September 25, 2017

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!

Gear Review: Canons Image Stabilized Binoculars.

Every once in a while, we here at Astroguyz find a toy that surpasses expectations. Canon’s Image Stabilized (IS) binoculars are one such gizmo. I’ve had my trusty pair of 15 X 45’s for almost ten years now, and they’ve worked flawlessly! They also fit my two criteria for taking on new technology; they’re simple to use (there’s only one button to push!), and they’re maintenance free.

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Viewing a Low Altitude Occultation

This past Thursday, I got an e-mail from Sky & Telescopes’ automated alert system; Monday, the 18th of June, there would be an occultation of Venus by the Moon visible from extreme northern New England and the Canadian Maritimes.  This occultation would also span the Atlantic, Europe, and into Asia, but would be especially difficult to spot from the continental US (what we in the miltary refer to as ConUS) due to its extremely low elevation in the day time sky.

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