Triple Nebula

Nebula is a young star formation in a molecular CO-cloud . The actually observed nebula represents the H II region of ionized hydrogen formed around the star HD 164492A of spectral class O7 , the fluorescence of a UV star ionized by hydrogen of this region causes the pinkish glow of the southern part of the nebula. The radius of this region of the nebula is ~ 2 pc , and the age is 3-4–5 ⁵ years (estimated from the size-age dependence of the H II regions). The spectrum of ionized hydrogen is superimposed by a continuous spectrum of the central star, reflected by dust: the dust concentration grows in the southwesterly direction, where the ionization front - the boundary of the HII region is closed with a massive (more than 1300 solar masses) molecular cloud ^[2] . Observations in the infrared range of this cloud showed the presence of condensations (TC2, TC3 and TC4) in it of a protostar type with masses up to 90 solar (TC3) ^[2] .

The northern part of the nebula is a reflection nebula, that is, its blue radiation is caused by the scattering of radiation from external stars on its dust component, the stars - the sources of the “backlight” are not currently installed.

This is one of the most interesting nebulae of the summer southern sky for amateur observations in a telescope of medium and large aperture (from 150 mm). If in the field binoculars just north of the “ Lagoon ” it is visible only as a nondescript spot, then you can see it better in a large amateur telescope in a good moonless sky.

First, a couple of stars right in the center of the bright part of the nebula attract attention. Then it becomes clear that the nebula is as if broken by a dark brightness dip into two. Then a dark crossbar over the main discontinuity becomes visible, the dark line acquires a T-shape and it is clear where its name comes from. A careful study and if you are lucky with the place of observation, you can see that in fact the dark lines divide the body of the nebula into four parts, and to the northeast of the main nebula there is another, dimmer one.

It helps a lot with Observations of the “Three-Part” “Deepskay” filter (UHC, O _III ), it gives the image of the nebula more contrast and visually increases its size.

Neighbors in the sky from the Messier catalog

• M 21 - (slightly to the north) a small open cluster;
• M 8 - (slightly to the south) a large nebula "Lagoon", it is brighter, but it has a not so contrasting pattern;
• M 28 and M 22 — two globular clusters to the east;
• M 24 - (to the north) fragment of the Milky Way;
• M 6 and M 7 - (to the south-west) a pair of rich open clusters in Scorpio

Sequence of observation in the Messier Marathon

... M 25 → M 8 → M 20 → M 21 → M 7 ...

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  A photo of the Palomar Observatory in pseudocolor in the emission lines of ionized hydrogen , sulfur and oxygen (the highlighted section is shown below).

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  A photo of the Hubble telescope in a false color obtained by a combination of images in the emission lines of ionized hydrogen , sulfur and doubly ionized oxygen .

• The nebula under the name Trifid is mentioned in the novel “Knight of the Order of Llornov” by Sergei Sukhinov (2001), written based on E. Hamilton 's works. It contains the Rainbow Star hidden by the dust flow, the light of which gives people immortality. The planet Altar of this star is the birthplace of the superraces of the Second, Third and Fourth people.
• A photograph of the nebula was used to cover the cover of the King Crimson Islands Islands album.

• Star associations

• Triple nebula in the Messier catalog on the SEDS pages (inaccessible link) . Archived May 10, 2005.
• Poles and jets in the Tripartite Nebula (photo of the Hubble telescope)
• Astronomy Picture of the Day. The Trifid Nebula is Stars and Dust ( July 28, 2010). The appeal date is February 16, 2014.