Long before the term “citizen science” was coined, the field of astronomy has benefited from countless men and women who
study the sky in their spare time. These amateur astronomers devote hours exploring the cosmos through a variety of
telescopes that they acquire, maintain, and improve on their own. Some of these amateur astronomers specialize in capturing
what is seen through their telescopes in images and are astrophotographers.
What happens when the work of amateur astronomers and astrophotographers is combined with the data from some of the world’s
most sophisticated space telescopes? Collaborations between professional and amateur astronomers reveal the possibilities and
are intended to raise interest and awareness among the community of the wealth of data publicly available in NASA’s various
mission archives. This effort is particularly appropriate for this month because April marks Global Astronomy Month, the
world’s largest global celebration of astronomy.
The images in this quartet of galaxies represent a sample of composites created with X-ray data from NASA’s Chandra X-ray
Observatory, infrared data from the Spitzer Space Telescope, and optical data collected by an amateur astronomer. In these
images, the X-rays from Chandra are shown in pink, infrared emission from Spitzer is red, and the optical data are in red,
green, and blue. The two astrophotographers who donated their images for these four images — Detlef Hartmann and Rolf Olsen
— used their personal telescopes of 17.5 inches and 10 inches in diameter respectively. More details on how these images
were made can be found in this blog post.
Starting in the upper left and moving clockwise, the galaxies are M101 (the “Pinwheel Galaxy”), M81, Centaurus A, and M51
(the “Whirlpool Galaxy”). M101 is a spiral galaxy like our Milky Way, but about 70% bigger. It is located about 21 million
light years from Earth. M81 is a spiral galaxy about 12 million light years away that is both relatively large in the sky and
bright, making it a frequent target for both amateur and professional astronomers. Centaurus A is the fifth brightest galaxy
in the sky — making it an ideal target for amateur astronomers — and is famous for the dust lane across its middle and a
giant jet blasting away from the supermassive black hole at its center. Finally, M51 is another spiral galaxy, about 30
million light years away, that is in the process of merging with a smaller galaxy seen to its upper left.
For many amateur astronomers and astrophotographers, a main goal of their efforts is to observe and share the wonders of the
Universe. However, the long exposures of these objects may help to reveal phenomena that may otherwise be missed in the
relatively short snapshots taken by major telescopes, which are tightly scheduled and often oversubscribed by professional
astronomers. Therefore, projects like this Astro Pro-Am collaboration might prove useful not only for producing spectacular
images, but also contributing to the knowledge of what is happening in each of these cosmic vistas.
NASA’s Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA’s Science Mission Directorate
in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Mass., controls Chandra’s science and flight
Original caption/more images: www.nasa.gov/chandra.harvard.edu/photo/2014/proam/
Image credit: Image credit: X-ray: NASA/CXC/SAO; Optical: Detlef Hartmann; Infrared: NASA/JPL-Caltech
Where Does the Solar System End?
A Second Sedna
- Title: A Sedna-like body with a perihelion of 80 astronomical units
- Authors: C. A. Trujillo & S. S. Sheppard
Sedna, a dwarf planet that resides far out in the depths of the solar system, is the first known objects that belongs to the inner Oort cloud. Discovered in 2003, Sedna became a very important trans-Neptunian object, aiding in the quest to learn about the evolution of the Solar System. With a perihelion of 76 AU, Sedna was the farthest known body in the Solar System. Recently, an object called 2012VP113 was found to be another inner Oort cloud object. This confirms that Sedna is not an isolated body and that there may be more inner Oort cloud objects out there.
The authors conducted a sky survey that focused on objects with perihelion distances between 50 AU to around 300 AU. 2012VP113 was found to have a perihelion distance of 80 AU, making it farther away from the Sun than Sedna is. The surface color of 2012VP113 is moderately red, which is consistent with formation in the gas giant region, not in the classical Kuiper belt region.
An important question from the discoveries of Sedna and 2012VP113 is how do these inner Oort cloud objects form? Currently there are two preferred models, along with one lesser studied model. One model explores the possibility that a Kuiper belt object is perturbed by some planet-sized object out towards the inner Oort cloud region. The next model suggests that inner Oort cloud objects could have been created from a close stellar encounter during the formation of the early Solar System. The third model suggests that inner Oort cloud objects could be extrasolar planetesimals captured in the formation of the early Solar System. Each theory has different possibilities, and the discovery of additional inner Oort cloud objects would provide more insight into the formation of these bodies as well as our Solar System.
Image: A combination of three images showing 2012VP113, each taken two hours apart, on November 5, 2012. (Credit: Scott S. Sheppard/Carnegie Institution for Science)
A cross-section of the Universe
Massive Nearby Spiral Galaxy NGC 2841
NGC 7293, better known as the Helix nebula, is the nearest example of a planetary nebula, which is the eventual fate of a star, like our own Sun, as it approaches the end of its life. As it runs out of fuel, the star expels its outer envelope of gas outward to form a nebula like the Helix.
Images: different views of NGC 7293. Credit: ESA, NASA, ESO.
Asteroids, Exomoons, and a Crash on the Moon
Another World (Sunrise) - Digital Painting 1440 x 900 wallpaper
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