. 24/7 Space News .
Building planets from protoplanetary disks
by Staff Writers
Boston MA (SPX) Nov 02, 2021

stock illustration only

Planets and their stars form from the same reservoir of nebular material and their chemical compositions should therefore be correlated but the observed compositions of planets do not match completely those of their central stars.

In our Solar system, for example, all the rocky planets and planetesimals contain near-solar proportions of refractory elements (elements like aluminum that condense from a gas when the temperature falls below about 1500 kelvin) but are depleted in volatile elements (those that evaporate easily, like nitrogen). Astronomers think that this was the result of planets forming by the coalescence of already-condensed mineral dust.

As the initial, cold molecular cloud core collapses and a disc forms, heating from the new star (plus the viscosity of the disc) can vaporize some of the primordial condensed material - forcing the condensation sequence to begin anew but now under higher temperature and pressure conditions that evolve relatively rapidly.

Astronomers also analyze meteorites of various types to determine their chemical compositions. Depending upon the properties of the initial molefular cloud core and the disc, the temperatures produced during planet formation may not have been sufficient to vaporize the most refractory of the pre-existing material. Since different minerals in planetesimals condense under different conditions, times, and places, the overall situation is complex, making it hard to understand the observed chemistry of planets.

CfA geologist Michail Petaev and his colleagues simulated the collapse of a molecular cloud core and the formation of the star, disk and planets, and analyzed the evolving distribution of temperatures across the disk to infer the mineral condensation sequence. They find that the properties of the initial cloud core significantly affect the maximum temperatures reached in the disk and the resultant compositions of the planets and asteroids; the maximum temperature occurs around the end of the collapse phase, after a few hundreds of thousands of years.

They also find that while the composition of the star is similar to that of the molecular cloud core, the star might be slightly depleted in some of the most refractory elements - and thus the stellar composition may not be a good approximation to the initial composition of the core.

Only cloud cores with high initial temperatures (or low disk rotation) will produce refractory-rich planets. Significantly, they conclude that in order to reproduce the composition seen in Solar system meteorites and the terrestrial planets either the initial core had rare properties like temperatures near 2000 kelvin (well above the expected median value of 1250 kelvin), or else some other source of heating must have raised the protoplanetary disk's temperature.

Research Report: "Maximum Temperatures in Evolving Protoplanetary Discs and Composition of Planetary Building Blocks"

Related Links
Center for Astrophysics | Harvard and Smithsonian
Lands Beyond Beyond - extra solar planets - news and science
Life Beyond Earth

Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Monthly Supporter
$5+ Billed Monthly

paypal only
SpaceDaily Contributor
$5 Billed Once

credit card or paypal

How to find hidden oceans on distant worlds? use chemistry
Pasadena CA (SPX) Oct 28, 2021
A new study shows how the chemicals in an exoplanet's atmosphere can, in some cases, reveal whether or not the temperature on its surface is too hot for liquid water. In our solar system, planets are either small and rocky (like Earth) or large and gaseous (like Neptune). But around other stars, astronomers have found planets that fall in between - worlds slightly larger than Earth but smaller than Neptune. These planets may have rocky surfaces or liquid-water oceans, but most are likely to be top ... read more

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Harris to announce first National Space Council meeting in nearly a year

NASA, SpaceX Reviewing Commercial Crew Rotation Plans

Astronauts to return from space station next week: NASA

Mind the stars

Hypersonix to use Siemens' software in design of its hydrogen fuelled launchers

NASA prepares to fuel James Webb telescope for Dec. 18 launch

Major Artemis engine part arrives at Stennis for certification testing

NASA, SpaceX reschedule Crew-3 launch due to weather

Flight #15 - Start of the Return Journey

Sols 3287-3288: Assessing a New Potential Drill Target

Smart focus on Mars

Researchers begin to understand correlation of schumann resonances and dust storms on Mars

Shenzhou XIII crew ready for first spacewalk

Chinese astronauts arrive at space station for longest mission

China's longest-yet crewed space mission impressive, expert says

Chinese astronaut bridges gender gap

OneWeb and Leonardo DRS announce partnership to offer low earth orbit services for Pentagon

Intelsat and OneWeb demo global multi-orbit satellite service to Pentagon

SpaceFund Invests in Rhea Space Activity

iRocket And Turion Space ink agreement for 10 launches to low earth orbit

Georgia State University astronomy researcher wins grant to improve detection, monitoring of satellites

Healable carbon fiber composite offers path to long-lasting, sustainable materials

Simulations in 3D improve understanding of energetic-particle radiation and help protect space assets

Shape-shifting materials with infinite possibilities

Tidying up planetary nurseries

To find life on other planets, NASA rocket team looks to the stars

Rocky Exoplanets Are Even Stranger Than We Thought

Building planets from protoplanetary disks

Science results offer first 3D view of Jupiter's atmosphere

Juno peers deep into Jupiter's colorful belts and zones

Scientists find strange black 'superionic ice' that could exist inside other planets

Jupiter's Great Red Spot is deeper than thought, shaped like lens

The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.