Pure iron grains are rare in the universe

Abstract

The abundant forms in which the major elements in the universe exist have been determined from numerous astronomical observations and meteoritic analyses. Iron (Fe) is an exception, in that only depletion of gaseous Fe has been detected in the interstellar medium, suggesting that Fe is condensed into a solid, possibly the astronomically invisible metal. To determine the primary form of Fe, we replicated the formation of Fe grains in gaseous ejecta of evolved stars by means of microgravity experiments. We found that the sticking probability for formation of Fe grains is extremely small; only several atoms will stick per hundred thousand collisions, so that homogeneous nucleation of metallic Fe grains is highly ineffective, even in the Fe-rich ejecta of Type Ia supernovae. This implies that most Fe is locked up as grains of Fe compounds or as impurities accreted onto other grains in the interstellar medium.

References in corpus (13)

• The chemical composition of the Sun
• High molecular gas fractions in normal massive star forming galaxies in the young Universe
• The Evolution of the Elemental Abundances in the Gas and Dust Phases of the Galaxy
• Herschel Detects a Massive Dust Reservoir in Supernova 1987A
• The evolution of the ultraviolet and infrared luminosity densities in the universe at 0<z<1
• Dust in Historical Galactic Type Ia Supernova Remnants with Herschel
• Iron: A Key Element for Understanding the Origin and Evolution of Interstellar Dust
• Formation of Dust in the Ejecta of Type Ia Supernovae
• Polarization of Magnetic Dipole Emission and Spinning Dust Emission from Magnetic Nanoparticles
• Homogeneous SPC/E water nucleation in large molecular dynamics simulations
• Formulation of Non-steady-state Dust Formation Process in Astrophysical Environments
• Pure iron grains are rare in the universe
• Dust Formation Observed in Young Supernova Remnants with Spitzer

Cited by in corpus (9)

• Alignment of Irregular Grains by Mechanical Torques
• Iron and silicate dust growth in the Galactic interstellar medium: clues from element depletions
• Nucleation and growth of iron pebbles explains the formation of iron-rich planets akin to Mercury
• $\eta$ Carinae's Dusty Homunculus Nebula from Near-Infrared to Submillimeter Wavelengths: Mass, Composition, and Evidence for Fading Opacity
• Pure iron grains are rare in the universe
• Element Abundances in the Unshocked Ejecta of Cassiopeia A
• Near L-Edge Single and Multiple Photoionization of Doubly Charged Iron Ions
• On massive dust clumps in the envelope of the red supergiant VY Canis Majoris
• High-Resolution X-Ray Spectroscopy of Interstellar Iron Toward Cygnus X-1 and GX 339-4