M16 and the Pillars of Creation

 

M16 and the Pillars of Creation
 - Data Credit: telescope.org, Open Observatories, Open University.
Image Credit: Kurt Thrust at the Jodrell Plank Observatory.

" The 'Pillars of Creation' may be seen virtually at the centre of this image. The data was curated from both the COAST and PIRATE robotic telescopes using SHO filters on Mount Teide,  Tenerife as programmed by Kurt. Nebulae shown red relate to Sulphur11, shown green or white relate to Hydrogen alpha and  shown blue relate to Oxygen111. There are also a lot of dark dust clouds in this image" - Joel Cairo CEO of the Jodrell Plank Observatory. 

Messier 16 
- captured with the Seestar S30 in EQ mode and Neb filter. 60x30 second subs.
Credit: Kurt Thrust.

" Messier 16 is an interesting nebulous region in the constellation Serpens. Sadly, Messier 16  aka the Eagle Nebula never gets that high above our southern horizon at the Jodrell Plank Observatory. The little Seestar provides a less detailed but wider view (Field of vision - FOV) than the robotic telescopes on Mount Teide. So all three help to provide a better representation of this interesting part of the night sky. Our visiting astrophysicist, G.P.T Chat, will provide further details". - Kurt Thrust current Director of the Jodrell Plank Observatory.

" Messier 16 (M16), also known as the Eagle Nebula, is a young open star cluster embedded within a diffuse emission nebula located in the constellation Serpens, approximately 7,000 light-years from Earth. The nebula is most famous for containing the "Pillars of Creation", a striking region of active star formation made famous by the Hubble Space Telescope.

1. Structure and Components of Messier 16

a. Open Star Cluster (NGC 6611)

Age: Approximately 1–2 million years old.

Stellar Population: Contains several thousand stars, including massive O-type and B-type stars.

These stars are young, hot, and very luminous, providing the energy that excites the surrounding nebula.

The ultraviolet radiation from these massive stars plays a critical role in shaping the surrounding nebula.

b. Emission Nebula

Type: H II region (a cloud of ionized hydrogen).

The emission nebula is a region of interstellar gas and dust that is ionized by high-energy UV radiation from the hot stars of NGC 6611.

As the hydrogen atoms recombine, they emit light in specific emission lines, especially the H-alpha line, giving the nebula its characteristic reddish glow in optical wavelengths.

2. Glowing Nebula: Physical Mechanism

The glow of the Eagle Nebula arises primarily from photoionization:

High-energy UV photons from O- and B-type stars ionize the surrounding hydrogen gas.

Electrons recombine with protons, and during this recombination, hydrogen emits photons, particularly in the Balmer series (notably H-alpha at 656.3 nm).

This process creates the glowing reddish-pink emission seen in visible light.

Additional emissions also come from ionized oxygen ([O III], giving a greenish hue) and sulfur ([S II]), especially in narrowband imaging.

3. Dark Pillars and Clouds

The dark, finger-like features known as the Pillars of Creation are dense molecular clouds composed of cold gas and dust.

a. Nature of the Pillars

These are evaporating gaseous globules (EGGs), where regions of dense gas resist the ionizing radiation longer than their surroundings.

They are several light-years long and are sites of ongoing star formation.

Protostars can be embedded within these pillars, slowly accreting material from their surroundings.

b. Erosion by Radiation and Winds

The edges of the pillars are illuminated by the intense UV radiation from nearby massive stars.

Photoevaporation occurs at the surfaces: UV photons heat and ionize the outer layers, causing the gas to stream away.

Stellar winds and radiation pressure further sculpt and compress these clouds, triggering gravitational collapse in some regions—leading to new star formation (a process called radiation-driven implosion).

4. Astrophysical Significance

M16 is a classic example of feedback in star formation: newly formed massive stars influence their environment, possibly triggering or inhibiting further star formation.

The Eagle Nebula's structure gives insights into early stellar evolution, molecular cloud dynamics, and interactions between stars and the interstellar medium (ISM).

Summary

Feature Description

Distance ~7,000 light-years

Type Open cluster with emission nebula

Main Components NGC 6611 (young stars), H II region, molecular pillars

Ionization Source UV radiation from hot, massive stars

Nebular Glow Hydrogen recombination (H-alpha), [O III], [S II] lines

Dark Clouds Dense, cold molecular gas and dust (EGGs, pillars)

Activity Active star formation, photoevaporation, feedback mechanisms

M16 remains one of the most studied star-forming regions in our galaxy, particularly due to the "Pillars of Creation", which vividly illustrate the complex processes driving the birth and evolution of stars". - Professor G.P.T. Chat