Phase curves of >40,000 small solar system bodies obtained by the Tomo-e Gozen transient survey

2020 ◽  
Author(s):  
Fumi Yoshida ◽  
Takashi Ito ◽  
Seitaro Urakawa ◽  
Tsuyoshi Terai ◽  
Nozomu Tominaga ◽  
...  
Keyword(s):  
Solar System ◽  
Moving Objects ◽  
Surface Characteristics ◽  
Absolute Magnitude ◽  
Daily Basis ◽  
Wide Field ◽  
Cmos Camera ◽  
Cmos Image Sensors ◽  
Solar System Bodies ◽  
Solar Phase

<p>The Tomo-e Gozen project conducts optical wide-field survey programs with a wide-field CMOS camera, Tomo-e Gozen, attached on the 105-cm Schmidt telescope at the Kiso Observatory, the University of Tokyo, Japan. Tomo-e Gozen is the world's first wide-field CMOS camera which covers 20 square degrees with 84 chips of 35 mm full HD CMOS image sensors. A wide-field and high-cadence survey in the optical wavelengths began in 2018 with the Tomo-e Gozen (hereafter referred to as the Tomo-e Gozen transient survey). The main purpose of this survey is to detect young supernovae. However, the survey simultaneously detects a large number of moving objects in their images. As one of the by-products of the survey, here we show our preliminary result about production of phase curves (solar phase angles versus absolute magnitude) of more than 44,000 small solar system bodies including main-belt asteroids, near-Earth asteroids, Jupiter Trojans, Centaurs, and Transneptunian objects (this number is as of April 11, 2020). Combining the moving object catalogue derived from the survey and the output ephemeris that the Horizons/JPL system provides, we are now able to obtain phase curves of these objects almost automatically. As the Kiso moving object catalogue is updated and being expanded on a daily basis, the number of the objects (small bodies) that we deal with goes up as well. Our result, when completed, will make a fair complement as well as a significant keystone to what is already published such as from the Pan-STARRS systematic survey on the knowledge of the surface characteristics of the small solar system bodies.</p>

NEOSM Survey Cadence and Simulation

2020 ◽  
Author(s):  
Sarah Sonnett ◽  
Amy Mainzer ◽  
Tommy Grav ◽  
Tim Spahr ◽  
Eva Lilly ◽  
...  
Keyword(s):  
Moving Objects ◽  
Small Body ◽  
Absolute Magnitude ◽  
Reference Population ◽  
Space Mission ◽  
Physical Characterization ◽  
Ongoing Work ◽  
Solar System Bodies ◽  
Source Populations ◽  
A Minor

<p>The Near-Earth Object Surveillance Mission (NEOSM) is a planned space-based infrared mission that will nominally launch in 2025 and librate at the Earth-Sun L1 Lagrange point.  The NEOSM Project was formulated to address the need to detect, catalog, and characterize near-Earth objects (NEOs) to support informed decision making for any potential mitigation activity. NEOSM detects NEOs, obtains high quality orbits for them, provides physical characterization of the NEOs and their source populations, and provides more detailed physical characterization for individual targets with significant impact probabilities.  Specifically, NEOSM will detect, track, and characterize 2/3 of potentially hazardous asteroids (PHAs) larger than 140m - large enough to cause potentially significant regional damage.  NEOSM is expected to detect thousands of comets, hundreds of thousands of NEOs and millions of main belt asteroids. Since moving objects, in particular NEOs, are the main focus of the NEOSM project, the survey can be optimized for maximum discovery rate by adjusting the survey cadence to ensure efficient and reliable linking observations into tracklets, which are position-time sets of a minor planet. It is also important for the survey cadence to provide self-followup that yields orbits with quality similar to that of the known NEOs today. The NEOSM Investigation Software Suite (NISS) is a set of tools being developed to support the efforts to optimize the survey and verify the ability of the designed mission to meet its scientific objectives. The NISS consists of a comprehensive representation of the mission performance, including the flight system hardware, mission operations, and ground data system processing. The NSS takes as its input a reference population of solar system bodies, the NEOSM Reference Small Body Population Model (RSBPM), and performs a frame-by-frame simulation of the survey over the course of its entire operational lifetime. Note that the RSBPM allows for performance to be evaluated as a function of diameter, rather than the traditional method of equating absolute magnitude H = 22 mag as a proxy for 140m. It has been shown that a completeness of 90% of objects with H < 23 mag is needed in order to ensure that 90% of objects larger than 140 m are found. We present here our ongoing work on mission architecture trades and the optimization of the survey cadence for NEO discovery and tracking. We will present the latest NEOSM survey cadence and its expected performance.  We will present the completeness rate after the baseline 5-year mission and a possible extended mission.  Studies have previously shown that the 90% goal can be achieved by a combination of a space mission like NEOCam and a ground based survey like LSST. We will also present how the survey cadence provides self-followup of the NEOs population and ensures orbital quality on par with the current NEO population.</p>

Spectropolarimetric device for overatmospheric investigations of Solar system bodies

2008 ◽  
Vol 14 (2) ◽  
pp. 56-67
Author(s):  
Ya.S. Yatskiv ◽  
◽  
A.P. Vidmachenko ◽  
O.V. Morozhenko ◽  
M.G. Sosonkin ◽  
...  
Keyword(s):  
Solar System ◽  
Solar System Bodies

scholarly journals Organic matter and water from asteroid Itokawa

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Q. H. S. Chan ◽  
A. Stephant ◽  
I. A. Franchi ◽  
X. Zhao ◽  
R. Brunetto ◽  
...  
Keyword(s):  
Organic Matter ◽  
Solar System ◽  
Parent Body ◽  
Asteroid Belt ◽  
True Nature ◽  
Water Ice ◽  
Nanocrystalline Graphite ◽  
Terrestrial Water ◽  
Solar System Bodies ◽  
Small Dust

AbstractUnderstanding the true nature of extra-terrestrial water and organic matter that were present at the birth of our solar system, and their subsequent evolution, necessitates the study of pristine astromaterials. In this study, we have studied both the water and organic contents from a dust particle recovered from the surface of near-Earth asteroid 25143 Itokawa by the Hayabusa mission, which was the first mission that brought pristine asteroidal materials to Earth’s astromaterial collection. The organic matter is presented as both nanocrystalline graphite and disordered polyaromatic carbon with high D/H and 15N/14N ratios (δD =  + 4868 ± 2288‰; δ15N =  + 344 ± 20‰) signifying an explicit extra-terrestrial origin. The contrasting organic feature (graphitic and disordered) substantiates the rubble-pile asteroid model of Itokawa, and offers support for material mixing in the asteroid belt that occurred in scales from small dust infall to catastrophic impacts of large asteroidal parent bodies. Our analysis of Itokawa water indicates that the asteroid has incorporated D-poor water ice at the abundance on par with inner solar system bodies. The asteroid was metamorphosed and dehydrated on the formerly large asteroid, and was subsequently evolved via late-stage hydration, modified by D-enriched exogenous organics and water derived from a carbonaceous parent body.

scholarly journals The Grand Tack model: a critical review

2014 ◽  
Vol 9 (S310) ◽  
pp. 194-203 ◽  
Author(s):  
Sean N. Raymond ◽  
Alessandro Morbidelli
Keyword(s):  
Solar System ◽  
Building Blocks ◽  
Protoplanetary Disk ◽  
Giant Planets ◽  
Asteroid Belt ◽  
Terrestrial Planets ◽  
Saturn’S Satellites ◽  
Internal Inconsistency ◽  
Solar System Bodies ◽  
Gas Accretion

AbstractThe “Grand Tack” model proposes that the inner Solar System was sculpted by the giant planets' orbital migration in the gaseous protoplanetary disk. Jupiter first migrated inward then Jupiter and Saturn migrated back outward together. If Jupiter's turnaround or “tack” point was at ~ 1.5 AU the inner disk of terrestrial building blocks would have been truncated at ~ 1 AU, naturally producing the terrestrial planets' masses and spacing. During the gas giants' migration the asteroid belt is severely depleted but repopulated by distinct planetesimal reservoirs that can be associated with the present-day S and C types. The giant planets' orbits are consistent with the later evolution of the outer Solar System.Here we confront common criticisms of the Grand Tack model. We show that some uncertainties remain regarding the Tack mechanism itself; the most critical unknown is the timing and rate of gas accretion onto Saturn and Jupiter. Current isotopic and compositional measurements of Solar System bodies – including the D/H ratios of Saturn's satellites – do not refute the model. We discuss how alternate models for the formation of the terrestrial planets each suffer from an internal inconsistency and/or place a strong and very specific requirement on the properties of the protoplanetary disk.We conclude that the Grand Tack model remains viable and consistent with our current understanding of planet formation. Nonetheless, we encourage additional tests of the Grand Tack as well as the construction of alternate models.

Orthopteran DCMD neuron: a reevaluation of responses to moving objects. II. Critical cues for detecting approaching objects

1992 ◽  
Vol 68 (5) ◽  
pp. 1667-1682 ◽  
Author(s):  
P. J. Simmons ◽  
F. C. Rind
Keyword(s):  
Moving Objects ◽  
Optic Lobe ◽  
Receptive Fields ◽  
Wide Field ◽  
Motion Detector ◽  
Dark Light ◽  
Subsequent Response ◽  
Object Movement ◽  
Line Movement ◽  
Important Stimulus

1. We examine the critical image cues that are used by the locust visual system for the descending contralateral motion detector (DCMD) neuron to distinguish approaching from receding objects. Images were controlled by computer and presented on an electrostatic monitor. 2. Changes in overall luminance elicited much smaller and briefer responses from the DCMD than objects that appeared to approach the eye. Although a decrease in overall luminance might boost the response to an approaching dark object, movement of edges of the image is more important. 3. When two pairs of lines, in a cross-hairs configuration, were moved apart and then together again, the DCMD showed no preference for divergence compared with convergence of edges. A directional response was obtained by either making the lines increase in extent during divergence and decrease in extent during convergence; or by continually increasing the velocity of line movement during divergence and decreasing velocity during convergence. 4. The DCMD consistently gave a larger response to growing than to shrinking solid rectangular images. An increase compared with a decrease in the extent of edge in an image is, therefore, an important cue for the directionality of the response. For single moving edges of fixed extent, the neuron gave the largest response to edges that subtended 15 degrees at the eye. 5. The DCMD was very sensitive to the amount by which an edge traveled between frames on the display screen, with the largest responses generated by 2.5 degrees of travel. This implies that the neurons in the optic lobe that drive this movement-detecting system have receptive fields of about the same extent as a single ommatidium. 6. For edges moving up to 250 degree/s, the excitation of the DCMD increases with velocity. The response to an edge moving at a constant velocity adapts rapidly, in a manner that depends on velocity. Movement over one part of the retina can adapt the subsequent response to movement over another part of the retina. 7. For the DCMD to track and continue to respond to the image of an approaching object, the edges of the image must continually increase in velocity. This is the second important stimulus cue. 8. Edges of opposite contrasts (light-dark compared with dark-light) are processed in separate pathways that inhibit each other. This would contribute to the reduction of responses to wide-field movements.

Orthopteran DCMD neuron: a reevaluation of responses to moving objects. I. Selective responses to approaching objects

1992 ◽  
Vol 68 (5) ◽  
pp. 1654-1666 ◽  
Author(s):  
F. C. Rind ◽  
P. J. Simmons
Keyword(s):  
Moving Objects ◽  
Temporal Frequency ◽  
Angular Acceleration ◽  
Spike Rate ◽  
Single Peak ◽  
Wide Field ◽  
Movement Detector ◽  
Star Wars ◽  
Wide Range ◽  
Real Objects

1. The "descending contralateral movement detector" (DCMD) neuron in the locust has been challenged with a variety of moving stimuli, including scenes from a film (Star Wars), moving disks, and images generated by computer. The neuron responds well to any rapid movement. For a dark object moving along a straight path at a uniform velocity, the DCMD gives the strongest response when the object travels directly toward the eye, and the weakest when the object travels away from the eye. Instead of expressing selectivity for movements of small rather than large objects, the DCMD responds preferentially to approaching objects. 2. The neuron shows a clear selectivity for approach over recession for a variety of sizes and velocities of movement both of real objects and in simulated movements. When a disk that subtends > or = 5 degrees at the eye approaches the eye, there are two peaks in spike rate: one immediately after the start of movement; and a second that builds up during the approach. When a disk recedes from the eye, there is a single peak in response as the movement starts. There is a good correlation between spike rate and angular acceleration of the edges of the image over the eye. 3. When an object approaches from a distance sufficient for it to subtend less than one interommatidial angle at the start of its approach, there is a single peak in response. The DCMD tracks the approach, and, if the object moves at 1 m/s or faster, the spike rate increases throughout the duration of object movement. The size of the response depends on the speed of approach. 4. It is unlikely that the DCMD encodes the time to collision accurately, because the response depends on the size as well as the velocity of an approaching object. 5. Wide-field movements suppress the response to an approaching object. The suppression varies with the temporal frequency of the background pattern. 6. Over a wide range of contrasts of object against background, the DCMD gives a stronger response to approaching than to receding objects. For low contrasts, the selectivity is greater for objects that are darker than the background than for objects that are lighter.

Power Laws of Topography and Gravity Spectra of the Solar System Bodies

2018 ◽  
Vol 123 (8) ◽  
pp. 2038-2064 ◽  
Author(s):  
A. I. Ermakov ◽  
R. S. Park ◽  
B. G. Bills
Keyword(s):  
Solar System ◽  
Power Laws ◽  
Solar System Bodies
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