Astronomers map exoplanet atmosphere of super-Earth
Worlds without end: Using both the Hubble and Spitzer space telescopes, astronomers have characterized the atmosphere of an exoplanet with a mass between that of the Earth and Neptune.
Astronomers enlisted the combined multi-wavelength capabilities NASA’s Hubble snd Spitzer space telescopes to do a first-of-a-kind study of GJ 3470 b’s atmosphere. This was accomplished by measuring the absorption of starlight as the planet passed in front of its star (transit) and the loss of reflected light from the planet as it passed behind the star (eclipse). All totaled, the space telescopes observed 12 transits and 20 eclipses. The science of analyzing chemical fingerprints based on light is called “spectroscopy.”
“For the first time we have a spectroscopic signature of such a world,” said Benneke. But he is at a loss for classification: Should it be called a “super-Earth” or “sub-Neptune?” Or perhaps something else?
Fortuitously, the atmosphere of GJ 3470 b turned out to be mostly clear, with only thin hazes, enabling the scientists to probe deep into the atmosphere. “We expected an atmosphere strongly enriched in heavier elements like oxygen and carbon which are forming abundant water vapor and methane gas, similar to what we see on Neptune”, said Benneke. “Instead, we found an atmosphere that is so poor in heavy elements that its composition resembles the hydrogen/helium rich composition of the Sun.”
To me, our knowledge of exoplanets today is beginning to resemble our knowledge of the planets in the solar system c. 1950. The little data we have gives us a vague idea of what’s there, but there are so many gaps and uncertainties that no one should be confident about drawing any firm conclusions.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Worlds without end: Using both the Hubble and Spitzer space telescopes, astronomers have characterized the atmosphere of an exoplanet with a mass between that of the Earth and Neptune.
Astronomers enlisted the combined multi-wavelength capabilities NASA’s Hubble snd Spitzer space telescopes to do a first-of-a-kind study of GJ 3470 b’s atmosphere. This was accomplished by measuring the absorption of starlight as the planet passed in front of its star (transit) and the loss of reflected light from the planet as it passed behind the star (eclipse). All totaled, the space telescopes observed 12 transits and 20 eclipses. The science of analyzing chemical fingerprints based on light is called “spectroscopy.”
“For the first time we have a spectroscopic signature of such a world,” said Benneke. But he is at a loss for classification: Should it be called a “super-Earth” or “sub-Neptune?” Or perhaps something else?
Fortuitously, the atmosphere of GJ 3470 b turned out to be mostly clear, with only thin hazes, enabling the scientists to probe deep into the atmosphere. “We expected an atmosphere strongly enriched in heavier elements like oxygen and carbon which are forming abundant water vapor and methane gas, similar to what we see on Neptune”, said Benneke. “Instead, we found an atmosphere that is so poor in heavy elements that its composition resembles the hydrogen/helium rich composition of the Sun.”
To me, our knowledge of exoplanets today is beginning to resemble our knowledge of the planets in the solar system c. 1950. The little data we have gives us a vague idea of what’s there, but there are so many gaps and uncertainties that no one should be confident about drawing any firm conclusions.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
I would say that comparing our knowledge of planets hundreds and thousands of light years away to our knowledge of the Solar System in 1950 is high praise.
Blair Ivey: If you knew how little turned out to be right about the planets, based on 1950s knowledge, you would realize that what I am saying here is not high praise, but a warning to not put much value on any conclusions about any exoplanets, based on what little has been gleaned so far.
Well, we did know what the planets out to Saturn *looked* like.
Blair Ivey: Actually, no, we really didn’t know what the inner planets really looked like, with the exception of the facing hemisphere of the Moon. In fact, until the first flyby of Mars by Mariner 4 in 1965, the question of whether there were canals on Mars was still an open question.