TechnologyObserving FacilitiesEducation and OutreachAbout Haystack

Deuterium Abundance

Following the detection of the 1420 MHz (21 cm) hyperfine line of hydrogen and its use in the mapping of the interstellar gas in the Galaxy, the detection of the similar ground state spin-flip transition of deuterium at 327 MHz (92 cm) was considered one of the most important efforts in radio astronomy.  Its measurement constrains the photon to baryon ratio based upon the theory of nucleosynthesis during the big bang.  Estimates of the primordial deuterium-to-hydrogen (D/H) abundance ratio from the ultraviolet Lyman alpha lines have differed by more than a factor of two.  While most of the differences are now thought to be the result of astration and the depletion of deuterium by attachment to interstellar grains, the small isotope shift in the optical lines could lead to systematic errors.  While the radio lines of hydrogen and deuterium are well separated, the deuterium radio line is extremely weak and most observers have only been able to set an upper limit on the D/H ratio. 

Observations made with the Deuterium Array at Haystack Observatory resulted in a 6 sigma detection of the 327 MHz line of deuterium. An estimate of 21 ppm (3 σ error limits from 10 to 35 ppm) was derived for the D/H ratio towards anticenter, where the errors are ± 3 σ and include some uncertainty in conversion of the observed line amplitude to D/H ratio.


HOME  |  CONTACT  |  DIRECTIONS  |  WEATHER  |  INTRANET  |  SITEMAP  |  SEARCH
Astronomy

Science

Haystack Radio Telescope

Wideband VLBI

Radio Arrays (EDGES, MWA, SKA, MAPS, Deuterium)

Small Radio Telescope (SRT)

Publications

Geodesy

Science

Westford Radio Telescope

Mark 4 VLBI Correlator

VLBI Technique Development

International VLBI Service (IVS)

Publications

Atmospheric Sciences

Science

Millstone Hill Observatory

Madrigal

Array Systems

Open Source Projects

Space Science Resources

Publications

Technology

Radio Arrays (EDGES, MWA, SKA, MAPS, Deuterium)

Very Long Baseline Interferometry (VLBI)

Ionospheric Techniques

Open Source Projects

Observing Facilities

Haystack Radio Telescope

Westford Radio Telescope

Millstone Hill Radar

Deuterium Array

Atmospheric Optics Facility

Education and Outreach

Undergraduate Research

Research Experiences for Undergraduates (REU)

Research Experiences for Teachers (RET)

Pre-College Resources

Public Outreach Activities

About Haystack

Northeast Radio Observatory Corp. (NEROC)

Publications

News Archive

Glossary

Staff

Positions Available

Art at Haystack

History

Computing

Library

Networks

Safety Manual

Seminars

CloseSEARCH: