Phosphorus surrounding distant stars could be a sign of life-friendly worlds
Break dancing is back!
By breaking light from distant stars apart, and examining the spectrum of light produced reveals the composition of stars. As light passes through the visible surface (or photosphere) of stars, some of the energy is absorbed, creating dark gaps in the frequencies of light seen by astronomers.
Currently, it is not possible to measure the chemical composition of the bodies ofplanets in distant solar systems. Therefore, astronomers assume that exoplanets are composed of materials similar to their parent stars.
“Of course, there are some exceptions to this relationship… For example, the Sun, Earth, and Mars all agree to within 10% in the relative proportions of the major rocky planet-building elements. However, the chemical connection between star and planet offers a starting point for modeling the interior composition and mineralogy of an exoplanet,” researchers wrote in an article describing the study, published in theAstrophysical Research Letters.
However, we can now begin to glimpse the chemical makeup of the atmospheres of exoplanets that pass in front of their stars as seen from Earth. As light from a star passes through theatmosphere of a distant planetduring these transits, some wavelengths of light are absorbed by gases, revealing the chemical makeup of that world’s atmosphere.
“Direct compositional measurements of the planet are limited to atmospheric spectroscopy which can only occur during transit. Yet, knowing the composition of the planet’s atmosphere is only one factor in determining whether a planet is habitable from a chemical perspective,” researchers describe.
A modern database for an ancient librarian
TheHypatia Catalog, developed by Hinkel, provides a public database of chemical compositions of stars collected by astronomers around the globe. The team compared the figures to chemical ratios found in the crust of the Earth, terrestrial silica deposits, and marine plankton.
“But there’s so little phosphorus stellar abundance data. Phosphorus data exists for only about 1% of stars. That makes it really difficult to figure out any clear trends in between the stars, let alone the role of phosphorus in the evolution of an exoplanet,” Hinkel said.
Each element gives away its presence by forming lines in the spectra of stars. When produced by the formation of light, these bright markings are called emission lines. Light passing through theatmospheres of planetsor stars form dark markers called absorption lines.
The region at which these absorption lines of phosphorus are found sit at the region at the red edge of the rainbow, just before the electromagnetic spectrum turns to infrared. This part of the rainbow is little-studied by astronomers, and few instruments are available to examine these frequencies.
“We find that, in general, plankton, Earth, and Mars are N-poor and P-rich compared with nearby stars. However, the dearth of P abundance data, which exists for only ~1% of all-stars and 1% of exoplanet hosts, makes it difficult to deduce clear trends in the stellar data, let alone the role of P in the evolution of an exoplanet,”researchers describe.
Our ownSunis home to a fairly high concentration of phosphorus, and biology on Earth uses some of this to drive the mechanisms of life.
Small rocky planets would draw phosphorus into their cores, leaving the surface devoid of this element vital to biological systems. Hinkel believes systems, where phosphorus is more common and available for biological processes, may be among the best places to search foralien life.
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This article was originally published onThe Cosmic CompanionbyJames Maynard, founder and publisher of The Cosmic Companion. He is a New England native turned desert rat in Tucson, where he lives with his lovely wife, Nicole, and Max the Cat. You can read this original piecehere.
Astronomy News with The Cosmic Companionis also available as a weekly podcast, carried on all major podcast providers. Tune in every Tuesday for updates on the latest astronomy news, and interviews with astronomers and other researchers working to uncover the nature of the Universe.
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Exploring the wonders of the Cosmos, one mystery at a time.Exploring the wonders of the Cosmos, one mystery at a time.
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