A better way to learn if alien planets have the right stuff

A better way to learn if alien planets have the right stuff
Yale University researchers have developed a new method for analyzing the chemical composition of stars, providing a better indication of the conditions present when their planets formed. Credit: Michael S. Helfenbein/Yale University

A new method for analyzing the chemical composition of stars may help scientists winnow the search for Earth 2.0.

Yale University researchers Debra Fischer and John Michael Brewer, in a new study that will appear in the Astrophysical Journal, describe a computational modeling technique that gives a clearer sense of the chemistry of stars, revealing the conditions present when their planets formed. The system creates a new way to assess the habitability and biological evolution possibilities of planets outside our solar system.

"This is a very useful, easy diagnostic to tell whether that pale blue dot you see is more similar to Venus or the Earth," said Fischer, a Yale professor of astronomy. "Our field is very focused on finding Earth 2.0, and anything we can do to narrow the search is helpful."

Lead author Brewer, a postdoctoral researcher at Yale, has used the technique previously to determine temperature, surface gravity, rotational speed, and information for 1,600 stars, based on 15 elements found within those stars. The new study looks at roughly 800 stars, focusing on their ratio of carbon to oxygen, and magnesium to silicon.

Brewer explained that understanding the makeup of stars helps researchers understand the planets in orbit around them. "We're getting a look at the primordial materials that made these planets," he said. "Knowing what materials they started with leads to so much else."

For instance, the new study shows that in many cases, carbon isn't the driving force in planetary composition. Brewer found that if a star has a carbon/oxygen ratio similar to or lower than that of our own Sun, its planets have mineralogy dominated by the magnesium/silicon ratio. About 60% of the stars in the study have magnesium/silicon ratios that would produce Earth-like compositions; 40% of the have silicate-heavy interiors.

"This will have a profound impact on determining habitability," Brewer said. "It will help us make better inferences about which planets will be ones where life like ours can form."

In addition to helping identify planets more like Earth, the study sheds light on the occurrence of "diamond" planets—planets with a high carbon-to-oxygen abundance. Brewer and Fischer found that it is "exceedingly rare" to find a star with a carbon/oxygen ratio high enough to produce a diamond planet. In fact, the new data reveals that the star of the much discussed diamond planet, 55 Cancri e, does not have a high enough carbon/oxygen ratio to support its nickname.

"They're even more rare than we thought a few years ago," Fischer said. "Diamond truly are the most precious."


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Journal information: Astrophysical Journal

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Aug 24, 2016
"It will help us make better inferences about which planets will be ones where life like ours can form."

The eternal search for spontaneous generation of life continues. In spite of all the most logical common sense produced by Louis Pasteur or the intense analysis by Hoyle and Wickramasinghe. This is what happens when one has to lie to oneself about the obvious appearance of design in biological systems, as advocated by one Francis Crick.

Aug 24, 2016
"..postdoktorand Researcher at Yale, used the technique of pre-determined temperature, surface gravity, the speed of rotation and chemical composition information for 1,600 stars .."

Although the article was only the wandering, this is approaching WD theory. For the first time, the rotation take seriously as a major factor.
It would be interesting to see why the author uses the rotation, what is the point of rotation.

Aug 25, 2016
@wduckss:
you can't even read well. Here is what is in the article:

"...postdoctoral researcher at Yale, has used the technique previously to determine temperature, surface gravity, rotational speed, and chemical composition information for 1,600 stars..."

He used data from 15 specific elements of those stars to determine rotational speed among other data.

Aug 25, 2016
It does not matter how much is specific elements of those stars measured. It is important to understand the process and to figure out what those elements mean.
I want to believe that the observation of the rotation as the an essential element novelty, but you do me slowly back to reality. Thank you.

Aug 26, 2016
@FJ: "Spontaneous generation" was rejected nearly 2 centuries ago. It isn't "common sense" which is useless in science (cf quantum physics), but an easy enough experiment when you know what to do. [ https://en.wikipe...neration ]

What interests these researchers isn't emergence of life which is an even easier observation, the young Earth was accretion heat sterilized and now it is not [ https://en.wikipe...ogenesis ], but how often it can happen and what planets life could be found on.

Aug 26, 2016
It is interesting to note how average the solar system is in magnesium/silicon, meaning the mantle is deep and viscous (plate tectonics). While perhaps 40 % of systems have more "crusty" planets.

Solar system carbon content is a bit high, but presumably that won't affect chances for a biosphere even if maximum productivity may be lower in general. Rather it should mean that the runway Venus carbon dioxide hothouse is a bit of an outlier.

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