Tuesday, November 24, 2015
Quintenary Star System: Anything But Ordinary
We’ve all heard about binary stars (one star revolving around another). The most popular binary stars are Mizar and its fainter companion star Alcor. To find them, look for the Big Dipper and find the handle; you’ll spot Mizar first as the middle star of the Big Dipper’s handle. Look closely and you’ll see Alcor right next to Mizar.
Harder to find are the trinary star systems, or triple star systems. It’s interesting to me because usually two of the stars form a close binary system while the third star orbits this pair at a distance in a much larger orbit. One such system is the Alpha Centauri star system with Proxima Centauri at a distance of 4.22 light years. It is the closest star to Earth beyond our own Sun.
The Kepler Space Telescope observed KIC 2856960 for four straight years before astronomers seemed to have enough data to make a determination. But when three astronomers, Marsh, Armstrong, and Carter in the UK started digging into the numbers, they discovered the system was anything but ordinary. First they observed two stars in close orbit of one another: a binary system. The smaller star seemed to orbit the larger one every 6 hours. However, there appeared to be a third star that entered into the equation every 204 days. This was throwing off their results. As they diligently worked out their dilemma on paper, other astronomers became involved. It’s the fact that they could not find a precise set of masses and radii for the component stars. We can’t explain why this star system is producing an ‘impossible’ light curve.
As the team studied the data from KIC 2856960 they saw a small dip in brightness about 4 times a day and a larger dip every 204 days. Okay, not a big deal; it’s a triple star system, so let’s move on to other data. But they were drawn back to their results to look at it with even more detail. After all, this was tricky, and there were all sorts of things that threw off results, such as starspots and other stellar activity. The more they looked at the data, the more confusing things got. At first glance, it looked like a triple star system, but the stars’ orbits didn’t seem to fit. They kind of fit, but there were fluctuations in the data. So the team tried another scenario and found that a four-star system worked—a quintenary system—two sets of binary stars!
This is anything but ordinary, and further data needs to be collected, but it’s clear that this is not a simple, boring triple-star system. We just don’t understand it yet. Perhaps the Transiting Exoplanet Survey Satellite, or TESS, will be able to shed some light on this. TESS is scheduled to launch in 2017. Until then KIC 2856960 is likely to remain a mystery. Is this a quintenary star system? Is there a planet hidden in this system? Don’t you love a good mystery?
Recommended link: http://www.atlasoftheuniverse.com/orbits.html
My sources: AtlasoftheUniverse.com, space.com, phys.org, pbs.org, atrobites.org, astronomy.com, and American Association of Variable Star Observers (AAVSO)
Sunday, September 6, 2015
Mordor Macula, Vader Crater, Nostromo Chasma…
By Jean E. Lane
New Horizons’ flyby of Pluto and Charon, its largest moon provided us with many incredible images. But the highly detailed images gave the New Horizons team an unanticipated problem: What do they call all those mountain ranges, plains, and craters?
What happens next is that the team intends to submit them to the International Astronomical Union (IAU), who is the official governing body for names of celestial objects. Here’s what’s currently being proposed to the committee; how about choosing names from Star Trek, Star Wars, Doctor Who, Firefly, Alien, and Lord of the Rings? The New Horizons team actually asked for submissions from the public, and they were only too happy to oblige.
Since Pluto was named after a god of the underworld, the names must be drawn from underworld mythology. NASA offered the Cthulu regio (a large region with color variances). Also chosen was the name Balrog macula (meaning dark spot) which honored Lovercraft’s dark god and the underground demons from stories by J.R.R. Tolkein.
All that’s wonderful news, but it’s Charon, Pluto’s moon, and the IAU rules permit names that reference “destinations and milestones of fictional space” as well as fictional spaceships and travelers. This notion grabbed the imaginations of many space fans, and their thoughts went directly to the iconic science fiction shows and movies that they revere.
Thus, the suggestions were presented, and the unofficial names, of craters are Vader, Skywalker and Leia Organa. For the plains they propose names of Spock, Kirk, Sulu, and Uhura, which would dot the Vulcan Planum. How about the Tardis chasma that crosses the Gallifrey macula? This name, of course is in reference to The Doctor’s (Doctor Who) vessel and planet. It also has been proposed that names from Alien, such as Ripley crater and Nostromo chasma, would be excellent choices. The name Serenity chasma in respect for Firefly also has a chance to become a real place on Charon. There’s room for one from Lord of the Rings, the giant Mordor macula at Charon’s North Pole.
Although they are nevertheless provisional, “We still have a decent chance of getting these names approved,” stated New Horizons planetary scientist Mark Showalter. After all, the IAU has previously approved features on Saturn’s moon, Titan, named Frodo and Bilbo, and the first landing site on Mars is now called Bradbury’s Landing!
Ah, this is news that stirs the creative abyss of a science fiction or science “faction” heart!
References: NASA, The Planetary Society, Mashable.com, International Astronomical Union, EarthSky, Washington Post, and National Geographic
Saturday, August 1, 2015
GLOBULAR CLUSTERS…What are they?
You may have heard the term “Globular Clusters” before, but exactly what are they? According to the Planetary Society: “Like stellar time capsules adorning the periphery of galaxies, globular clusters contain some of the oldest stars in the universe.” Some of these star clusters may seem to have the appearance of galaxies. This is because they are a symmetrical system of stars with the highest concentration of stars near their own center and bound together by gravity. Imagine yourself on a world where the sky is always ablaze with the sight of hundreds of thousands of stars as bright as the full Moon. Most likely these stars would be the older, fainter, red and yellow stars.The more dense globular clusters can be found in the halo of a galaxy, whereas the less dense galactic, or open, clusters are located in the disk of a galaxy. The clusters in the halo contain considerably more stars than the open clusters. Globular clusters are fairly common; there are about 157 of them currently known in the Milky Way Galaxy. Larger galaxies, such as our neighbor Andromeda, may have as many as 500. Moreover, the giant elliptical galaxies may have as many as 13,000 globular clusters.
The first globular cluster discovered was M22 in 1665 by Abraham Ihle, a German amateur astronomer. However, given the poor aperture ability of early telescopes, individual stars within a globular cluster were not resolved until Charles Messier observed M4, discovered in 1746. The designation before a number refers to the catalog where the discovery is listed. The letter “M” tells us it is listed in the Messier catalog, whereas “NGC” tell us it could be found in the New General Catalog by John Dreyer. The designation letter is something that I’ve wondered about and just learned more details in this research.
We have 157 cataloged globular clusters right in our own galactic neighborhood, the Milky Way. There are too many to list here, but our largest cluster is Omega Centauri (NGC5139) and second is 47 Tucanae, both of which can be observed with the naked eye under the right conditions., M4 and NGC6397 are both 7200 light years away. Some other noteworthy clusters are NCG104, NGC4833, M55, M69, and M13. There are so many of these beautiful star clusters - out there, waiting for you to discover.
Stunning images and more info at: http://www.astro.keele.ac.uk/workx/globulars/globulars.html
My sources: NASA.gov, en.wikipedia.org, spider.seds.org, astrosociety.org, hyperphysicis.phy-astr.gsu.edu, astro.keele.ac.uk, Britannica.com, The Planetary Society, ned.ipac,caltech.edu, and astronomy.com.
Saturday, May 2, 2015
Does a Real-Life Death Star Exist?
No, I’m not talking about something from the movies. That star would need to get close to a planet to destroy it. WR104, however, has the potential to burn worlds from thousands of light years away. This is Wolf-Rayet 104 located in the constellation of Sagittarius about 2,222 parsecs away. Okay, that’s about 8,000 light-years from us which may seem like a safe distance, but consider that WR104 is 25 times the size of our sun, very dense, and much, much hotter. Add to that mix the fact that this star is rotating rapidly and expelling its gases creating a spiral around it; it is dying.
At this level of brightness the radiation field around the star takes on a life of its own and plays a most unusual role; it sheds off the outer atmosphere of the star by photon pressure. Therefore, Wolf-Rayet stars are so luminous that they are literally flying apart! This creates a high-velocity stellar wind surrounding the star which first grabbed the attention of astronomers. Wolf-Rayet stars are very rare, only 230 have been discovered, so far, in our Milky Way Galaxy. Of these stars, half of them have a binary companion star which burns just as hot as the main star.
First discovered in 1998 by the Keck 1 Telescope, this star was photographed, studied, measured, and cataloged. Scientists were first taken by the size and beauty of this spiral image. They determined the diameter to be 160AU (Astronomical Units), which is 160 times the distance from Earth to the sun. Peter Tuthill, at the University of Sydney in Australia, has been studying WR104 for years. He realized it rotated in a circle every eight months and found one devastating fact: Earth looks down the axis of the system. We are not looking at it from an angle, but dead-on, like looking down the barrel of a rifle.
Another fact which concerns astronomers is that WR104 is not a single star system, rather a binary system. It has another Class OB star locked in orbit with it. As they circle one another, plumes of streaming gas are driven from their surfaces creating a fiery, colorful pinwheel in space. Astronomers fear the fuse for this star is very short; it may explode within the next few hundred thousand years. When it does it may emit an intense beam or ‘gamma ray burst.’ It is impossible to predict whether or not it will actually create the dreaded gamma ray beam directed at Earth; the exact outcome is still unknown. Some reports say, “Not to worry,” others say, “Earth is in line with a death-star.” I say, it’s a long time away; we have more important things to worry about until then.
For an image of WR104 visit: http://www.space.com/5081-real-death-star-strike-earth.html
My Sources: Astro Dept. at University of Michigan, nature.com/news, dailygalaxy.com, popsci.com, science.time.com, universetoday.com, space.com, and en.wikipedia.org
Saturday, March 14, 2015
Planet Hunter: TESS
Transiting Exoplanet Survey Satellite (TESS) will be launched in 2017 as an Astrophysics Explorer mission. This satellite will be an Explorer class planet finder. As the first ever spaceborne all-sky transit survey, TESS will identify planets ranging from Earth-sized to gas giants that orbit around their bright host star in the solar neighborhood. The mission goal is to find detailed characterizations of these planets and determine their atmospheres.
NASA will launch TESS from Cape Canaveral, Florida in August of 2017 on a SpaceX Falcon 9 rocket and will achieve a unique high altitude orbit according to the mission’s top scientist, George Ricker. The satellite will carry four wide field-of-view 16.8 megapixel cameras to cover 400 times the area of the sky seen by Kepler. In its two year mission TESS will be circle nearby stars and look for planets. Part of the mission is a follow up of observations from Earth to determine whether the alien worlds might be suitable for life.
TESS is expected to monitor more than 500,000 stars during its mission, searching for temporary fluctuations in brightness caused by planetary transits. Transits occur when a planet’s orbit carries it directly in front of its host star as viewed from Earth. It should be able to catalog more than 3,000 transiting exoplanet candidates. This would include 500 Earth-sized and super-Earth sized planets as well as smaller rocky ice planets in the ‘goldilocks’ or habitable zone. It is hoped that these observations will refine the measurements of the planet masses, sizes, densities, and atmospheric properties.
This will be the first ever spaceborne all-sky transit survey which means that the search for exoplanets is heating up, and it appears that Earth’s scientists have no intention of slowing down. Our sun is a Class G star – or a yellow-white main sequence star. TESS will be able to detect the variances in a star’s brightness and will be looking for Class M stars (or suns) that are a bit cooler than our own sun. Class M stars are reddish stars 2 to 3 times more abundant as solar type stars. How many of these suns will we actually find? What are the chances of finding another planet similar to Earth? What are the odds of finding a planet that supports any type of life? I, for one, am very curious to see what is out there. Aren’t you?
Tuesday, January 27, 2015
WAITING FOR DAWNCeres the largest object in the main Asteroid Belt is waiting for the arrival of Dawn as early as March 6th, 2015. This icy mass was originally called a planet when discovered in 1801 by an Italian astronomer named Giuseppe Piazzi. Since that time and with some debate its definition was changed in 2006 by the International Astronomical Union and Ceres is now classified as a dwarf planet.
If you are not familiar with Ceres, here are some interesting facts:
· It is fourteen times smaller than Pluto.
· It is 590 miles in diameter.
· It constitutes about 30% of the mass of everything in the asteroid belt.
· It completes a rotation every 9 hours and 4 minutes.
· It is believed to have a rocky core with an icy mantle.
· Its surface can warm to -36 degrees Fahrenheit.
· It has an atmosphere but it is very weak.
· It has a mysterious bright ‘white’ spot.
While the world awaits the first visit to Pluto this July by another mission, the space probe Dawn is nearing the end of its seven-year, 3.1 billion mile journey deep into the Asteroid Belt. I’m, wondering about the nature of this alien world. What does it look like? Will there be mountains, craters, and “cryovolcanoes” that spew frozen water miles into its thin atmosphere? What is that bright ‘white’ spot anyway? What lies below that frozen surface…a liquid ocean? Although the chance of life existing on Ceres is very low, scientists claim that if there is water there may be life. Nevertheless, it’s exciting to imagine a mysterious, strange-looking sea-monster world.
Dawn could change the shape and scope of future space missions. Dawn has already visited Vesta, the second largest object in the Asteroid Belt a few years ago and will enter the orbit of Ceres in early March. Travelling at 24,000 miles per hour is possible due to its twin ion thruster engines where xenon atoms are bombarded with electrons to form ions. The ions are charged and shoot out the engines up to 90,000 miles per hour. However, the thrust effect is minimal on the probe because of a zero-gravity, frictionless environment. Does this sound like science fiction to you? Perhaps you’ve already seen it in Star Wars, when Darth Vader’s TIE fighter would speed through the galaxy. Just like Darth Vader’s super-speedy vehicle, Dawn uses solar energy to feed electrons into its power-hungry engines. I believe this technology to be a stepping-stone to Mars.
More info at this link: “Where is Dawn Now”: http://dawn.jpl.nasa.gov/mission/live_shots.asp
My reference sources: www.earthsky.org, www.space.com, www.planetary.org, www.popsci.com, http://solarsystem.nasa.gov, http://news.discovery.com
To find out what Dawn discovered about Vesta you can see what Emily Lakdawalla, of the Planetary Society has to say in her Blog at http://www.planetary.org/blogs/emily-lakdawalla/2014/10091306-what-did-dawn-learn-at-vesta.html.