Observing stellar coronae with the Goddard High Resolution Spectrograph. 1: The dMe star AU microscopoii

Maran, P.; Robinson, Richard D.; Shore, Steven N.; Brosius, J. W.; Carpenter, Kenneth G.; Woodgate, B. E.; Linsky, J. L.; Brown, Alexander; Byrne, P. B.; Kundu, M. R.; White, S.; Brandt, J. C.; Shine, R. A.; Walter, Frederick M.

doi:10.1086/173692

Cited by 37 publications

(25 citation statements)

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“…The UV line at 1354.1Å has been studied from Skylab and SMM observations and more recently stellar spectra have been obtained with the Goddard High Resolution Spectrograph on the Hubble Space Telescope (Maran et al 1994). Highly ionized iron lines have been recorded for several stars with EUVE, and electron density values have been deduced for the stellar atmospheres from the Fe XXI line ratios (Dupree et al 1993).…”

Section: The Carbon Isoelectronic Sequencementioning

confidence: 99%

CHIANTI - an atomic database for emission lines

Dere

Landi

Mason

et al. 1997

Astron. Astrophys. Suppl. Ser.

1,979

1,669

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Abstract. A comprehensive set of accurate atomic data is required for analyses of astrophysical and solar spectra. CHIANTI provides a database of atomic energy levels, wavelengths, radiative data and electron excitation data for ions which are abundant in cosmic plasmas. The most recent electron excitation data have been assessed and stored following the method of Burgess & Tully (1992). The current version is essentially complete for specifying the emission spectrum at wavelengths greater than 50Å. A list of observed lines in the spectral region between 50 and 1100Å has been compiled and compared with the lines predicted by the CHIANTI database. The CHIANTI database reproduces the vast majority of lines observed at these wavelengths. CHIANTI includes IDL (Interactive Data Language) routines to calculate optically thin synthetic spectra for equilibrium conditions. IDL routines to calculate theoretical line intensities required for electron density or temperature diagnostics and emission measure studies are also included. The CHIANTI atomic database and supporting IDL routines are available by anonymous FTP.

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Section: The Carbon Isoelectronic Sequencementioning

confidence: 99%

CHIANTI - an atomic database for emission lines

Dere

Landi

Mason

et al. 1997

Astron. Astrophys. Suppl. Ser.

1,979

1,669

View full text Add to dashboard Cite

show abstract

“…3.1). However, in most of the literature (see, e.g., Brown et al 1984b;Brown et al 1984a;Hartmann et al 1985;Jordan et al 1985;Byrne et al 1987;Jordan et al 1987;Linsky et al 1989;Quin et al 1993;Maran et al 1994;Linsky et al 1995;Doschek 1997;Griffiths & Jordan 1998;Brandt et al 2001), these lines have been used for solar and stellar emission measure analyses, since they are among the most prominent ones in the FUV. In this paper we show that erroneous results are obtained if these lines are used, in particular in terms of DEM , elemental abundances and electron densities.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic diagnostics of stellar transition regions and coronae in the XUV: AU Mic in quiescence

Zanna

Landini

Mason

2002

A&A

111

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Abstract. In this paper we review the spectroscopic diagnostic techniques that can be applied to XUV observations of active stars. In particular, we discuss methods for the determination of electron densities, emission measures and the chemical composition of the stellar transition regions and coronae. We pay particular attention to the atomic data used and we revise several previous analyses with the most recent atomic data (from CHIANTI). We find severe limitations to some of the commonly used methods and atomic data and we obtain results which are significantly different from other authors. We illustrate this with a number of examples. We analyse a combined set of multi-wavelength observations (EUVE, HST/STIS, FUSE) for the quiescent phase of the dMe star AU Mic. A major conclusion of this paper is that the use of spectral lines from the Li and Na isoelectronic sequences, common in previous literature, produces erroneous results in the determination of emission measures, elemental abundances and transition region densities.

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“…On the stellar side, the solar flare line Fe xxi 1354 was discovered in Hubble Space Telescope (HST) Goddard High-Resolution Spectrograph (GHRS) observations of the dMe star AU Microscopii (M0 V) by Maran et al (1994) and subsequently in the hyperactive RS Canum Venatico-rum binary HR 1099 (K1 IV+G5 V) by Robinson et al (1996) and in Capella ( Aur; G8 III+G1 III) 1 by Linsky et al (1998). More recently, Johnson et al (2002) compared HST observations of Capella 4 yr apart and found that the previously strong Fe xxi 1354 emission of the G8 star in the GHRS spectrum had faded into invisibility in the STIS epoch, while the G1 component was relatively unchanged.…”

Section: Introductionmentioning

confidence: 99%