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dc.contributor.authorHARPER, GRAHAM
dc.date.accessioned2009-09-22T12:07:10Z
dc.date.available2009-09-22T12:07:10Z
dc.date.issued2005
dc.date.submitted2005en
dc.identifier.citationAyres, T. R., Brown, A. and Harper, G. M. `Chandra observations of coronal emission from the early-G supergiants Alpha and Beta Aquarii? in Astrophysical Journal, 627, 2005, L53en
dc.identifier.otherY
dc.identifier.otherYen
dc.identifier.urihttp://hdl.handle.net/2262/33128
dc.descriptionPUBLISHEDen
dc.description.abstractWe report Chandra detections of coronal X-rays from the early-G supergiants ? Aquarii (HD209750: G2 Ib) and ? Aquarii (HD204867: G0 Ib). Previous ROSAT observations of these archetype \hybrid chromosphere" stars were in- conclusive in the case of ? Aqr, owing to a 380 mispointing; and although clearly detecting a source near ? Aqr, a small positional discrepancy called the iden- ti?cation into question. The Chandra High Resolution Camera (HRC-I), with its superior spatial resolution and sensitivity, has obtained a positive detection of ? Aqr, and recovered faint emission at the location of ? Aqr, now well sepa- rated from the stronger source to the SE that dominated the earlier ROSAT im- age. The coronal LX=LC IV luminosity ratios of both supergiants are extremely depressed relative to early-G main sequence stars, continuing the \X-ray de?- ciency" trend originally identi?ed in late-F/early-G luminosity class III giants of the Hertzsprung gap.en
dc.description.sponsorshipThis work was supported by Chandra grant G05-6010X from the Smithsonian Astro- physical Observatory, and NASA grant NAG5-13058. Observations from the Chandra X-ray Observatory were collected and processed at the Chandra X-ray Observatory Center, op- erated for NASA by Smithsonian Astrophysical Observatory. This research also utilized the SIMBAD database, maintained by CDS, Strasbourg, France; the ROSAT and XMM{ Newton public archives at the HEASARC of the NASA Goddard Space Flight Center; and HST data from the Multimission Archive at Space Telescope (MAST), including the \Cool- CAT" cool-star spectral catalog. We also made use of the X-ray count-rate tool provided by HEASARC and the hydrogen column density calculator hosted by MAST.en
dc.format.extentL53en
dc.format.extent210716 bytes
dc.format.mimetypeapplication/pdf
dc.language.isoenen
dc.publisherUniversity of Coloradoen
dc.relation.ispartofseriesAstrophysical Journalen
dc.relation.ispartofseries627en
dc.rightsYen
dc.subjectStars: individual | X-rays: coronae | ultraviolet: spectraen
dc.titleChandra observations of coronal emission from the early-G supergiants Alpha and Beta Aquariien
dc.typeJournal Articleen
dc.contributor.sponsorNASA
dc.type.supercollectionscholarly_publicationsen
dc.type.supercollectionrefereed_publicationsen
dc.identifier.peoplefinderurlhttp://people.tcd.ie/harperg
dc.identifier.rssurihttp://casa.colorado.edu/~gmh/pubs/abh2005.pdf


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