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Storey, J. W. V.

Publications and source records attributed to Storey, J. W. V..

35 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Detection of CO J = 21-20 /124.2 microns/ and J = 22-21 /118.6 microns/ emission from the Orion nebula

The first observation of far-infrared molecular line emission from the interstellar medium is reported. Strong emission from the J = 21-20 and J = 22-21 rotational transitions of carbon monoxide was detected in the Kleinmann-Low/shocked H2 region of the Orion Molecular Cloud. The results imply that the region is optically thin in these lines and that much of the carbon is in the form of CO. This work also represents the first use of an antimony-doped germanium photoconductor in an astronomical application.

Watson, D. M.↗
NASA NTRS1980

An airborne far-infrared spectrometer for astronomical observations

A Fabry-Perot spectrometer for airborne observations of astronomical spectral lines has been designed for use in the 50 to 200 micron region of the far-infrared. The spectrometer uses a fixed wavelength Fabry-Perot filter cooled to 4.2 K in conjunction with a high order scanning Fabry-Perot at room temperature. This arrangement provides high spectral resolution and also minimizes the thermal background radiation on the detector. The instrument has been successfully used to study all the presently detected fine structure lines between 50 and 120 microns.

Storey, J. W. V.↗
NASA NTRS1979

Observations of far-infrared fine structure lines - Forbidden O III 88.35 microns and forbidden O I 63.2 microns

Results are presented for observations of the fine-structure lines of forbidden O III at 88.35 microns and forbidden O I at 63.2 microns in a number of sources by means of an airborne far-IR spectrometer. The sources M17, NGC 7538, and W51 are mapped in the forbidden O III line with a resolution of 1 arcmin, and the emission peak is found to coincide with the maximum radio continuum in all cases. The far-IR continuum is simultaneously mapped where possible; the continuum peak is shown to be distinct from the center of ionization in the same three sources. The forbidden O III line is also detected in W3, W49, and several positions in M42 (Orion). The forbidden O I line is detected in M17, in M42, and marginally in DR 21. An unsuccessful search for the J = 1-0 transition of HD at 112 microns in the direction of the Kleinmann-Low nebula is also reported.

Storey, J. W. V.↗
NASA NTRS1979

The brightness distribution of IRC +10216 at 11 microns

The brightness distribution of IRC +10216 at a wavelength of 11 microns has been measured in detail by using spatial interferometer. This brightness distribution appears to have azimuthal symmetry; an upper limit of 1.1 may be set to the ellipticity at 11 microns if the object has a major axis oriented either along or perpendicular to the major axis of the optical image. The radial distribution shows both compact and extended emission. The extended component, which is due to thermal emission from circumstellar dust, contributes 91% of the total flux and has a 1/e diameter of 0.90 arcsec. The tapered shape of this component is consistent with a dust density dependence on the inverse square of radial distance. The compact component is unresolved (less than 0.2 arcsec in diameter) and represents emission from the central star seen through the circumstellar envelope.

Sutton, E. C.↗
NASA NTRS1979

The brightness distribution of IRC +10216 at 11 microns

The brightness distribution of IRC +10216 at a wavelength of 11 microns was measured in detail using a spatial interferometer. This brightness distribution appears to have azimuthal symmetry; an upper limit of 1.1 may be set to the ellipticity at 11 microns if the object has a major axis oriented either along or perpendicular to the major axis of the optical image. The radial distribution shows both compact and extended emission. The extended component, which is due to thermal emission from circumstellar dust, contributes 91% of the total flux and has a 1/e diameter of 0.90 minutes. The tapered shape of this component is consistent with a l/r squared dust density dependence. The compact component is unresolved (less than 0.2 minutes in diameter) and represents emission from the central star seen through the circumstellar envelope.

Sutton, E. C.↗
NASA NTRS1979

Observations of far-infrared fine structure lines: o III88.35 micrometer and oI 63.2 micrometer

Observations of the O III 88.35 micrometer line and the O I63.2 micrometer were made with a far infrared spectrometer. The sources M17, NGC 7538, and W51 were mapped in the O III line with 1 arc minute resolution and the emission is found to be quite widespread. In all cases the peak of the emission coincides with the maximum radio continuum. The far infrared continuum was mapped simultaneously and in M17, NGC 7538, and W51 the continuum peak is found to be distinct from the center of ionization. The O III line was also detected in W3, W49, and in a number of positions in the Orion nebula. Upper limits were obtained on NGS 7027, NGC 6572, DR21, G29.9-0.0 and M82. The 63.2 micrometer O I line was detected in M17, M42, and marginally in DR21. A partial map of M42 in this line shows that most of the emission observed arises from the Trapezium and from the bright optical bar to the southeast.

Storey, J. W. V.↗
NASA NTRS1979

A search for interstellar glycine

A search has been made for the simplest amino acid - glycine - in Sgr B2, Ori A, and seven other molecular clouds. Six different lines were sought ranging from 83.4 GHz down to 22.7 GHz, and radio telescopes at Parkes, New South Wales, Kitt Peak, Arizona, and Onsala, Sweden, were used. On the assumption of reasonable values for excitation temperature and Boltzmann distributions over rotational energy states, upper limits of column densities for glycine of a few times 10 to the 12th per sq cm to a few times 10 to the 14th per sq cm were typically established in the sources surveyed. Glycine appears to be less abundant than ethanol or ethyl cyanide in molecular clouds such as Sgr B2 and Ori A.

Brown, R. D.↗
NASA NTRS1979

The potential for astrometry in the infrared

Using a 10-micron heterodyne interferometer, it proved possible to obtain measurements of the star alpha-Orionis, which exhibit phase coherence over a period of at least 1000 seconds and which are equivalent to a positional determination of 60 milliarcsecond accuracy every 5 seconds of integration. A feature of the IR interferometer that makes it an attractive instrument for astrometry is its capability of measuring the relative positions of stars with a precision independent of how widely the stars are separated, or the amount of time that elapses between measurements.

Storey, J. W. V.↗
NASA NTRS1978

Variations in the spatial distribution of 11 micron radiation from Omicron Ceti

The spatial distribution of 11-micron radiation from Omicron Ceti has been observed at various phases of its light cycle by using a stellar interferometer. Variations have been seen in the strength of thermal emission from circumstellar dust relative to the stellar continuum at 11 microns. These variations are shown to be correlated with the changes in luminosity of Omicron Ceti in such a way that dust-grain emission at 11 microns was increased more than the continuum during the period of maximum luminosity. The degree of the change in dust-grain emission implies that the maximum dust temperature is in the range of 500 to 700 K during minimum stellar luminosity.

Sutton, E. C.↗
NASA NTRS1978

The potential for astrometry in the infrared

Infrared interferometry promises to be a useful astrometric technique. Preliminary measurements of the star alpha Orionis made with a heterodyne interferometer exhibit phase coherence over a period of at least 1000 seconds. The measurements were equivalent to a positional determination of 60 milliarcsecond accuracy every 5 seconds of integration.

Storey, J. W. V.↗
NASA NTRS1978

An upper limit to the interstellar abundance of the HCN dimer

An unsuccessful search is described for the J = 7-6 transition of HCN ... HCN in several interstellar clouds known to be rich in HCN. An upper limit to the abundance of the dimer relative to the monomer is typically 1 percent. It is suggested that this implies a low abundance for similar weakly bound species.

Storey, J. W. V.↗
NASA NTRS1978

Infrared heterodyne interferometry

The possibilities for infrared heterodyne interferometry are examined. First the characteristics of atmospheric seeing in the infrared are considered, in order to determine the sizes of collecting apertures and baselines which can be used for relatively simple interferometers. The advantages of heterodyne over direct detection are pointed out. For example, when long baselines are used, the narrow bandwidth of heterodyne detection makes matching the path lengths easier. Experimental results on the spatial distribution of warm dust around stars and on astrometric precision obtained with prototype systems are given. Telescope design for a heterodyne interferometer is discussed.

Townes, C. H.↗
NASA NTRS1977

Detection of interstellar DNC - Difficulties of chemical equilibrium hypothesis for enrichment

The J = 1-0 transition of DNC at 76.3058 GHz has been observed in emission in NGC 2264. Comparison with previous observations of HN(C-13) indicates that deuterium is enriched in DNC similarly to the enrichment reported for DCO(+) in this source. The DNC/HNC ratio is estimated to be about 1/24. The results cannot readily be interpreted in terms of chemical equilibria relating to the formation of DNC. It is suggested that the explanation must be sought in isotope effects on rates of formation of interstellar molecules.

Godfrey, P. D.↗
NASA NTRS1977

Observation of J = 1-0 emission from H/N-15/C

Emission from the J = 1-0 transition of H(N-15)C has been detected in the direction of DR21(OH). The transition frequency of 88,865.69 MHz was measured in the laboratory by microwave absorption spectroscopy. The computed N-15/C-13 isotopic abundance ratio of 1.01 for DR21(OH) is larger than those calculated from isotopes of HCN in other interstellar clouds, perhaps implying a localized enrichment in N-15 in DR21(OH).

Brown, R. D.↗
NASA NTRS1977

Variations in the spatial distribution of 11 Micron radiation from omicron Ceti

The spatial distribution of 11 micron radiation from omicron Ceti was observed at various phases of its light cycle using a stellar interferometer. Changes were seen which can be attributed to variation in the strength of thermal emission from circumstellar dust relative to the stellar continuum at 11 microns. These changes are shown to be correlated with the changes in luminosity of micron Ceti in such a way that dust grain emission at 11 microns was increased more than the continuum during the period of maximum luminosity. The degree of the change in dust grain emission implies that the maximum dust temperature is in the range of 500 K to 700 K during minimum stellar luminosity.

Sutton, E. C.↗