The Science behind theEagle Nebula Image

Howard E. Bond

Space Telescope Science Institute

and

Co-founder, Hubble Heritage Team

Dust pillar in theEagle Nebula, Messier 16

Credit: NASA, ESA,and the Hubble Heritage Team

Dust pillar in theEagle Nebula, Messier 16

Credit: NASA, ESA,and the Hubble Heritage Team

What’s this?

The Hubble Heritage Program

• Founded in 1998 to bring the most compelling Hubble images to the public

• Main criterion is pictorial beauty, with scientific interest also considered

• Images are taken from archive, sometimes supplemented by new observations obtained by the Heritage team through Director’s Discretionary time, and processed for release

The Hubble Heritage Program

• Some observations, including the Eagle Nebula Pillar released today, are entirely new images obtained by Heritage team

• Prizes & honors:– Images on US & British postage stamps– 2003 Klumpke-Roberts Award of the

Astronomical Society of the Pacific for contributions to public appreciation of astronomy

The Hubble Heritage Gallery

Visit our website: http://heritage.stsci.edu

Location of M16 in Milky Way

Approx 6500 lt-yr from Earth, in constellation Serpens

Amateur Photograph of M16

M16 is an emission nebula or H II region;red color is due to ionized hydrogen gas

Professional Photograph of M16

T. Rector,Kitt Peak 36-inch

Location of 1995 Hubble Image

T. Rector,Kitt Peak 36-inch

The Famous WFPC2 Image“Pillars of Creation”

Locations of ACS & WFPC2 Images

How Big is it?

What’s Going on Here?

Star Formation in the Eagle Nebula

• Dense cloud of interstellar gas, molecules, & dust contracts under its own gravity

• Massive, hot, blue stars form inside the cloud

• Stellar winds and UV light push gas & dust away

• Dense clouds can resist this erosion longer, forming pillars pointing back toward hot stars

Cluster of hot, young stars,recently formed from dust & gas

Dense dust& gas

UV radiation & winds create cavityaround hot stars

Pillars are denser regions thatresist erosion

A Geological Analog: Hoodoos

A Geological Analog: Hoodoos

Easily eroded rock

Resistant rock prevents erosion, creating a“pillar”

Closeup of Tip of Pillar

Blue = oxygen atoms ionized by UV light

Dark = dense dust & molecules

Gas evaporating off pillar

Dust & gas compressedby stellar winds, formingnew stars—currently visible only in infraredlight

Red = cooler hydrogen &nitrogen ions

Visible-light and Infrared Images

Hubble Infrared Space Observatory

IR revealsvery youngstarsembeddedIn dust

Summary

• The pillars in the Eagle Nebula illustrate some of the complex events that accompany the formation of new stars

• First-generation stars produce a cavity in their dust cocoons with pillars pointing back to the hot young stars

Summary contd.

• Second-generation stars can form within the pillars due to compression of the dust and gas

• Within a few million years, the pillars will completely disappear, leaving only a cluster of newly formed stars