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At least 379 records · Page 21
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NASA NTRS2026

Isotopic Signature of Organic Molecules from Beyond the Solar System: An Enriched Methane D/H Ratio in the Interstellar Object 3I/ATLAS

Interstellar objects are interlopers from other planetary systems, and their volatile compositions provide a glimpse into planet formation around their host star. We present near-infrared spectra of the coma of interstellar object 3I/ATLAS measured with the James Webb Space Telescope. Our results demonstrate an unexpectedly high D/H = (3.31 ± 0.34)% for methane and represent an exceedingly rare detection of deuterated organic molecules in an interstellar object. This D/H ratio is a factor of 14 ± 2 higher than that measured in comet 67P/Churyumov-Gerasimenko by the Rosetta spacecraft, the only other comet for which CH3D has been detected, yet the ratio of deuteration in methane compared with water is consistent for both comets within 1.2σ. The D/H ratio in methane is observationally unconstrained in extrasolar sources to date, but the enriched ratio in 3I/ATLAS is most similar to those measured in other organic molecules toward primitive environments. The high D/H ratios of water and methane in 3I/ATLAS are a natural consequence of formation in a high D/H elemental ratio environment as a result of locally cold conditions in the protoplanetary disk and prior interstellar cloud. Thus, 3I/ATLAS formed in an environment very different from that in which our Sun and planets originated.

Interstellar Object 3I/ATLAS↗
NASA NTRS1966

System locates randomly placed remote objects

System to locate objects submerged underwater uses active/passive sonar techniques in which a transmitter is attached to the object to be recovered and a receiver is used for search. The system is rugged, has a long term operating life, and furnishes a precise bearing on the object.

Lovelady, R. W.↗
NASA NTRS1971

Improvements in Ross type astrometric objectives

It is shown that aspheric deformations of the first and fourth elements of the four element Ross objective can be introduced to permit one to obtain improved color corrections for astrometric purposes. The usual monochromatic aberrations are as well corrected as for the standard Ross lens. In addition, one can eliminate or reduce additional aberrations, such as secondary spectrum, chromatic spherical aberration, chromatic coma and chromatic distortion. The resulting objectives are suitable for use as intermediate and long focus astrometric objectives covering large angle fields.

Baker, J.↗
NASA NTRS1972

The optical object identified with 3C 455.

It is shown that the optical object identified with 3C 455 is a quasi-stellar object with a redshift z = 0.543. The QSO is situated 23 sec northeast of the S0 galaxy NGC 7413, which has a redshift of 0.0332. It is pointed out that the discovery of the present object in a position so close to a galaxy is further evidence in favor of the existence of a physical association between 3C QSOs and bright galaxies.

Arp, H. C.↗
NASA NTRS1973

2.2- and 3.5-micron polarization measurements of the Becklin-Neugebauer object in the Orion Nebula.

Independent measurements of the Becklin-Neugebauer (BN) object in the Orion Nebula yield large values of linear polarization in wavelength bands centered at 2.2 and 3.4 microns. The 10 to 15% polarization at 2.2 microns of the BN object is larger than any yet measured for an extraterrestrial object. The large polarization probably originates from the scattering of the radiation by dust grains.

Loer, S. J.↗
NASA NTRS1974

Improvements in estimating proportions of objects from multispectral data

Methods for estimating proportions of objects and materials imaged within the instantaneous field of view of a multispectral sensor were developed further. Improvements in the basic proportion estimation algorithm were devised as well as improved alien object detection procedures. Also, a simplified signature set analysis scheme was introduced for determining the adequacy of signature set geometry for satisfactory proportion estimation. Averaging procedures used in conjunction with the mixtures algorithm were examined theoretically and applied to artificially generated multispectral data. A computationally simpler estimator was considered and found unsatisfactory. Experiments conducted to find a suitable procedure for setting the alien object threshold yielded little definitive result. Mixtures procedures were used on a limited amount of ERTS data to estimate wheat proportion in selected areas. Results were unsatisfactory, partly because of the ill-conditioned nature of the pure signature set.

Horwitz, H. M.↗
NASA NTRS1974

Derivation of formulas for root-mean-square errors in location, orientation, and shape in triangulation solution of an elongated object in space

Formulas are derived for the root-mean-square (rms) displacement, slope, and curvature errors in an azimuth-elevation image trace of an elongated object in space, as functions of the number and spacing of the input data points and the rms elevation error in the individual input data points from a single observation station. Also, formulas are derived for the total rms displacement, slope, and curvature error vectors in the triangulation solution of an elongated object in space due to the rms displacement, slope, and curvature errors, respectively, in the azimuth-elevation image traces from different observation stations. The total rms displacement, slope, and curvature error vectors provide useful measure numbers for determining the relative merits of two or more different triangulation procedures applicable to elongated objects in space.

Long, S. A. T.↗
NASA NTRS1973

Kinetic theory analysis of solar wind interaction with planetary objects

A purely kinetic treatment is proposed for the interaction of the solar wind with any small planetary object. Small refers to those cases where the solar wind proton's thermal gyroradius is arbitrarily taken to be greater than 0.1 radius of the object under investigation. The 'object' may possibly include an ionosphere or magnetosphere. The collisionless Boltzmann equation, neglecting the magnetic field, is used to calculate steady-state profiles of density and velocity around the obstacle. A low density plasma void in the umbral region and a compression in the penumbral region are clearly found. The present technique, despite its neglect of the interplanetary magnetic field, is proposed as an alternative zeroth order approach to the continuum, local magnetic anomaly, and guiding center approaches used by others for the particular case of moon. Some recent, potentially relevant, observations on and in front of the moon are discussed.

Wu, S. T.↗
NASA NTRS1974

Detection of new celestial objects at far-infrared wavelengths

During a high-altitude balloon flight, sources of far-infrared radiation have been detected with apparent fluxes greater than or about equal to 3 pW/sq cm in the spectral band from 50 to 500 microns. While the sources are not uniquely identifiable with any well-known class of celestial objects, two associations should be noted. Many of the objects lie close to local stars; there is also a tendency to cluster around the ecliptic plane. Alternatively, a new class of celestial objects may have been observed.

Friedlander, M. W.↗
NASA NTRS1975

Emission-line strengths and the chemical compositions of quasi-stellar objects

Estimates of emission-line strengths in 160 QSOs are listed. They are used, together with those for 60 objects published earlier, to compile a table of rest-frame equivalent widths for a composite QSO containing 28 lines seen in objects with z from 0.06 to 3.53. Models are computed for matter partially filling a spherical volume, ionized by ultraviolet flux from a central object and optically thick with absorption from heavy elements taken into account. Constant temperature and density are taken for the He II region, where most of the important lines are emitted. Allowance is made for lower and higher temperatures in the H I and He III regions. Emergent emission-line equivalent widths are computed and compared with the observations. An abnormally low helium abundance is not needed to achieve a fit, since the only anomalously weak line is He II 4686 A whose upper level may be depopulated by stimulated emission of He II 1215 A caused by very strong L-alpha 1216 A flux.

Chan, Y.-W. T.↗
NASA NTRS1976

Calculation of the twilight visibility function of near-sun objects

The visibility function, defined here as the magnitude difference between the excess brightness of a given object and that of the background sky, of near-sun objects during twilight is obtained from a general calculation which considers the twilight sky background, atmospheric extinction, and night glow. Visibility curves are computed for a number of cases in which observations have been recorded, particularly that of comet Kohoutek. For this object, the computed visibility maxima agree well in time with the reported times of observation.

Kastner, S. O.↗
NASA NTRS1976

An extrasolar extreme-ultraviolet object. II - The nature of HZ 43

A variety of data are presented concerning the spectrum, distance, temperature, and evolutionary state of the hot white dwarf HZ 43, the first extrasolar object to be detected in the EUV band. The data include spectrophotometry of the star and its red dwarf companion (HZ 43B), a trigonometric parallax for the star, its tangential velocity, and results of soft X-ray and EUV observations. The main conclusions are that: (1) the spectrum of HZ 43A is that of a hot DAwk star, (2) HZ 43B is a dM3.5e star, (3) the distance of the system is about 65 pc, (4) the tangential velocity is not atypical of white dwarfs, and (5) the stellar energy distribution of HZ 43A is well fitted by a black body with an effective temperature of approximately 110,000 K. Evolutionary implications of the existence of an object as hot as HZ 43A are briefly considered, and it is suggested that the progenitors of hot DA stars must include objects hotter than spectral type sdB, with logical possibilities being nuclei of planetary nebulae and sdO stars.

Margon, B.↗
NASA NTRS1975

Identification and promulgation of objectives for OAST R and T programs, Task 2

Overall perspectives and guidelines are discussed for defining and promulgating NASA's Office of Aeronautics and Space Technology (OAST) objectives to meet national needs and goals in aeronautical, space, and nuclear technology. Emphasis is placed on the practicality of ultimately instituting objective-setting processes within the normal OAST operation, and of establishing quantitative measures to be used as a working management tool in determining the degree to which the objectives have been or are being met.

Source record↗
NASA NTRS1977

New infrared objects associated with OH masers

Results of a search for IR radiation at 10 microns from a sample of OH maser sources are reported. An IR source is discovered near each of six OH masers which emit mainly at 1612 MHz in two distinct velocity ranges. It is shown that all the sources have varied with time, that two sources have exhibited significant variations in color temperature, and that the energy distributions of the six objects over the spectral range from 2 to 20 microns fall into two categories. Absorption in the 2.3-micron band of CO is detected in two sources, and four are found to display substantial silicate absorption features. The energy distributions of the sources indicate that pumping by 35-micron photons is feasible, but 2.8-micron pumping is very unlikely; the distributions are best explained as emission from very thick dust shells at temperatures of about 500 K. The data are taken as supporting the hypothesis that every double-peaked OH maser emitting principally at 1612 MHz is associated with an IR object. The nature of the objects inside the dust shells and their evolutionary state are briefly discussed.

Evans, N. J., II↗
NASA NTRS1978

Minor planets and related objects. XXV - UBV photometry of 145 faint asteroids

Magnitudes and colors on the UBV system are presented for 145 minor planets, including 31 objects in the Eos family, 14 in the Koronis family, 6 in the Nysa family, 11 in the Themis family, 4 Hungarias, 7 Hildas, 8 Trojans, and several objects in unusual orbits. Clearly defined color groups for the Eos, Koronis, Nysa, and Themis family members are strongly suggestive of origin from discrete parent bodies. The Nysas apparently show large light-curve amplitudes. The Mars-orbit crossers 1977RA and 1980 = 1950LA, the earth-orbit crosser 1976UA, and several main-belt asteroids are found to show peculiar colors of unknown significance. The Mars-orbit crosser 1916 = 1953RA appears to be a typical S object, while 1474 Beira and 1977VA show neutral colors. Asteroids at semimajor axis in excess of 4 AU (Trojans preceding and following Jupiter, 279 Thule, and 944 Hidalgo) all belong to a color group centered at B-V = 0.72, U-B = 0.24.

Degewij, J.↗
NASA NTRS1978

IUE observations of extragalactic objects

During the commissioning phase of IUE several extragalactic objects were observed spectrally at low dispersion in the UV range lambda lambda 1150-3200: the Seyfert galaxies NGC4151 and NGC1068, the QSO 3C273, the BL Lacertae object B2 1101+38, the giant elliptical galaxy M87 and the spiral galaxy M81. The results obtained are presented and a preliminary analysis given for all six objects, discussing the continuous spectrum, extinction, emission line spectrum and absorption line spectrum, where possible for each case. Several new or confirmatory astrophysical results are obtained.

Boksenberg, A.↗
NASA NTRS1978

Calculation of Pareto-optimal solutions to multiple-objective problems using threshold-of-acceptability constraints

A technique is presented for the calculation of Pareto-optimal solutions to a multiple-objective constrained optimization problem by solving a series of single-objective problems. Threshold-of-acceptability constraints are placed on the objective functions at each stage to both limit the area of search and to mathematically guarantee convergence to a Pareto optimum.

Giesy, D. P.↗