[ITAL]Chandra[/ITAL] Detection of Doppler-shifted X-Ray Line Profiles from the Wind of ζ Puppis (O4 [CLC]f[/CLC])

Cassinelli, J. P.; Miller, N. A.; Waldron, W. L.; Macfarlane, J. J.; Cohen, David H.

doi:10.1086/320916

Cited by 115 publications

(183 citation statements)

References 23 publications

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“…Although unresolved, several emission lines reveal their presence as "bump" features, including Mg, Si, and likely S. The crowded region around 1 keV is probably due to numerous lines of Fe, by analogy with the resolved X-ray spectra from O stars (e.g., Kahn et al 2001;Cassinelli et al 2001). Of special interest is the suggestive presence of N line emission at 0.43 keV and N at 0.50 keV.…”

Section: X-ray Spectramentioning

confidence: 87%

XMM-Newton observations of the nitrogen-rich Wolf-Rayet star WR 1

Ignace

Oskinova²,

Brown

2003

A&A

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Abstract. We present XMM-Newton results for the X-ray spectrum from the N-rich Wolf-Rayet (WR) star WR 1. The EPIC instrument was used to obtain a medium-resolution spectrum. The following features characterize this spectrum: (a) significant emission "bumps" appear that are coincident with the wavelengths of typical strong lines, such as Mg, Si, and S; (b) little emission is detected above 4 keV, in contrast to recent reports of a hard component in the stars WR 6 and WR 110 which are of similar subtype; and (c) evidence for sulfur K-edge absorption at about 2.6 keV, which could only arise from absorption of X-rays by the ambient stellar wind. The lack of hard emission in our dataset is suggestive that WR 1 may truly be a single star, thus representing the first detailed X-ray spectrum that isolates the WR wind alone (in contrast to colliding wind zones). Although the properties of the S-edge are not well-constrained by our data, it does appear to be real, and its detection indicates that at least some of the hot gas in WR 1 must reside interior to the radius of optical depth unity for the total absorptive opacity at the energy of the edge.

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Section: X-ray Spectramentioning

confidence: 87%

XMM-Newton observations of the nitrogen-rich Wolf-Rayet star WR 1

Ignace

Oskinova²,

Brown

2003

A&A

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“…Lucy & White 1980;Casinelli et al 1994;Casinelli et al 2001;Kahn et al 2001;Schulz et al 2003). However, the wind shock model would not predict the observed hot plasma component of T 2 ∼ 16 MK.…”

Section: The B1 III Star O Permentioning

confidence: 95%

XMM-Newtonstudy of the very young stellar cluster IC 348

Preibisch¹,

Zinnecker²

2004

A&A

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Abstract. We analyze a XMM-Newton X-ray imaging observation of the very young stellar cluster IC 348 with an observing time of 12 h and a corresponding total (all detector) MOS-equivalent exposure time of 207 ks. Our observation is strongly affected by a very intense solar particle flare, due to which only the first half of the exposure time can be used for scientific analysis. We compare the X-ray sources seen by XMM-Newton with those found in our previous Chandra study of IC 348 and find that XMM-Newton reveals 71 new X-ray sources, most of which are located outside the field-of-view of the Chandra observation. 20 of these new X-ray sources can be identified with known cluster members, and 19 sources are likely to be new low-mass members of the cluster. The lightcurves of the XMM-Newton sources show at most moderate levels of variability, but no large flares. We compare the spectral fitting results for 10 stars for which we have good spectra from both Chandra and XMM-Newton, and find good agreement in the fitted plasma temperatures, but a systematic difference in the fitted values of the hydrogen column density (extinction). We finally discuss the X-ray properties of the optically bright B1 star o Per and the X-ray detections among the deeply embedded young stellar objects to the south of the optical cluster center (including HH 211-mm), and find that none of the 23 spectroscopically identified brown dwarfs in IC 348 is detected in our XMM-Newton data. Key words.Galaxy: open clusters and associations: individual: IC 348 -stars: formation -stars: coronaestars: low-mass, brown dwarfs -stars: pre-main sequence -X-rays: stars IntroductionIC 348 is a very young stellar cluster in the Perseus molecular cloud complex, associated with the Per OB2 association and located at a distance of about 310 pc (cf. Herbig 1998). The cluster is exceptionally well investigated in optical and infrared wavelengths. Several studies have identified cluster members by extensive spectroscopy and photometry at optical and IR wavelengths (cf. Herbig 1998;Lada & Lada 1995;Luhman et al. 1998;Luhman 1999) or narrow-band photometry (Najita et al. 2000). Studies of the infrared luminosity function have provided information on the stellar and sub-stellar mass function Muench et al. 2003;Preibisch et al. 2003). Recently, Luhman et al. (2003) presented a new census of the stellar and substellar members of IC 348. From spectroscopy of candidate cluster members they identified numerous new members, including several brown dwarfs. Their final, extinction-limited (A V ≤ 4 mag) sample of members is unbiased in mass, nearly complete down to masses of M ≥ 0.03 M , and contains 288 spectroscopically identified cluster members, including 23 brown dwarfs.The basic properties of IC 348 can be summarized as follows: the mean age of the cluster members is ∼2 Myr and most of the stars exhibit relatively low extinction (A V < ∼ 4 mag). The majority of the cluster members is in the T Tauri stage of premain sequence evolution, and more than 50 stars can be class...

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“…Observable diagnostics of the former include extended black absorption troughs in saturated UV P Cygni profiles Send offprint requests to: R. K. Prinja, e-mail: rkp@star.ucl.ac.uk (Lucy 1983), X-ray emission (Lucy & White 1980;Feldmeier et al 1997;Kahn et al 2001;Cassinelli et al 2001), and non-thermal radio emission (Bieging et al 1989;Scuderi et al 1998). The small-scale wind structures responsible for these signatures are believed to result from a strong instability in the line-driven winds, which operates on linear scales smaller than the Sobolev length.…”

Section: Introductionmentioning

confidence: 99%

Wind variability of B supergiants

Prinja

Massa²,

Fullerton

2002

A&A

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Abstract. We present the most suitable data sets available in the International Ultraviolet Explorer (IUE) archive for the study of time-dependent stellar winds in early B supergiants. The UV line profile variability in 11 B0 to B3 stars is analysed, compared and discussed, based on 16 separate data sets comprising over 600 homogeneously reduced high-resolution spectrograms. The targets include "normal" stars with moderate rotation rates and examples of rapid rotators. A gallery of grey-scale images (dynamic spectra) is presented, which demonstrates the richness and range of wind variability and highlights different structures in the winds of these stars. This work emphasises the suitability of B supergiants for wind studies, under-pinned by the fact that they exhibit unsaturated wind lines for a wide range of ionization. The wind activity of B supergiants is substantial and has highly varied characteristics. The variability evident in individual stars is classified and described in terms of discrete absorption components, spontaneous absorption, bowed structures, recurrence, and ionization variability and stratification. Similar structures can occur in stars of different fundamental parameters, but also different structures may occur in the same star at a given epoch. We discuss the physical phenomena that may be associated with the spectral signatures. The diversity of wind patterns evident likely reflects the role of stellar rotation and viewing angle in determining the observational characteristics of azimuthally extended structure rooted at the stellar surface. In addition, SEI line-synthesis modelling of the UV wind lines is used to provide further information about the state of the winds in our program stars. Typically the range, implied by the line profile variability, in the product of mass-loss rate and ion fraction (Ṁ qi) is a factor of ∼1.5, when integrated between 0.2 and 0.9 v∞; it can however be several times larger over localised velocity regions. At a given effective temperature the mean relative ion ratios can differ by a factor of 5. The general excess in predicted (forward-scattered) emission in the low velocity regime is discussed in terms of structured outflows. Mean ion fractions are estimated over the B0 to B1 spectral classes, and trends in the ionic ratios as a function of wind velocity are described. The low values obtained for the ion fractions of UV resonance lines may reflect the role of clumping in the wind.

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[ITAL]Chandra[/ITAL] Detection of Doppler-shifted X-Ray Line Profiles from the Wind of ζ Puppis (O4 [CLC]f[/CLC])

Cited by 115 publications

References 23 publications

XMM-Newton observations of the nitrogen-rich Wolf-Rayet star WR 1

XMM-Newton observations of the nitrogen-rich Wolf-Rayet star WR 1

XMM-Newtonstudy of the very young stellar cluster IC 348

Wind variability of B supergiants

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