The Eagle Nebula (M16) Imaged by Chris Thayer

Chris Thayer — By pcburns on August 23, 2009 at 3:43 pm

The Eagle Nebula, M16 is a region of star formation in the constellation Serpens – it has already created an open cluster of stars (the cluster is designated NGC 6611 and the nebula is IC 4703). It was discovered by Jean-Philippe de Cheseaux in 1745-4.

The Eagle Nebula features in one of the most iconic Hubble Space telescope images – the Pillars of Creation, which shows pillars of star-forming gas and dust within the nebula.

Stars form from a clouds of cool, dense gas. A disturbance, maybe the shock wave from an exploding star or maybe gravitational tidal effects of nearby objects causes a gravitational imbalance and the cloud to contract. Under its own gravitational force, the cloud continues to contract into a smaller and smaller volume and the pressure builds up in the core as the density increases. If the temperature increases so that the energy of the colliding hydrogen nuclei overcomes their natural repulsion. Nuclear fusion begins, and a star is born. Young stars are usually bright X-ray sources. However, observations by Chandra has found very few X-ray sources in the pillars. This would suggest that the pillars, and the few stars forming inside them are the last vestiges of star formation in the nabula which peaked several million years earlier. This differs from other nebulae where Chandra has detected very active star forming regions

The dark hydrogen clouds at the top of the fingers are resisting erosion – the hydrogen gas and dust have withstood the ultraviolet light from the hot, young stars longer than the surrounding gas. Research by the Dublin Institute of Advanced Studies suggests that shadows hold the key to how giant star-forming structures like these form. The Dublin group suggests that partially-shadowed clumps of gas creep towards darker areas, causing pile-ups behind dense knots of gas and dust that screen the intense ultraviolet light emitted by the stars.

Lookup M16 on SEDS