scholarly journals Meet Hygiea, the Smallest Dwarf Planet in Our Solar System

Eos ◽  
2019 ◽  
Vol 100 ◽  
Author(s):  
Javier Barbuzano

New observations confirm that main asteroid belt object Hygiea is round. It now fulfills all the requirements to graduate from asteroid to dwarf planet.

2020 ◽  
Vol 497 (1) ◽  
pp. L46-L49 ◽  
Author(s):  
A Morbidelli ◽  
K Batygin ◽  
R Brasser ◽  
S N Raymond

ABSTRACT In two recent papers published in MNRAS, Namouni and Morais claimed evidence for the interstellar origin of some small Solar system bodies, including: (i) objects in retrograde co-orbital motion with the giant planets and (ii) the highly inclined Centaurs. Here, we discuss the flaws of those papers that invalidate the authors’ conclusions. Numerical simulations backwards in time are not representative of the past evolution of real bodies. Instead, these simulations are only useful as a means to quantify the short dynamical lifetime of the considered bodies and the fast decay of their population. In light of this fast decay, if the observed bodies were the survivors of populations of objects captured from interstellar space in the early Solar system, these populations should have been implausibly large (e.g. about 10 times the current main asteroid belt population for the retrograde co-orbital of Jupiter). More likely, the observed objects are just transient members of a population that is maintained in quasi-steady state by a continuous flux of objects from some parent reservoir in the distant Solar system. We identify in the Halley-type comets and the Oort cloud the most likely sources of retrograde co-orbitals and highly inclined Centaurs.


2015 ◽  
Vol 10 (S318) ◽  
pp. 9-15
Author(s):  
Gal Sarid ◽  
Sarah T. Stewart ◽  
Zoë M. Leinhardt

AbstractErosive collisions among planetary embryos in the inner solar system can lead to multiple remnant bodies, varied in mass, composition and residual velocity. Some of the smaller, unbound debris may become available to seed the main asteroid belt. The makeup of these collisionally produced bodies is different from the canonical chondritic composition, in terms of rock/iron ratio and may contain further shock-processed material. Having some of the material in the asteroid belt owe its origin from collisions of larger planetary bodies may help in explaining some of the diversity and oddities in composition of different asteroid groups.


2021 ◽  
Vol 922 (1) ◽  
pp. L8 ◽  
Author(s):  
Colin Orion Chandler ◽  
Chadwick A. Trujillo ◽  
Henry H. Hsieh

Abstract We present archival observations of main-belt asteroid (248370) 2005 QN173 (also designated 433P) that demonstrate this recently discovered active asteroid (a body with a dynamically asteroidal orbit displaying a tail or coma) has had at least one additional apparition of activity near perihelion during a prior orbit. We discovered evidence of this second activity epoch in an image captured 2016 July 22 with the DECam on the 4 m Blanco telescope at the Cerro Tololo Inter-American Observatory in Chile. As of this writing, (248370) 2005 QN173 is just the eighth active asteroid demonstrated to undergo recurrent activity near perihelion. Our analyses demonstrate (248370) 2005 QN173 is likely a member of the active asteroid subset known as main-belt comets, a group of objects that orbit in the main asteroid belt that exhibit activity that is specifically driven by sublimation. We implement an activity detection technique, wedge photometry, that has the potential to detect tails in images of solar system objects and quantify their agreement with computed antisolar and antimotion vectors normally associated with observed tail directions. We present a catalog and an image gallery of archival observations. The object will soon become unobservable as it passes behind the Sun as seen from Earth, and when it again becomes visible (late 2022) it will be farther than 3 au from the Sun. Our findings suggest (248370) 2005 QN173 is most active interior to 2.7 au (0.3 au from perihelion), so we encourage the community to observe and study this special object before 2021 December.


2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Timothy O’Brien ◽  
John A. Tarduno ◽  
Atma Anand ◽  
Aleksey V. Smirnov ◽  
Eric G. Blackman ◽  
...  

AbstractMeteorite magnetizations can provide rare insight into early Solar System evolution. Such data take on new importance with recognition of the isotopic dichotomy between non-carbonaceous and carbonaceous meteorites, representing distinct inner and outer disk reservoirs, and the likelihood that parent body asteroids were once separated by Jupiter and subsequently mixed. The arrival time of these parent bodies into the main asteroid belt, however, has heretofore been unknown. Herein, we show that weak CV (Vigarano type) and CM (Mighei type) carbonaceous chondrite remanent magnetizations indicate acquisition by the solar wind 4.2 to 4.8 million years after Ca-Al-rich inclusion (CAI) formation at heliocentric distances of ~2–4 AU. These data thus indicate that the CV and CM parent asteroids had arrived near, or within, the orbital range of the present-day asteroid belt from the outer disk isotopic reservoir within the first 5 million years of Solar System history.


2015 ◽  
Vol 10 (S318) ◽  
pp. 99-110
Author(s):  
Henry H. Hsieh

AbstractOur knowledge of main-belt comets (MBCs), which exhibit comet-like activity likely due to the sublimation of volatile ices, yet orbit in the main asteroid belt, has increased greatly since the discovery of the first known MBC, 133P/Elst-Pizarro, in 1996, and their recognition as a new class of solar system objects after the discovery of two more MBCs in 2005. I review work that has been done over the last 10 years to improve our understanding of these enigmatic objects, including the development of systematic discovery methods and diagnostics for distinguishing MBCs from disrupted asteroids (which exhibit comet-like activity due to physical disruptions such as impacts or rotational destabilization). I also discuss efforts to understand the dynamical and thermal properties of these objects.


Author(s):  
Aaron R. Hurst

The supercharged nature of the Earth’s geothermal core can be demonstrated by three thought experiments exhibiting it is tremendously more powerful than any other terrestrial object in the solar system (planet or moon). Identifying a minimum of four byproduct asteroid blast patterns linked to the formation of Earth’s supercharged geothermal core is critical to properly identifying stars that also have these four byproduct asteroid blast patterns. These stars are the most likely to host an Earth-like planet qualified by having a supercharged geothermal core. The Planetary Vaporization-Event (PVE) Hypothesis provides a basis for correlation between the supercharged nature of Earth’s geothermal core and at least 14 listed side effects: (1) the asteroid-wide/planet-scale homogenization and lack thereof of 182W ε for Earth, the Moon, Mars and meteors, (2) the primary and secondary shifting of Earth’s tectonic plates, (3) the solar system wide displacement of Earth’s wayward moons (including Ceres, Pluto, Charon and Orcus) outgassing identical samples of ammoniated phyllosilicates, (4) the formation of asteroids at 100+ times the expected density of a nebular cloud vs. pre-solar grains formation density at the expected density of a nebular cloud, (5) three distinct formation timestamps for all known asteroids within a 5 million year window 4.55+ billion years ago, (6) the estimated formation temperature of CAI at 0.86 billion Kelvin and (7) the remaining chondritic meteorite matrix flash vaporizing at 1,200–1,900 °C, (8) followed by rapid freezing near 0 K, (9) the development of exactly 2 asteroid belts and a swarm of non-moon satellites, (10) particulate size distinction between the 2 asteroid belts of small/inner, large/outer, (11) the proximity of the Trojan Asteroid Groups to the Main Asteroid Belt, (12) observation of a past or present LHB, (13) the development of annual meteor showers for Earth proximal to apogee and/or perigee, (14) the Sun being the most-likely object struck by an asteroid in the inner solar system. Through better understanding of the relevant data at hand and reclassification of the byproducts of supercharging the core of a planet, at least 5 new insights can be inferred and are listed as: (1) the original mass, (2) distance and (3) speed of Earth Mark One, (4) the original order of Earth’s multi-moon formation and (5) the high probability of finding detectable signs of life on a planet orbiting the stars Epsilon Eridani and Eta Corvi. There are at least 6 popular hypothesis that the PVE Hypothesis is in conflict with, listed they are: (1) a giant impact forming the Moon, (2) asteroids being the building blocks of the solar system, (3) the Main Asteroid Belt being the result of a planet that never formed, (4) the LHB being a part of the accretion disk process, (5) the heat in Earth’s core coming primarily from the decay of radioactive elements, (6) the Oort Cloud being the source of ice comets.


2020 ◽  
Author(s):  
Kateryna Frantseva ◽  
Michael Mueller ◽  
Petr Pokorný ◽  
Floris F. S. van der Tak ◽  
Inge Loes ten Kate

<p>Are minor bodies and dust delivering volatile and/or refractory materials in exoplanetary systems?<span class="Apple-converted-space"> </span></p> <p>Around ~20% of the nearest stars are found to host analogues of the main asteroid belt and the Kuiper belt. Our aim is to study the possibility of material delivery through minor bodies and dust to the planetary surfaces. To shed light on these delivery processes we extrapolate our Solar System scenarios to the exoplanetary system HR 8799. The system is known to host four giant planets and two belts of minor bodies.</p> <p>We performed a set of N-body simulations to study the impact rates of minor bodies and dust on the HR 8799 planets. We find that the planets suffer impacts by objects from the inner and outer belt. We convert these to volatile and refractory delivery rates using our best estimates of the total mass contained in the belts and their volatile/refractory content. Over their lifetime, the four giant planets receive between 10<sup>-4</sup> and 10<sup>-3 </sup>M<sub>Earth</sub> of material from both belts. This delivery leads to volatile and refractory enrichment of the planets that may be observable. Since the four giants HR 8799 e, d, c, b are located beyond the snow line (and presumably formed there), we expect them to be born volatile-rich. Therefore any future detection of refractories might imply delivery through impacts.</p>


2019 ◽  
Author(s):  
Αθανασία Τόλιου

Τις τελευταίες δεκαετίες η κατανόησή μας για την εξέλιξη του Ηλιακού Συστήματος έχει βελτιωθεί σε μεγάλο βαθμό. Οι πάλαι ποτέ θεωρούμενες «στατικές» τροχιές των γιγάντων πλανητών, πιστεύουμε πλέον πως είναι αποτέλεσμα ενός βίαιου παρελθόντος, το οποίο επηρέασε και το υπόλοιπο Ηλιακό Σύστημα. Οι ελάσσονες πλανήτες, συγκεντρωμένοι σε πληθυσμούς όπως η Κυρια Ζώνη των Αστεροειδών, η ζώνη του Κάιπερ και το νέφος του Όορτ αποτελούν αξιόπιστα μέσα για την εξερεύνηση αυτού του εξελικτικού μονοπατιού. Θεωρώντας την «Αστάθεια των Γιγάνων Πλανητών» ως ένα ορόσημο στην ιστορία του Ηλιακού Συστήματος, χαρακτηρίζουμε ως «πρώιμη» την δομή της κύριας ζώνης των αστεροειδών που προϋπάρχει αυτού του γεγονότος. Η παρούσα εργασία εστιάζει στην εξέλιξη της πρώιμης ζώνης των αστεροειδών κατά τα πρώτα στάδια της ζωής του Ηλιακού Συστήματος, ξεκινώντας πριν απο τη διάλυση του πρωτοπλανητικού δίσκου αερίου και εκτείνεται μέχρι τη δημιουργία των γήινων πλανητών. Είναι ευρέως αποδεκτό οτι ένας αρχικά «επίπεδος» δίσκος αστεροειδών, κινούμενων σε σχεδόν κυκλικές και συνεπίπεδες τροχιές δεν μπορεί να εξελιχθεί στην σημερινή παρατηρήσιμη κατανομή εαν οι γίγαντες πλανήτες ακολουθούσαν για πάντα τις ίδιες αναλλοίωτες τροχιές. Συνεπώς η Κύρια Ζώνη των Αστεροειδών πρέπει να είχε υποστεί απώλεια μάζας και διέγερση στις κλίσεις και εκκεντρότητες των τροχιών, πριν οι πλανήτες φθάσουν στην τελική τους θέση. Στο μοντέλο ελέλιξης του πρώιμου Ηλιακού Συστήματος που κατασκευάσαμε, θεωρήσαμε το Δία και τον Κρόνο παγιδευμένους σε συντονισμό μέσης κίνησης, οι οποίοι αλληλεπιδρούν βαρυτικά με έναν αρχικά επίπεδο δίσκο αστεροειδών και έναν πληθυσμό πλανητικών εμβρύων με μάζες ίσες με του Άρη. Ταυτόχρονα το όλο σύστημα βρίσκεται στο βαρυτικό πεδίο του συνεχώς εξαντλούμενου δίσκου αερίου. Ο δίσκος αυτός μεταβάλλει με το χρόνο το ρυθμό μετάπτωσης του μήκους του αναβιβάζοντος συνδέσμου και του μήκους του περιηλίου των τροχιών όλων των σωμάτων που κινούνται μέσα σε αυτόν. Αυτό οδηγεί στην εμφάνιση αιώνιων συντονισμών οι οποίοι σαρώνουν ολόκληρη ή μέρη της Κύριας Ζώνης καθώς ο δίσκος διαλύεται. Η συνέργεια όλων αυτών των μηχανισμών μπορεί κάτω απο συγκεκριμένες συνθήκες, όπως φανερώνουν τα αποτελέσματά μας, να εξηγήσει την πρώιμη κατανομή της Κύριας Ζώνης των αστεροειδών, όπως επίσης την κατανομή της μάζας και των τροχιών των γήινων πλανητών.


2012 ◽  
Vol 8 (S293) ◽  
pp. 212-218 ◽  
Author(s):  
Henry H. Hsieh

AbstractAs a recently recognized class of objects exhibiting apparently cometary (sublimation-driven) activity yet orbiting completely within the main asteroid belt, main-belt comets (MBCs) have revealed the existence of present-day ice in small bodies in the inner solar system and offer an opportunity to better understand the thermal and compositional history of our solar system, and by extension, those of other planetary systems as well. Achieving these overall goals, however, will require meeting various intermediate research objectives, including discovering many more MBCs than the currently known seven objects in order to ascertain the population's true abundance and distribution, confirming that water ice sublimation is in fact the driver of activity in these objects, and improving our understanding of the physical, dynamical, and thermal evolutionary processes that have acted on this population over the age of the solar system.


2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Kosuke Kurosawa ◽  
Ryota Moriwaki ◽  
Hikaru Yabuta ◽  
Ko Ishibashi ◽  
Goro Komatsu ◽  
...  

AbstractCarbonaceous asteroids, including Ryugu and Bennu, which have been explored by the Hayabusa2 and OSIRIS-REx missions, were probably important carriers of volatiles to the inner Solar System. However, Ryugu has experienced significant volatile loss, possibly from hypervelocity impact heating. Here we present impact experiments at speeds comparable to those expected in the main asteroid belt (3.7 km s−1 and 5.8 km s−1) and with analogue target materials. We find that loss of volatiles from the target material due to impacts is not sufficient to account for the observed volatile depletion of Ryugu. We propose that mutual collisions in the main asteroid belt are unlikely to be solely responsible for the loss of volatiles from Ryugu or its parent body. Instead, we suggest that additional processes, for example associated with the diversity in mechanisms and timing of their formation, are necessary to account for the variable volatile contents of carbonaceous asteroids.


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