<http://www.ivoa.net/rdf/uat#o-stars> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.w3.org/2002/07/owl#NamedIndividual> . <http://www.ivoa.net/rdf/uat#o-stars> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.w3.org/2004/02/skos/core#Concept> . <http://www.ivoa.net/rdf/uat#o-stars> <http://www.w3.org/2004/02/skos/core#prefLabel> "O stars" . <http://www.ivoa.net/rdf/uat#o-stars> <http://www.w3.org/2004/02/skos/core#definition> "A luminous, hot, blue star whose spectrum is dominated by the lines of hydrogen, atomic helium, and ionized helium; also known as O-type star. This is the earliest spectral type and the only main sequence star in which ionized helium is present. The effective temperatures of these stars range from about 30,000 K to 50,000 K, their luminosities from 50,000 to 1,000,000 times that of solar luminosity, and their masses from about 20 to 100 solar masses. The hottest O-type stars display high ionization emission features such as N III and He II, Of star. They are divided into subtypes O2, the hottest, to O9.7, the coldest. O-type stars are relatively rare, for each star of 100 solar masses there are 10^6 stars of solar mass. They are relatively short-lived since they spend only a few million years on the main sequence. The brightest O-type star in the sky visible with naked eye is Alnitak." . <http://www.ivoa.net/rdf/uat#o-stars> <http://data.bioontology.org/metadata/def/mappingLoom> "ostars" . <http://www.ivoa.net/rdf/uat#o-stars> <http://data.bioontology.org/metadata/def/mappingSameURI> <http://www.ivoa.net/rdf/uat#o-stars> . <http://www.ivoa.net/rdf/uat#o-stars> <http://www.w3.org/2004/02/skos/core#exactMatch> <http://astrothesaurus.org/uat/1137> . <http://www.ivoa.net/rdf/uat#o-stars> <http://www.w3.org/2004/02/skos/core#broader> <http://www.ivoa.net/rdf/uat#early-type-stars> . <http://www.ivoa.net/rdf/uat#o-stars> <http://www.w3.org/2004/02/skos/core#broader> <http://www.ivoa.net/rdf/uat#stellar-spectral-types> . <http://www.ivoa.net/rdf/uat#o-stars> <http://www.w3.org/2004/02/skos/core#related> <http://www.ivoa.net/rdf/uat#stellar-classification> . <http://www.ivoa.net/rdf/uat#o-stars> <http://data.bioontology.org/metadata/def/mappingSameURI> <http://www.ivoa.net/rdf/uat#o-stars> . <http://www.ivoa.net/rdf/uat#o-dwarf-stars> <http://www.w3.org/2004/02/skos/core#broader> <http://www.ivoa.net/rdf/uat#o-stars> . <http://www.ivoa.net/rdf/uat#o-giant-stars> <http://www.w3.org/2004/02/skos/core#broader> <http://www.ivoa.net/rdf/uat#o-stars> . <http://www.ivoa.net/rdf/uat#o-subdwarf-stars> <http://www.w3.org/2004/02/skos/core#broader> <http://www.ivoa.net/rdf/uat#o-stars> . <http://www.ivoa.net/rdf/uat#o-subgiant-stars> <http://www.w3.org/2004/02/skos/core#broader> <http://www.ivoa.net/rdf/uat#o-stars> . <http://www.ivoa.net/rdf/uat#o-supergiant-stars> <http://www.w3.org/2004/02/skos/core#broader> <http://www.ivoa.net/rdf/uat#o-stars> . <http://www.ivoa.net/rdf/uat#oe-stars> <http://www.w3.org/2004/02/skos/core#broader> <http://www.ivoa.net/rdf/uat#o-stars> . <http://www.ivoa.net/rdf/uat#oef-stars> <http://www.w3.org/2004/02/skos/core#broader> <http://www.ivoa.net/rdf/uat#o-stars> . <http://www.ivoa.net/rdf/uat#of-stars> <http://www.w3.org/2004/02/skos/core#broader> <http://www.ivoa.net/rdf/uat#o-stars> . <http://www.ivoa.net/rdf/uat#stellar-classification> <http://www.w3.org/2004/02/skos/core#related> <http://www.ivoa.net/rdf/uat#o-stars> .