Tucana II Dwarf Galaxy
E507098
Tucana II Dwarf Galaxy is an ultra-faint, ancient dwarf satellite galaxy of the Milky Way, notable for its extremely low luminosity and very metal-poor stellar population.
All labels observed (1)
| Label | Occurrences |
|---|---|
| Tucana II Dwarf Galaxy canonical | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T4618746 — 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: Tucana II Dwarf Galaxy Context triple: [Milky Way subgroup, hasMember, Tucana II Dwarf Galaxy]
-
A.
Tucana Dwarf Galaxy
The Tucana Dwarf Galaxy is a faint, isolated dwarf spheroidal galaxy located on the outskirts of the Local Group, notable for its old stellar population and lack of recent star formation.
-
B.
Ursa Minor Dwarf Galaxy
The Ursa Minor Dwarf Galaxy is a faint, spheroidal satellite galaxy of the Milky Way located in the constellation Ursa Minor and composed primarily of old, metal-poor stars.
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C.
Canes Venatici II Dwarf Galaxy
Canes Venatici II Dwarf Galaxy is a faint, small satellite galaxy of the Milky Way located in the constellation Canes Venatici and classified as an ultra-faint dwarf spheroidal galaxy.
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D.
Reticulum II Dwarf Galaxy
Reticulum II Dwarf Galaxy is an ultra-faint satellite galaxy of the Milky Way notable for its extreme dark matter dominance and unusually high abundance of heavy r-process elements.
-
E.
Bootes II Dwarf Galaxy
Bootes II Dwarf Galaxy is a faint, ultra-low-luminosity satellite galaxy of the Milky Way located in the constellation Boötes.
- 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: Tucana II Dwarf Galaxy Target entity description: Tucana II Dwarf Galaxy is an ultra-faint, ancient dwarf satellite galaxy of the Milky Way, notable for its extremely low luminosity and very metal-poor stellar population.
-
A.
Tucana Dwarf Galaxy
The Tucana Dwarf Galaxy is a faint, isolated dwarf spheroidal galaxy located on the outskirts of the Local Group, notable for its old stellar population and lack of recent star formation.
-
B.
Ursa Minor Dwarf Galaxy
The Ursa Minor Dwarf Galaxy is a faint, spheroidal satellite galaxy of the Milky Way located in the constellation Ursa Minor and composed primarily of old, metal-poor stars.
-
C.
Canes Venatici II Dwarf Galaxy
Canes Venatici II Dwarf Galaxy is a faint, small satellite galaxy of the Milky Way located in the constellation Canes Venatici and classified as an ultra-faint dwarf spheroidal galaxy.
-
D.
Reticulum II Dwarf Galaxy
Reticulum II Dwarf Galaxy is an ultra-faint satellite galaxy of the Milky Way notable for its extreme dark matter dominance and unusually high abundance of heavy r-process elements.
-
E.
Bootes II Dwarf Galaxy
Bootes II Dwarf Galaxy is a faint, ultra-low-luminosity satellite galaxy of the Milky Way located in the constellation Boötes.
- F. None of above. chosen
Statements (39)
| Predicate | Object |
|---|---|
| instanceOf |
Local Group galaxy
ⓘ
dwarf galaxy ⓘ ultra-faint dwarf galaxy ⓘ |
| absoluteMagnitudeV | about −3.8 ⓘ |
| ageOfDominantPopulation | older than 10 billion years ⓘ |
| alternativeName |
Tuc II
ⓘ
linked to:
Tucana II
|
| classificationBasis | resolved stellar overdensity relative to Milky Way foreground ⓘ |
| contains |
ancient stars
ⓘ
horizontal branch stars ⓘ red giant branch stars ⓘ |
| currentStarFormation | no significant ongoing star formation detected ⓘ |
| darkMatterContent | dark-matter-dominated system ⓘ |
| discoveredAs | Milky Way satellite candidate in Dark Energy Survey data ⓘ |
| discoveryMethod | resolved stellar photometry in wide-field imaging surveys ⓘ |
| distanceFromEarth |
approximately 190,000 light-years
ⓘ
approximately 58 kiloparsecs ⓘ |
| environment | outer halo of the Milky Way ⓘ |
| epochOfStarFormation | early universe ⓘ |
| galaxyType | dwarf spheroidal galaxy ⓘ |
| gasContent | gas-poor ⓘ |
| hemisphere | southern celestial hemisphere ⓘ |
| hostGalaxy | Milky Way ⓘ |
| kinematics | stars show low velocity dispersion consistent with dwarf spheroidal nature ⓘ |
| locatedInConstellation | Tucana ⓘ |
| luminosityClass | ultra-faint ⓘ |
| massToLightRatio | very high mass-to-light ratio ⓘ |
| meanMetallicity | [Fe/H] ≈ −2.4 ⓘ |
| memberOf | Milky Way satellite system ⓘ |
| metallicitySpread | shows internal spread in [Fe/H] among member stars ⓘ |
| observationalChallenge | detection limited by extremely low luminosity and surface brightness ⓘ |
| observedWith |
Dark Energy Camera (DECam)
ⓘ
linked to:
Dark Energy Camera
Magellan telescopes ⓘ
linked to:
Magellan Telescopes
|
| researchUse |
constraint on dark matter models
ⓘ
probe of early chemical enrichment in the Milky Way halo ⓘ testbed for galaxy formation at the lowest masses ⓘ |
| starFormationHistory | dominated by very old stellar population ⓘ |
| stellarPopulation | very metal-poor ⓘ |
| surfaceBrightness | extremely low ⓘ |
| totalLuminosity | of order 10^3 solar luminosities ⓘ |
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: Tucana II Dwarf Galaxy Description of subject: Tucana II Dwarf Galaxy is an ultra-faint, ancient dwarf satellite galaxy of the Milky Way, notable for its extremely low luminosity and very metal-poor stellar population.
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.