Accurate measurements of the local deuterium abundance from HST spectra

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Published by National Aeronautics and Space Administration, National Technical Information Service, distributor in [Washington, DC, Springfield, Va .

Written in English

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Subjects:

  • Deuterium.,
  • Abundance.,
  • Lyman spectra.,
  • Line spectra.,
  • Universe.,
  • Spaceborne astronomy.

Edition Notes

Book details

StatementJeffrey L. Linsky.
Series[NASA contractor report] -- NASA-CR-205284., NASA contractor report -- NASA CR-205284.
ContributionsUnited States. National Aeronautics and Space Administration.
The Physical Object
FormatMicroform
Pagination1 v.
ID Numbers
Open LibraryOL15495040M

Download Accurate measurements of the local deuterium abundance from HST spectra

Linsky J.L. () Accurate Measurements of the Local Deuterium Abundance from HST Spectra. In: Kafatos M., Kondo Y. (eds) Examining the Big Bang and Diffuse Background Radiations.

International Astronomical Union/Union Astronomique Internationale, vol Author: Jeffrey L. Linsky. ACCURATE MEASUREMENTS OF THE LOCAL DEUTERIUM ABUNDANCE FROM HST SPECTRA O q -_-_/_7. JEFFREY L. LINSKY I Joint Institute for Laboratory Astrophysics University of Colorado and T.

Boulder CO Abstract. An accurate measurement of the primordial value of D/H would provide a critical test of nucleosynthesis models for the early. Get this from a library. Accurate measurements of the local deuterium abundance from HST spectra.

[J L Linsky; United States. National Aeronautics and Space Administration.]. Accurate Measurements of the Local Deuterium Abundance from HST Spectra An accurate measurement of the primordial value of D/H would provide a critical test of nucleosynthesis models for the early universe and the baryon density.

I briefly summarize the ongoing HST observations of the interstellar H and D Lyman-alpha absorption for lines of Author: Jeffrey L. Linsky. AIREX: Accurate Measurements of the Local Deuterium Abundance from HST Spectra An accurate measurement of the primordial value of D/H would provide a critical test of nucleosynthesis models for the early universe and the baryon : Jeffrey L.

Linsky. Abstract. Excellent HST/GHRS spectra of interstellar hydrogen and deuterium Lyman-α absorption toward nearby stars allow us to identify systematic errors that have plagued earlier work and to measure accurate values of the D/H ratio in local interstellar gas.

Excellent HST/GHRS spectra of interstellar hydrogen and deuterium Lyman-α absorption toward nearby stars allow us to identify systematic errors that have plagued earlier work and to measure accurate values of the D/H ratio in local interstellar gas.

Analysis of 12 sightlines through the Local Interstellar Cloud leads to a mean value of D/H = ( +/- ) × with all data Author: Jeffrey L. Linsky, Brian E. Wood. Analysis of UV spectra obtained with the HST, FUSE and other satellites provides a new understanding of the deuterium abundance in the local region of the galactic disk.

The wide range of gas-phase D/H measurements obtained outside of the Local Bubble can now be explained as due to different amounts of deuterium depletion on carbonaceous by: Therefore, the measurements are thought to represent a direct sampling of the deuterium abundance produced in the Big Bang.

The numbers are not consistent with expectations, in that the values are not constant across different sightlines and in that the mean is Cited by: 3. The deuterium abundance evaluation in the direction of Capella has for a long time been used as a reference for the local interstellar medium (ISM) within Accurate measurements of the local deuterium abundance from HST spectra book Galaxy.

Excellent HST/GHRS spectra of interstellar hydrogen and deuterium Lyman-(alpha) absorption toward nearby stars allow us to identify systematic errors that have plagued earlier work and to measure accurate values of the D/H ratio in local interstellar gas.

Analysis of 12 sightlines through the Local Interstellar Cloud leads to a mean value of D/H = ( +/- ) x 10(exp -5) with all data. Measurement of intergalactic deuterium abundances errors that have plagued earlier work and to measure accurate values of the D/H ratio in local interstellar gas.

new STIS spectra from the. Hence, deuterium appears as a key element for cosmology and subsequent evolution. Notwithstanding the meteoritic/solar system abundance of deuterium, the first measurements of the interstellar D/H ratio were reported in the early seventies, and their number have then increased following the availability of the adequate instrumentation.

Deuterium abundance measurements. The different D/H evaluations are shown as a of time (for Q0 = 1, q0 =H0 = 50 km/s/Mpc). The primordial measurements plotted (QSO) are from Buries &: Tytler (a,b) and Songaila () [high redshifts] and from Webb et al.

(1!)97) and Tytler et al. () [moderate redshift]. lower limit to the primordial deuterium abundance. Recent reviews of deuterium abundance measurements can be found in Lemoine et al. (), Linsky (), and Moos et al. Linsky () reviews measurements of the deuterium abundance for material in the local interstellar cloud (LIC), which are consistent with a common value for D/H of.

We report a further analysis of the ratio of deuterium to hydrogen (D/H) using HST spectra of the z = Lyman limit system towards the QSO PG+ Initial analyses of this absorber found it gave a high D/H value, −×10 −4 (Webb et al.

), inconsistent with several higher redshift measurements. Deuterium has an abundance of x 10^−4 compared to for ordinary hydrogen.

The goal of this experiment is to calculate the mass ratio between hydrogen and deuterium by measuring the wavelength splitting between the hydrogen and deuterium emission lines. Abstract. Excellent HST/GHRS spectra of interstellar hydrogen and deuterium Lyman-a absorption toward nearby stars allow us to identify systematic errors that have plagued earlier work and to measure accurate values of the D/H ratio in local interstellar gas.

Analysis of 12 sightlines through. with previous inferences about the deuterium abundance from D/O and D/N measurements. Short lines of sight with H i column densities of logN(H i) Local Bubble is (D=H) LBg ¼ ( ) ;10 5.

However, the four longest Galactic lines of sight with measured D/H, which. in the deuterium abundance in 15 Gyrs (see e.g., Galli et al. ; Tosi et al.

Hence, any abundance of deuterium measured at any metallicity should provide a lower limit to the primordial deuterium abundance. This picture is essentially constrained by deuterium abundance measurements at look-backtimes of ∼ 14 Gyrs (primordial.

Abstract. We report on a further analysis of the ratio of deuterium to hydrogen (D/H) using Hubble Space Telescope (HST) spectra of the z= Lyman limit system towards the quasi-stellar object (QSO) PG+Initial analyses of this absorber found it gave a high D/H value, – × 10 −4, inconsistent with several higher redshift by: 8.

measurement of deuterium in systems with higher velocity dispersions. The dependence of the shape of the Lyman continuum cutoff on deuterium abundance, velocity dispersion, and column density is also examined in detail, and low- to moderate-resolution synthetic spectra are presented.

For clouds of Doppler dispersion. We report the discovery of deuterium absorption in the very metal-poor ([Fe/H] =−) damped Lyα system at z abs = toward the QSO SDSS J+ On the basis of 13 resolved Di absorption lines and the damping wings of the Hi Lyα transition, we have obtained a new, precise measure of the primordial abundance of by: Both measurements use multiple-component Voigt profile analysis of high resolution, high signal-to-noise spectra and determinations of the Lyman continuum optical depth in low resolution spectra to constrain the column densities of deuterium and hydrogen.

The measurements are consistent with a single primordial value of D/H = $ \pm hydrogen enriched with deuterium so that both spectra are produced simultaneously. En-richment of the hydrogen is necessary as the natural abundance of deuterium is about%.

From the Rydberg formula corrected for reduced mass, Eq. (7), we see that the wavelengthFile Size: KB. somewhat more accurate than most earlier values. Comparing with inferences of protosolar D/H from solar wind measurements, it is con rmed that Jupiter is a reliable indicator of the protosolar D/H ratio.

The protosolar deuterium abundance inferred from the jovian value, ( ) 10−5, indicates a minor decrease of the D/H. Measurements of the deuterium abundance in the early Universe provide a sensitive test of the 'standard' Big Bang cosmology.

The probable detection of deuterium absorption by a Cited by: The zabs∼ absorption system towards QSO PG+ is the only example of a QSO absorption system which might have a deuterium/hydrogen ratio approximately ten times the value found towards other QSOs.

We have obtained new STIS spectra from the Hubble Space Telescope (HST) of the Lyα and Lyman limit regions of the system. These spectra give the redshift and velocity. High mass resolution can help to alleviate this problem, and algorithms have been developed to estimate accurate deuterium content in spectra with overlapping distributions at low signal-to-noise.

At sufficiently high resolving powers (m /∆ m 50% ≥ ,), elemental compositions of peptides can be used to reliably assign overlapping Cited by: 6. prim measurement, this suggests a deuterium destruction factor of ∼ − in the local disk region of the Galaxy.

The actual average (D/H) LDg value and the average deuterium destruction factor are presumably somewhere in the middle of the above ranges, but it is not yet clear exactly where. WHAT IS THE TOTAL DEUTERIUM ABUNDANCE IN THE LOCAL GALACTIC DISK?1 Jeffrey L.

Linsky,2 Bruce T. Draine,3 H. Moos,4 Edward B. Jenkins,5 Brian E. Wood,2 Cristina Oliveira,4 William P. Blair,4 Scott D. Friedman,6 Cecile Gry,7 David Knauth,8 Jeffrey W. Kruk,4 Sylvestre Lacour,9 Nicolas Lehner,10 Seth Redfield,11 J.

Michael Shull,12 George Sonneborn,13 and Gerard M. Williger4. The ratio of deuterium to hydrogen (D/H) within such clouds—which is determined from absorption lines in the spectra of more distant quasars that lie along the same line of sight—provides the Cited by: Observational constraints on the primordial deuterium-to-hydrogen ratio (D/H) can test theories of the early universe and provide constraints on models of big bang nucleosynthesis (BBN).

We measure deuterium absorption in high-redshift, metal-poor QSO absorption systems and directly infer the Author: S M Burles and D Tytler. As discussed in this book, an accurate value for this quantity, denoted by Y p, provides a very important constraint on the baryon density via primoridal nucleosynthesis.

Olive etal. summarize a variety of new observations including a) a plethora of H II region abundance measurements in very chemically unevolved galaxies and b) the recent HST. Deuterium, also called heavy hydrogen, is a stable isotope of hydrogen with a natural abundance in the oceans of Earth of approximately one atom in of hydrogen (~ PPM).Deuterium thus accounts for approximately % (on a weight basis, %) of all naturally occurring hydrogen in the oceans on Earth (see VSMOW; the abundance changes slightly from one kind of natural water to another).

This cloud has many characteristics that permit an accurate determination of the ratio of deuterium to ordinary hydrogen, D/H.

The ration that Songaila et al. measure, D/H = ×is much higher than the ratio determined—after significant corrections for local effects—in the nearby interstellar medium of our own Galaxy 3.

Deuterium (or hydrogen-2, symbol 2 H or D, also known as heavy hydrogen) is one of two stable isotopes of hydrogen (the other being protium, or hydrogen-1).The nucleus of a deuterium atom, called a deuteron, contains one proton and one neutron, whereas the far more common protium has no neutrons in the ium has a natural abundance in Earth's oceans of about one atom in of Names: deuterium, H-2, hydrogen A side from ordinary hydrogen, only four other nuclear species (2H, 3He, 4He and 7Li are left over from the Big Bang.

Of these, deuterium (2H) is the one whose obsei^ved abundance provides the most accurate determination of the crucial cosmological parameter ρb, the present‐day average mass density of ordinary baryonic matter (made up of protons and neutrons) in the : Bertram Schwarzschild.

Deuterium Abundance. The stability of deuterium is one of the "windows of creation" that are critical in the standard "big bang" deuterium tends to fuse quickly to form helium, so the abundance of deuterium in the present universe is a sensitive probe into. A robust deuterium abundance; re-measurement of the z = absorption system towards the quasar PKS − S.

Riemer-Sørensen,1,2 3‹ J. Webb, 4N. Crighton,5 V. Dumont, K. Ali, S. Kotuˇs, 5 M. Bainbridge,4 M. Murphy5 and R. Carswell6 1Institute of Theoretical Astrophysics, The University of Oslo, Boks Blindern, NO Cited by:.

Deuterium is only produced in primordial Big Bang nucle-osynthesis (BBN), and destroyed in stellar interiors (Epstein, Lattimer & Schramm ). Hence, any abundance of deu-terium measured at any metallicity should provide a lower limit to the primordial deuterium abundance (Reeves et al.

).In collaboration with his former students and colleagues, Dr. Linsky's research involves the analysis of high-resolution stellar spectra, primarily in the ultraviolet, to measure the physical properties of stars, the atmospheres of exoplanets, gas in the local interstellar medium, and the abundance of deuterium .The natural abundance of deuterium in the ocean is approximately ppm, which is one atom in 6, of hydrogen.

In other words, % of hydrogen in the ocean is protium and only % is deuterium (or % by mass). The natural abundance of deuterium is slightly different from one water source to another.

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