Feb 7 2013

From The Space Library

RELEASE: 13-041 - NASA TELESCOPES DISCOVER STROBE-LIKE FLASHES IN A SUSPECTED BINARY PROTOSTAR --WASHINGTON -- Two of NASA's great observatories, the Spitzer and Hubble space telescopes, have teamed up to uncover a mysterious infant star that behaves like a strobe light. Every 25.34 days, the object, designated LRLL 54361, unleashes a burst of light. Although a similar phenomenon has been observed in two other young stellar objects, this is the most powerful such beacon seen to date. The heart of the fireworks is hidden behind a dense disk and envelope of dust. Astronomers propose the light flashes are caused by periodic interactions between two newly formed stars that are binary, or gravitationally bound to each other. LRLL 54361 offers insights into the early stages of star formation when lots of gas and dust is being rapidly accreted, or pulled together, to form a new binary star. Astronomers theorize the flashes are caused by material suddenly being dumped onto the growing stars, known as protostars. A blast of radiation is unleashed each time the stars get close to each other in their orbits. This phenomenon, called pulsed accretion, has been seen in later stages of star birth, but never in such a young system or with such intensity and regularity. This protostar has such large brightness variations with a precise period that it is very difficult to explain, said James Muzerolle of the Space Telescope Science Institute in Baltimore, Md. His paper recently was published in the science journal Nature. Discovered by NASA's Spitzer Space Telescope, LRLL 54361 is a variable object inside the star-forming region IC 348, located 950 light-years from Earth. Data from Spitzer revealed the presence of protostars. Based on statistical analysis, the two stars are estimated to be no more than a few hundred thousand years old. The Spitzer infrared data, collected repeatedly during a period of seven years, showed unusual outbursts in the brightness of the suspected binary protostar. Surprisingly, the outbursts recurred every 25.34 days, which is a very rare phenomenon. Astronomers used NASA's Hubble Space Telescope to confirm the Spitzer observations and reveal the detailed stellar structure around LRLL 54361. Hubble observed two cavities above and below a dusty disk. The cavities are visible by tracing light scattered off their edges. They likely were blown out of the surrounding natal envelope of dust and gas by an outflow launched near the central stars. The disk and the envelope prevent the suspected binary star pair from being observed directly. By capturing multiple images over the course of one pulse event, the Hubble observations uncovered a spectacular movement of light away from the center of the system, an optical illusion known as a light echo. Muzerolle and his team hypothesized the pair of stars in the center of the dust cloud move around each other in a very eccentric orbit. As the stars approach each other, dust and gas are dragged from the inner edge of a surrounding disk. The material ultimately crashes onto one or both stars, which triggers a flash of light that illuminates the circumstellar dust. The system is rare because close binaries account for only a few percent of our galaxy's stellar population. This is likely a brief, transitory phase in the birth of a star system. Muzerolle's team next plans to continue monitoring LRLL 54361 using other facilities including the European Space Agency's Herschel Space Telescope. The team hopes to eventually obtain more direct measurements of the binary star and its orbit.

RELEASE: 13-042 - NASA HOSTS ITS FIRST GOOGLE+ HANGOUT CONNECTING WITH SPACE STATION --WASHINGTON -- NASA will host its first Google+ Hangout live with the International Space Station from 10:30 a.m. to 11:30 a.m. EST, Friday, Feb. 22. This event will connect NASA's social media followers with astronauts on the ground and living and working aboard the laboratory orbiting 240 miles above Earth. NASA's social media followers may submit video questions prior to the Hangout. During the event, several video questions will be selected and answered by the station crew and astronauts on the ground. Unique and original questions are more likely to be selected. Additionally, NASA also will take real-time questions submitted by fans on Google+, Twitter and Facebook. The deadline to submit video questions is Feb. 12. To be considered, video clips must be no longer than 30 seconds and must be uploaded to YouTube and tagged with #askAstro.

MEDIA ADVISORY: M13-028 - NASA ADMINISTRATOR, INTERIOR SECRETARY ATTEND LANDSAT LAUNCH --WASHINGTON -- NASA Administrator Charles Bolden and Interior Secretary Ken Salazar will attend the launch of the Landsat Data Continuity Mission (LDCM) from Vandenberg Air Force Base in California on Monday, Feb. 11. The launch is scheduled for 10:02 a.m. PST. LDCM is a collaboration between NASA and the Department of the Interior's U.S. Geological Survey. The mission will continue the Landsat program's 40-year continuous data record by Earth's landscapes by satellite from space. LDCM will expand and improve on that record with observations that advance a wide range of Earth sciences and contribute to the management of agriculture, water and forest resources. Administrator Bolden and Interior's Assistant Secretary for Water and Science Anne Castle will meet with news media Sunday, Feb. 10, at Vandenberg's Atlas V/LDCM launch pad for interviews and a photo opportunity. The Atlas V rocket carrying the satellite will be visible within the gantry. A media escort will depart Vandenberg's South Base gate on Highway 246 and Arguello Boulevard for Space Launch Complex-3 at 2:45 p.m. on Sunday. After launch Monday, Bolden and Salazar will meet with reporters at 11:30 a.m. at the NASA complex on the southern area of Vandenberg. Following the post-launch news conference, Bolden will visit the SpaceX launch pad at 1:30 p.m. The launch pad, which is being built at Space Launch Complex-4, will support the SpaceX Falcon 9 and Falcon Heavy rockets. In 2015, a Falcon 9 rocket will launch the Jason-3 sea surface monitoring mission from Vandenberg. NASA's Goddard Space Flight Center manages the LDCM Project. Orbital Sciences Corp. built, integrated, and tested the spacecraft. NASA's Launch Services Program at the agency's Kennedy Space Center in Florida is managing the launch. United Launch Alliance supplied the Atlas V rocket. After launch and the initial checkout phase, the U.S. Geological Survey will take operational control of the satellite, and LDCM will be renamed Landsat 8.