SPACE: WHERE ARE WE GOING? : HERTZSPRUNG-RUSSEL DIAGRAM

Sunday, May 3, 2015

SPIRAL GALAXY NGC 5023

FROM: NASA

This NASA/ESA Hubble Space Telescope image shows an edge-on view of the spiral galaxy NGC 5023. Due to its orientation we cannot appreciate its spiral arms, but we can admire the elegant profile of its disk.

The galaxy lies over 30 million light-years away from us. NGC 5023 is part of the M51 group of galaxies. The brightest galaxy in this group is Messier 51, the Whirlpool Galaxy, which has been captured by Hubble many times. NGC 5023 is less fond of the limelight and seems rather unsociable in comparison — it is relatively isolated from the other galaxies in the group. Astronomers are particularly interested in the vertical structure of disks like these. By analyzing the structure above and below the central plane of the galaxy they can make progress in understanding galaxy evolution. Astronomers are able to analyze the distribution of different types of stars within the galaxy and their properties, in particular how well evolved they are on the Hertzsprung–Russell Diagram — a scatter graph of stars that shows their evolution. NGC 5023 is one of six edge-on spiral galaxies observed as part of a study using Hubble’s Advanced Camera for Surveys. They study this vertical distribution and find a trend which suggests that heating of the disc plays an important role in producing the stars seen away from the plane of the galaxy. In fact, NGC 5023 is pretty popular when it comes to astronomers, despite its unsociable behavior.

The galaxy is also one of 14 disk galaxies that are part of the GHOSTS survey — a survey which uses Hubble data to study galaxy halos, outer disks and star clusters. It is the largest study to date of star populations in the outskirts of disk galaxies. The incredible sharp sight of Hubble has allowed scientist to count more than 30,000 individual bright stars in this image. This is only a small fraction of the several billion stars that this galaxy contains, but the others are too faint to detect individually even with Hubble. European Space Agency Credit-ESA-NASA

STAR FLASH

What caused this outburst of V838 Mon? For reasons unknown, star V838 Mon's outer surface suddenly greatly expanded with the result that it became the brightest star in the entire Milky Way Galaxy in January 2002. Then, just as suddenly, it faded. A stellar flash like this had never been seen before -- supernovas and novas expel matter out into space. Although the V838 Mon flash appears to expel material into space, what is seen in the above image from the Hubble Space Telescope is actually an outwardly moving light echo of the bright flash. In a light echo, light from the flash is reflected by successively more distant rings in the complex array of ambient interstellar dust that already surrounded the star. V838 Mon lies about 20,000 light years away toward the constellation of the unicorn (Monoceros), while the light echo above spans about six light years in diameter. Image Credit: NASA, ESA

THE SPIDERWEB GALAXY

Looking like a spider's web swirled into a spiral, Galaxy IC 342 presents its delicate pattern of dust in this image from NASA's Spitzer Space Telescope. Seen in infrared light, faint starlight gives way to the glowing bright patterns of dust found throughout the galaxy's disk. At a distance of about 10 million light-years, IC 342 is relatively close by galactic standards, however our vantage point places it directly behind the disk of our own Milky Way. The intervening dust makes it difficult to see in visible light, but infrared light penetrates this veil easily. IC 342 belongs to the same group as its even more obscured galactic neighbor, Maffei 2. IC 342 is nearly face-on to our view, giving a clear, top-down view of the structure of its disk. It has a low surface brightness compared to other spirals, indicating a lower density of stars (seen here as a blue haze). Its dust structures show up much more vividly (red). Blue dots are stars closer to us, in our own Milky Way. New stars are forming in the disk at a healthy rate. The very center glows especially brightly in the infrared, highlighting an enormous burst of star formation occurring in this tiny region. To either side of the center, a small bar of dust and gas is helping to fuel this central star formation. Data from Spitzer's infrared array camera are shown in blue (3.6 microns), green (4.5 microns) and red (5.8 and 8.0 microns). Image Credit: NASA/JPL-Caltech

JUMPING TO WARP SPEED

This cockpit view of a hypothetical spacecraft traveling at eight-tenths the speed of light shows the visual distortions that would be experienced at such high speeds. The star field is actually being wrapped toward the front of the craft in addition to being significantly blue-shifted. NASA Glenn leads the Breakthrough Propulsion Physics Project, NASA's primary effort to produce near-term, credible, and measurable progress toward the technology breakthroughs needed to revolutionize space travel and enable interstellar voyages. NASA Lewis (now Glenn) Research Center, Cleveland, Ohio.

OBSERVATION FROM THE SPACE STATION