Chandra observations of coronal emission from the early-G supergiants Alpha and Beta Aquarii
Citation:
Ayres, 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, L53Download Item:
Chandra Observations.pdf (published (author copy) peer-reviewed) 205.7Kb
Abstract:
We 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.
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Author: HARPER, GRAHAM
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Astrophysical Journal627
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