Detecting the Yarkovsky effect using the GAIA DR2 catalogue

2020 ◽  
Author(s):  
Karolina Dziadura ◽  
Dagmara Oszkiewicz ◽  
Przemysław Bartczak
Keyword(s):  
Direct Detection ◽  
Close Approach ◽  
Fortran Program ◽  
Main Belt ◽  
Small Bodies ◽  
Yarkovsky Effect ◽  
Impact Monitoring ◽  
The Times ◽  
First Time ◽  
Gaia Dr2

<p>The orbital motion of small bodies is affected by the Yarkovsky effect. First-time the effect was proposed by Yarkovsky in 1901 and then popularized by Öpik in 1950s. However, the first direct detection was only made in 2003 using radar observations. Nowadays there are hundreds of detections for NEAs and only a few for Main-Belt objects. In this work, I attempt to detect the Yarkovsky effect among multiple Main-Belt objects and other asteroids. I will show preliminary results for five asteroids using the OrbFit software.  OrbFit is a Fortran program for orbit propagation, ephemerides computation, orbit determination, close approach analysis, and impact monitoring. Orbits were calculated using FitObs with and without the Yarkovsky effect. Next, the ephemeris were computed for the times of GAIA observations and compared with the GAIA DR2 data.</p>

Yarkovsky drift detectability using the Gaia DR2 asteroid astrometry  

2021 ◽  
Author(s):  
Karolina Dziadura ◽  
Dagmara Oszkiewicz ◽  
Federika Spoto ◽  
Przemysław Bartczak
Keyword(s):  
Direct Detection ◽  
Signal To Noise Ratio ◽  
Parameter Determination ◽  
Small Bodies ◽  
Radar Observations ◽  
Orbital Parameters ◽  
Yarkovsky Effect ◽  
Reliable Detection ◽  
Right Ascension ◽  
Gaia Dr2

<div>The orbital motion of small bodies is affected by the Yarkovsky effect (semiminor axes change in time (da/dt)). The first direct detection was only made in 2003 thanks to radar observations. Nowadays there are over a hundred detections for NEAs and only a few for Main-Belt objects, however, the Yarkovsky effect remains difficult to detect for a large group of asteroids.</div> <div>The ESA Gaia mission was claimed to provide extremely precise astrometry of asteroids. Gaia observations were expected to lead to new Yarkovsky detections. In this work, we present the results for the most promising Yarkovsky candidates indexed before the start of the mission.</div> <div>We converted all available data (ground-based optical astrometry, satellite astrometry measurements, radar observations and GAIA DR2 data) to ADES format and then used it for orbit determination. We included the standard error of right ascension (RA), declination (Dec) and correlation of Ra and Dec errors for Gaia astrometry. We found a reliable detection of the Yarkovsky effect with a signal-to-noise ratio (SNR) greater than 3 for 21 asteroids, including 7 confirmations and 14 new detections. In 10 cases the resulting da/dt parameter SNR increased with the usage of the DR2 catalogue data, but no reliable detection can yet be claimed. Furthermore, we present a comparison of our empirical results with expected values estimated using physical and orbital parameters of studied objects. GAIA DR2 asteroids astrometry impacts positively the Yarkovsky drift determination. GAIA DR3 will elongate the observational arc, therefore, contribute to A2 parameter determination.</div>

Delhi in Transition, 1821 and Beyond

2018 ◽  
Keyword(s):  
Nineteenth Century ◽  
Lived Experience ◽  
English Translation ◽  
East India Company ◽  
Multiple Sources ◽  
Original Manuscript ◽  
English East India Company ◽  
The Times ◽  
First Time ◽  
The City

Commissioned by the English East India Company to write about contemporary nineteenth-century Delhi, Mirza Sangin Beg walked around the city to capture its highly fascinating urban and suburban extravaganza. Laced with epigraphy and fascinating anecdotes, the city as ‘lived experience’ has an overwhelming presence in his work, Sair-ul Manazil. Sair-ul Manazil dominates the historiography of eighteenth- and nineteenth-century compositions on Delhi in Persian and Urdu, and remains unparalleled in its architecture and detailed content. It deals with the habitations of people, bazars, professions and professionals, places of worship and revelry, and issues of contestation. Over fifty typologies of structures and several institutions that find resonance in the Persian and Ottoman Empires can also be gleaned from Sair-ul Manazil. Interestingly, Beg made no attempt to ‘monumentalize’ buildings; instead, he explored them as spaces reflective of the sociocultural milieu of the times. Delhi in Transition is the first comprehensive English translation of Beg’s work, which was originally published in Persian. It is the only translation to compare the four known versions of Sair-ul Manazil, including the original manuscript located in Berlin, which is being consulted for the first time. It has an exhaustive introduction and extensive notes, along with the use of varied styles in the book to indicate the multiple sources of the text, contextualize Beg’s work for the reader and engage him with the debate concerning the different variants of this unique and eclectic work.

scholarly journals New Tools for the Optimized Follow-Up of Imminent Impactors

Universe ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 10
Author(s):  
Maddalena Mochi ◽  
Giacomo Tommei
Keyword(s):  
Orbit Determination ◽  
Main Belt ◽  
Impact Monitoring ◽  
The Earth ◽  
Current Observation ◽  
Short Period ◽  
Fly Eye ◽  
Near Earth Asteroids ◽  
Near Earth Objects

The solar system is populated with, other than planets, a wide variety of minor bodies, the majority of which are represented by asteroids. Most of their orbits are comprised of those between Mars and Jupiter, thus forming a population named Main Belt. However, some asteroids can run on trajectories that come close to, or even intersect, the orbit of the Earth. These objects are known as Near Earth Asteroids (NEAs) or Near Earth Objects (NEOs) and may entail a risk of collision with our planet. Predicting the occurrence of such collisions as early as possible is the task of Impact Monitoring (IM). Dedicated algorithms are in charge of orbit determination and risk assessment for any detected NEO, but their efficiency is limited in cases in which the object has been observed for a short period of time, as is the case with newly discovered asteroids and, more worryingly, imminent impactors: objects due to hit the Earth, detected only a few days or hours in advance of impacts. This timespan might be too short to take any effective safety countermeasure. For this reason, a necessary improvement of current observation capabilities is underway through the construction of dedicated telescopes, e.g., the NEO Survey Telescope (NEOSTEL), also known as “Fly-Eye”. Thanks to these developments, the number of discovered NEOs and, consequently, imminent impactors detected per year, is expected to increase, thus requiring an improvement of the methods and algorithms used to handle such cases. In this paper we present two new tools, based on the Admissible Region (AR) concept, dedicated to the observers, aiming to facilitate the planning of follow-up observations of NEOs by rapidly assessing the possibility of them being imminent impactors and the remaining visibility time from any given station.

scholarly journals Direct detection of atomic dark matter in white dwarfs

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
David Curtin ◽  
Jack Setford
Keyword(s):  
Dark Matter ◽  
Energy Loss ◽  
Cooling Rate ◽  
White Dwarf ◽  
White Dwarfs ◽  
Luminosity Function ◽  
Direct Detection ◽  
Matter Density ◽  
Mixing Parameter ◽  
First Time

Abstract Dark matter could have a dissipative asymmetric subcomponent in the form of atomic dark matter (aDM). This arises in many scenarios of dark complexity, and is a prediction of neutral naturalness, such as the Mirror Twin Higgs model. We show for the first time how White Dwarf cooling provides strong bounds on aDM. In the presence of a small kinetic mixing between the dark and SM photon, stars are expected to accumulate atomic dark matter in their cores, which then radiates away energy in the form of dark photons. In the case of white dwarfs, this energy loss can have a detectable impact on their cooling rate. We use measurements of the white dwarf luminosity function to tightly constrain the kinetic mixing parameter between the dark and visible photons, for DM masses in the range 10−5–105 GeV, down to values of ϵ ∼ 10−12. Using this method we can constrain scenarios in which aDM constitutes fractions as small as 10−3 of the total dark matter density. Our methods are highly complementary to other methods of probing aDM, especially in scenarios where the aDM is arranged in a dark disk, which can make direct detection extremely difficult but actually slightly enhances our cooling constraints.

scholarly journals Impact hazard monitoring: theory and implementation

2015 ◽  
Vol 10 (S318) ◽  
pp. 221-230
Author(s):  
D. Farnocchia
Keyword(s):  
Hazard Assessment ◽  
Yarkovsky Effect ◽  
Monte Carlo Algorithms ◽  
Impact Monitoring ◽  
Successful Technique ◽  
Low Probability ◽  
Computationally Intensive ◽  
Orbit Estimation ◽  
Near Earth Asteroids ◽  
The Impact

AbstractWe review the most standard impact monitoring techniques. Linear methods are the fastest approach but their applicability regime is limited because of the chaotic dynamics of near-Earth asteroids. Among nonlinear methods, Monte Carlo algorithms are the most reliable ones but also most computationally intensive and so unpractical for routine impact monitoring. In the last 15 years, the Line of Variations method has been the most successful technique thanks to its computational efficiency and capability of detecting low probability events deep in the nonlinear regime. We also present some more recent techniques developed to deal with the new challenges arising in the impact hazard assessment problem. In particular, we describe keyhole maps as a tool to go beyond strongly scattering encounters and how to account for nongravitational perturbations, especially the Yarkovsky effect, when their contribution is the main source of prediction uncertainty. Finally, we discuss systematic ranging to deal with the short-term hazard assessment problem for newly discovered asteroids, when only a short observed arc is available thus leading to severe degeneracies in the orbit estimation process.

Profaning the Sacred: The Unorthodox Financial Activities of Catholic Clerics During the Napoleonic Period, 1796–1814

2021 ◽  
Vol 51 (4) ◽  
pp. 523-542
Author(s):  
Christopher Korten
Keyword(s):  
Precious Metals ◽  
Religious Communities ◽  
Critical Periods ◽  
For Profit ◽  
Sacred And Profane ◽  
The Rich ◽  
The Times ◽  
First Time ◽  
Insight Into

This article reveals for the first time how Catholic clerics survived financially during the Napoleonic period in Italy (1796–1814). Despite the very rich, 200-year historiography on one of the Church's most critical periods, there is almost nothing on how religious clerics coped at this time. Their institutions had been despoiled by the French, often in collaboration with locals, negating traditional forms of clerical income, such as alms or rental income from non-ecclesiastical properties. This caused clerics to search out unorthodox – at times, non-canonical – ways of eking out a living, either for themselves, their religious communities or both, as such distinctions were often blurred. Masses were monetized and traded; ecclesiastical paraphernalia composed of precious metals were smelted and commodified, and relics were sold for profit. The uncovering of these controversial acts by men who in normal times were upstanding reveals the desperation of the times and provides insight into the rich discussion on determining the degrees of separation (and overlap) between the sacred and profane.

scholarly journals Orbital and atmospheric characterization of the planet within the gap of the PDS 70 transition disk

2018 ◽  
Vol 617 ◽  
pp. L2 ◽  
Author(s):  
A. Müller ◽  
M. Keppler ◽  
Th. Henning ◽  
M. Samland ◽  
G. Chauvin ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Near Infrared ◽  
Direct Detection ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Infrared Range ◽  
Data Set ◽  
Cloud Properties ◽  
Spectrophotometric Data ◽  
First Time

Context. The observation of planets in their formation stage is a crucial but very challenging step in understanding when, how, and where planets form. PDS 70 is a young pre-main sequence star surrounded by a transition disk, in the gap of which a planetary-mass companion has recently been discovered. This discovery represents the first robust direct detection of such a young planet, possibly still at the stage of formation. Aims. We aim to characterize the orbital and atmospheric properties of PDS 70 b, which was first identified on May 2015 in the course of the SHINE survey with SPHERE, the extreme adaptive-optics instrument at the VLT. Methods. We obtained new deep SPHERE/IRDIS imaging and SPHERE/IFS spectroscopic observations of PDS 70 b. The astrometric baseline now covers 6 yr, which allowed us to perform an orbital analysis. For the first time, we present spectrophotometry of the young planet which covers almost the entire near-infrared range (0.96–3.8 μm). We use different atmospheric models covering a large parameter space in temperature, log g, chemical composition, and cloud properties to characterize the properties of the atmosphere of PDS 70 b. Results. PDS 70 b is most likely orbiting the star on a circular and disk coplanar orbit at ~22 au inside the gap of the disk. We find a range of models that can describe the spectrophotometric data reasonably well in the temperature range 1000–1600 K and log g no larger than 3.5 dex. The planet radius covers a relatively large range between 1.4 and 3.7 RJ with the larger radii being higher than expected from planet evolution models for the age of the planet of 5.4 Myr. Conclusions. This study provides a comprehensive data set on the orbital motion of PDS 70 b, indicating a circular orbit and a motion coplanar with the disk. The first detailed spectral energy distribution of PDS 70 b indicates a temperature typical of young giant planets. The detailed atmospheric analysis indicates that a circumplanetary disk may contribute to the total planetflux.

Orishatukeh Faduma and the New Theology

1994 ◽  
Vol 63 (1) ◽  
pp. 60-80 ◽  
Author(s):  
Moses Nathaniel Moore
Keyword(s):  
Nineteenth Century ◽  
Historical Development ◽  
Christian Ethics ◽  
Comparative Religion ◽  
Religion And Science ◽  
Historical Significance ◽  
Dark Continent ◽  
Theological Orientation ◽  
The Times ◽  
First Time

In 1890 theBoston Heraldcarried the following review of an article entitled “Thoughts for the Times or The New Theology”: “A curiosity is a paper by a native African, Orishatukeh Faduma, on ‘Thoughts for the Times,’ by which he means the new theology. This is the first time that a criticof the new theology has turned up from the dark continent, and is a curious and significant paper. When a native can write like this on subjects in which he has been obliged to educate himself, it means that we are to say nothing more against the intelligence of the African race.” While correct in noting the historical significance of Faduma's efforts, the reviewer's condescension disclosed his failure to appreciate and understand the sophistication and depth of Faduma' theological analysis and agenda. Faduma's critique of elements of the New Theology did not entail his rejection of this controversial theological synthesis which emerged during the last quarter of the nineteenth century. Rather, his comments on religion and science, the historicalcritical method, comparative religion, missiology, the historical development of Christianity, and Christian ethics reveal that he essentially shared the theological orientation of its formulators.

scholarly journals GEM-Based Detectors for Direct Detection of Low-Mass WIMP, Solar Axions and Narrow Resonances (Quarks)

2021 ◽  
Author(s):  
Victor Parusov ◽  
Boris Ovchinnikov
Keyword(s):  
Direct Detection ◽  
Detection System ◽  
Beta Particle ◽  
Gaseous Mixtures ◽  
Low Mass ◽  
Nonzero Spin ◽  
Time Projection ◽  
First Time ◽  
Solar Axions ◽  
Low Mass Wimp

Gas electron multipliers (GEMs) with wire (WGEMs) or metal electrodes (MGEMs), which don’t use any plastic insulators between electrodes are created. The chambers containing MGEMs (WGEMs) with pin-anodes are proposed as detectors for searching of spin-dependent interactions between Dark Matter (DM) particles and gases with nonzero-spin nuclei (H2, D2, 3He, 21Ne, CF4, CH4, etc.). In this paper, we present a review of such chambers. For investigation of the gas mixtures Ne+10%H2, H2 (D2) +3ppmTMAE, the chamber containing WGEM with pin-anode detection system was constructed. In this paper we present the results of an experimental study of these gaseous mixtures exited by an α - source. Mixture of Ar + 40 ppm C2H4 and mixture 50% Xe + 50%CF4 have been investigated. The spatial distributions of photoelectron clouds produced by primary scintillations on α- and β-particle tracks, as well as the distributions of photoelectron clouds due to photons from avalanches at the pin-anode, have been measured for the first time. In our experiments as another filling of the chambers for search of low-mas WIMP (<10 GeV/c2), solar neutrino and solar axions with spin-dependent interaction we propose to use the mixtures: D2 + 3ppmTMAE, 3He + 3%CH4, 21Ne + 10%H2, at pressure 10-17 bar. And in our experiment with liquid gases is used the mixtures with 19F (LAr + CF4, LXe + CF4) and mixture LCH4 + 40ppm TMAE. The time projection chamber (TPC) with the mixture D2 + 3ppmTMAE filling allow to search of spin-dependent interactions of solar axions and deuterium. As well as we present the detecting systems for search of narrow pp-resonances (quarks) in accelerators experiments.

scholarly journals Historiography at the Crossroads

2020 ◽  
Vol 13 (33) ◽  
pp. 229-270
Author(s):  
Dmitri Starostin
Keyword(s):  
Old Testament ◽  
End Of History ◽  
The End Of History ◽  
The Creation ◽  
The Times ◽  
First Time ◽  
Sacred History

This article suggests that the Carolingian effort in resetting the calendar of history at the time of Charlemagne’s coronation to the year 6000 from the Creation and 801 from the Incarnation of Christ must be considered as only one of the period in the cycle of the processes of realigning, resetting and redeploying the calendar since the times of Augustine. During this period, the calculations necessary for the construction of the calendars and timelines lead to concerns regarding the end of history and the “end of times”. The first time scholars like Jerome and Augustine had to address the ending of the calendar of the universal sacred history that the Christians inherited from the Old Testament was during the 4th and 5th centuries. The Carolingian period witnessed the second “time of reckoning” when Eusebius’ date for the Incarnation of the Anno Mundi 5199 prompted scholars to reconsider the meaning of the Carolingian rule around the year 801, that is, the Anno Mundi 6000.

Sign in / Sign up

Export Citation Format

Share Document