The Search for Other Earths

star field

Dust in Hubble Image

The tiny pink ring in the Hubble image shows where a shock wave from the blast is hitting the surrounding material expelled from the star before the explosion. The cause for the outer, faint rings is unknown.  Because Herschel sees far infrared and submillimeter radiation that is much longer in wavelength than the Hubble light, the bright spot representing the supernova remnant is not as sharp. But it reveals dust grains at about 20 Kelvin emitting more than 200 times the energy of the Sun.

Analysis of the Herschell pictures in different wavelengths indicates that the total mass of the dust is about 0.4-0.7 the mass of our sun (as much as 230,000 Earth masses).

SN 1987A is located in the Large Magellanic Cloud, a satellite galaxy to our own Milky Way. As there is a supernova of this type in the LMC every 300 years, this could be the origin of a substantial fraction of the dust in the LMC and is consistent with that required to account for the dust observed in high red-shift galaxies. That is, supernovas are likely to be the primary source of dust in the very early universe.

Cosmic dust is made of various elements, such as carbon, oxygen, iron and other atoms heavier than hydrogen and helium. Although dust elements are only a minor part of the universe and our solar system, they are essential for star formation and are the main constituents of rocky planets like Earth and of life itself.

The complete Herschel image is part of a survey of the LMC. The filamentary structures surrounding the region of SN 1987A are clouds of dust as cold as 10 to 20 Kelvin, filling the space between the stars. Many of the atoms we are made of were once part of such clouds.

Reference

M. Matsuura, et al. 'Herschel Detects a Massive Dust Reservoir in Supernova 1987A', Science Express, 7 July 2011.