NASA – Rare Stellar Alignment Offers Opportunity To Hunt For Planets

Hubble Proxima Centauri

This plot shows the projected motion of the red dwarf star Proxima Centauri (green line) over the next decade, as plotted from Hubble Space Telescope observations. Because of parallax due to Earth’s motion around the sun, the path appears scalloped. Because Proxima Centauri is the closest star to our sun (distance, 4.2 light-years), its angular motion across the sky is relatively fast compared to much more distant background stars. This means that in 2014 and 2016 Proxima Centauri will pass in front of two background stars that are along its path. The background image shows a wider view of the region of sky in the southern constellation Centaurus that Proxima is traversing. Credit:NASA, ESA, K. Sahu and J. Anderson (STScI), H. Bond (STScI and Pennsylvania State University), M. Dominik (University of St. Andrews), and Digitized Sky Survey (STScI/AURA/UKSTU/AAO)

NASA’s Hubble Space Telescope will have two opportunities in the next few years to hunt for Earth-sized planets around the red dwarf Proxima Centauri.

The opportunities will occur in October 2014 and February 2016 when Proxima Centauri, the star nearest to our sun, passes in front of two other stars. Astronomers plotted Proxima Centauri’s precise path in the heavens and predicted the two close encounters using data from Hubble.

“Proxima Centauri’s trajectory offers a most interesting opportunity because of its extremely close passage to the two stars,” said Kailash Sahu, an astronomer with the Space Science Telescope Institute in Baltimore, Md. Sahu leads a team of scientists whose work he presented Monday at the 222nd meeting of American Astronomical Society in Indianapolis.

Red dwarfs are the most common class of stars in our Milky Way galaxy. Any such star ever born is still shining today. There are about 10 red dwarfs for every star like our sun. Red dwarfs are less massive than other stars. Because lower-mass stars tend to have smaller planets, red dwarfs are ideal places to go hunting for Earth-sized planets.

via NASA – Rare Stellar Alignment Offers Opportunity To Hunt For Planets.

Faint Portraits of First Galaxies Shed Light on Cosmic Dawn: Scientific American

Hubble Ultra-Deep FieldThe Hubble Ultra-Deep Field shows galaxies as they were when the Universe was young. Those with the highest estimated redshifts (numbers and insets) were born more than 13 billion years ago, soon after the Big Bang.Image: NASA, ESA, R. Ellis (Caltech), UDF 2012 Team

For one sleepless week in early September 2009, Garth Illingworth and his team had the early Universe all to themselves. At NASA’s request, Illingworth, Rychard Bouwens and Pascal Oesch had just spent the previous week staring into their computer screens at the University of California, Santa Cruz, scanning through hundreds of black-and-white portraits of faint galaxies recorded in a multi-day time exposure by a newly installed infrared camera on the Hubble Space Telescope. NASA simply wanted the three astronomers to preview the images and make sure that the camera was working correctly, before the agency released the data more widely.

But Illingworth, Bouwens and Oesch were hoping that they would find more — that at least some of those smudges of light would prove to be among the first galaxies to form in the Universe, less than 1 billion years after the Big Bang. Even a faint glimpse of such objects could provide fresh insights into some of the biggest questions in cosmology, ranging from the nature of the first stars to the tumultuous beginnings of galaxy formation.

That week, the astronomers began to focus on two dozen tiny candidate images — each so dim and grainy that they might easily be noise in the camera’s digital sensors. But as their analysis proceeded, it became clear that these patches of light had the right color, appearing only in the camera’s reddest filters — exactly what would be expected of newborn galaxies seen at a very great distance and very high redshift. And when the three colleagues started digitally adding together exposures of each candidate, says Illingworth, “suddenly there they were” — fuzzy, but undeniable images of galaxies. “That week in September was one of the most exciting times of my career!”

via Faint Portraits of First Galaxies Shed Light on Cosmic Dawn: Scientific American.

NASA – Hubble reveals the Ring Nebula’s true shape

A core disc of dark, smokey blue crossed with wisps of violet and ringed with all the colors of the rainbow before exploding into shells of red gasses streaking out across the stars

In this composite image, visible-light observations by NASA’s Hubble Space Telescope are combined with infrared data from the ground-based Large Binocular Telescope in Arizona to assemble a dramatic view of the well-known Ring Nebula. Credit: NASA, ESA, C.R. Robert O’Dell (Vanderbilt University), G.J. Ferland (University of Kentucky), W.J. Henney and M. Peimbert (National Autonomous University of Mexico)Credit for Large Binocular Telescope data: David Thompson (University of Arizona) › Larger image

The Ring Nebula’s distinctive shape makes it a popular illustration for astronomy books. But new observations by NASA’s Hubble Space Telescope of the glowing gas shroud around an old, dying, sun-like star reveal a new twist.

“The nebula is not like a bagel, but rather, it’s like a jelly doughnut, because it’s filled with material in the middle,” said C. Robert O’Dell of Vanderbilt University in Nashville, Tenn. He leads a research team that used Hubble and several ground-based telescopes to obtain the best view yet of the iconic nebula. The images show a more complex structure than astronomers once thought and have allowed them to construct the most precise 3-D model of the nebula.

The Ring Nebula is about 2,000 light-years from Earth and measures roughly 1 light-year across. Located in the constellation Lyra, the nebula is a popular target for amateur astronomers.

Previous observations by several telescopes had detected the gaseous material in the ring’s central region. But the new view by Hubble’s sharp-eyed Wide Field Camera 3 shows the nebula’s structure in more detail. O’Dell’s team suggests the ring wraps around a blue, football-shaped structure. Each end of the structure protrudes out of opposite sides of the ring.

via NASA – Hubble reveals the Ring Nebula’s true shape.