts of energy and is responsible for explosive events on the Sun, such as flares, that can cause communication and power system disruptions on Earth.
High resolution movies of a relatively small but clear magnetic reconnection event and other spectacular solar activity observed by TRACE were presented today during the spring meeting of the American Geophysical Union in Boston.
"The TRACE spacecraft is unique in that it has both high spatial and temporal resolution in the extreme ultraviolet, wavelengths of light that reveal the multimillion degree temperature of the Sun," said Dr. Alan Title, TRACE Principal Investigator from the Stanford Lockheed Institute for Scientific Research (SLISR) in Palo Alto, CA. "We can image solar activity in finer detail than existing spacecraft, and we can take a new image once every few seconds. Both are necessary for our mission, which is to understand in great detail how energy is transported from the solar surface into the outer atmosphere. In the past, spacecraft of lower resolution were forced to average over much larger areas and periods of time. This made it difficult to get at the fundamental physics."
"In our magnetic reconnection movie, we can distinguish the fine details of the magnetic fields and see how they change during time periods of about a minute. TRACE has given us many surprises, and new ones occur nearly every observation. We found that even large areas of the Sun, some more than 60,000 miles long, can heat up or cool down significantly and thus appear and disappear in just a few minutes," said Title.
The TRACE spacecraft, launched from Vandenberg AFB, CA, on April 1, 1998, joins a multinational fleet of International Solar Terrestrial Physics project spacecraft studying the Sun during a critical period when solar activity is beginning its rise to a peak early in the new millennium. The Sun goes through an 11-year cycle from a period of numerous intense storms and sunspots to a period of relative calm and then back again. The coming months in the Sun's cycle will provide solar scientists with periods of intense solar activity interspersed with periods when the Sun is relatively passive and quiet. This will give TRACE the chance to study the full range of solar conditions, even in its relatively short planned lifetime.
TRACE is training its powerful telescope on the so-called "transition region" of the Sun's atmosphere, a dynamic region between the relatively cool surface and lower atmosphere regions of the Sun (about 10,000 degrees Fahrenheit) and the extremely hot upper atmosphere called the corona (up to three million degrees Fahrenheit). Using portions of the telescope sensitive to extreme-ultraviolet and ultraviolet wavelengths of light, TRACE is studying the detailed connections between the fine-scale surface features and the overlying, changing atmospheric structures of hot, electrically charged gas called plasma. The surface features and atmospheric structures are linked by fine-scale solar magnetic fields. The solar atmosphere is constantly evolving because the magnetic fields that dominate the corona are continuously displaced by the convective motions in the outer layers of the Sun just below the photosphere.
The TRACE science team also will study the evolution of events, such as massive flarings and huge eruptions, in the Sun's atmosphere. These events originate at the Sun's visible surface, the photosphere, and travel upward through its atmosphere (chromosphere and transition region), and then into its super-hot corona before speeding out into space, sometimes towards Earth.
The power of the TRACE telescope to do detailed studies of the solar atmosphere makes this observatory unique among the current group of spacecraft studying the Sun. The spacecraft has roughly 10 times the temporal resolution and five times the spatial resolution of previously launched solar spacecraft. A Sun-synchronous orbit is uninterrupted by EarthÕs shadow for eight months at a time, allowing the mission the greatest chance to observe the random processes which lead to flares and massive eruptions in the Sun's atmosphere.
The TRACE core team consists scientists from Lockheed Martin Advanced Technology Center, Stanford University, NASAÕs Goddard Space Flight Center, the University of Chicago, Montana State University, and the Harvard-Smithsonian Center for Astrophysics. Images to support this story are available at:
FTP://PAO.GSFC.NASA.GOV/newsmedia/TRACE/.
NASA News
National Aeronautics and Space Administration
John F. Kennedy Space Center
March 24, 1998
The 465-pound TRACE spacecraft will study the evolution of events in the Sun's atmosphere that originate at the solar surface and travel through the four regions of the Sun on their way towards Earth. The coming months in the Sun's cycle will provide solar scientists with periods of intense solar activity - massive flarings and huge eruptions - interspersed with periods when the Sun is relatively passive and quiet. Thus, TRACE will be able to study the full range of solar conditions, even in its relatively short one-year life.
The prelaunch news conference, to be carried live on NASA Television, is scheduled to occur on launch day, Wednesday, April 1, at 11 a.m. PST in the conference room of the NASA-KSC Resident Office at Vandenberg Air Force Base. Two-way question and answer capability will be available from NASA Headquarters, Kennedy Space Center and Goddard Space Flight Center.
Participating in the prelaunch news conference will be:
- Ray Lugo, NASA Launch Manager,
Kennedy Space Center
- Bruce Clark, Pegasus Launch Vehicle Manager,
Goddard Space Flight Center
- J.R. Thompson, Manager, Orbital Launch Services
Orbital Sciences Corporation
- Jim Watzin, TRACE Mission Director/Manager, Small Explorer Project
Goddard Space Flight Center
- Dr. Alan Title, TRACE Principle Investigator
Stanford-Lockheed Institute for Scientific Research
- Captain Tamara Parsons, Launch Weather Officer
USAF 30th Weather Squadron, Vandenberg Air Force Base
NASA Headquarters, Washington, DC
Goddard Space Flight Center, Greenbelt, MD
March 19, 1998
The TRACE mission will join a fleet of spacecraft studying the Sun during a critical period when solar activity is beginning its rise to a peak early in the new millennium. The Sun goes through an 11-year cycle from a period of numerous intense storms and sunspots to a period of relative calm and then back again. The coming months in the Sun's cycle will provide solar scientists with periods of strong solar activity interspersed with periods when the Sun is relatively passive and quiet. This will give TRACE the chance to study the full range of solar conditions, even in its relatively short planned lifetime.
TRACE will train its powerful telescope on the dynamic so- called 'transition region' of the Sun's atmosphere, between the relatively cool surface and lower atmosphere of the Sun where temperatures are about 6,000 degrees Fahrenheit, and the extremely hot upper atmosphere called the corona, where temperatures are up to 16 million degrees Fahrenheit. Using instruments sensitive to extreme-ultraviolet and ultraviolet wavelengths of light, TRACE will study the detailed connections between the fine-scale surface features and the overlying, changing atmospheric structures of hot, ionized gas, called plasma. The surface features and atmospheric structures are linked by fine-scale solar magnetic fields.
The power of the TRACE telescope to do detailed studies of the solar atmosphere makes this observatory unique among the current group of spacecraft studying the Sun.
"The spacecraft has roughly ten times the temporal resolution and five times the spatial resolution of previously launched solar spacecraft. Its findings are eagerly awaited by the solar science community," said Dr. Alan Title, TRACE principal investigator from the Stanford Lockheed Institute for Scientific Research in Palo Alto, CA. "We can expect to resolve some present mysteries of the Sun's atmospheric dynamics as well as discover new and exciting phenomena."
TRACE will be launched into a polar orbit to enable virtually continuous observations of the Sun, uninterrupted by the Earth's shadow for months at a time. This orbit will give the mission the greatest chance of observing the random processes which lead to flares and massive eruptions in the Sun's atmosphere.
The TRACE telescope is really four telescopes in one. Its 30-centimeter (12-inch) primary and six-centimeter (2-inch) secondary super-polished mirrors are individually coated in four distinct quadrants to allow light from different bandwidths (colors) to be reflected and analyzed. An electronic detector collects images over a 231,000-by-231,000- mile field of view, nearly 25 percent of the Sun's disk. A powerful data handling computer enables very flexible use of the detector array including adaptive target selection, data compression and image stabilization.
"TRACE was completed on time, under budget, and met all performance goals," said Jim Watzin, Small Explorer project manager, NASA Goddard Space Flight Center, Greenbelt, MD. "I'm really proud of this team. They have produced a magnificent observatory in a manner that saved NASA nearly $9.7 million over the initial cost estimate." TRACE, which costs $49 million, is the third launch in the Small Explorer series of small, quickly developed, relatively low-cost missions.
TRACE will be launched on an Orbital Sciences Corp., Dulles, VA, Pegasus-XL rocket released from an L-1011 jet aircraft at the Western Range, Vandenberg Air Force Base, CA. The launch window is open for 10 minutes.
TRACE will be the first space science mission with an open data policy. All data obtained by TRACE will be available to other scientists, students and the general public shortly after the information becomes available to the primary science team.
The TRACE telescope was designed and developed in cooperation between Lockheed Martin Corp. and Stanford University. The spacecraft was designed and tested at Goddard, which manages the mission for the Office of Space Science at NASA Headquarters, Washington, DC.
Further information about the TRACE mission can be found on the Internet at:
http://sunland.gsfc.nasa.gov/smex/trace
TRACE science information can be found at:
http://www.space.lockheed.com/TRACE/welcome.html
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