October 19, 2017

24.05.11: Throwing Exo-Planets into “The Blender.”

Artists’ conception of the Kepler-10 system. (Credit: NASA/Ames/JPL/CALTech).

On Monday, scientists unveiled a powerful new technique to quickly validate transiting exoplanets. The method, known as the “Blender,” combines data gathered for both the Kepler and Spitzer Space Telescopes in an effort to identify tiny transiting exo-worlds that would otherwise go unnoticed by ground-based instruments. [Read more...]

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!

19.10.09: 32 New Exoplanets Revealed!

Anybody notice the exoplanet tally on our front page hop up to 402 this morning? That’s because the European Southern Observatory (ESO) revealed a stunning 32 (count em!) new exoplanets identified this morning at their conference at Porto, Portugal. The discoveries were thanks to HARPS, the High Accuracy Radial Velocity Planet Searcher, a sensitive spectrograph attached to the 3.6 meter telescope at La Silla. First installed in 2003, HARPS has thus far discovered 75 of the 400+ worlds now known, or nearly 25%! today’s haul represents the largest single day release. Any special firsts? Well, the grab bag of exo-worlds substantially increases the pool of “super-earths”, as well as three planets found orbiting metal deficient stars, something that may be cause for tweaking planetary formation theory a bit. HARPS is capable of measuring radial shifts as small as 2 miles per hour, an impressive feat. The gauntlet has now been thrown; will the Kepler space telescope rise to the challenge as it stares into Cygnus looking for exo-transits? Do we sense a “exoplanet-war” brewing on mountain tops and chat boards across the world? Stay tuned!

23.9.9 CoRoT-7b: A Rare Earth.

The “Super-Earths” are getting smaller. Recently, the ESA announced that an exoplanet discovered on February 3rd of this year by the CoRoT (Convection Rotation and planetary Transit) satellite is one of the lightest yet… at about five Earth masses, this transiting exoplanet is about twice the diameter of the Earth. But don’t pack your bags just yet; CoRoT-7b as its designated, also zips around its host star every 20.4 hours at a distance 23 times closer than Mercury! This bakes the rocky world with temps in excess of 2000 degrees Celsius. The parent star itself is slighter cooler and younger than our Sun. Follow up measurements by HARPS, the ground based High Accuracy Radial velocity planet Searcher spectrograph at the La Silla Observatory in Chile helped tease out the radial speed and yielded an unexpected bonus; another Earth-like world, CoRoT-7c, which orbits at a relatively sedate 3 days and 17 hours and is 8 times the mass of the Earth. Such bizzare systems may become the norm in the coming years, as exoplanet detection technology becomes more sensitive. The CoRoT-7 system is located about 500 light years away in the plane of the Milky Way galaxy in the constellation Monoceros.