Title: ROSAT X-ray observations of late-type evolved stars: On the relationship between coronal temperatures and luminosities
Abstract: view Abstract Citations (14) References (16) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS ROSAT X-Ray Observations of Late-Type Evolved Stars: On the Relationship between Coronal Temperatures and Luminosities Maggio, A. ; Sciortino, S. ; Harnden, F. R., Jr. Abstract We present ROSAT Position Sensitive Proportional Counters (PSPC) X-ray observations of three near-solar-mass stars, in different evolutionary phases beyond the main sequence: eta Sco (F3 III-IV), iota Vir (F6 III), and HD 74772 (G5 III). All three of these nearby, presumably single stars have been detected, and we have collected enough counts to perform a detailed analysis of their soft X-ray spectra. While the X-ray spectra of eta Sco and HD 74772 can be fitted with Raymond-Smith thermal models with temperatures around 2 x 106 K, the high signal-to-noise spectrum of iota Vir provides unambiguous evidence of a multitemperature plasma, with a two-temperature best-fit model with components at approximately 2 x 106 K and 8 x 106 K. Evidence of some hot plasma (T approximately 107 K) has been also found for HD 74772. The present data, compared with spectral fitting results for other late-type stars observed with the Einstein Observatory, indicate that the low X-ray luminosity giants (Lx is less than 5 x 1028 ergs/s) do not share with the higher X-ray luminosity stars of the same class the property of having substantial amount of 107 K plasma. Moreover, our results confirm the trend of increasing X-ray luminosities with increasing coronal temperatures. Publication: The Astrophysical Journal Pub Date: September 1994 DOI: 10.1086/174609 Bibcode: 1994ApJ...432..701M Keywords: Late Stars; Main Sequence Stars; Spectrum Analysis; Stellar Evolution; Stellar Luminosity; X Ray Astronomy; X Ray Spectra; Emission Spectra; Rosat Mission; Stellar Coronas; Astrophysics; STARS: CORONAE; STARS: LATE-TYPE; X-RAYS: STARS full text sources ADS | data products SIMBAD (3) HEASARC (1)
Publication Year: 1994
Publication Date: 1994-09-01
Language: en
Type: article
Indexed In: ['crossref']
Access and Citation
Cited By Count: 3
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot