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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

Coronal mass ejections: The long-term variation of their occurrence rate and the solar wind mass flux

Solar Coronal Mass Ejections (CMEs) from the Sun are an important aspect of coronal physics, and a potentially important contributor to the solar wind mass flux. However, despite significant progress in studies of CMEs since their discovery in the early 70's, questions remain about their effects on the interplanetary medium. A study is done of the long-term variations of the occurrence rates of CMEs, of activity tracers related to CMEs, and of the solar wind particle flux. CMEs are most directly detected by scattered electron radiation in white light. To estimate their long-term occurrence frequency and their contributions to the in-ecliptic solar wind mass flux, observed CME rates must be corrected for instrumental duty cycles, detection efficiency out of the plane of the sky, mass detection thresholds, and geometrical considerations. These corrections are evaluated using data on solar CMEs from the spaceborne Skylab, SMM, and SOLWIND coronagraphs and on interplanetary plasma clouds from the HELIOS white light photometers. Variations in the CME rate and the contribution of CMEs to the solar wind mass flux are traced over nearly a complete solar activity cycle.

Webb, David F.↗
NASA NTRS1989

The modified correlation mass method for detecting neutrino mass from astrophysical neutrino bursts

A modified correlation mass method for calculating the value of a possible neutrino mass from neutrino bursts of astrophysical origin is proposed which can more sensitively detect small neutrino masses than previous methods. Application of the method to the neutrinos detected from SN 1987 A yields a value of 3.6 + or - 0.3 eV for the neutrino mass energy with a confidence level of 97 percent. Assuming a neutrino mass of 3.6 eV, and transforming all of the detected neutrino events back to the point of emission, it is shown that bursts are composed of a short initial pulse (which lasts for about 0.1 sec and contains 30-40 percent of the total neutrinos) and an extended emission lasting for about 10 sec.

Chan, Kwing L.↗
NASA NTRS1992

Estimation of the mass of a coronal mass ejection from radio observations

The mass of a coronal mass ejection (CME) is estimated using meter-decametric observations obtained with the Clark Lake multifrequency radioheliograph. Mass estimates in the past were made using coronagraph and white-light photometer observations. Since the radiation at radio and optical wavelength regimes has different physical origins, the radio method can provide an independent check on the mass estimates. The estimate of the 1986 February 16 CME using the radio method is close to the average value of CME masses reported in the literature.

Gopalswamy, N.↗
NASA NTRS1994

The solar cycle variation of coronal mass ejections and the solar wind mass flux

Coronal mass ejections (CMEs) are an important aspect of coronal physics and a potentially significant contributor to perturbations of the solar wind, such as its mass flux. Sufficient data on CMEs are now available to permit study of their longer-term occurrency patterns. Here we present the results of a study of CME occurrence rates over more than a complete 11-year solar sunspot cycle and a comparison of these rates with those of other activity related to CMEs and with the solar wind particle flux at 1 AU. The study includes an evaluation of correlations to the CME rates, which include instrument duty cycles, visibility functions, mass detection thresholds, and geometrical considerations. The main results are as follows: (1) The frequency of occurrence of CMEs tends to track the solar activity cycle in both amplitude and phase; (2) the CME rates from different instruments, when corrected for both duty cycles and visibility functions, are reasonably consistent; (3) considering only longer-term averages, no one class of solar activity is better correlated with CME rate than any other; (4) the ratio of the annualized CME to solar wind mass flux tends to track the solar cycle; and (5) near solar maximum, CMEs can provide a significant fraction (i.e., approximately equals 15%) of the average mass flux to the near-ecliptic solar wind.

Webb, David F.↗
NASA NTRS1995

On the deficit problem of mass and energy of solar coronal mass ejections connected with interplanetary shocks

Mean values of a number of parameters of the most powerful coronal mass ejections (CMEs) and interplanetary shocks generated by these ejections are estimated using an analysis of data obtained by the cosmic coronagraphs and spacecrafts, and geomagnetic storm measurements. It was payed attention that the shock mass and mechanical energy, averaging 5 x 10(exp 16) grm and 2 x 10(exp 32) erg respectively, are nearly 10 times larger than corresponding parameters of the ejections. So, the CME energy deficit problem seems to exist really. To solve this problem one can make an assumption that the process of the mass and energy growth of CMEs during their propagation out of the Sun observed in the solar corona is continued in supercorona too up to distances of 10-30 solar radii. This assumption is confirmed by the data analysis of five events observed using zodiacal light photometers of the HELIOS- I and HELIOS-2 spacecrafts. The mass growth rate is estimated to be equal to (1-7) x 10(exp 11) grm/sec. It is concluded that the CME contribution to mass and energy flows in the solar winds probably, is larger enough than the value of 3-5% adopted usually.

Ivanchuk, V. I.↗
NASA NTRS2016

The Exoplanet Mass-Ratio Function From the MOA-II Survey: Discovery of a Break and Likely Peak at a Neptune Mass

We report the results of the statistical analysis of planetary signals discovered in MOA-II microlensing survey alert system events from 2007 to 2012. We determine the survey sensitivity as a function of planet star mass ratio, q, and projected planet star separation, s, in Einstein radius units. We find that the mass-ratio function is not a single power law, but has a change in slope at q approx.10(exp -4), corresponding to approx. 20 Stellar Mass for the median host-star mass of approx. 0.6 M. We find significant planetary signals in 23 of the 1474 alert events that are well-characterized by the MOA-II survey data alone. Data from other groups are used only to characterize planetary signals that have been identified in the MOA data alone. The distribution of mass ratios and separations of the planets found in our sample are well fit by a broken power-law model. We also combine this analysis with the previous analyses of Gould et al. and Cassan et al., bringing the total sample to 30 planets. The unbroken power-law model is disfavored with a p-value of 0.0022, which corresponds to a Bayes factor of 27 favoring the broken power-law model. These results imply that cold Neptunes are likely to be the most common type of planets beyond the snow line.

MOA-II microlensing survey alert↗
NASA NTRS1974

In situ mass analysis of particles by surface ionization mass spectrometry

A qualitative study of the application of surface ionization and mass spectrometry to the in situ detection and constituent analysis of atmospheric particles was conducted. The technique consists of mass analysis of ions formed as a result of impingement of a stream of particles on a hot filament where, it is presumed, surface ionization takes place. Laboratory air particles containing K, Ca, and possibly hydrocarbons were detected. Other known particles such as Al2O3, Pb(NO3)2, and Cr2O3 were analyzed by detecting the respective metal atoms making up the particles. In some cases, mass numbers indicative of compounds making up the particles were detected showing surface ionization of particles sometimes leads to chemical analysis as well as to elemental analysis. Individual particles were detected, and it was shown that the technique is sensitive to Al2O3 particles with a mass of a few nanograms.

Lassiter, W. S.↗
NASA NTRS1978

A highly accurate method for the determination of mass and center of mass of a spacecraft

An extremely accurate method for the measurement of mass and the lateral center of mass of a spacecraft has been developed. The method was needed for the Voyager spacecraft mission requirement which limited the uncertainty in the knowledge of lateral center of mass of the spacecraft system weighing 750 kg to be less than 1.0 mm (0.04 in.). The method consists of using three load cells symmetrically located at 120 deg apart on a turntable with respect to the vertical axis of the spacecraft and making six measurements for each load cell. These six measurements are taken by cyclic rotations of the load cell turntable and of the spacecraft, about the vertical axis of the measurement fixture. This method eliminates all alignment, leveling, and load cell calibration errors for the lateral center of mass determination, and permits a statistical best fit of the measurement data. An associated data reduction computer program called MASCM has been written to implement this method and has been used for the Voyager spacecraft.

Chow, E. Y.↗
NASA NTRS1981

The close multiple system mu Orionis - Masses and the mass-luminosity relation

The observations made of the secondary component B of the close visual binary mu Ori are described. The Reticon observations made at red wavelengths showed the secondary to be a double-lined spectroscopic binary with a period of 4.78 days and nearly identical components having minimum masses of 1.1 solar mass each. Previous estimates are corroborated by the large spectroscopic mass ratio of B to A and B. The discovery that B is a pair of late-F dwarfs solves the apparent mass-luminosity relation discrepancy noted in previous studies.

Fekel, F. C., Jr.↗
NASA NTRS1991

Interpretation of the ion mass spectra in the mass per charge range 25-35 amu/e obtained in the inner coma of Halley's comet by the HIS-sensor of the Giotto IMS experiment

The IMS-HIS double-focusing mass spectrometer that flew on the Giotto spacecraft covered the mass per charge range from 12 to 56 (amu/e). By comparing flight data, calibration data and results of model calculations of the ion population in the inner coma, the absolute mass scale is established, and ions in the mass range 25 to 35 are identified. Ions resulting from protonation of molecules with high proton affinity are relatively abundant, enabling us to estimate relative source strengths for H2CO, CH3OH, HCN, and H2S, providing for the first time a positive in situ measurement of methanol. Also, upper limits for NO and some hydrocarbons are derived.

Geiss, J.↗
NASA NTRS1991

Interpretation of the ion mass spectra in the mass range 25-35 obtained in the inner coma of Halley's comet by the HIS-sensor of the Giotto IMS Experiment

The IMS-HIS double-focussing mass spectrometer that flew on the Giotto spacecraft covered the mass per charge range from 12 to 56 (AMU/e). By comparing flight data, calibration data, and results of model calculations of the ion population in the inner coma, the absolute mass scale is established, and ions in the mass range 25 to 35 are identified. Ions resulting from protonation of molecules with high proton affinity are relatively abundant, enabling us to estimate relative source strengths for H2CO, CH3OH, HCN, and H2S, providing for the first time a positive in situ measurement of methanol. Also, upper limits for NO and some hydrocarbons are derived.

Geiss, J.↗
NASA NTRS2011

The Miller Range Nakhlites: A Summary of the Curatorial Subdivision of the Main Mass in Light of Newly Found Paired Masses

The 2003-2004 ANSMET team re-covered a 715.2 g nakhlite from the Miller Range (MIL) region of the Transantarctic Mountains (MIL 03346). This was the first nakhlite for the US Antarctic meteorite program, and after the announcement in 2004 [1], JSC received over 50 requests for this sample for the Fall 2004 Meteorite Working Group meeting. Since then it has been subdivided into >200 splits, and distributed to approx.70 scientists around the world for study. The 2009-2010 ANSMET team recovered three additional masses of this nakhlite [2], making the total amount of mass 1.871 kg (Table 1). Given that the original find (MIL 03346) has been heavily studied and these new masses are available, we will present a comprehensive overview of the subdivision of the original mass as well as the scientific findings to date.

Righter, Kevin↗
NASA NTRS2012

On Dark Peaks and Missing Mass: A Weak-Lensing Mass Reconstruction of the Merging Cluster System A520

Merging clusters of galaxies are unique in their power to directly probe and place limits on the self-interaction cross-section of dark matter. Detailed observations of several merging clusters have shown the intracluster gas to be displaced from the centroids of dark matter and galaxy density by ram pressure, while the latter components are spatially coincident, consistent with collisionless dark matter. This has been used to place upper limits on the dark matter particle self-interaction cross-section of order 1 sq cm/g. The cluster A520 has been seen as a possible exception. We revisit A520 presenting new Hubble Space Telescope Advanced Camera for Surveys mosaic images and a Magellan image set. We perform a detailed weak-lensing analysis and show that the weak-lensing mass measurements and morphologies of the core galaxy-filled structures are mostly in good agreement with previous works. There is, however, one significant difference: We do not detect the previously claimed "dark core" that contains excess mass with no significant galaxy overdensity at the location of the X-ray plasma. This peak has been suggested to be indicative of a large self-interaction cross-section for dark matter (at least approx 5alpha larger than the upper limit of 0.7 sq cm/g determined by observations of the Bullet Cluster). We find no such indication and instead find that the mass distribution of A520, after subtraction of the X-ray plasma mass, is in good agreement with the luminosity distribution of the cluster galaxies.We conclude that A520 shows no evidence to contradict the collisionless dark matter scenario.

Clowe, Douglas↗
NASA NTRS1975

Composition measurements of the topside ionosphere using a magnetic mass spectrometer, ion mass spectrometer on ISIS-2 spacecraft

The ion mass spectrometer (IMS) on the ISIS-II satellite is described; it measures the composition and distribution of positive ions in the earth's ionosphere in the mass range of 1 to 64 atomic mass units. Significant data were received which show a wide variation in ion composition at night near the equator and in the daytime poleward of the plasmapause. It was found that these data enable further study of the polar wind and that the experiment produced timely data during the August, 1972 magnetic storm to show the development of a unique ionosphere above the plasmapause during the period of the storm. The scientific objectives and results of the experiment, the technical description of the instrument, a bibliography with sample papers attached, and a summary of recommendations for further study are presented.

Hoffman, J. H.↗
NASA NTRS1978

CNO abundances and hydrodynamic studies of the Nova outburst. V - 1.00-solar-mass models with small mass envelopes

The paper reports on an investigation into the consequences of thermonuclear runaways in accreted hydrogen envelopes of 100 millionths of a solar mass on 1-solar-mass white dwarfs. These evolutionary sequences predict that from 10 to 50 millionths of a solar mass will be ejected with speeds from 300 to 3800 km/s (kinetic energies of 10 to the 44th-45th power ergs). Absolute visual magnitudes as high as -8.1 are attained, well within the observed range for fast novae. In addition, the shapes of the theoretical light curves are more reminiscent of an observed fast-nova light curve than those in earlier studies. The ejected material is strongly enhanced in the products of incomplete CNO burning; the most abundant of the ejected nuclei is C-13, followed by N-14 and C-12. The differences from previous studies are attributable to the lower peak temperatures reached in these sequences. These models also produce a large overabundance of Li-7, suggesting that novae may represent significant contributors to the galactic enrichment of this nucleus.

Starrfield, S.↗
NASA NTRS1985

The geomagnetic mass spectrometer - Mass and energy dispersions of ionospheric ion flows into the magnetosphere

Observations of ion flows in the polar magnetosphere, made by the retarding ion mass spectrometer on NASA's Dynamics Explorer (DE) 1, are compared with those made simultaneously in the topside ionosphere by the ion drift meter on the lower-altitude DE 2 spacecraft. The results show the dayside auroral ionosphere to be a significant and highly persistent source of plasma for the magnetosphere. The upwelling ionospheric ions are spatially dispersed, according to both their energy and mass, by the combined actions of the geomagnetic field and the dawn-to-dusk convection electric field, in an effect analogous to the operation of an ion mass spectrometer.

Lockwood, M.↗
NASA NTRS1987

Gravitational lensing of supernovae by dark matter candidates of mass M greater than about 0.001 solar masses

A review is presented concerning the gravitational lensing of supernovae by intervening condensed objects, including dark matter candidates such as dim stars and black holes. the expansion of the supernova beam within the lens produces characteristic time-dependent amplification and polarization which depend upon the mass of the lens. The effects of the shearing of the beam due to surrounding masses are considered, although the study of these effects is confined to isolated masses whose size is much less than that of the supernova (about 10 to the 15th cm). Equations for the effects of lensing and graphs comparing these effects in different classes of supernovae are compared. It is found that candidates for lensing would be those supernovae at least as bright as their parent galaxy, or above the range of luminosities expected for their spectral class.

Wagoner, Robert V.↗