720 XTF Search Results (expand=subject;f1-subject=Star);f1-subject%3DStar Results for your query: expand=subject;f1-subject=Star Thu, 01 Jan 1970 12:00:00 GMT First stars. An artist's concept of the first stars forming after the Big Bang. The first stars should have been supermassive and metal poor stars that would end with a collapsar and a GRB, but there is currently no evidence of these earliest GRBs. Thu, 01 Jan 1970 12:00:00 GMT Far Ultraviolet Spectroscopic Explorer (FUSE) Spectrum of a Star in the Large Magellanic Cloud. The LMC star is Sanduleak -67 166. The top two panels cover the spectral region from 920 - 1120 Å. To obtain this spectrum a special telescope, FUSE, had to be built with very few reflections and with a much more sophisticated detector than was used for Copernicus. This spectrum took 60 hours to record, three times longer than it took the Copernicus satellite to observe 50 Å in zeta Ophiuchi, a star that is 10,000 time brighter than this one. For this example, FUSE is effectively 7,500 times more efficient than Copernicus. The spectrum is completely dominated by the lines of molecular hydrogen from interstellar space, some in our Galaxy and some in the Large Magellanic Cloud. The spectrum of molecular hydrogen, which contains two hydrogen nuclei (protons) and two electrons, is obviously much more complex than the spectrum of atomic hydrogen. The vibration of the two protons leads to the bands denoted 1-0, 2-0, 4-0, etc., at the top of the two panels. Within each band are very narrow components more closely sp... Thu, 01 Jan 1970 12:00:00 GMT X-ray Moon and X-ray Star. This image of the Moon in X-rays was made in 1991 using data from the Roentgen Satellite (ROSAT), an X-ray observatory. In this picture, pixel brightness corresponds to X-ray intensity. The Moon reflects lower energy X-rays (shown as red) from the Sun. The source of high energy X-rays (shown as yellow) is a distant binary star system. The background is speckled with X-rays from many distant, powerful active galaxies. The picture also shows the Moon passing in front of of and obscuring the binary star, a phenomenon called occultation. Tue, 01 Jan 1991 12:00:00 GMT Artist’s visualization of a collapsar. The collapsing star scenario that is one of the leading contenders as the cause of gamma-ray bursts. This artist's concept of the collapsar model shows the center of a dying star collapsing minutes before the star implodes and emits a gamma-ray burst that is seen across the universe. Many scientists say longer bursts (more than four seconds in duration) are caused by massive star explosions. Thu, 01 Jan 1970 12:00:00 GMT Artist’s visualization of a merging binary system. Gamma-ray bursts are common, yet random, and fleeting events that have mystified astronomers since their discovery in the late 1960s. Shorter bursts (less than two seconds in duration) are thought to be caused by mergers of binary systems with black holes or neutron stars. Thu, 01 Jan 1970 12:00:00 GMT Artist’s visualization of J1550-5418. Gamma-ray flares from SGR J1550-5418 may arise when the magnetar's surface suddenly cracks, releasing energy stored within its powerful magnetic field. Thu, 01 Jan 1970 12:00:00 GMT