October 25, 2014

04.06.10- “Hot Jupiters” in Retrograde.

An Artist's family portrait of retrograde exo-worlds. (Credit: ESO/A. C. Cameron).

An Artist's family portrait of retrograde exo-worlds. (Credit: ESO/A. C. Cameron).

 

   A unique battery of telescopes is revealing an unusual feature in many exoplanetary systems. Earlier this year, the Royal Astronomical Society unveiled nine new exoplanets, transiting “hot Jupiters” that cross the face of their parent star as seen from Earth. No big deal nowadays, as the exoplanet count sits at 455 and climbing, and at the time of discovery, 73 transiting exoplanets were known. What makes these beasties so unusual is that they all orbit their host in retrograde orbits. That is, their orbits run counter to their host stars’ rotation.  And just how do you discern the direction of motion for a transiting exoplanet? That’s our impromptu astro-vocabulary builder term of the day; the Rossiter-McLaughlin Effect.  The motion of a spinning star can be discerned in its spectra; the approaching limb is ever so slightly blue shifted, and the receding limb is red shifted. Enter our dark transiting body. When the planet enters the frame, a slight but perceptible “spectral mis-match” occurs; if this occurs in the blue shifted portion, the orbit is prograde; in the red shifted end, the orbit is retrograde. The observations were conducted via the Super-WASP (Wide Angle Search for Planets) consortium. This is a pair of robotic instruments each consisting of eight CCD coupled telephoto lenses (they’re Canon 200mm f/1.8s!) each capable of capturing a field of view 7.8° degrees square. Super-WASP North is located in the Canary Islands, while Super-WASP South is stationed at the site of the South African Observatory. These enable a cost affordable way to survey the entire sky looking for the tiny signature dimming of a transiting exoplanet. Conceived in the 1990s by Don Pollacco, Super-WASP has identified 26 extra-solar planets to date. How these retrograde hot Jupiters came to be remains to be solved… but it is still truly awesome how much data we can glean from a tiny string of photons!

04.03.10- The Edgar Wilson Award: A Look at Last Year’s Winners.

One of the Wilson Awards more illustrious winners...(Credit: IAU Central Bureau for Astronomical Telegrams).

One of the Wilson Awards more illustrious winners...(Credit: IAU Central Bureau for Astronomical Telegrams).

 

   In this age of astronomical automation and ever increasingly deeper sky surveys, many believe the era of the amateur comet discoveries to be over. A look at last year’s Edgar Wilson Award winners, however, tells a different tale. Established in 1998, this award has historically split a $20,000 purse among 2 to 6 individuals who have discovered a comet in an amateur capacity. [Read more...]

24.02.10: A Robotic Telescope Raffle!

A robotic telescope; yours to play with before bedtime? (Credit: AAVSO).

A robotic telescope; yours to play with before bedtime? (Credit: AAVSO).

   Ever wish you could have your very own robotic telescope based at a world class dark sky site to utilize on those murky winter nights? Well, the American Association of Variable Star Observers (AAVSO) is having a raffle next month to award a winner a years’ free access to their recently established AAVSONet, a network of 5 robotic telescopes in New Mexico. [Read more...]