Engineering topics

Lovas, F. J.

Publications and source records attributed to Lovas, F. J..

28 records · Page 2

NASA NTRS1980

A search for the lowest-energy conformer of interstellar glycine

The first search for the lowest-energy conformation of interstellar glycine has been carried out. An emission line has been detected in Sgr B2 which is coincident in frequency with the J(K-K+) = 14(1, 14)-13(1, 13) transition of conformer I glycine; while the carrier of the observed line is uncertain, no other frequency-coincident species are known, and hence glycine cannot be ruled out. Several previously unidentified lines have been identified as methyl formate. Evidence for the existence of the elusive interstellar ethylene oxide, the only reported interstellar ring-structure molecule, is discussed.

Hollis, J. M.↗

NASA NTRS1980

A radio search for interstellar phosphorus compounds

The J = 1-0 and 3-2 transitions of phosphorus nitride, PN, with resolvable hyperfine components at 46.99 GHz and blended components at 140.97 GHz, and transitions of phosphine, PH3, at 47.39 and 46.94 GHz, arising from a small induced dipole moment, have been searched for but not found in interstellar molecular clouds. The J = 3/2-1/2, F - 3/2-3/2 transition of nitric oxide, NO, and the J(K-K+) = 16(4, 12) -15(5, 11) transition of sulfur dioxide, SO2, have been detected in Orion and Sagittarius B2. An unidentified emission line, U140921.8 MHz, has been observed in IRC + 10216.

Hollis, J. M.↗

NASA NTRS1980

Vibrationally excited silicon monoxide masers

Published data on a select group of SiO maser sources have been analyzed for velocity variations as a function of phase. No apparent correlation was found to a level of about 2 km/s. This places constraints on the location of the maser molecules. Such a correlation should be present at some level. The implications for future high resolution infrared measurements are discussed.

Buhl, D.↗

NASA NTRS1978

Rapid space/time variations in mesospheric ozone

A 5 meter telescope was used to observe variations in the narrow emission line which is present in the nightime emission spectrum of ozone. The line was measured for several nights on two different transitions of the ozone molecule at 110.8 GHz and 142.2 GHz. Individual spectra with a time resolution of 5 minutes were taken. The narrow emission line showed considerable variation in intensity indicating that the ozone layer from which its arises has a rather detailed structure. Analysis of the line profile shows that the emission is coming from an ozone layer in the 55-75 km region of the mesosphere. This layer has a column density of 2 x 10 to the 16th power molecules/sq cm in a vertical path through the region.

Buhl, D.↗

NASA NTRS1977

Detection of interstellar ethyl cyanide

Twenty-four millimeter-wave emission lines of ethyl cyanide (CH3CH2CN) have been detected in the Orion Nebula (OMC-1) and seven in Sgr B2. To derive precise radial velocities from the astronomical data, a laboratory measurement of the rotational spectrum of ethyl cyanide has been made at frequencies above 41 GHz. In OMC-1, the rotational temperature of ethyl cyanide is 90 K (in good agreement with other molecules), the local-standard-of-rest radial velocity is 4.5 + or - 1.0 km/s (versus 8.5 km/s for most molecules), and the column density is 1.8 by 10 to the 14th power per sq cm (a surprisingly high figure for a complicated molecule). The high abundance of ethyl cyanide in the Orion Nebula suggests that ethane and perhaps larger saturated hydrocarbons may be common constituents of molecular clouds and have escaped detection only because they are nonpolar or only weakly polar.

Johnson, D. R.↗

NASA NTRS1976

Millimeter emission lines in Orion A

During the course of a search of Orion A for signals from three large organic molecules, several millimeter-wave lines from known interstellar molecules were observed. Results are reported for observations of methanol (CH3OH), methyl cyanide (CH3CN), methyl acetylene (CH3CCH), acetaldehyde (CH3CHO) and (Si-29)O. Emission signals from two hydrogen recombination lines (H41-alpha and H42-alpha) detected from the H II region of Orion A are also reported. Negative results were obtained for several millimeter-wave transitions of ethylene oxide, acetone, and cyclopropenone.

Lovas, F. J.↗

NASA NTRS1976

Radio detection of interstellar DCO/+/

The J = 1-0 transition of the deuterated formyl ion, DCO(+), has been detected in emission from NGC 2264 and DR 21(OH) and from the cool dust cloud L134. Estimates for the column-density ratios of H(C-13)O(+) to DCO(+) are given for NGC 2264 and DR 21(OH); lower limits for the ratios are given for five other clouds. The DCO(+) detection in L134 provides unique observational evidence in support of chemical fractionation. The L134 results also suggest that the dust clouds may act as repositories for primordial deuterium.

Hollis, J. M.↗

NASA NTRS1975

Is there a maser in the silicon monoxide ground state

Observations are reported of weak emission from the ground vibrational state of SiO in the Orion molecular cloud. It is shown that this emission has a rather smooth low-intensity profile extending over a large velocity range and is present at velocities where maser emissions from the first and second vibrational states are absent. Based on this difference, the present emission is interpreted as thermal emission in the ground state in regions where there is insufficient excitation to produce the vibrationally excited masers. Possible origins are considered for the Orion SiO maser, and it is noted that only VY CMa shows a profile that could be interpreted as ground-state maser emission.

Buhl, D.↗

NASA NTRS1975

Radio detection of interstellar sulfur dioxide

Interstellar sulfur dioxide (SO2) has been detected in emission from the direction of the Orion Nebula molecular cloud and from Sgr B2. SO2 is the heaviest interstellar molecule detected to date, and the only nonlinear triatomic molecule which does not contain hydrogen. The remarkable Orion emission profiles suggest that two components are supporting the SO2 emission: a dense circumstellar-type envelope, which may be in maser emission, and a warm galactic cloud component.

Snyder, L. E.↗

NASA NTRS1974

Radio detection of interstellar dimethyl ether

The detection of interstellar dimethyl ether, in emission from the direction of the Orion Nebula molecular cloud, is reported. The largest molecule detected in space, dimethyl ether has a large collisional cross section and C (sub 2V) symmetry. Hence, it should be useful for future studies of molecular pumping models.

Snyder, L. E.↗