Trifid Nebula
What is Trifid Nebula?
Nebulae· Distance 4,100 ly. Red emission nebula, blue reflection nebula and dark dust lanes that split it three ways, all in one object — "Trifid" means three-lobed. It sits just above the Lagoon Nebula, so both fit in one field of view.
📍 Visible from where you are right now — computed in your browser
bearing · altitude · rise time · best time tonight
Where Trifid Nebula is in your sky right now: https://nowsky.org/solar/sky?sel=trifid nebula — location and time set automatically, no login.
Its place in the sky
A nebula, in the direction of Sagittarius, spanning about 28 arcminutes of sky — 0.9 times the width of the full Moon.
Distance and scale
| Distance | ~4,100 ly |
|---|---|
| Size | ~40 ly across |
| Type | emission, reflection and dark nebula |
| Constellation | Sagittarius |
Figures are representative approximations. Source: compiled from NASA and IAU public data.
Discovery and name
Latin "three-lobed" — John Herschel named it for the three dark lanes dividing it.
Frequently asked
- How far is Trifid Nebula from Earth?
- ~4,100 ly.
- What kind of object is Trifid Nebula?
- emission, reflection and dark nebula.
- Where in the sky is Trifid Nebula?
- In the direction of Sagittarius.
- Where is Trifid Nebula in the sky right now?
- Open the sky view for your location and time and it shows the position in the sky right now.
The dark lanes that split it in three — Barnard 85
The dark lanes that divide the Trifid into three have a name of their own: in 1919 Barnard listed them as Barnard 85 in his catalogue of the sky's dark nebulae. The lanes are not empty space but a cold, dense dust cloud in front of the nebula, blocking the red light behind so that they appear as shadows. Stars are forming inside them, and in 1997 Hubble photographed a jet from a newborn star at the tip of one lane.
At about 300,000 years the Trifid is among the youngest known star-forming regions. Its central hot star has only recently begun to light the surrounding gas, so red emission, blue reflection and dark absorption nebulae overlap in one field, and within a few hundred thousand years the dark lanes will be eroded away by starlight. The three-way split is a shape seen only briefly.
The nebula in depth
The Trifid Nebula (M20) is a star-forming region about 4,100 light-years away in Sagittarius, roughly 40 light-years across. Messier found it in 1764, and John Herschel coined the name in the 1840s for its three-lobed appearance. It is a rare object where a red emission nebula, a blue reflection nebula to the north, and the dark dust lanes that carve the glow into three pieces coexist.
The red light comes from hydrogen ionized by the hot central triple star HD 164492; the blue is starlight scattered by dust. Hubble's 1997 image caught a jet from a protostar shooting 0.75 light-years out of a dusty pillar. At only about 300,000 years old, the nebula is very young and its star formation is still in an early stage.
In the Sky view, look above the spout of the Sagittarius teapot low in the south on summer evenings, about 1.5° north of the Lagoon Nebula. Binoculars show a faint patch with a cluster; a telescope of 15 cm or more under dark skies reveals the three dust lanes. The colors never show to the eye — they come alive only in photographs.
Related
Figures are representative approximations. Simulated positions use J2000 mean elements.