Brazilian Astronomer Looking for "Twins" of the Sun with NASA

06/25/2014 - 08h42

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SALVADOR NOGUEIRA

REPORTS FOR FOLHA

A Brazilian researcher is using NASA's Kepler satellite, looking for "twins" of the Sun. The project is an attempt to understand how solar systems like our own are born.

"My job is first to find the right stars - the twins, in this case - and then afterwards look for planets," says José Dias do Nascimento, an astronomer at the Federal University of Rio Grande do Norte (UFRN) and at the Harvard-Smithsonian Center for Astrophysics, in the United States.

Kepler, which is responsible for the discovery of nearly a thousand planets outside the Solar System between 2009 and 2013, broke down in May of 2013, ending its original mission. However, NASA scientists came up with a strategy to fix it.

Originally, Kepler needed at least three reaction wheels (it was built with four) to function accurately. One of the reaction wheels broke in 2012, and another the following year, rendering its operation impossible.

NASA scientists then suggested that solar radiation could be used like a reaction wheel, stabilizing the telescope on one of its three axes, with a test being carried out at the beginning of this year.

NASA decided that the spaceship could remain in operation, but that the original trajectory at which it was aimed would have to be abandoned. Instead, it would have to be changed every 75 days as the satellite continues its orbit around the Sun. This new mission has been baptized "K2".

LOOKING FOR THE TWINS

As a result of this constant adjustment to its aim, Kepler will observe the group of stars known as M67, in the constellation of Cancer. It is thought that this group contains more than a hundred stars similar to our Sun.

Nascimento expects to find there some solar twins - in other words, stars of the same composition and temperature as our own Sun.

However, with the loss of the two reaction wheels, Kepler will have great difficulty in detecting planets the size of Earth orbiting these sunlike stars. The objective, therefore, is simply to characterize the stars.

"Once they have been discovered, and their orbit, age and mass established by Kepler, then it will be time to use a high-resolution spectroscope in order to look for traces of planets like Earth," says Nascimento.

This phase will be carried out later, with telescopes based on Earth.

One of the aims is also to test a hypothesis developed by the astronomer Jorge Melendez, at the University of São Paulo (USP).

Melendez believes that the lack of certain chemical elements in the composition of stars similar to the Sun would be indicative of a solar system like our own.

Currently, Melendez is at work collecting data in the La Silla Observatory, in Chile, in the hope of testing this hypothesis.

Translated by TOM GATEHOUSE

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