Crystal Rain Cradles Infant Star


Thanks to the infrared eye of the Spitzer Space Telescope, researchers have captured evidence of “crystal rain” collapsing around a forming star. These tiny bits of green mineral – olivine – are also found in meteorites, but it’s the first time it has been observed in the dusty embryo of the stellar creation process. While it’s still unclear how these crystals formed, the suspect may be jets of superheated gas.

“If you could somehow transport yourself inside this protostar’s collapsing gas cloud, it would be very dark,” said Charles Poteet, lead author of the new study, also from the University of Toledo. “But the tiny crystals might catch whatever light is present, resulting in a green sparkle against a black, dusty backdrop.”

Located in the constellation of Orion, protostar HOPS-68 shares its forsterite crystals with a host of terrestrial souces, too. The forsterite crystal rain chemical compositions belongs to the olivine family of silicate minerals. Not only is it found in meteorites, but it’s part of common Earthly deposits, such as a periodot gemstone and the green sand beaches of Hawaii. In space you’ll find it in remote galaxies and NASA’s Stardust and Deep Impact missions both located the crystals in their close-up studies of comets. But it takes a mighty furnace to forge forsterite.

“You need temperatures as hot as lava to make these crystals,” said Tom Megeath of the University of Toledo in Ohio. He is the principal investigator of the research and the second author of a new study appearing in Astrophysical Journal Letters. “We propose that the crystals were cooked up near the surface of the forming star, then carried up into the surrounding cloud where temperatures are much colder, and ultimately fell down again like glitter.”

While the presence of olivine might be new, capturing the forsterite signature has occurred before – spotted in the swirling, planet-forming disks that surround young stars. What’s unusual is finding it in such at cool temperature… about minus 280 degrees Fahrenheit (minus 170 degrees Celsius). This leads researchers to believe the crystals are cooked below then “served up” in the outer structure. This line of reasoning might also explain why comets also contain the same minerals. As the rocky travellers move through infant solar systems, they collect the crystals where they have moved away to cooler climes.

Could this be true of what we know of our own solar system’s formation? Poteet and his colleagues say it’s plausible, but speculate that jets might have lifted crystals into the collapsing cloud of gas surrounding our early sun before raining onto the outer regions of our forming solar system. Eventually, the crystals would have been frozen into comets. The Herschel Space Observatory, a European Space Agency-led mission with important NASA contributions, also participated in the study by characterizing the forming star.

“Infrared telescopes such as Spitzer and now Herschel are providing an exciting picture of how all the ingredients of the cosmic stew that makes planetary systems are blended together,” said Bill Danchi, senior astrophysicist and program scientist at NASA Headquarters in Washington.

Original story source can be found at JPL News.

8 Replies to “Crystal Rain Cradles Infant Star”

  1. Forsterite is Mg2SiO4; olivine allows for Mg to be replaced with Fe. So, these are mostly light-ish period 2-3 elements.

    That’s pretty cool that protostellar chemical reactions favor planetary formation. I wonder how the mass expelled through the jet varies with the size and composition of the star. Maybe we can get clues about a star’s likely satellites just by observing it.

    1. Also, pretty cool that it is a recycle process (star – jet – disk rain – disk settling). Tends to complexify stuff.

  2. Olivine is a main component of the Earth’s mantle. So the formation of Fe_2SiO_4 and Mg_2SO_4 seems to be acoomon step in the formation of planets.


  3. Hmm… Olivine is a magnesium iron silicate.

    From Wikipedia – “Iron (Atomic number 26) is the most common element in the whole planet Earth, forming much of Earth’s outer and inner core, and it is the fourth most common element in the Earth’s crust. is produced in abundance as a result of fusion in high-mass stars, where the production of nickel-56 (which decays to iron) is the last nuclear fusion reaction that is exothermic, becoming the last element to be produced before collapse of a supernova leads to events that scatter the precursor radionuclides of iron into space.

    Silicon (Atomic number 14) is the eighth most common element in the universe by mass, but very rarely occurs as the pure free element in nature. It is more widely distributed in dusts, sands, planetoids and planets as various forms of silicon dioxide (silica) or silicates. In Earth’s crust, silicon is the second most abundant element after oxygen, making up 27.7% of the crust by mass.

    Magnesium (Atomic number 12) constitutes about 2% by mass, and ninth in the known Universe as a whole. This preponderance of magnesium is related to the fact that it is easily built up in supernova stars from a sequential addition of three helium nuclei to carbon (which in turn is made from three helium nuclei.”

    THEN… those elements are combined into Olivine….

    So once again we see all elements are made in supernova… or are they? I mean NO WAY could there be an unknown(able) process occurring in the cores of infant stars… right? NO WAY! That is of course, unless gravity and relativity gang up on energy to somehow transmute (Alchemy!) that energy into matter? Dang.. I wish we could peer into the core of one of them babies!

  4. This article brings up a couple of questions for me and, if anyone cares to answer them, I’ll throw them out there (please keep in mind that I am not a scientist and only know about astronomy from books/websites that I’ve read):

    1) Can we ever see a star “ignite”, or does this process happen over millions or thousands of years?

    2) Why is it that heavier elements remain outside of the star and form planets – with more mass, wouldn’t they be more attracted by gravity to the protostar than lighter elements, like helium and hydrogen?

    1. @Kawarthajon

      I’ll try to answer this question, with references, and then post the whole to this comment section for you. Additionally I shall try to answer the inherent questions leading to the question you asked.

      This will take a slight bit of time though to do the proper job, do not expect an answer today.


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