Sodium Atoms in the Lunar Exotail: Observed Velocity and Spatial Distributions

The lunar sodium tail extends long distances due to radiation pressure on sodium atoms in the lunar exosphere. Our earlier observations measured the average radial velocity of sodium atoms moving down the lunar tail beyond Earth (i.e., near the anti-lunar point) to be ~ 12.5 km/s. Here we use the Wisconsin H-alpha Mapper to obtain the first kinematically resolved maps of the intensity and velocity distribution of this emission over a 15 x 15 deg region on the sky near the anti-lunar point. We present both spatially and spectrally resolved observations obtained over four nights bracketing new Moon in October 2007. The spatial distribution of the sodium atoms is elongated along the ecliptic with the location of the peak intensity drifting 3 deg east along the ecliptic per night. Preliminary modeling results suggest the spatial and velocity distributions in the sodium exotail are sensitive to the near surface lunar sodium velocity distribution. Future observations of this sort along with detailed modeling offer new opportunities to describe the time history of lunar surface sputtering over several days

Observed and Modeled Solar Cycle Variation in Geocoronal Hydrogen Using NRLMSISE-00 Thermosphere Conditions and the Bishop Analytic Exosphere Model

High precision observations during Solar Cycle 23 using the Wisconsin H‐alpha Mapper (WHAM) Fabry‐Perot quantify a factor of 1.5 ± 0.15 higher Balmer α column emission intensity during near‐solar‐maximum than during solar minimum conditions. An unresolved question is how does the observed solar cycle variation in the hydrogen column emission compare with that calculated from the hydrogen distribution in atmospheric models? We have compared WHAM solar minimum and near‐solar‐maximum column intensity observations with calculations using the thermospheric hydrogen density profile and background thermospheric conditions from the Mass Spectrometer Incoherent Scatter (NRLMSISE‐00) empirical model extended to exospheric altitudes using the analytic exosphere model of Bishop (1991). Using this distribution, we apply the lyao_rt global resonance radiative transfer code of Bishop (1999) to calculate expected intensities that would be observed from the ground for the viewing conditions of the observations. The observed intensities are brighter than those calculated for the corresponding conditions, indicating that when MSIS is used as the thermospheric hydrogen distribution the derived intensities are too low. Additionally, both the observed and calculated WHAM hydrogen column emission intensities are higher for near‐solar‐maximum than for solar minimum conditions. There is better agreement between observations and intensities calculated using the evaporative analytic exosphere model at solar maximum, suggesting an underestimation of modeled satellite atoms at high altitudes. This result is consistent with sensitivity studies using the option for a quasi‐exobase for satellite atoms to account for the creation of satellite orbits from charge exchange collisions

The Geocoronal H α Cascade Component Determined from Geocoronal H β Intensity Measurements

Geocoronal H α and H β intensity measurements using the Wisconsin H α Mapper Fabry-Perot are used to determine the intensity of the H α cascade component. From basic atomic physics and the work of Meier (1995), we show that the total cascade in geocoronal H α emission is 0.52 ± 0.03 times the geocoronal H β intensity, I(H β), for solar Lyman series excitation of geocoronal hydrogen. The results are consistent with the H α cascade measurements of Mierkiewicz et al. (2012), which were determined directly from the analysis of H α line profile measurements, and significantly narrow the range of uncertainty in the cascade measurement. Accounting for cascade is essential in determining exospheric effective temperatures and dynamics from the shape of the geocoronal H α line. --From publisher\u27s website

Production, Outflow, Velocity, and Radial Distribution of H2O and OH in the Coma of Comet C/1995 O1 (Hale-Bopp) from Wide-field Imaging of OH

Observations of OH are a useful proxy of the water production rate (Q H2O) and outflow velocity (VH2O) in comets. From wide-field images taken on 1997 March 28 and April 8 that capture the entire scale length of the OH coma of comet C/1995 O1 (Hale-Bopp), we obtain Q OH from the model-independent method of aperture summation and Q H2O from the OH photochemical branching ratio, BROH. Using an adaptive ring summation algorithm, we extract the radial brightness distribution of OH 0-0 band emission out to cometocentric distances of up to 10 to the sixth power km, both as azimuthal averages and in quadrants covering different position angles relative to the comet-Sun line. These profiles are fitted using both fixed and variable velocity two-component spherical expansion models to estimate VOH with increasing distance from the nucleus. The OH coma of Hale-Bopp was more spatially extended than those of previous comets, and this extension is best matched by a variable acceleration of H 2O and OH that acted across the entire coma, but was strongest within 1-2 × 104 km from the nucleus. Our models indicate that VOH at the edge of our detectable field of view (10 to the sixth power km) was ∼2-3 times greater in Hale-Bopp than for 1P/Halley class comet at 1 AU, which is consistent with the results of more sophisticated gas-kinetic models, extrapolation from previous observations of OH in comets with QH2O \u3e 10 to the twenty-ninth power s superscript -1, and direct radio measurements of the outer coma Hale-Bopp OH velocity. The likely source of this acceleration is thermalization of the excess energy of dissociation of H2O and OH over an extended collisional coma. When the coma is broken down by quadrants in position angle, we find an azimuthal asymmetry in the radial distribution that is characterized by an increase in the spatial extent of OH in the region between the orbit-trailing and anti-Sunward directions. Model fits specific to this area and comparison with radio OH measurements suggest greater acceleration here, with VOH ∼ 1.5 times greater at a 10 to the sixth power km cometocentric distance than elsewhere in the coma. We discuss several mechanisms that may have acted within the coma to produce the observed effect

Observed Seasonal Variations in Exospheric Effective Temperatures

High spectral resolution line profile observations indicate a reproducible semi-annual variation in the geocoronal hydrogen Balmer α effective temperature. These observations were made between 08 January 2000 and 21 November 2001 from Pine Bluff Observatory (WI) with a second generation double etalon Fabry-Perot annular summing spectrometer operating at a resolving power of 80,000. This data set spans sixty-four nights of observations (1404 spectra in total) over 20 dark-moon periods. A two cluster Gaussian model fitting procedure is used to determine Doppler line widths, accounting for fine structure contributions to the line, including those due to cascade; cascade contributions at Balmer α are found to be 5 ± 3%. An observed decrease in effective temperature with increasing shadow altitude is found to be a persistent feature for every night in which a wide range of shadow altitudes were sampled. A semiannual variation is observed in the column exospheric effective temperature with maxima near day numbers 100 and 300 and minima near day numbers 1 and 200. Temperatures ranged from ∼710 to 975 K. Average MSIS model exobase temperatures for similar conditions are approximately 1.5× higher than those derived from the Balmer α observations, a difference likely due to contributions to the observed Balmer αcolumn emission from higher, cooler regions of the exosphere

Radial Velocity Observations of the Extended Lunar Sodium Tail

We report the first velocity resolved sodium 5889.950 Å line profile observations of the lunar sodium tail observed in the anti-lunar direction near new Moon. These observations were made on 29 March 2006, 27 April 2006 and 28 April 2006 from Pine Bluff (WI) observatory with a double etalon Fabry-Perot spectrometer at a resolving power of ∼80,000. The observations were made within 2–14 hours from new Moon, pointing near the anti-lunar point. The average observed radial velocity of the lunar sodium tail in the vicinity of the anti-lunar point for the three nights reported was 12.4 km s−1 (from geocentric zero). The average Doppler width of a single Gaussian fit to the emission line was 7.6 km s−1. In some cases the line profile appears asymmetric, with excess lunar sodium emission at higher velocity (∼18 km s−1 from geocentric zero) that is not accounted for by our single Gaussian fit to the emission

Will the Polish Deal Contribute to the End of the Uncontrolled Growth of Self-Employment?

1 January 2022 marks the date of entering into force provisions of the Polish Order – the biggest reform of the tax system in recent years. Initially, it seemed that the new regulations were aimed at combating the uncontrolled development of self-employment, which has become a popular and misused form of gainful employment in Poland. The main task of this paper will be to answer the question whether the newly introduced regulations may become a solution preventing the so-called bogus self-employment or on the contrary, may promote self-employment among the labour market participants.1 stycznia 2022 r. weszły w życie przepisy tzw. Polskiego Ładu, czyli największej reformy systemu podatkowego ostatnich lat. Początkowo wydawało się, że nowe przepisy są ukierunkowane na walkę z niekontrolowanym rozwojem samozatrudnienia, które stało się popularną, a zarazem często nadużywaną formą wykonywania pracy zarobkowej w Polsce. Głównym zadaniem opracowania będzie odpowiedź na pytanie, czy nowo wprowadzone regulacje mogą okazać się skutecznym środkiem zapobiegającym fikcyjnemu samozatrudnieniu, czy też wprost przeciwnie, będą promować samozatrudnienie wśród uczestników rynku pracy

Early Results from the Wisconsin H-Alpha Mapper Southern Sky Survey

After a successful eleven-year campaign at Kitt Peak, we moved the Wisconsin H-Alpha Mapper (WHAM) to Cerro Tololo in early 2009. Here we present some of the early data after a few months under southern skies. These maps begin to complete the first all-sky, kinematic survey of the diffuse H-alpha emission from the Milky Way. Much of this emission arises from the Warm Ionized Medium (WIM), a significant component of the ISM that extends a few kiloparsecs above the Galactic disk. While this first look at the data focuses on the H-alpha survey, WHAM is also capable of observing many other optical emission lines, revealing fascinating trends in the temperature and ionization state of the WIM. Our ongoing studies of the physical conditions of diffuse ionized gas will continue from the southern hemisphere following the H-alpha survey. In addition, future observations will cover the full velocity range of the Magellanic Stream, Bridge, and Clouds to trace the ionized gas associated with these neighboring systems.Comment: 4 pages, 2 figures. To appear in "The Dynamic ISM: A celebration of the Canadian Galactic Plane Survey," ASP Conference Serie

High-Resolution Spectroscopy of the Lunar Sodium Exosphere

We have applied high-resolution Fabry-Perot spectroscopy to the study of the lunar sodium exosphere for the study of exospheric effective temperature and velocity variations. Observing from the National Solar Observatory McMath-Pierce Telescope, we used a dual-etalon Fabry-Perot spectrometer with a resolving power of 180,000 to measure line widths and Doppler shifts of the sodium D2 (5889.95 ) emission line. Our field of view was 360 km, and measurements were made in equatorial and polar regions from 500 km to 3500 km off the limb. Data were obtained from full moon to 3 days following full moon (waning phase) in March 2009. Measured Doppler line widths within 1100 km of the sunlit east and south lunar limbs for observations between 5 and 40 deg lunar phase imply effective temperatures ranging between 3260 +/- 190 and 1000 +/- 135 K. Preliminary line center analysis indicates velocity displacements between different locations off the lunar limb ranging between 100 and 600 m/s from the lunar rest velocity with a precision of +/-20 to +/-50 m/s depending on brightness. Based on the success of these exploratory observations, an extensive program has been initiated that is expected to constrain lunar atmospheric and surface-process modeling and help quantify source and escape mechanisms

Observations of Solar Cyclical Variations in Geocoronal Hα Column Emission Intensities

Observations of thermospheric + exospheric Hα column emissions by the Wisconsin Hα Mapper (WHAM) Fabry-Perot (Kitt Peak, Arizona) over the 1997–2001 rise in solar cycle 23 show a statistically significant solar cyclical variation. The higher signal-to-noise WHAM observations corroborate suggestions of a solar cycle trend in the Hα emissions seen in Wisconsin observations over solar cycle 22. Here we compare WHAM 1997 and 2000–2001 winter solstice geocoronal Hα observations toward regions of the sky with low galactic emission. The observed variation in geocoronal hydrogen column emission intensities over the solar cycle is small compared with variations in hydrogen exobase densities. Higher Hα emissions are seen during solar maximum periods of the solar cycle. At a mid range shadow altitude (3000 km), WHAM geocoronal Hα intensities are about 45% higher during solar maximum than during solar minimum