The Sky is Waiting.
A fragment of the Zagami meteorite!
It�s a long journey, from the shores of the Florida Space Coast to the surface of Mars. This past week, we made the journey from Astroguyz HQ in Florida to the Laboratory for Atmospheric and Space Physics (LASC) to attend the New Media Workshop in Boulder, Colorado for the upcoming launch of MAVEN, the Mars Atmosphere and Volatile EvolutioN mission. [Read more...]
The Kepler space telescope may have bagged an unexpected prize during its hunt for exo-planets.�Along with five published exoplanets illustrated above, Kepler snared two potentially bizarre objects. Dubbed KOI (Kepler Objects of Interest) -81 and 74, these companions actually appear dimmer passing behind the parent star rather than in front of it. This suggests a bright luminous object(s) with an Earth-like diameter but much more massive� a white dwarf? Possibly, but the objects seem to be physically too large to fit this class of objects. White dwarfs have an upper limit of about 1.4 solar masses, also known famously as the Chandrasekhar limit. Recently, scientist Jason Rowe of NASA Ames research center has been able to directly measure the masses of these companions by measuring the way the companions physically warp, or distort the bodies of their primary companions. The result; these stars are in the realm of 0.1 solar masses, which would make them some the lightest white dwarfs known. Obviously, this also becomes a problem because although small and luminous, KOI-81 and -74 probably aren�t supported solely by electron degeneracy pressure that characterizes standard classical white dwarfs. The situation just got stranger and stranger� were these objects large super-heated planets or light white dwarfs?
Enter an international team of astronomers meeting at Kavli Institute in Peking (Beijing) China. Using an innovative technique known as Doppler boosting, they were able to pinpoint the mystery objects mass at 0.2 solar masses, on the low end but still in the realm of a white dwarf. This makes even more sense if one considers a white dwarf accreting mass from a primary companion, ala a Type 1A supernovae candidate�(hey, didn�t we write in this space last week about the lack of these beasties?) ��Doppler boosting works in terms of catching subtle fluctuations in the brightening of an approaching object as measured by photons received over a given unit of time and dimming as it recedes�altogether a complicated affair, considering this must be untangled from a flurry of other signals. This unexpected find illustrates that surreptitious discoveries are often the norm in astronomy, if only someone is willing to look for them!
The formation of the Earth poses a key dilemma to planetary accretionary theory; namely, why are we here at all? Standard models would say that the Earth and other planets coalesced out of the proto-solar nebula to form. However, spiral density waves within the same nebula should have drawn down orbital energy to shorten the planets orbit, slowly drawing it in. Looking at other �hot Jupiter� systems, that�s just what we see; large gas giant worlds that formed further out, only to migrate inward into tight orbits� just how did we end up in our nice, neat orbit?
Now, computational astrophysicist Mordecai-Mark Mac Loc at the American Museum of Natural History may have the answer. Accounting for temperature and spin variability, resonance key holes can occur; planets like Earth may simply spiral inward and get hung up in these safe zones between dragging pressure waves. Of course, a majority of proto-planets don�t make the cut and simply spiral inward to a fiery end, but they�re not around for us to see today. One discovery that would perhaps give observational weight to this theory would be the discovery of exo-Earths also parked in nice neat orbits� the Kepler space telescope may pave the way for this discovery as it stares off into Cygnus. For now, thank computational mathematics that you�re here reading this, just as it says you should be!
It�s hard to believe that a little�less than two decades ago, no extra-solar planets were known. Now, the count climbs daily, and platforms like the Kepler Space Telescope threaten to launch the tally into the thousands. Recently, an international team of astronomers made six new discoveries in two nearby star systems that may eventually lead towards the cosmic Holy Grail; an exoplanet resembling Earth. The team was led by prolific planet hunter Paul Butler and Steve Vogt, who discovered the super-Earths by combining radial velocity data gathered from the Anglo-Australian telescope and the Keck observatory. First up is 61 Virginis, a Sun-like star 28 light years away. This system has always been of interest to astronomers because it is a near twin to our own Sun and is on the short list for NASA�s Terrestrial Planet Finder. The team discovered three worlds ranging in mass from 5 Earths to 25. In addition, follow-up studies with the Spitzer Space telescope find evidence for a dust ring around 61 Virginis about twice Pluto�s distance from our own Sun. The second discovery is one 7.5 Earth mass planet and a possible two more found around the star HD 1461 in the constellation Cetus about 76 light years distant. Again, HD 1461 could pass for our Sun in terms of age, size, and mass. Both stars would be visible to the naked eye under reasonably dark skies. It remains to be seen if these worlds are rocky terrestrial planets or Uranus-like slush balls. Evidence is mounting, however, that planets may be common around nearby Sun-like stars. The innermost planetary detection for 61 Virginis also represents the smallest amplitude discovery ever made by astronomers. These discoveries were backed up by brightness measurements made by robotic telescopes based in Arizona and operated by Tennessee University�s George Henry. This ruled out the possibility that the amplitude variations seen were due to variability or �starspots�. The Lick-Carnegie Exoplanet Survey Team will also soon have a new weapon in its arsenal; the recently completed Automated Planet Finder (APF) Telescope atop Mount Hamilton. All that�s needed now is for the Discovery Channel to fund a new hit series; The Exoplanet Hunters!
2009 was a year of silent triumph in the world of science. Unmanned spacecraft scoured the solar system, while at home, we saw the first tentative steps signaling a transitioning of manned spaceflight. Indeed, as we pause to enter a new decade, all eyes are on change and what it will bring about for science and the world at large. As we endeavor to keep up with our ceaseless calendar, here�s the Astroguyz down and dirty on happenings in 2009 A.D. and a look ahead;
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Pictured is a Delta IV rocket launch from Cape Canaveral on November 21st, 2010. The image is a 20 second exposure taken at dusk, shot from about 100 miles west of the launch site. The launch placed a classified payload in orbit for the United States Air Force.
Difficult but not impossible to catch against the dawn or dusk sky, spotting an extreme crescent moon can be a challenge. The slender crescent pictured was shot 30 minutes before sunrise when the Moon was less than 20 hours away from New.� A true feat of visual athletics to catch, a good pair of binoculars or a well aimed wide field telescopic view can help with the hunt.
The Sun is our nearest star, and goes through an 11-year cycle of activity. This image was taken via a properly filtered telescope, and shows the Sun as it appeared during its last maximum peak in 2003. This was during solar cycle #23, a period during which the Sun hurled several large flares Earthward. The next solar cycle is due to peak around 2013-14.
Located in the belt of the constellation Orion, Messier 42, also known as the Orion Nebula is one of the finest deep sky objects in the northern hemisphere sky. Just visible as a faint smudge to the naked eye on a clear dark night, the Orion Nebula is a sure star party favorite, as it shows tendrils of gas contrasted with bright stars. M42 is a large stellar nursery, a star forming region about 1,000 light years distant.
Orbiting the planet in Low Earth Orbit (LEO) every 90 minutes, many people fail to realize that you can see the International Space Station (ISS) from most of the planet on a near-weekly basis. In fact, the ISS has been known to make up to four visible passes over the same location in one night. The image pictured is from the Fourth of July, 2011 and is a 20 second exposure of a bright ISS pass.
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Next to the Sun, the two brightest objects in the sky are the Moon and the planet Venus. In fact, when Venus is favorably placed next to the Moon, it might just be possible to spot the two in the daytime. Another intriguing effect known as earthshine or ashen light is also seen in the image on the night side of the Moon; this is caused by sunlight reflected back off of the Earth towards our only satellite.
A mosaic of three images taken during the total lunar eclipse of December 21st, 2010. The eclipse occurred the same day as the winter solstice. The curve and size of the Earth�s shadow is apparent in the image.
KIC Dreams: Thoughts on Tabby’s Star
Time to contemplate the cosmos…
All right. I know that, by now, much good ink (real and cyber) has been spilled over KIC 8462852. I also know that I’m probably not the very last science writer to turn our attention towards this strange star, drudged up in the Kepler Space Telescope data. And things have only gotten stranger, as search back through glass-plate archives has revealed that KIC 8462852 has gotten continuously fainter over the past century. [Read more...]