麻豆淫院

(麻豆淫院Org.com) -- Astronomers using the W. M. Keck Observatory have peered far into a young planetary system, giving an unprecedented view of dust and gas that might eventually form planets similar to Jupiter, Venus, or even Earth. The researchers used the Keck Interferometer, which combines the light-gathering power of both 10-meter Keck telescopes to act as an 85-meter telescopemuch larger than any existing or planned telescope.

鈥淏ecause the gas, dust and debris that orbit young stars provide the raw materials for planets, probing the inner regions of those stars lets us learn about how Earth-like planets form,鈥� said astronomer Sam Ragland of Keck Observatory. He and his collaborators recently measured the properties of a young planetary system at distances closer to the star than Venus is to the Sun.

The researchers used the Keck Interferometer, which combines the light-gathering power of both 10-meter Keck telescopes to act as an 85-meter telescope, much larger than any existing or planned telescope.

鈥淣othing else in the world provides us with the types of measurements the Keck Interferometer does,鈥� said Wesley Traub of Caltech鈥檚 Jet Propulsion Laboratory. 鈥淚n effect, it鈥檚 a zoom lens for the Keck telescopes.鈥�

The 鈥渮oom lens鈥� allowed the researchers to probe MWC 419, a blue, B-type star that has several times the mass of the Sun and lies about 2,100 light-years away in the constellation Cassiopeia. With an age less than ten million years, MWC 419 ranks as a stellar kindergartener.

With the interferometer and the increased ability to observe fine detail, the team measured temperatures in the planet-forming disk to within about 50 million miles of the star. 鈥淭hat鈥檚 about half of Earth鈥檚 distance from the Sun, and well within the orbit of Venus,鈥� said team member William Danchi of NASA鈥檚 Goddard Space Flight Center in Greenbelt, Md.

For comparison, astronomers using a single telescope have directly observed HR 8799, Fomalhaut and GJ 758 and their orbiting planets, which are 40 to 100 times farther away from their stars.

The interferometry results were taken in near-infrared light (3.5 to 4.1 micrometers), which is a wavelength slightly longer than red light and is invisible to the human eye. The researchers used a newly implemented infrared camera, which is the only one of its kind on Earth, to make the first 鈥淟-band鈥� interferometric observations of MWC 419.

鈥淭his unique infrared capability adds a new dimension to the Keck Interferometer in probing the density and temperature of planet-forming regions around young stars. This wavelength region is relatively unexplored,鈥� Ragland said. 鈥淏asically, anything we see through this camera is brand new information.鈥�

With the data, Ragland and his collaborators measured the temperature of dust at various regions throughout MWC 419鈥檚 inner disk. Temperature differences throughout the disk may indicate that the dust has different chemical compositions and physical properties that may affect how planets form. For example, in the Solar System, conditions were just right to allow rocky worlds to form closer to the Sun, while gas giants and icy moons assembled farther our in the system. The team reported their findings in the Sept. 20 issue of the Astrophysical Journal.

The observations are an 鈥渋mportant first step鈥� in a larger program to collect data on young stars that span the lower-mass T Tauri stars, which are the progenitors of Sun-like stars, to their more massive counterparts, like MWC 419, explained John Monnier, an interferometry scientist at the University of Michigan who was not involved with the study.

The astronomers want to study the range of developing stars because their mass, size and luminosity might affect the composition and physical characteristics of the surrounding disk. Ragland and his collaborators are continuing to collect data on young stars and will combine their infrared observations with new data from the Keck Interferometer鈥檚 鈥渘ulling鈥� mode, a technique which will block out the light from the central star in a young planetary system.