Transit Of Mercury Research Articles

Occultation records in the Royal Frankish Annals for A.D. 807: Knowledge transfer from Arabia to Frankia?

The Royal Frankish Annals (RFA) report under A.D. 807 three lunar and one solar eclipse (complete and dated correctly), a lunar occultation of Jupiter, and “a small spot” on the Sun interpreted as Mercury transit. This transmission is embedded between texts on the landing of diplomatic delegates from Baghdad and Jerusalem in Venice and on their meeting with Charlemagne. Technology transfer is explicitly mentioned (a mechanical water clock). The interpretation of a spot on the Sun as planetary transit is attested in Arabic reports since A.D. 840. The Jupiter occultation by the Moon is dated “Luna 17,” correctly counted in Muslim calendar practice since the first crescent detection. Eclipse predictions and records by astronomers from the cAbbasid caliphate using Ptolemy’s Almagest are extant from the early ninth century. There are time-spans of 6 months each between the three reported lunar eclipses (806 Sep 1/2, 807 Feb 25/26, Aug 21/22), a period of possible repetition given in the Almagest, but not known to the Carolingians. The 6-month rule for lunar eclipses might be preserved in the Carolingian Seven Book Computus. We present multiple evidence that visitors from Baghdad brought new insight and fostered the Carolingian progress in astronomy.

Effects of circulating ash and dolomite on mercury transition during coal step conversion of pyrolysis and combustion

In aim to study the influence of circulating ash used as heat carrier and dolomite used as catalyst on mercury transition during the step conversion of coal pyrolysis and combustion, five experiments with different operating conditions were conducted in this study, including four pyrolysis experiments of raw coal, coal/ash, coal/dolomite, coal and ash/dolomite, and combustion experiment of pyrolysis solid product. By changing the experimental conditions including final pyrolysis temperature, heating rate, coal-ash ratio and dolomite type, the transition path and final mercury distribution in the step conversion process were comprehensively analyzed. Experiments results indicated that mercury completely released out from coal when the final pyrolysis temperature was 600 °C. The individual addition of ash could promote the mercury release from coal at lower temperature. Dolomite could catalyze the oxidation of Hg0 in gas phase, and the modified dolomite had better catalytic capacity for Hg0 oxidation than natural dolomite. The addition of circulating ash and natural dolomite both had a certain catalytic effect on Hg0 emission peaks during the coal pyrolysis. Increasing the coal-ash ratio was conducive to the oxidation of Hg0 in pyrolysis gas. During the direct combustion of coal, the content of Hg0 released into the gas phase could reach to 69.97%. By adding ash, ash/natural dolomite and ash/modified dolomite to the coal pyrolysis process, the content of Hg0 in pyrolysis gas decreased to 58.99%, 34.77% and 31.30%, respectively. The research is able to offer the theoretical foundation for mercury contaminants’ removal and process optimization of the step conversion technology.

Computer simulation and modeling the metal to insulating transition of liquid mercury via pair, empirical, and many-body potentials.

In this study, Monte Carlo simulations were carried out to detect the metal-insulator transition in liquid mercury by changing the static properties at the microscopic scale. In the simulations pair, empirical, and many-body potentials govern metal-metal interactions in the canonical ensemble. The structural and thermodynamic changes over a wide temperature range from 773 to 1773K are described in the first coordination shell and residual internal energy, respectively. The results reveal that during the simulated heating process, the properties undergo significant change at 1673K, which is in connection with the metal-nonmetal transition in the liquid. These findings coincide with the experimental observations of this thermodynamic phenomenon. Notably, the free energy of association that renders the system to this thermodynamic state is estimated.

Leveraging Space-based Data from the Nearest Solar-type Star to Better Understand Stellar Activity Signatures in Radial Velocity Data

Stellar variability is a key obstacle in reaching the sensitivity required to recover Earth-like exoplanetary signals using the radial velocity (RV) detection method. To explore activity signatures in Sun-like stars, we present SolAster, a publicly distributed analysis pipeline 10 10 https://tamarervin.github.io/SolAster/ that allows for comparison of space-based measurements with ground-based disk-integrated RVs. Using high-spatial-resolution Dopplergrams, magnetograms, and continuum filtergrams from the Helioseismic and Magnetic Imager aboard the Solar Dynamics Observatory (SDO), we estimate “Sun-as-a-star” disk-integrated RVs due to rotationally modulated flux imbalances and convective blueshift suppression, as well as other observables such as unsigned magnetic flux. Comparing these measurements with ground-based RVs from the NEID instrument, which observes the Sun daily using an automated solar telescope, we find a strong relationship between magnetic activity indicators and RV variation, supporting efforts to examine unsigned magnetic flux as a proxy for stellar activity in slowly rotating stars. Detrending against measured unsigned magnetic flux allows us to improve the NEID RV measurements by ∼20% (∼50 cm s−1 in a quadrature sum), yielding an rms scatter of ∼60 cm s−1 over five months. We also explore correlations between individual and averaged spectral line shapes in the NEID spectra and SDO-derived magnetic activity indicators, motivating future studies of these observables. Finally, applying SolAster to archival planetary transits of Venus and Mercury, we demonstrate the ability to recover small amplitude (<50 cm s−1) RV variations in the SDO data by directly measuring the Rossiter–McLaughlin signals.

Mercury transit observed in Ghana

The planet Mercury transited the face of the Sun in a rare spectacle on 11 November 2019. It was an awe-inspiring moment for 300 students from Kwabenya Community High School and Ghana Atomic Energy Commission Basic School in Ghana to see this wonder of the cosmos. Celestron Power Seeker 60 mm diameter telescopes were used to project the Sun’s image on a white card on the ground to observe safely. It was a time for the kids to relate the theory of eclipse and transits to a practical life experience. This was an avenue to introduce astronomy to the kids.

Doppler-Shifted Alkali D Absorption as Indirect Evidence for Exomoons

Sodium and potassium signatures in transiting exoplanets can be challenging to isolate from the stellar absorption lines. Here, these challenges are discussed in the framework of Solar System observations, and transits of Mercury in particular. Radiation pressure is important for alkali gas dynamics in close-orbiting exoplanets since the D lines are efficient at resonant scattering. When the star-planet velocity is ≳10 km/s, eccentric exoplanets experience more than an order of magnitude higher radiation pressures, aiding atmospheric escape and producing a larger effective cross-section for absorbing starlight at the phase of transit. The Doppler shift also aids in isolating the planetary signature from the stellar photosphere’s absorption. Only one transiting exoplanet, HD 80606b, is presently thought to have both this requisite Doppler shift and alkali absorption. Radiation pressure on a planetary exosphere naturally produces blue-shifted absorption, but at levels insufficient to account for the extreme Doppler shifts that have been inferred from potassium transit measurements of this system. In the absence of clear mechanisms to generate such a strong wind, it is described how this characteristic could arise from an exomoon-magnetosphere interaction, analogous to Io-Jupiter. At low contrasts presented here, follow-up transit spectra of HD 80606b cannot rule out a potassium jet or atmospheric species with a broad absorption structure. However, it is evident that line absorption within the imaging passbands fails to explain the narrow-band photometry that has been reported in-transit. New observations of energetic alkalis produced by the Io-Jupiter interaction are also presented, which illustrate that energetic sodium Doppler structure offers a more valuable marker for the presence of an exomoon than potassium.

Science Highlights and Final Updates from 17 Years of Total Solar Irradiance Measurements from the SOlar Radiation and Climate Experiment/Total Irradiance Monitor (SORCE/TIM)

The final version (V.19) of the total solar irradiance data from the SOlar Radiation and Climate Experiment (SORCE) Total Irradiance Monitor has been released. This version includes all calibrations updated to the end of the mission and provides irradiance data from 25 February 2003 through 25 February 2020. These final calibrations are presented along with the resulting final data products. An overview of the on-orbit operations timeline is provided as well as the associated changes in the time-dependent uncertainties. Scientific highlights from the instrument are also presented. These include the establishment of a new, lower TSI value; accuracy improvements to other TSI instruments via a new calibration facility; the lowest on-orbit noise (for high sensitivity to solar variability) of any TSI instrument; the best inherent stability of any on-orbit TSI instrument; a lengthy (17-year) measurement record benefitting from these stable, low-noise measurements; the first reported detection of a solar flare in TSI; and observations of two Venus transits and four Mercury transits.

Design of an automated solar tracker for teaching astronomy and mechatronic engineering

Astronomy is one of the sciences that attracts a large number of people, because of the celestial bodies and phenomena that can be observed, such as the moon, planets, constellations and the sun during the day. Telescopes, the main observation tool employed for astronomical observation, are often not very accessible for the majority of the population, due to their cost. This problem has been addressed through the design of low-cost three-dimensional printed telescopes or the use of digital cameras and cell phones with filters suitable for this purpose. This work describes the components and building of an automatized light tracker that can be coupled to a digital camera, protected by a white light filter, to emulate a low-cost solar telescope. The resulting device can also be operated manually, serving as a teaching tool for astronomy that illustrates how mechatronics and programming can be employed for scientific outreach. Aided by a digital camera, the robotic solar tracker was used by students to observe and record the 2019’s Mercury transit.

The determination of mercury levels in the blood and hair of rabbits with amalgam fillings

Purpose: This study was conducted to investigate the level of blood and hair mercury transition in rabbits depending on the number of amalgam filled teeth in the mouth.&#x0D; Material and Methods: A total of 18 male rabbits from New Zealand were used in the study. The rabbits were separated into three groups in this study. The first group was named as control group, the second group was named as dichotomous filled group, and the third group was named as quadruple amalgam filled group. Blood samples were collected from filler animals before the filling, at 24 hour, at the first week and month and also hair samples were taken before the filling and at the first month. The transfer of mercury, taken by the blood and feather samples of rabbits in the study, was made with the hydride system in the absorption spectrophometer.&#x0D; Results: The data’s, obtained from the study, were evaluated by using the SPSS 21 package program. Compared by the control group at the 24th hour, any statically difference wasn’t seen between dichotomous and quadruple amalgam filling groups in terms of blood mercury level. (P&gt;0.05). However, the level of blood mercury, one week and one month later was significantly higher than the control group.(P&lt;0.05) In the all periods, the level of blood mercury was found similar between dichotomous and quadruple amalgam filling groups (P&gt;0.05).&#x0D; Conclusions: Mercury couldn’t be detected in hair samples. As a result, it was revealed that amalgam filling affects the blood mercury level.&#x0D; &#x0D; How to cite this article: Yerebasan Ü, Servi K, Ataş O, Doğan MS. The determination of mercury levels in the blood and hair of rabbits with amalgam fillings. Int Dent Res 2020;10(1):12-16. https://doi.org/10.5577/intdentres.2020.vol10.no1.3&#x0D; &#x0D; Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.&#x0D;

Development of online microdialysis–microfluidic-based photocatalyst-assisted vaporization device–inductively coupled plasma-mass spectrometry hyphenated analytical system for in vivo quantification of the transition of brain extracellular mercury after thimerosal administration

In this study, an ultrasensitive and salt-tolerant online microdialysis–microfluidic-based photocatalyst-assisted vaporization device–inductively coupled plasma-mass spectrometry (MD/μFPCAVD/ICPMS) hyphenated analytical system was developed for the in vivo quantification of the transition of mercurial concentration level in the extracellular fluid (ECF) of rat brains after the administration of thimerosal (TMHg). Under optimal operation conditions, the limits of detection (based on 3σ) of the proposed analytical system for methylmercury (MMHg) and TMHg in the saline solution corresponded to 2.7 and 1.7 ng L−1, respectively. We demonstrated the applicability of our proposed analytical system for animal experiment via observations of the variation in ECF mercurial concentration level after the administration of MMHg and TMHg. The results suggested that TMHg can penetrate through the blood–brain barrier as MMHg via an unclear mechanism. Based on the obtained results, our proposed analytical system exhibits satisfactory reliability and validity to monitor the transition of the ECF mercurial concentration level after the TMHg is administered. Hence, our proposed analytical system can provide a potential alternative method for toxicological research of TMHg in the brains of living animals.

The transit of Mercury: November 11, 2019

The transit of Mercury: November 11, 2019

Scope on the Skies: Mercury Transit of the Sun

Scope on the Skies: Mercury Transit of the Sun

Solar meridional circulation from twenty-one years of SOHO/MDI and SDO/HMI observations

Context. The solar meridional flow is an essential ingredient in flux-transport dynamo models. However, no consensus on its subsurface structure has been reached.Aims. We merge the data sets from SOHO/MDI and SDO/HMI with the aim of achieving a greater precision on helioseismic measurements of the subsurface meridional flow.Methods. The south-north travel-time differences are measured by applying time-distance helioseismology to the MDI and HMI medium-degree Dopplergrams covering May 1996–April 2017. Our data analysis corrects for several sources of systematic effects:P-angle error, surface magnetic field effects, and center-to-limb variations. For HMI data, we used theP-angle correction provided by the HMI team based on the Venus and Mercury transits. For MDI data, we used aP-angle correction estimated from the correlation of MDI and HMI data during the period of overlap. The center-to-limb effect is estimated from the east-west travel-time differences and is different for MDI and HMI observations. An interpretation of the travel-time measurements is obtained using a forward-modeling approach in the ray approximation.Results. In the latitude range 20°–35°, the travel-time differences are similar in the southern hemisphere for cycles 23 and 24. However, they differ in the northern hemisphere between cycles 23 and 24. Except for cycle 24’s northern hemisphere, the measurements favor a single-cell meridional circulation model where the poleward flows persist down to ∼0.8R⊙, accompanied by local inflows toward the activity belts in the near-surface layers. Cycle 24’s northern hemisphere is anomalous: travel-time differences are significantly smaller when travel distances are greater than 20°. This asymmetry between northern and southern hemispheres during cycle 24 was not present in previous measurements, which assumed a differentP-angle error correction where south-north travel-time differences are shifted to zero at the equator for all travel distances. In our measurements, the travel-time differences at the equator are zero for travel distances less than ∼30°, but they do not vanish for larger travel distances. This equatorial offset for large travel distances need not be interpreted as a deep cross-equator flow; it could be due to the presence of asymmetrical local flows at the surface near the end points of the acoustic ray paths.Conclusions. The combined MDI and HMI helioseismic measurements presented here contain a wealth of information about the subsurface structure and the temporal evolution of the meridional circulation over 21 years. To infer the deep meridional flow, it will be necessary to model the contribution from the complex time-varying flows in the near-surface layers.

An on Orbit Determination of Point Spread Functions for the Interface Region Imaging Spectrograph

Using the 2016 Mercury transit of the Sun, we characterize on orbit spatial point spread functions (PSFs) for the Near- (NUV) and Far- (FUV) Ultra-Violet spectrograph channels of NASA’s Interface Region Imaging Spectrograph (IRIS). A semi-blind Richardson–Lucy deconvolution method is used to estimate PSFs for each channel. Corresponding estimates of Modulation Transfer Functions (MTFs) indicate resolution of 2.47 cycles/arcsec in the NUV channel near 2796 Å and 2.55 cycles/arcsec near 2814 Å. In the short ({approx},1336~mathring{mathrm{A}}) and long ({approx},1394~mathring{mathrm{A}}) wavelength FUV channels, our MTFs show pixel-limited resolution (3.0 cycles/arcsec). The PSF estimates perform well under deconvolution, removing or significantly reducing instrument artifacts in the Mercury transit spectra. The usefulness of the PSFs is demonstrated in a case study of an isolated explosive event. PSF estimates and deconvolution routines are provided through a SolarSoft module.

Performance analysis of Real Time PPP for transit of Mercury

In recent years, Precise Point Positioning (PPP) techniques, which are alternative to relative positioning techniques, have begun to be widely used in Global Navigation Satellite System (GNSS) positioning applications. The PPP technique offers an effective solution to obtain coordinates at high accuracy with a single receiver. Real-time PPP (RT-PPP) solutions can also be provided with real-time correction data and products (ephemerides, satellite clock, bias, etc.) provided by different organizations (International GNSS Service (IGS), European Reference Frame (EUREF), Bundesamt für Kartographie und Geodäsie (BKG), European Space Agency (ESA), German Research Centre for Geosciences (GFZ), etc.). In this regard, RT-PPP applications are getting widespread day by day. Considering this situation in this study, the positional accuracy of RT-PPP was analyzed during the transit of Mercury which was determined to be about 7 h on May 9th, 2016. Two GNSS stations, POVE and BUCU that are in the global IGS network, were chosen. The RT-PPP solutions were performed with BKG Ntrip Client (BNC v2.11.2) software. In the analysis, “RTCM3EPH as the broadcast ephemeris stream and “CLK10” as the combined orbit/clock product of IGS were used. The results of the RT-PPP solutions were compared with the results of the Post-Process (PP) solutions of the 24-hour data of the same day by using the web-based online AUSPOS service. According to the results, it can be concluded that the positioning accuracies for the RT-PPP approach at the different phases of the transit of Mercury have different characters.

Efficient continuous wave second harmonic generation of 872 nm diode laser radiation using KNbO3 with high stability

We report on a highly stable laser system at a wavelength of 436 nm for the coherent excitation of the transition in mercury based on efficient second harmonic generation in a potassium niobate crystal. The system delivers up to 220 mW of blue light with a peak-to-peak stability of 2.3%. This stability is achieved by setting the whole build-up cavity inside a massive and temperature stabilized aluminum block. Absolute frequency stability to 480 kHz peak-to-peak is achieved by polarization spectroscopy. With a short time linewidth of 59.9 kHz and a tunability of more than 6 GHz the system is suitable for experiments requiring coherent excitation as well as applications in spectroscopy.

Homage to Quietanus

Jacques Mertzeisen and Jean-Pierre Luminet shed light on Johannes Remus Quietanus, a much neglected seventeenth-century astronomer and royal physician, a friend of Kepler, and one of the very first to observe a transit of Mercury.

Frequency stabilized diode laser with variable linewidth at a wavelength of 404.7 nm.

We report on a frequency stabilized laser system with a variable linewidth at a wavelength of 404.7 nm used as an incoherent repump on the 6P30↔7S31 transition in mercury. By directly modulating the laser diode current with Gaussian white noise, the laser linewidth can be broadened up to 68 MHz. A Doppler-free dichroic atomic vapor laser lock spectroscopy provides an error signal suitable for frequency stabilization even for the broadened laser. Without the need of an acousto-optic modulator for the linewidth tuning or lock-in technique for frequency stabilization, this laser system provides an inexpensive approach for an incoherent and highly efficient repumper in atomic experiments.

Using the 2016 Transit of Mercury to Find the Distance to the Sun

The May 9, 2016, transit of Mercury was observed simultaneously from the Big Bear Solar Observatory in California and from a site in Germany. From the measured displacement between the views from the two sites of Mercury’s disk silhouetted against the solar granulation, we were able to calculate the distance to the Sun in linear units (kilometers), not merely the proportionality given by Kepler’s third law.

Modelling of the mercury loss in fluorescent lamps under the influence of metal oxide coatings

The mercury transport and loss mechanisms in the metal oxide coatings of mercury low pressure discharge fluorescent lamps have been investigated. An existing model based on a ballistic process is discussed in the context of experimental mercury loss data. Two different approaches to the modeling of the mercury loss have been developed. The first one is based on mercury transition rates between the plasma, the coating, and the glass without specifying the underlying physical processes. The second one is based on a transport process driven by diffusion and a binding process of mercury reacting to mercury oxide inside the layers. Moreover, we extended the diffusion based model to handle multi-component coatings. All approaches are applied to describe mercury loss experiments under the influence of an Al2O3 coating.