Dusty globules in the Crab Nebula

Abstract

From existing broad-band images obtained with the Hubble Space Telescope, we located 92 globules, for which we derived positions, dimensions, orientations, extinctions, masses, proper motions, and their distributions. The globules have mean radii ranging from 400 to 2000 AU and are not resolved in current infrared images of the nebula. The extinction law for dust grains in these globules matches a normal interstellar extinction law. Derived masses of dust range from 1 to 60 x 10^(-6) solar masses, and the total mass contained in globules constitute a fraction of approximately 2% or less of the total dust content of the nebula. The globules are spread over the outer part of the nebula, and a fraction of them coincide in position with emission filaments, where we find elongated globules that are aligned with these filaments. Only 10% of the globules are coincident in position with the numerous H2-emitting knots found in previous studies. All globules move outwards from the centre with transversal velocities of 60 to 1600 km/s, along with the general expansion of the remnant. We discuss various hypotheses for the formation of globules in the Crab Nebula.

arXiv comment11 pages

References in corpus (22)

• Freshly Formed Dust in the Cassiopeia A Supernova Remnant as Revealed by the Spitzer Space Telescope
• The surprising Crab pulsar and its nebula: A review
• Dust Production and Particle Acceleration in Supernova 1987A Revealed with ALMA
• Massive-Star Supernovae as Major Dust Factories
• Detection of a Noble Gas Molecular Ion, {36}ArH^+, in the Crab Nebula
• A stubbornly large mass of cold dust in the ejecta of Supernova 1987A
• A Cool Dust Factory in the Crab Nebula: A Herschel Study of the Filaments
• Radiative hydrodynamics simulations of red supergiant stars: I. interpretation of interferometric observations
• A Precise Proper Motion for the Crab Pulsar, and the Difficulty of Testing Spin-Kick Alignment for Young Neutron Stars
• Spitzer Space Telescope Infrared Imaging and Spectroscopy of the Crab Nebula
• The dust and gas content of the Crab Nebula
• Dust yields in clumpy SN shells: SN 1987A revisited
• Dynamic atmospheres and winds of cool luminous giants, I. Al${}_2$O${}_3$ and silicate dust in the close vicinity of M-type AGB stars
• Electron-capture supernovae exploding within their progenitor wind
• The Importance of Physical Models for Deriving Dust Masses and Grain Size Distributions in Supernova Ejecta I: Radiatively Heated Dust in the Crab Nebula
• Numerical Simulations of Supernova Dust Destruction. II. Metal-Enriched Ejecta Knots
• Properties and Spatial Distribution of Dust Emission in the Crab Nebula
• New expansion rate measurements of the Crab Nebula in radio and optical
• A Survey of Molecular Hydrogen in the Crab Nebula
• The tiny globulettes in the Carina Nebula
• The Nature of the H2-Emitting Gas in the Crab Nebula
• Detecting the rapidly expanding outer shell of the Crab Nebula: where to look

Cited by in corpus (5)

• The dust content of the Crab Nebula
• Modelling the ArH${}^{+}$ emission from the Crab Nebula
• Illuminating a tadpole's metamorphosis III: quantifying past and present environmental impact
• Can Dust Injected by SNe Explain the NIR-MIR Excess in Young Massive Stellar Clusters?
• Dense Molecular Clouds in the Crab Supernova Remnant