Super Earth

Astronomers on Monday announced the discovery of 50 new planets circling 


stars beyond the sun, including one “super-Earth” that is the right distance 


from its star to possibly have water.


“If we are really, really lucky, this planet could be a habitat” like Earth, said 


Lisa Kaltenegger of the Max Planck Institute for Astronomy in Heidelberg, 


Germany.


The planet, dubbed HD85512b, circles an orange star somewhat smaller and 


cooler than our sun about 36 light-years away. The star, HD85512, is visible in 


the southern sky in the constellation Vela.


The newly found planet circles this star every 59 days, putting it at the edge 


of the “habitable zone” where water could exist if atmospheric conditions 


were right.


In a teleconference, Kaltenegger said that the planet is at the warm edge of 


its star’s habitable zone, as if “standing next to a bonfire.” That means the 


planet would require a lot of cloud cover — which reflects starlight — to keep 


the surface cool enough to prevent any water from boiling, she said.


Astronomers have not determined whether the new super-Earth is rocky like 


the Earth or gassy like Jupiter, let alone whether it has an atmosphere. The 


new super-Earth is 3.5 times the mass of Earth.


Astronomers inferred the existence of the planet by watching its star wobble 


ever so slightly. The speed of the wobble indicated the existence of a planet 


tugging at the star.


This “radial velocity” technique has been productive, offering astronomers 


working at La Silla Paranal Observatory in Chile evidence of the 50 new 


“exoplanets” announced Monday. The planet-hunting instrument, called 


HARPS, are operated by the European Southern Observatory.


Sixteen of the new planets announced Monday, including the new super-Earth, 


are of the right mass to be made of rock instead of gas.


“We are building up a target list of super-Earths in the habitable zone,” 


Kaltenegger said.


To determine whether the planet has an atmosphere, astronomers need to 


capture an image of the planet — which they have not done — and analyze the 


light for signs of water, carbon dioxide and other gases. No existing telescope 


is sensitive enough for that task.


But a new telescope to begin construction next year, the European Extremely 


Large Telescope, will be up to the task, said Markus Kissler-Patig of the 


European Southern Observatory. It will be “technically capable of finding life 


around the nearest stars,” he said, by analyzing the atmosphere of exoplanets. 


The new super-Earth is a “prime target” for the new telescope.


Since 1995, astronomers have found more than 600 planets beyond Earth, 


according to a catalog.


In the accelerating race to bag and tag planets outside our solar system, 


HD85512b marks the second super-Earth found at the right distance from its 


star to possibly hold water, considered a vital ingredient for life. The first, 


called Gliese 581d, was discovered by the same telescope in Chile in 2007.