Astronomy Photo of the Day: 9/26/15 — M17 (The Omega Nebula) Revisited

Messier 17 (M17)—otherwise known as the Lobster Nebula, the Swan Nebula, the Horseshoe Nebula, the Checkmark Nebula, and (most commonly) the Omega Nebula—may go by many names, but its beauty is universal no matter what you choose to call it.

Found around 5,500 light-years from Earth toward the Sagitarrius constellation, Messier 17 is impressively large—spanning around 15 light years across. Within it, over 800 stars have taken shape, with more flickering to life all the time. In fact, astronomers estimate that the nebula harbors more material than 30,000 Suns combined (or around 30,000 solar masses).

This new image, which was taken by the ESO’s Wide Field Imager (a tool on the 2.2-Meter Telescope at La Silla Observatory), is color-coded, you might say. Pinkish-red colors correspond to ionization (or HII regions), the big blue-tinged sections are places where dust is so prevalent, light from embedded stars can’t break through with ease. So it bounces back and forth, scattering more effectively at the blue end of the electromagnetic spectrum. Black can be attributed to dark nebulae. Finally, white colors are the result of interactions between hot gas and starlight.

The blue pinpoints of light signify the presence of high-mass stars.

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Image Credit: ESO

Sweeping the Dust from a Cosmic Lobster

A new image from ESO’s VISTA telescope captures a celestial landscape of glowing clouds of gas and tendrils of dust surrounding hot young stars. This infrared view reveals the stellar nursery known as NGC 6357 in a surprising new light. It was taken as part of a VISTA survey that is currently scanning the Milky Way in a bid to map our galaxy’s structure and explain how it formed.

Read More.

Composite images obtained with the 3.58-metre NTT at La Silla Observatory. 

The Omega Nebula, also known as the Swan Nebula, Checkmark Nebula, Lobster Nebula, and the Horseshoe Nebula (catalogued as Messier 17 or M17 and as NGC 6618) is an H II region in the constellation Sagittarius. It was discovered by Philippe Loys de Chéseaux in 1745. Charles Messier catalogued it in 1764. It is located in the rich starfields of the Sagittarius area of the Milky Way.

Credit: ESO

(via Astronomers Unveil Detailed View of Messier 17 | Astronomy | Sci-News.com)

Swiss astronomer Jean Philippe de Chéseaux discovered this nebula in 1745, but his discovery did not receive widespread attention.

The object was independently rediscovered almost twenty years later by French astronomer Charles Messier, who included it as the seventeenth object in his famous astronomical catalogue.

Although officially known as Messier 17, its nicknames include: the Omega Nebula, the Swan Nebula, the Checkmark Nebula, the Horseshoe Nebula and the Lobster Nebula.

The nebula lies in the heart of our Milky Way Galaxy in the constellation of Sagittarius and is about 5,920 light-years away from us.

It spans about 15 light-years across, and its total mass is an estimated 30,000 solar masses.

Messier 17 appears as a complex red structure with some graduation to pink. Its coloring is a signature of glowing hydrogen gas.

The short-lived blue stars that recently formed in the nebula emit enough UV light to heat up surrounding gas to the extent that it begins to glow brightly.

In the central region the colors are lighter, and some parts appear white. This white color is real – it arises as a result of mixing the light from the hottest gas with the starlight reflected by dust.

The nebula also contains NGC 6618, an open star cluster of 35 stars.

The total number of stars in the nebula, however, is much higher – there are almost 800 stars in the center with even more forming in its outer regions.

Throughout this rosy glow, Messier 17 shows a web of darker regions of dust that obscure the light.

This obscuring material is also glowing and – although these areas are dark in this visible-light image – they look bright when observed using IR cameras.

This image was taken by the Wide Field Imager (WFI) instrument on the MPG/ESO 2.2-m telescope at ESO’s La Silla Observatory, Chile.

(NASA)  What unusual eggs have been laid by this majestic swan? The star forming region above, known as Swan Nebula, is the home of hot red-glowing gas, dark lanes of dust,bright young stars and – what are those? Of the few stars visible in the Swan Nebula, several have quite unusual colors and are hypothesized to be very young stars still shrouded by gas from the cloud that formed them. The Swan Nebula is quite large and massive as it contains roughly 1000 times the mass of our Sun. The bright central region is about 15 light years across lies about 5000 light years away toward the constellation of Sagittarius. The distinctive shape causes this region to have several other names, including the Omega Nebula, the Horseshoe Nebula, and the Lobster Nebula.