NOAO News & Reports
December 19, 2011
NOAO: New Insight into the Bar in the Center of the Milky Way
The BRAVA fields are shown in this image montage. The center of the Milky Way is at coordinates L= 0, B=0. The regions observed are marked with colored circles. This montage shows the southern Milky Way all the way to the horizon, as seen from CTIO. The telescope in silhouette is the Blanco 4-meter, where the observation were made.
Image Credit: D. Talent, K. Don, P. Marenfeld & NOAO/AURA/NSF and the BRAVA Project
It sounds like the start of a bad joke: do you know about the bar in the center of the Milky Way Galaxy? Astronomers first recognized almost 80 years ago that the Milky Way Galaxy, around which the sun and its planets orbit, is a huge spiral galaxy. This isn’t obvious when you look at the band of starlight across the sky, because we are inside the galaxy: it’s as if the sun and solar system is a bug on the spoke of a bicycle wheel. But in recent decades astronomers have suspected that the center of our galaxy has an elongated stellar structure, or bar, that is hidden by dust and gas from easy view. Many spiral galaxies in the universe are known to exhibit such a bar through the center bulge, while other spiral galaxies are simple spirals. And astronomers ask, why? In a recent paper Dr. Andrea Kunder, of Cerro Tololo Inter-American Observatory (CTIO) in northern Chile, and a team of colleagues have presented data that demonstrates how this bar is rotating. NOAO Press Release 11-09
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November 30, 2011
NOAO: New Planet Kepler-21b discovery a partnership of both space and ground-based observations
The Kepler field as seen in the sky over Kitt Peak National Observatory. The approximate position of HD 179070 is indicated by the circle (sky imaged using a diffraction grating to show spectra of brighter stars, credit J. Glaspey; telescopes imaged separately and combined, credit P. Marenfeld)
The NASA Kepler Mission is designed to survey a portion of our region of the Milky Way Galaxy to discover Earth-size planets in or near the “habitable zone,” the region in a planetary system where liquid water can exist, and determine how many of the billions of stars in our galaxy have such planets. It now has another planet to add to its growing list. A research team led by Steve Howell, NASA Ames Research Center, has shown that one of the brightest stars in the Kepler star field has a planet with a radius only 1.6 that of the earth’s radius and a mass no greater that 10 earth masses, circling its parent star with a 2.8 day period. With such a short period, and such a bright star, the team of over 65 astronomers (that included David Silva, Ken Mighell and Mark Everett of NOAO) needed multiple telescopes on the ground to support and confirm their Kepler observations. These included the 4 meter Mayall telescope and the WIYN telescope at Kitt Peak National Observatory. NOAO Press Release 11-08
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November 21, 2011
NOAO: Student’s Work Helps to Detect Near Earth Asteroids
Asteroid NEO2008 QT3: Above is a still image from a four-frame animation showing the asteroid moving through the sky. Image taken at the 2.1-meter telescope on Kitt Peak.
An asteroid impact with the earth can really ruin your day: just consider the dinosaurs. Most asteroids, also known as minor planets, orbit the sun beyond the planet Mars and present no danger, but there is a class of asteroids whose orbits cross the orbit of the earth. If one of these asteroids and the earth are at the same point in their orbits at the same time, a collision could occur. Called Near Earth Objects (NEOs), astronomers are interested in discovering as many of these as possible, and then tracking them in order to compute more accurate orbits. In this way, if a potential future collision were to be identified many years in advance, space probes could carry out steps to tweak the path of the NEO and deflect the collision. A program to track NEOs is being carried out at NOAO by Mark Trueblood with Robert Crawford (Rincon Ranch Observatory) and Larry Lebofsky (Planetary Science Institute). And last summer, a Beloit College student, Morgan Rehnberg, has developed a computer program (PhAst), available via the web, to help with this effort. NOAO Press Release 11-07
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October 19, 2011
Blue Stragglers shown to form from mass transfer in Binary systems
This image of the open star cluster NGC 188 was taken at the WIYN 0.9m in V, B and I. The blue stragglers discussed in this paper are circled. (image credit: K. Garmany, F. Haase NOAO/AURA)
In a paper just published in Nature, Aaron Geller (Northwestern U) and Robert Mathieu (U of Wisconsin) have shown that blue stragglers are most probably formed from mass transfer or mergers in binary systems, rather than originating from stellar collisions as has also been proposed. Observations made at the WIYN 3.5m of the old open cluster NGC 188 show that blue stragglers in long period binaries have companions with masses ~ 0.5 solar mass, with very little scatter. NOAO Press Release 11-06
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October 5, 2011
Aden Meinel, First Director of Kitt Peak National Observatory, Passed Away
Dr. Aden Meinel
Astronomy and optical science lost a great pioneer and innovator when Dr. Aden Meinel passed away on 2 October 2011. Meinel led the development, and became the first Director, of the Kitt Peak National Observatory, located near Tucson, AZ. He then went on to become Director of the Steward Observatory at the University of Arizona, where he also founded the Optical Sciences program. NOAO Press Release 11-05
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