Stars’ Chemistry Key to Their Planets’ Ability to Support Life

Born in a disc of gas and rubble, planets eventually come together as larger and larger pieces of dust and rock stick together. They may be hundreds of light-years away from us, but astronomers can nevertheless watch these planets as they form.

One major point of interest is the chemistry of the rubble that forms around a star before a planetary system is formed, known as the protoplanetary disc.

The gas molecules that float in the disc could eventually become part of the atmosphere of the planets. If these molecules contain oxygen or nitrogen, the odds increase of a life-friendly planet forming. [The Strangest Alien Planets]

"It's very interesting to think about the molecular composition (of these discs)," said Catherine Walsh, an astronomer at Leiden Observatory in the Netherlands. The molecules that are in those discs will make up the molecules in planetary atmospheres, and planetesimals such as comets."

Walsh led a new study, "Complex organic molecules in protoplanetary disks," which was published in February 2014 in the journal Astronomy and Astrophysics. In the study, the astronomers modeled how complex molecules form in protoplanetary systems with the hopes of better understanding their observations.

Molecules in protoplanetary discs emit their light in the millimeter and sub-millimeter frequencies of light, which are between the observation ranges of radio telescopes and infrared telescopes. Until recently, however, there have been few observatories devoted to this particular band of light with the necessary capabilities to see complex molecules.

"There has been a lot of work done to date, mainly with single-dish submillimeter telescopes," Walsh said.

While any observation is helpful, the single dish meant that astronomers could not get the high spatial resolution and sensitivity that they need to see more complex molecules. This changed in 2013, however, when the Atacama Large Millimeter Array (ALMA) in Chile lighted up for the first time.

The observatory described as the largest astronomical project that exists right now will eventually include 66 antennas located at 5,000 meters altitude, which puts it above much of the section of the atmosphere that blocks millimeter light from arriving at the surface.

"This is really the next big thing in molecular astrophysics, and ALMA will give us orders of magnitude (of improvement) in sensitivity," Walsh said. [10 Biggest Telescopes on Earth: How They Measure Up]

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Stars' Chemistry Key to Their Planets' Ability to Support Life