Messier 81
E450569
Messier 81 is a prominent, nearby grand-design spiral galaxy in the constellation Ursa Major, notable for its brightness and well-defined structure.
All labels observed (1)
| Label | Occurrences |
|---|---|
| Messier 81 canonical | 3 |
How this entity was disambiguated
This entity first appeared as the object of triple T4531641 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: Messier 81 Context triple: [M81 Group, dominantGalaxy, Messier 81]
-
A.
NGC 2403
NGC 2403 is a nearby spiral galaxy in the constellation Camelopardalis, notable for its active star formation and numerous observed supernovae.
-
B.
Triangulum Galaxy
The Triangulum Galaxy is a nearby spiral galaxy in the Local Group, notable as one of the closest large galaxies to the Milky Way and a companion to the Andromeda Galaxy.
-
C.
Andromeda
Andromeda is a princess in Greek mythology who was rescued from a sea monster by the hero Perseus and later became his wife.
-
D.
Messier 8
Messier 8, also known as the Lagoon Nebula, is a large, bright emission nebula and active star-forming region visible in the constellation Sagittarius.
-
E.
Andromeda Galaxy
The Andromeda Galaxy is the nearest large spiral galaxy to the Milky Way and is on a collision course to eventually merge with it.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: Messier 81 Target entity description: Messier 81 is a prominent, nearby grand-design spiral galaxy in the constellation Ursa Major, notable for its brightness and well-defined structure.
-
A.
NGC 2403
NGC 2403 is a nearby spiral galaxy in the constellation Camelopardalis, notable for its active star formation and numerous observed supernovae.
-
B.
Triangulum Galaxy
The Triangulum Galaxy is a nearby spiral galaxy in the Local Group, notable as one of the closest large galaxies to the Milky Way and a companion to the Andromeda Galaxy.
-
C.
Andromeda
Andromeda is a princess in Greek mythology who was rescued from a sea monster by the hero Perseus and later became his wife.
-
D.
Messier 8
Messier 8, also known as the Lagoon Nebula, is a large, bright emission nebula and active star-forming region visible in the constellation Sagittarius.
-
E.
Andromeda Galaxy
The Andromeda Galaxy is the nearest large spiral galaxy to the Milky Way and is on a collision course to eventually merge with it.
- F. None of above. chosen
Statements (49)
| Predicate | Object |
|---|---|
| instanceOf |
Messier object
ⓘ
NGC object ⓘ extragalactic object ⓘ grand-design spiral galaxy ⓘ spiral galaxy ⓘ |
| absoluteMagnitude_V | about -20.8 ⓘ |
| AGNType | low-luminosity Seyfert 1 ⓘ |
| angularSize_arcmin | about 26.9 × 14.1 ⓘ |
| apparentMagnitude_V | about 6.9 ⓘ |
| bestSeenFrom | Northern Hemisphere NERFINISHED ⓘ |
| cataloguedBy | Charles Messier NERFINISHED ⓘ |
| centralBlackHoleMass_solar | about 7e7 ⓘ |
| companionGalaxy |
Messier 82
NERFINISHED
ⓘ
NGC 3077 NERFINISHED ⓘ |
| constellation | Ursa Major NERFINISHED ⓘ |
| declination_J2000 | +69°03′55″ ⓘ |
| diameter_ly | about 90000 ⓘ |
| discoveredBy | Johann Elert Bode NERFINISHED ⓘ |
| discoveryYear | 1774 ⓘ |
| distanceFromEarth_ly | about 12000000 ⓘ |
| distanceFromEarth_Mpc | about 3.6 ⓘ |
| groupMembership | M81 Group NERFINISHED ⓘ |
| hasCentralSupermassiveBlackHole | true ⓘ |
| hostTo | numerous H II regions ⓘ |
| inclination_degrees | about 59 ⓘ |
| interaction |
tidal interaction with Messier 82
ⓘ
tidal interaction with NGC 3077 ⓘ |
| luminosity_solar | about 2.5e10 ⓘ |
| mass_solar | about 7e11 ⓘ |
| messierNumber | 81 ⓘ |
| morphologicalType | SA(s)ab ⓘ |
| nearestMajorGalaxy | Milky Way NERFINISHED ⓘ |
| ngcNumber | 3031 ⓘ |
| notableFeature |
bright bulge
ⓘ
low-level active galactic nucleus ⓘ prominent dust lanes ⓘ well-defined spiral arms ⓘ |
| otherName |
Bode's Galaxy
NERFINISHED
ⓘ
M81 NERFINISHED ⓘ NGC 3031 NERFINISHED ⓘ |
| positionAngle_degrees | about 157 ⓘ |
| radialVelocity_km_per_s | about -34 ⓘ |
| redshift_z | about 0.000113 ⓘ |
| rightAscension_J2000 | 09h55m33.2s ⓘ |
| stellarMass_solar | about 1e11 ⓘ |
| supernovaDiscoveryYear | 1993 ⓘ |
| supernovaRecorded | SN 1993J NERFINISHED ⓘ |
| supernovaType | Type IIb (SN 1993J) NERFINISHED ⓘ |
| visibility | visible in small amateur telescopes ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: Messier 81 Description of subject: Messier 81 is a prominent, nearby grand-design spiral galaxy in the constellation Ursa Major, notable for its brightness and well-defined structure.
Referenced by (3)
Full triples — surface form annotated when it differs from this entity's canonical label.