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  • ASTROPHYSICS  (13)
  • AIRCRAFT DESIGN, TESTING AND PERFORMANCE  (5)
  • 1
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    HII regions in dwarf irregular galaxies of the local group (1990)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Deep, narrowband H alpha Charge Coupled Device (CCD) surveys of HII regions were carried out in several dwarf irregular galaxies in and near the local group. Data are now complete for these galaxies: NGC 6822, GR 8, IC 10, IC 1613, Sextans A, Sextans B, and Sag Irr. Observations are complete for DDO 47, 53, 167, 168 and 187. Details of some of the results for the surveys completed so far are discussed. For NGC 6822, CCD survey at H alpha resulted in the detection of 145 HII regions in the local group irregular galaxy NGC 6822. Most of them are newly detected, faint surface-brightness objects. Positions, maps and dimensions are being published elsewhere. For GR 8, a deep narrowband H alpha imaging of the nearby dwarf irregular galaxy GR 8 revealed a total of 32 HII regions. Positions, H alpha luminosities, and sizes of these objects were determined. The H alpha luminosity function has the same shape as that for more luminous galaxies, except for size of sample effects. Most HII regions detected are at the very low luminosity end of the general luminosity function. For IC 10, a deep CCD narrowband H alpha imaging of the local group dwarf irregular galaxy IC 10 revealed a total of 144 HII regions. Positions, H alpha luminosities, and sizes of these objects were determined. The H alpha luminosity function has the same shape as that for more luminous galaxies.
    Keywords: ASTROPHYSICS
    Type: NASA, Ames Research Center, The Interstellar Medium in External Galaxies: Summaries of Contributed Papers; p 160-162
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  • 2
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    H II regions in the dwarf galaxy UGC-A 86 (1993)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The uncertain nature of the dwarf irregular galaxy UGC-A 86 (VIIZw009) makes it a very interesting object for studying star formation at the low end of the galaxy luminosity function. Saha and Hoessel (1991) find that this object is composed of two main parts, one of which appears more resolved than the other. The more resolved component has an excess of blue stars, suggesting that it is currently undergoing star formation. Thus, they argue that UGC-A 86 could be either a superposition of unrelated galaxies, two interacting galaxies, or a single galaxy. However, surface photometry performed by Richter et al. (1991) indicates that it is a single galaxy with an exponential luminosity profile. Richter et al. also find UGC-A 86 to be extremely dusty and to be associated with the infrared source IRAS 3550+6657. The uncertainty is compounded by the large ambiguity in the distance, though a heliocentric H1 velocity of 80 plus or minus 7 km s(sup -1) suggests that it is either a member of the Local Group or perhaps the IC 342 group. A distance of 1.5 Mpc and a reddening of E(B - V) = 0.65 is adopted. UGC-A 86 in H-alpha was observed in order to measure its current star formation rate. This is part of a larger project to study the star formation rates and histories of a complete sample of dwarf galaxies in the Local Group and other nearby groups. The H region luminosity function and size distribution for UGC-A 86 are presented and compared with previous observations of similar dwarf galaxies.
    Keywords: ASTROPHYSICS
    Type: NASA. Ames Research Center, The Evolution of Galaxies and Their Environment; p 90-91
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  • 3
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    Physical properties of interplanetary grains (1976)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Morphological analyses of micrometeorite craters found on lunar rocks and laboratory simulation experiments are used to formulate a meteoritic interplanetary dust particle for optical scattering calculations that is roughly spherical and has a density of 2g cm/3. The model particle has chondritic elemental abundances and also contains a high content of finely dispersed carbon.
    Keywords: ASTROPHYSICS
    Type: NASA. Goddard Space Flight Center The Study of Comets, Part 2; p 962-982
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  • 4
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    NASA rotor systems research aircraft: Fixed-wing configuration flight-test results (1986)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The fixed-wing, airplane configuration flight-test results of the Rotor System Research Aircraft (RSRA), NASA 740, at Ames/Dryden Flight Research Center are documented. Fourteen taxi and flight tests were performed from December 1983 to October 1984. This was the first time the RSRA was flown with the main rotor removed; the tail rotor was installed. These tests confirmed that the RSRA is operable as a fixed-wing aircraft. Data were obtained for various takeoff and landing distances, control sensitivity, trim and dynamics stability characteristics, performance rotor-hub drag, and acoustics signature. Stability data were obtained with the rotor hub both installed and removed. The speed envelope was developed to 261 knots true airspeed (KTAS), 226 knots calibrated airspeed (KCAS) at 10,000 ft density altitude. The airplane was configured at 5 deg. wing incidence with 5 deg. wing flaps as a normal configuration. Level-flight data were acquired at 167 KCAS for wing incidence from 0 to 10 deg. Step inputs and doublet inputs of various magnitudes were utilized to acquire dynamic stability and control sensitivity data. Sine-wave inputs of constantly increasing frequency were used to generate parameter identification data. The maximum load factor attained was 2.34 g at 206 KCAS.
    Keywords: AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA-TM-86789 , A-85363 , NAS 1.15:86789
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  • 5
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    NASA rotor system research aircraft flight-test data report: Helicopter and compound configuration (1984)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The flight test activities of the Rotor System Research Aircraft (RSRA), NASA 740, from June 30, 1981 to August 5, 1982 are reported. Tests were conducted in both the helicopter and compound configurations. Compound tests reconfirmed the Sikorsky flight envelope except that main rotor blade bending loads reached endurance at a speed about 10 knots lower than previously. Wing incidence changes were made from 0 to 10 deg.
    Keywords: AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA-TM-85843 , NAS 1.15:85843
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  • 6
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    Comparison of analytical and flight test identified aerodynamic derivatives for a tandem-rotor transport helicopter (1980)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Flight tests for verifying an analytical aerodynamic derivative model of a CH-47 helicopter were conducted for low cruise speeds and transition to hover portions of curved, decelerating landing approach trajectories. All testing was performed on a closed loop basis with the stability augmentation system of the helicopter operating, and response data were obtained using both manual and computer generated input maneuvers. The results indicate some differences between the measured response time histories and those predicted by both analytical and flight test identified derivatives. With some exceptions the discrepancies are not severe, and the overall agreement between the measured and computed time histories is reasonably good. No adverse effects attributable to closed loop testing were noted, and the use of computer generated inputs proved to be superior to manual ones.
    Keywords: AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA-TP-1581 , L-13228
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  • 7
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    Ultraviolet studies of stars in the populous cluster NGC 2100 in the Large Magellanic Cloud (1985)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The ultraviolet energy distributions of the B stars in the LMC cluster NGC 2100 have been studied. The ultraviolet extinction law was studied for the LMC cluster. The T(eff)-luminosity diagrams were determined. The brightest stars in the cluster are evolved stars on the 'horizontal' supergiant branch. No P Cygni profiles indicating mass loss were recognized for these supergiants.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 292; 130-142
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  • 8
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    The ultraviolet spectra of the O and B stars in the young galactic cluster NGC 6530 (1984)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The UV spectra between 1200 and 3000 A of stars in the young galactic cluster NGC 6530 and the surrounding association are studied. From the UBV colors and empirical as well as theoretical calibrations, the T(eff) and L for those stars which follow a sequence in the H-R diagram corresponding to the main sequence are determined. From a comparison with theoretical evolutionary tracks, the age of the cluster is estimated to be 5 + or - 2 x 10 to the 6th yr, with a very small scatter for the different stars. The UV extinction is determined for the stars from a comparison of theoretical model energy distributions for the stellar T(eff)s and the observed energy distributions. The stellar wind lines are studied, and strong stellar winds are found for bolometric magnetidues less than -8.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 287; 825-839
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  • 9
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    Multifrequency observations of the BL Lacertae objects OQ 530 and ON 325 (1984)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Spectral measurements of the two BL Lac objects OQ 530 and ON 325 are presented. The measurements were taken at frequencies ranging from radio to ultraviolet. Both sources show spectral curvature between the infrared and ultraviolet frequencies. The intensity and spectral shape of OQ 530 vary, but the spectral shape of ON 325 appears to remain constant during intensity variability. A nonthermal theoretical model of jet emission is developed which incorporates both the spectral and time variability data. The model predicts that ON 325 radiates at X-ray frequencies with Compton radiation dominating over synchrotron emission. The angular size of the jet emission is predicted to be less than 0.1 milli-arcsec at high radio frequencies.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 284; 512-518
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  • 10
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    Analysis of interplanetary dust collections (1980)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Interplanetary dust particles collected in the form of micrometeorites in the stratosphere and meteor ablation spherules in deep sea sediments are possibly a relatively unbiased sample of the micrometeoroid complex near 1 AU. Detailed laboratory analysis of the particles has provided information on physical properties which may be useful in modeling a variety of aspects of interplanetary dust.
    Keywords: ASTROPHYSICS
    Type: Symposium on Solid particles in the solar system; Aug 27, 1979 - Aug 30, 1979; Ottawa; Canada
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