Goddard high-resolution spectrograph observations of the local interstellar medium and the deuterium/hydrogen ratio along the line of sight toward Capella

Linsky, Jeffrey L.; Brown, Alexander; Gayley, K. G.; Diplas, A.; Savage, Blair D.; Ayres, Thomas R.; Landsman, W. B.; Shore, Steven N.; Heap, Sara R.

doi:10.1086/172170

Cited by 233 publications

(113 citation statements)

References 0 publications

Supporting

Mentioning

103

Contrasting

Unclassified

Order By: Relevance

“…References.-(1) Linsky & Wood 1996; (2) Lallement et al 1995;(3) this paper; (4) Lallement et al 1994; (5) Dring et al 1997;(6) Linsky et al 1995; (7) (8) Ferlet et al 1995;(9) Linsky et al 1993;(10) Frisch et al 1999;(11) Lecavelier des Etangs et al 1997;(12) Lemoine et al 1996Lemoine et al . et al (1996.…”

Section: Velocity Distributionunclassified

The Structure of the Local Interstellar Medium. I. High‐Resolution Observations of Fe ii , Mg ii , and Ca ii toward Stars within 100 Parsecs

Redfield

Linsky

2002

ASTROPHYS J SUPPL S

Self Cite

View full text Add to dashboard Cite

High-resolution absorption measurements ( =D & 100;000) of the resonance lines of Fe ii, Mg ii, and Ca ii are presented for all available observed targets within 100 pc. The Fe ii and Mg ii spectra were obtained with the Goddard High Resolution Spectrograph (GHRS) and the Space Telescope Imaging Spectrograph (STIS) instruments aboard the Hubble Space Telescope (HST). Of the 63 observations of targets within 100 pc, we present new measurements for 24 lines of sight. We also compiled all published absorption measurements based on Ca ii spectra obtained by various ground-based instruments. For each observation we provide measurements of the central velocity, Doppler parameter, and column density for each absorption component. These three ions provide the best opportunity to measure the component velocity structure. Because these are the heaviest ions observed in absorption through the warm local interstellar medium (LISM), the narrow line widths minimize significant blending of components and allow for accurate measurements of the central velocity. We present a statistical analysis of the LISM absorption measurements, which provides an overview of some physical characteristics of warm clouds in the LISM, such as, temperature, turbulent velocity, ionization degree, and depletion. The complete collection and reduction of all LISM absorption measurements provides an important database for studying the structure of nearby warm clouds. Subsequent papers will present models for the morphology and physical properties of individual structures (clouds) in the LISM.

show abstract

Section: Velocity Distributionunclassified

The Structure of the Local Interstellar Medium. I. High‐Resolution Observations of Fe ii , Mg ii , and Ca ii toward Stars within 100 Parsecs

Redfield

Linsky

2002

ASTROPHYS J SUPPL S

Self Cite

View full text Add to dashboard Cite

show abstract

“…The solar value for D/H = (2.6 ±0.6±1.4)×10 −5 (see [23] for a recent discussion) has a considerable uncertainty. Individual ISM observations are much more accurate [24] but they appear to show dispersion along different lines of sight through the ISM [25,26]. This result is unexpected in standard models of chemical evolution, and again suggests their incompleteness.…”

Section: Deuteriummentioning

confidence: 99%

Model independent predictions of big bang nucleosynthesis from He and Li: consistency and implications

et al. 1996

View full text Add to dashboard Cite

We examine in detail how BBN theory is constrained, and what predictions it can make, when using only the most model-independent observational constraints. We avoid the uncertainties and model-dependencies that necessarily arise when solar neighborhood D and 3 He abundances are used to infer primordial D and 3 He via chemical and stellar evolution models. Instead, we use 4 He and 7 Li, thoroughly examining the effects of possible systematic errors in each. Via a likelihood analysis, we find near perfect agreement between BBN theory and the most model-independent data. Given this agreement, we then assume the correctness of BBN to set limits on the single parameter of standard BBN, the baryon-to-photon ratio, and to predict the primordial D and 3 He abundances. We also repeat our analysis including recent measurements of D/H from quasar absorption systems and find that the near perfect agreement between theory and observation of the three isotopes, D, 4 He and 7 Li is maintained. These results have strong implications for the chemical and stellar evolution of the light elements, in particular for 3 He. In addition, our results (especially if the D/H measurements are confirmed) have implications for the stellar depletion of 7 Li. Finally, we set limits on the number N ν of neutrino flavors, using an analysis which carefully and systematically includes all available experimental constraints. The value N ν = 3.0 fits best with BBN and a 95% CL upper limit of N ν < ∼ 4 is established.

show abstract

“…We assume that the temperature of the Local Cloud near the Sun is 7000 ± 1000 K. We base this assumption on recent highresolution absorption measurements of interstellar Lya observed toward the nearby stars of Cappella (Linsky et al 1993) and Procyon (Linsky et al 1994). This value is consistent with the slightly higher temperature of 8000 ± 1000 K derived by Bertaux et al (1985) using hydrogen gas cell Lya line widths of the local interstellar wind.…”

Section: Ionization S T a T E Of T H E G A S N E A R T H E S U Nmentioning

confidence: 99%

“…https://doi.org/10.1017/S0252921100036095 e C A M S MAJORIS AND IONIZATION (Linsky et al 1993) .019 .15…”

Section: Ionization S T a T E Of T H E G A S N E A R T H E S U Nmentioning

confidence: 99%

ϵ Canis Majoris and the Ionization of the Local Cloud

Vallerga

Welsh

1996

International Astronomical Union Colloquium

View full text Add to dashboard Cite

Using the EUV (70 -730 A) spectrum of the brightest EUV source, e CMa taken with the Extreme Ultraviolet Explorer Satellite (EUVE) and simple models that extrapolate this spectrum to the Lyman edge at 912 A, we have determined the local interstellar hydrogen photoionization parameter, T, solely from this B2 II star to be 1.1 x 10 -15 s -1 . This figure is a factor of 7 greater than previous estimates of T calculated for all nearby stars combined (Bruhweiler & Cheng 1988). Using measured values of the density and temperature of neutral interstellar hydrogen gas in the Local Cloud, we derive a particle density of ionized hydrogen, n(H + ), and electrons, n e , of 0.015 -0.019 cm -3 assuming ionization equilibrium and a helium ionization fraction of less than 20%. These values correspond to a hydrogen ionization fraction, Xs from 19% to 15%, respectively.

show abstract

Goddard high-resolution spectrograph observations of the local interstellar medium and the deuterium/hydrogen ratio along the line of sight toward Capella

Cited by 233 publications

References 0 publications

The Structure of the Local Interstellar Medium. I. High‐Resolution Observations of Fe ii , Mg ii , and Ca ii toward Stars within 100 Parsecs

The Structure of the Local Interstellar Medium. I. High‐Resolution Observations of Fe ii , Mg ii , and Ca ii toward Stars within 100 Parsecs

Model independent predictions of big bang nucleosynthesis from He and Li: consistency and implications

ϵ Canis Majoris and the Ionization of the Local Cloud

Contact Info

Product

Resources

About