Complex Organics on Mars

Leak in Mars Rover Curiosity’s Wet Chemistry Test Finds Organics 

curiosity-sam-sample-leak-organics

Credit: ASA/JPL-Caltech/MSSS 

This image from NASA’s Curiosity rover shows the first sample of powdered rock extracted by the rover’s drill from the Yellowknife study site. Curiosity used its Mastcam on Sol 193 (Feb. 20, 2013) of its mission to capture this photo.  An unexpected leak of a chemical designed to tag complex organic molecules in samples collected by NASA’s Mars rover Curiosity appears to have serendipitously done its job,

Curiosity’s onboard laboratory includes seven so-called “wet ” experiments designed to preserve and identify suspect carbon-containing components in samples drilled out from rocks.

None of the foil-capped metal cups has been punctured yet, but vapors of the fluid, known as N-methyl-N-tert-butyldimethylsilyl-trifluoroacetamide, or MTBSTFA, leaked into the gas-sniffing analysis instrument early in the mission.

Curiosity landed in a 96-mile wide impact basin known as Gale Crater in August 2012 to determine if the planet most like Earth in the solar system has or ever had the chemistry and environments to support microbial life. Scientists quickly fulfilled the primary goal of the mission, discovering sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon in powder Curiosity drilled out of an ancient mudstone in an area known as Yellowknife Bay.  That paved the way for a more ambitious hunt for complex organic , an effort complicated by the MTBSTFA leak. “This caused us a lot of headache in the beginning, frankly, because it has a lot of carbon in it and other fragments that can break apart,” Curiosity scientist Danny Glavin, with NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said on Tuesday at the Lunar and Planetary Science conference in Houston, Texas. “We’ve turned this sort of bad thing into a good thing because we’ve learned how to work around this leak. We’ve actually used this vapor from this leak to carry out derivitization,” he said, referring to the to tag organics. Samples drilled out from Yellowknife Bay were stored inside the Sample Analysis at Mars, or SAM instrument, as the rover made its way over the next two years to Mount Sharp, a three-mile high mound of sediments rising from the floor of Gale Crater. “These samples were just reacting with this MTBSTFA vapor, reacting with all that good organic stuff. That turned out to be a good thing,” Glavin said.

In addition to analyzing the doggy-bagged sample that had been reacting with the MTBSTFA vapors for two years, scientists also were able to compare the results with residue from a sample that had been heated twice, effectively killing off any volatiles, but which also had been exposed to the vapors for two years. Initial results show indigenous Mars complex organics in the fresh sample, though more work is needed to definitely peg the compounds.  “It’s probably going to be years of work trying to disentangle this story,” said Glavin. “This is really exciting stuff. We’ve got a mudstone on Mars in a habitable environment. There was a lake there at one point. We’ve got organic molecules, possibly some interesting ones, of astrobiological interest. Bottom line, this sample has an even more diverse set of organic compounds than we previously thought. “Million dollar question? Is this or not. I wish I had an answer I can’t tell you. We’ve got basically a few compounds that we’re dealing with here. You probably need a lot more before you can start discriminating between biological and non-biological origin,” Glavin added.

This article was provided by Discovery News. MeasureMeasure

Advertisements

Putting Exoplanets on the Scale

Astronomers have come up with a new technique for measuring an alien planet’s mass, and therefore its composition and potential habitability, even when standard methods don’t work.

You’d never ask a woman her weight. (Actually, you’d never ask a man either.) But for exoplanets, the answer is crucial.

Hot Jupiter

De Wit and Seager (both MIT) have found a new way to measure exoplanets’ mass. For now, the technique is largely only useful for hot Jupiters, but future telescopes will allow them to scale the technique to nearby Earth-sized planets.
C. Carreau / ESA / Nature

Knowing the mass of an alien planet, along with its radius, tells astronomers whether the exoplanet is rocky, watery, or gaseous. In modeling, the mass can even influence whether the planet could host magnetic fields or plate tectonics. In the December 20th Science, Julien de Wit and MacArthur Fellow Sara Seager (both MIT) have found a forward-thinking technique to measure the all-important number.

To measure the mass of an alien planet dozens or hundreds of light-years away, astronomers usually watch for the star’s wiggle in response to the planetary tug. The wiggle comes from the fact that planets don’t actually orbit their parent stars — the star and planet orbit a mutual center of mass. So as the planet orbits, the star orbits too, albeit in a much smaller circle. (The mutual center can be inside the star itself, even if not at the core.)

Stellar wobble is easiest to see when massive planets orbit close to their parent stars, such as with hot Jupiters. But the punier the planet and the farther it orbits, the more weakly the star wobbles. And even if we could measure a star’s slowest sway, which we can’t yet (current telescopes can only measure a star’s velocity down to about 1 mile per hour), starspots and other activity on the star’s surface might cover up a planet-induced signal. That’s the case for hot Jupiter WASP-33, whose parent star pulsates strongly.

A New Way to Weigh Exoplanets

With some creative thinking, de Wit and Seager have found a new way to weigh an exoplanet: by watching it transit across the face of its parent star. When a planet transits, starlight passes through the thin sliver of its outer atmosphere. This passage imprints the starlight with the chemical fingerprints of the atmosphere’s composition. Astronomers collect thistransmission spectrum during transit observations, measuring which wavelengths pass through the atmosphere and which are absorbed.

Transiting exoplanet

When an exoplanet transits across the face of its parent star, starlight passes through a thin sliver of its atmosphere. De Wit and Seager show how measuring the atmosphere’s extent can give the planet’s mass.
NASA Goddard Space Flight Center

De Wit and Seager determined that, because a more massive planet can collect a thicker gaseous shroud around itself, using these transmission spectra to measure the atmosphere’s extent could in theory also reveal the planet’s mass.

It’s not a clear-cut connection: the atmosphere’s extent also depends on its temperature (heat comes from the parent star and the planet itself) and the weight of its molecules. A hot Jupiter will have light molecules in its atmosphere, mostly hydrogen and helium. But a rocky planet’s atmosphere will be composed of heavier stuff such as oxygen, carbon dioxide, and nitrogen. De Wit and Seager show that they can calculate each of these parameters directly from the same transmission spectrum.

This isn’t just a theoretical exercise: the astronomers used the well-studied hot Jupiter HD 189733b to prove the technique works. Radial velocity had already shown the planet has a mass between 1.1 and 1.2 Jupiters; de Wit and Seager’s transmission spectroscopy calculations gave a mass of 1.15 Jupiters.

“This [technique] appears to be very promising,” says exoplanetary scientist Jonathan Fortney (University of California, Santa Cruz). “I think that in practice clouds will confound the technique a bit more than they suggest, but I think it will work a lot of the time.”

Scaling Down

TESS satellite

The TESS satellite will monitor bright, nearby stars for transiting exoplanets. Though its focus is Sun-like stars, it will also catch some 10,000 M dwarfs in its view.
TESS team

For now, hot Jupiters remain the main target for the new technique. Their puffy, extended atmospheres make them good targets for transmission spectroscopy. But de Wit and Seager aim to describe super-Earths and Earth-size planets. Current telescopes can’t take transmission spectra of these smaller words, but the upcoming James Webb Space Telescope could. Scheduled for launch in 2018, it will be able to weigh Earth-size planets orbiting the coolest M dwarf stars up to about 160 light-years away. Its reach will extend twice that far for super-Earths.

Unfortunately, that meansKepler’s 167 confirmed exoplanets and 3,500 candidates will be largely out of reach.

“You wouldn’t be able to do this for stars in the Kepler field, which are too far away and faint,” Fortney explains. “But Kepler wasn’t designed to find planets around bright stars that would be amenable to atmospheric characterization.” Instead a number of upcoming projects, including SPECULOOS and TESS (launching in 2017), will focus on finding planets orbiting nearby stars, whose atmospheres will be easier to study.

The ultimate goal. says de Wit, is to combine all the available data for an exoplanet — including both the wobble of its star and the extent of its atmosphere — to better estimate its mass and understand its atmosphere . The more tools in astronomers’ toolbox, the better, because it’s not enough to just count exoplanets anymore, it’s time to see what they’re made of.

Extract from Sky & Telescope Magazine December 2013

There’s water – is there life?

Hubble Discovers Water Plumes Erupting from Europa

It’s been known since 2005 that Saturn’s 300-mile-wide moon Enceladus has geysers spewing ice and dust out into orbit from deep troughs that rake across its south pole. Now, thanks to the Hubble Space Telescope, we know of another moon with similar jets: Europa, the ever-enigmatic ice-shelled moon of Jupiter.

Read more:http://www.universetoday.com/107144/hubble-discovers-water-plumes-erupting-from-europa/#ixzz2nHZp0ONc