May 22, 2017

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...]

September 2013-Life in the Astro-Blogosphere: Touching Mars

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...]

12.05.10- White Dwarf Lite?

 

A comparison of Kepler's latest planetary finds. (Graphic Credit: NASA).

A comparison of Kepler's latest planetary finds. (Graphic Credit: NASA).

 

   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!

24.04.10-Our Existence: Justified.

(Credit: NASA/JPL).

(Credit: NASA/JPL).

 Earth: Safe & Sound?

   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!

18.04.10- Zeroing in on Nearby Exoplanets.

 

(Credit: NASA/JPL).

(Credit: NASA/JPL).

A scale comparison of a possible Super-Earth.

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!

2010: A Lookback at the Year in Science and a Look Ahead.

 

 

New Hubble pics! (Credit: NASA/ESA/STS Inst.)

New Hubble pics! (Credit: NASA/ESA/STS Inst.)

 

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;   [Read more...]