Messier 21
E450596
Messier 21 is a young open star cluster in the constellation Sagittarius, notable for its bright, densely packed hot stars and proximity to the Trifid Nebula.
Statements (47)
| Predicate | Object |
|---|---|
| instanceOf |
Messier object
ⓘ
NGC object ⓘ open star cluster ⓘ |
| age | ~4.6 million years ⓘ |
| angularSize | 13 arcminutes ⓘ |
| apparentBrightnessDescription | moderately bright ⓘ |
| apparentMagnitudeV | 6.5 ⓘ |
| appearsIn | Messier marathon lists ⓘ |
| bestSeenFrom | Northern Hemisphere NERFINISHED ⓘ |
| bestSeenIn | summer ⓘ |
| cataloguedIn |
Messier Catalogue
NERFINISHED
ⓘ
New General Catalogue NERFINISHED ⓘ |
| constellation | Sagittarius NERFINISHED ⓘ |
| contains |
B-type stars
ⓘ
hot blue stars ⓘ pre-main-sequence stars ⓘ |
| declination | −22° 30′ ⓘ |
| discoveredBy | Charles Messier NERFINISHED ⓘ |
| discovererNationality | French ⓘ |
| discoveryDate | 1764 ⓘ |
| distanceFromEarth |
~1.2 kiloparsecs
ⓘ
~4000 light-years ⓘ |
| estimatedNumberOfStars | ~60 ⓘ |
| galacticArm | Sagittarius Arm NERFINISHED ⓘ |
| has |
bright member stars
ⓘ
dense stellar concentration ⓘ |
| interstellarExtinction | moderate ⓘ |
| locatedIn | Milky Way ⓘ |
| locatedNear | galactic plane ⓘ |
| metallicity | near-solar ⓘ |
| near |
Messier 20
NERFINISHED
ⓘ
Trifid Nebula NERFINISHED ⓘ |
| observedIn |
infrared wavelengths
ⓘ
optical wavelengths ⓘ |
| otherName |
C 1800-225
NERFINISHED
ⓘ
Cr 362 NERFINISHED ⓘ M21 NERFINISHED ⓘ NGC 6531 NERFINISHED ⓘ |
| rightAscension | 18h 04m ⓘ |
| separationFromTrifidNebula | ~0.75 degrees ⓘ |
| skyLocationDescription | north of the Trifid Nebula ⓘ |
| stellarPopulation | young ⓘ |
| structure |
compact core
ⓘ
loosely concentrated halo ⓘ |
| TrumplerClass | I3p ⓘ |
| visibleIn |
binoculars
ⓘ
small telescopes ⓘ |
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.