Minor Planets Research Articles

ВОПРОСЫ И ПЕРСПЕКТИВЫ ПРЕПОДАВАНИЯ ТЕМЫ «СОЛНЕЧНАЯ СИСТЕМА» ПО УЧЕБНИКАМ АСТРОНОМИИ

The article deals with the issues of teaching the topic "Solar system" of the discipline "Astronomy". The old textbook "Astronomy" by E.P. Levina and new - B.A. Vorontsova–Velyaminova, E.K. Strout and V.M. Charugin - in which the material about the planetary system is borrowed from publications of the last century. At present, what is stated in the textbook by B.A. Vorontsova-Velyaminov and E.K. Strout, the historically established idea of the formation and structure of the solar system (from planets alone) contradicts new discoveries and the observed harmonious structure of the solar system. The erroneousness of assigning the status of "minor planet" to asteroids of the main belt and many objects of the Kuiper belt is substantiated. this leads students to the misconception that there are many planets in the solar system. To the textbook "Astronomy" V.M. Charugin, the author of this article prepared a textbook "The Solar System of the 21st Century", which provides a model of the structure of the entire Solar System and the cometary hypothesis of its origin. The textbook contains a table "Periodic system of celestial bodies of the entire solar system" for astronomy classrooms, similar in significance to the table "Periodic system of chemical elements of D.I. Mendeleev.

The utility of the euronear software in the detection of NEA asteroids

This paper presents some of the software techniques used in astronomy to detect celestial bodies near the Earth, called NEO bodies, Near Earth Object, including NEA asteroids, Near Earth Asteroids. The software and utilities created or only used in the research projects coordinated by the EURONEAR consortium were Astrometrica and Nearby, respectively among the utilities necessary for the new asteroid detections were Asteroids Identifications, Astrocheck, Nea Checker, Neo Checker-MPC, Find Orb Project Pluto-MPC, Minor Planet Center. Packages of images were taken through the ING Telescope in the Canary Islands, La Palma, Spain. These software techniques were implemented and tested at the University of Craiova, in research projects and through students of the Faculty of Sciences.

Planets or asteroids? A geochemical method to constrain the masses of White Dwarf pollutants

ABSTRACT Polluted white dwarfs that have accreted planetary material provide a unique opportunity to probe the geology of exoplanetary systems. However, the nature of the bodies that pollute white dwarfs is not well understood: are they small asteroids, minor planets, or even terrestrial planets? We present a novel method to infer pollutant masses from detections of Ni, Cr, and Si. During core–mantle differentiation, these elements exhibit variable preference for metal and silicate at different pressures (i.e. object masses), affecting their abundances in the core and mantle. We model core–mantle differentiation self-consistently using data from metal–silicate partitioning experiments. We place statistical constraints on the differentiation pressures, and hence masses, of bodies which pollute white dwarfs by incorporating this calculation into a Bayesian framework. We show that Ni observations are best suited to constraining pressure when pollution is mantle-like, while Cr and Si are better for core-like pollution. We find three systems (WD0449-259, WD1350-162, and WD2105-820) whose abundances are best explained by the accretion of fragments of small parent bodies (<0.2 M⊕). For two systems (GD61 and WD0446-255), the best model suggests the accretion of fragments of Earth-sized bodies, although the observed abundances remain consistent (<3σ) with the accretion of undifferentiated material. This suggests that polluted white dwarfs potentially accrete planetary bodies of a range of masses. However, our results are subject to inevitable degeneracies and limitations given current data. To constrain pressure more confidently, we require serendipitous observation of (nearly) pure core and/or mantle material.

EARLY KYIV OBSERVATIONS OF ASTEROIDS: ANALYSIS AND NEW REDUCTION WITH TYCHO-2 AND GAIA CATALOGS

For more than 50 years, the continuous photographic observations of asteroids have been carried outwith telescopes of the Astronomical Observatory of the Taras Shevchenko National University of Kyiv and the Main Astronomical Observatory of the National Academy of Sciences of Ukraine. About 3,000 photographic plates were obtained, some of which were exposed in 1908. We collected the data on more than 5,500 positions and magnitudes of asteroids on these astroplates taking into account all results of the processing of observations available in various publications and in the Minor Planet Center database. All positional data were compared with JPL ephemeris and analyzed. From different series of asteroid observations the values of positional accuracy were obtained, depending on the methods of measuring and processing the plates and reference catalogs of stars. In order to systematically improve the obtained asteroid positions, we evaluated the possibilities of reprocessing some of the earliest asteroid observations applying the modern star high accuracy catalogs. Using the Tycho-2, Gaia DR2, and Gaia EDR3 as the reference catalogs, the 590 astroplates exposed on the MAO NASU Double Long-Focus Astrograph (DLA) in 1952-1986 were reprocessed based on old plate measurements. All newly determined and previous original asteroid positions were compared with the JPL ephemeris. The comparison results show an improvement in the systematic and random components of the accuracy of coordinates for new positions of asteroids. When comparing the new positions of the asteroids determined in the Tycho-2 and Gaia catalog systems, no significant changes in accuracy were found.

FIRST RESULTS OF PROCESSING DIGITIZED V-PLATES TAKEN WITH THE TAUTENBURG 2m SCHMIDT TELESCOPE

The process of treatment of about 500 digitized plates has started in MAO NAS of Ukraine. Plates were taken with the Tautenburg 2m Schmidt telescope in 1963-1989. Linear dimensions of plates are 24x24 cm with a working field of 3.3x3.3 degrees and a scale of 51.4 "/ mm. Astronegatives were digitized on the Tautenburg Plate Scanner in five strips with linear dimensions of 5 400x23 800 px. The software developed in MAO NAS of Ukraine for the image processing of these scans takes into account the horizontal overlap and the vertical offset of strips. The photometric range of fixed objects is 12 magnitudes, around V = 7 m - 19 m , due to the separation of objects into faint and bright parts by their images’ diameters. Positions of stars and other fixed objects are obtained in the GAIA DR2 reference system. Magnitudes are defined in the V-band of the Johnson color system. The resulted positional accuracy defined from 180 plates’ processing is σ RA,DEC = 0.10"for both coordinates, photometric error on the whole range of magnitudes is σ V = 0.14 m . The convergence of resulted magnitudes with ones from photoelectric standards’ data is 0.19 m . In parallel with image processing and plate data reduction, the search for minor planets’ images was carried out. Nine positions and magnitudes of 4 asteroids registered on the plates obtained in 1963-1965 were defined and used for further analysis.

Mysterious Dust-emitting Object Orbiting TIC 400799224

Abstract We report the discovery of a unique object of uncertain nature—but quite possibly a disintegrating asteroid or minor planet—orbiting one star of the widely separated binary TIC 400799224. We initially identified the system in data from TESS Sector 10 via an abnormally shaped fading event in the light curve (hereafter “dips”). Follow-up speckle imaging determined that TIC 400799224 is actually two stars of similar brightness at 0.″62 separation, forming a likely bound binary with projected separation of ∼300 au. We cannot yet determine which star in the binary is host to the dips in flux. ASAS-SN and Evryscope archival data show that there is a strong periodicity of the dips at ∼19.77 days, leading us to believe that an occulting object is orbiting the host star, though the duration, depth, and shape of the dips vary substantially. Statistical analysis of the ASAS-SN data shows that the dips only occur sporadically at a detectable threshold in approximately one out of every three to five transits, lending credence to the possibility that the occulter is a sporadically emitted dust cloud. The cloud is also fairly optically thick, blocking up to 37% or 75% of the light from the host star, depending on the true host. Further observations may allow for greater detail to be gleaned as to the origin and composition of the occulter, as well as to a determination of which of the two stars comprising TIC 400799224 is the true host star of the dips.

Near-UV Reddening Observed in the Reflectance Spectrum of High-inclination Centaur 2012 DR30

Abstract Centaurs with high orbital inclinations and perihelia (i > 60°; q ≳ 5 au) are a small group of poorly understood minor planets that are predicted to enter the giant planet region of the solar system from the inner Oort Cloud. As such, they are one of the few samples of relatively unaltered Oort Cloud material that can currently be directly observed. Here we present two new reflectance spectra of one of the largest of these objects, 2012 DR30, in order to constrain its color and surface composition. Contrary to reports that 2012 DR30 has variable optical color, we find that consistent measurements of its spectral gradient from most new and published data sets at 0.55–0.8 μm agree with a spectral gradient of S ′ ≃ 10 % ± 1 % / 0.1 μ m within their uncertainties. The spectral variability of 2012 DR30 at near-UV/blue and near-IR wavelengths, however, is still relatively unconstrained; self-consistent rotationally resolved follow-up observations are needed to characterize any spectral variation in those regions. We tentatively confirm previous detections of water ice on the surface of 2012 DR30, and we also consistently observe a steady steepening of the gradient of its spectrum from λ ∼ 0.6 μm toward near-UV wavelengths. Plausible surface materials responsible for the observed reddening may include ferric oxides contained within phyllosilicates and aromatic refractory organics.

Studying the fractal properties of Ceres

Currently, the asteroid Ceres belongs to small celestial bodies with the most well-known physical parameters. The study of the structural and real properties of Ceres is an urgent and modern task, the solution of which will make it possible to develop the evolutionary theory of a minor planet. In this work, the fractal properties of the dwarf planet Ceres were analyzed using data from the Dawn space mission. Using the expansion in a harmonic series in spherical functions the height parameters of the structural model of Ceres, a 3D model of Ceres was constructed. The analysis showed that the resulting system has a complex multiparameter fractal configuration. The study of such objects requires the use of harmonic multiparameter methods. Multivariate fractal analysis allows to represent systems similar to the Ceres model in the form of a spectrum of fractal dimensions. The advantage of fractal analysis is the ability to explore local areas of the physical surface. In this work, the Minkowski algorithm was used for this purpose. At the final stage, an overdetermined system was solved for various local areas of topocentric information in order to postulate a model that takes into account external measures. Fractal dimensions D are determined for local regions and the entire model of the planet. Fractal dimensions vary from 1.37 to 1.92 depending on the longitude and latitude of Ceres. The main results are as follows: 1) the structure of the Ceres surface varies more strongly in longitude; 2) the structure of Ceres is smoother in latitude; 3) the coefficient of self-similarity changes rather quickly in longitude, which indicates that different local regions of the minor planet were formed under the influence of various physical processes. It is necessary to emphasize that the resulting fractal dimensions are significantly scattered both in longitude and latitude of Ceres. This fact confirms the presence of a complex structure in the spatial model of a minor planet. This also applies to the actual physical surface of Ceres. The results of the work allow us to conclude that fractal modeling can give independent values of the fractal dimension both for the entire model of Ceres and for its local macrostructural regions.

Who Owns Space?

Space mining is no longer a figment of fringe science fiction. Due to the recent passage of the Space Resource Exploration and Utilization Act of 2015 (SREU Act), U.S. domestic space companies now have a semblance of legislative backing to launch commercial resource acquisition ventures in space. Previously, such companies floundered as capital from investors was reasonably sparse. Uncertainty created by the previously untested Outer Space Treaty (OST) perpetuated worry surrounding the existence of private property rights in space. With the passage of the recent SREU Act, many domestic worries were dismissed by the definitive granting of commercial property rights to U.S. citizens, yet equally many worries continue to surround the legitimacy of the SREU Act itself, as certain legal experts both inside and outside the U.S. argue the Act to be a violation of U.S. international obligations.
 In contrast to the OST, the SREU Act explicitly grants Americans the right to hold and obtain material resources from celestial bodies such as asteroids and minor planets. This paper examines the implications of such a legal gray area by examining the extent to which select clauses of the OST may or may not conflict with such definitive legislation. Ultimately, it is concluded that the issue is far from settled, as the existence of celestial property rights may not presently be as clear as investors might hope.

OSSOS Finds an Exponential Cutoff in the Size Distribution of the Cold Classical Kuiper Belt

Abstract The cold main classical Kuiper Belt consists of the nonresonant small solar system bodies with low orbital inclinations and orbital semimajor axes between 42.4 and 47.7 au. These objects likely formed in situ, and the population has experienced minimal collisional modification since formation. Using the Outer Solar System Origins Survey ensemble sample and characterization, combined with constraints from deeper surveys and supported by evidence from the Minor Planet Center catalog and the Deep Ecliptic Survey, we determine the absolute magnitude H r distribution of the cold classical belt from H r ≃ 5 to 12 (roughly diameters of 400–20 km). We conclude that the cold population’s H r distribution exhibits an exponential cutoff at large sizes. Exponential cutoffs at large sizes are not a natural outcome of pairwise particle accretion, but exponentially tapered power-law size distributions are a feature of numerical simulations of planetesimal formation via a streaming instability. Our observation of an exponential cutoff agrees with previous observational inferences that no large objects (D ≳ 400 km) exist in the cold population. We note that the asymptotic slope of the H r distribution is consistent with α ∼ 0.4. This asymptotic slope is also found in streaming instability modeling of planetesimal formation and is thus not necessarily associated with achieving collisional equilibrium. Studies of the trans-Neptunian region are providing the parameters that will enable future streaming-instability studies to determine the initial conditions of planetesimal formation in the ≈45 au region of the Sun’s protoplanetary disk.

Photometry of four long-period comets

In this work we studied the activity of four long period comets at different heliocentric distances in order to explore their dust production and characteristics. The targets were the comets C/2011 A3 (Gibbs), C/2012 K1 (PanStarrs), C/2012 LP26 (Palomar) and C/2013 F3 (McNaught). Some of these objects have never been studied before. We analyzed images in V and R filters taken with the 2.15 ​m telescope at Complejo Astronómico El Leoncito (CASLEO), Argentina, to characterize their dust coma features and to investigate the morphology, photometry and dust production. The morphological analysis showed some differences among the sample while the Afρ values measured in a reference aperture of radius ρ ​= ​104 ​km showed a scenario of bodies that fit the profile of a long period comet. This is corroborated by the Minor Planet Center dynamical classification.

Outer Solar System Perihelion Gap Formation through Interactions with a Hypothetical Distant Giant Planet

Abstract Among the outer solar system minor planet orbits there is an observed gap in perihelion between roughly 50 and 65 au at eccentricities e ≳ 0.65. Through a suite of observational simulations, we show that the gap arises from two separate populations, the Extreme Trans-Neptunian Objects (ETNOs; perihelia q ≳ 40 au and semimajor axes a ≳ 150 au) and the Inner Oort Cloud objects (IOCs; q ≳ 65 au and a ≳ 250 au), and is very unlikely to result from a realistic single, continuous distribution of objects. We also explore the connection between the perihelion gap and a hypothetical distant giant planet, often referred to as Planet 9 or Planet X, using dynamical simulations. Some simulations containing Planet X produce the ETNOs, the IOCs, and the perihelion gap from a simple Kuiper-Belt-like initial particle distribution over the age of the solar system. The gap forms as particles scattered to high eccentricity by Neptune are captured into secular resonances with Planet X where they cross the gap and oscillate in perihelion and eccentricity over hundreds of kiloyears. Many of these objects reach a minimum perihelia in their oscillation cycle within the IOC region increasing the mean residence time of the IOC region by a factor of approximately five over the gap region. Our findings imply that, in the presence of a massive external perturber, objects within the perihelion gap will be discovered, but that they will be only ∼20% as numerous as the nearby IOC population (65 au ≲ q ≲ 100 au).

Orbit Determination of the Asteroid (469219) Kamoòalewa and Its Error Analysis

As an Earth co-orbital asteroid, (469219) Kamoòalewa is a near earth object (NEO) with high value of research, and one of the targets explored by the first Chinese asteroid exploration mission. Given its orbit characteristics, we build a refined dynamical model for this asteroid, in which the effects induced by nonspherical gravitational fields of the Sun, the Earth, and the Moon are combined. On the basis of the dynamical model of the asteroid (469219) Kamoòalewa, its orbit is determined with optical data from 2004 to 2018 available on the Minor Planet Center (MPC) database. The root mean square error of post-fit residuals is about 0.2 arc second (comparable with that of the Jet Propulsion Laboratory (JPL)/Horizons), and the post-fit residuals of optical observations in 2004 are decreased. At the end, we implement error analysis on the asteroid (469219) Kamoòalewa's orbit in detail, and also predict its orbit error at the time interval between 2020 and 2025.

The entry geometry and velocity of planetary debris into the Roche sphere of a white dwarf

ABSTRACT Our knowledge of white dwarf planetary systems predominately arises from the region within a few Solar radii of the white dwarfs, where minor planets breakup, form rings and discs, and accrete on to the star. The entry location, angle, and speed into this Roche sphere has rarely been explored but crucially determines the initial geometry of the debris, accretion rates on to the photosphere, and ultimately the composition of the minor planet. Here, we evolve a total of over 105 asteroids with single-planet N-body simulations across the giant branch and white dwarf stellar evolution phases to quantify the geometry of asteroid injection into the white dwarf Roche sphere as a function of planetary mass and eccentricity. We find that lower planetary masses increase the extent of anisotropic injection and decrease the probability of head-on (normal to the Roche sphere) encounters. Our results suggest that one can use dynamical activity within the Roche sphere to make inferences about the hidden architectures of these planetary systems.

How the formation of Neptune shapes the Kuiper belt

Hydrodynamical simulations predict the inward migration of giant planets during the gas phase of the protoplanetary disc. This phenomenon is also invoked to explain resonant and near-resonant exoplanetary system structures. The early inward migration may also have affected our Solar System and sculpted its different minor planet reservoirs. In this study we explore how the early inward migration of the giant planets shapes the Kuiper belt. We test different scenarios with only Neptune and Uranus and with all the four giant planets, also including some models with the subsequent outward planetesimal-driven migration of Neptune after the gas dispersal. We find objects populating mean motion resonances even when Neptune and Uranus do not migrate at all or only migrate inwards. When the planets are fixed, planetesimals stick only temporarily to the mean motion resonances, while inwards migration yields a new channel to populate the resonances without invoking convergent migration. However, in these cases, it is hard to populate mean motion resonances that do not cross the planetesimal disc (such as 2:1 and 5:2) and there is a lack of resonant Kuiper belt objects (KBOs) crossing Neptune’s orbit. These Neptune crossers are an unambiguous signature of the outward migration of Neptune. The starting position and the growth rate of Neptune have consequences for the contamination of the classical Kuiper belt region from neighbouring regions. The eccentricity and inclination space of the hot classical Kuiper belt objects and the scattered disc region become much more populated when all the giant planets are included. The 5:2 resonance with Neptune becomes increasingly populated with deeper inward migrations of Neptune. However, the overall inclination distribution is still narrower than suggested by observations, as is generally the case for Kuiper belt population models.

Apsidal asymmetric-alignment of Jupiter Trojans

ABSTRACT The most distant Kuiper belt objects exhibit the clustering in their orbits, and this anomalous architecture could be caused by Planet 9 with large eccentricity and high inclination. We then suppose that the orbital clustering of minor planets may be observed somewhere else in the Solar system. In this paper, we consider the over 7000 Jupiter Trojans from the Minor Planet Center, and find that they are clustered in the longitude of perihelion ϖ, around the locations ϖJ + 60○ and ϖJ − 60○ (ϖJ is the longitude of perihelion of Jupiter) for the L4 and L5 swarms, respectively. Then we build a Hamiltonian system to describe the associated dynamical aspects for the co-orbital motion. The phase space displays the existence of the apsidally aligned islands of libration centred on Δϖ = ϖ − ϖJ ≈ ±60○, for the Trojan-like orbits with eccentricities e < 0.1. Through a detailed analysis, we have shown that the observed Jupiter Trojans with proper eccentricities ep < 0.1 spend most of their time in the range of |Δϖ| = 0°–120○, while the more eccentric ones with ep > 0.1 are too few to affect the orbital clustering within this Δϖ range for the entire Trojan population. Our numerical results further prove that, even starting from a uniform Δϖ distribution, the apsidal alignment of simulated Trojans similar to the observation can appear on the order of the age of the Solar system. We conclude that the apsidal asymmetric-alignment of Jupiter Trojans is robust, and this new finding can be helpful to design the survey strategy in the future.

The population of near-earth asteroids revisited and updated

In this paper we update, extend, and improve upon the recent paper on Near-Earth Asteroid (NEA) population by Harris and D'Abramo (2015). We update the population estimate taking into account discoveries to August 3, 2020. Shortly after the previous paper was published, we identified a problem in our previous studies due to rounding off of absolute magnitude H by the Minor Planet Center to 0.1 magnitude that implicitly shifted our bin boundaries by 0.05 magnitude. Here we correct the problem by choosing H bin boundaries at 0.25–0.75 magnitude, rather than 0.00–0.50 magnitude thereby eliminating the round-off shift. We also introduce an updated model distribution of NEA orbits (Granvik et al. 2018) in our survey simulations. This new population model includes orbital distributions as a function of size, allowing us to test our presumption that distributions are homologous with respect to size. The change in distribution of orbits between that used by Harris and D'Abramo (2015) and the newer Granvik et al. (2018) distributions was substantially greater than the range over size given in the latter, but made almost no difference in population estimates, suggesting that the re-detection algorithm is robust and does not depend strongly on the detailed orbit distribution, and also validates our presumption of homologous distribution over size. For the current analysis, we have added ATLAS and Zwicky Transient Facility (ZTF) to our analysis. We have separately analyzed the re-detection ratio versus size (H magnitude) for each of four surveys (Catalina + Mt. Lemmon, Pan-STARRS, ATLAS and ZTF) to investigate any differences between the various systems and cadences, and found none of significance, thus again, the re-detection algorithm appears very robust and mostly independent of survey parameters. With these changes and more recent discovery statistics to 2020, we estimate the number of NEAs of absolute magnitude H < 17.75 (nominally D > 1 km) to be 940 ± 10. Following the updated population estimate, we examine more closely the rates of discovery of the largest NEAs (absolute magnitude H < 17.75, nominally diameter D > 1 km) to make a more detailed estimate of the numbers of these large objects that remain undiscovered. Lastly we use the distribution of albedos of NEAs from NEOWISE observations (Mainzer et al. 2011) to transform our population estimate from number versus H, N(<H), to number versus D, N(>D). Unfortunately this transformation depends substantially on only minor uncertainties in the albedo distribution, so N(>D) remains much less certain than N(<H).

Granular flow on a rotating and gravitating elliptical body

Abstract

A radiolytic origin of organic matter in primitive chondrites and trans-neptunian objects? New clues from ion irradiation experiments

We question here the radiolytic origin of (i) polyaromatic insoluble organic matter (IOM) recovered from primitive chondrites, and (ii) organics at the surface of reddish Trans-Neptunian Objects (TNOs), some minor planets and icy satellites. Organic synthesis by ion irradiation was investigated through experiments on a variety of targets: Polyethylene glycol 1450, lignin, cellulose and sucrose, exposed to low (C 40 keV and Ne 170 keV) and high energy (C 12 MeV, Ni 17 MeV, 78Kr 59 MeV) ions. These experiments show that all carbonaceous precursors evolve towards a sp2-rich amorphous carbon (a-C) above a critical nuclear dose of 10−7+10 eV.atom−1. A thorough review of the literature shows that this value applies for a large range of carbonaceous materials, including C-rich simple ices. Below this critical dose, irradiated targets are carbonized and transformed into cross-linked polymeric disordered solids, with abundant olefinic and acetylenic bonds, but devoid of aromatic or polyaromatic species. Ion irradiation of simple compounds, e.g. ices, is thereby not a viable process to synthesize IOM. However, in the case of aromatic-rich precursors, swift heavy ions irradiation leads to polyaromatic materials, by bridging existing aromatic or polyaromatic units. In the context of Early Solar System, i.e. Galactic Cosmic Rays (GCR) irradiation during 10–20 Myr, the formation of chondritic IOM from simple ices mixed with interstellar Polycyclic Aromatic Hydrocarbons (PAHs) appears as a plausible mechanism. This scenario, based on the recycling of existing carbonaceous interstellar grains under low-temperature conditions, would account for the heterogeneity of the D, 15N and 13C isotopic fractionations at the molecular scale, and the preservation of deuterium hot spots that are highly sensitive to high-temperature conditions (> 300 °C). At the surface of TNOs, sp2-rich amorphous carbons are formed by the implantation of GCRs and Solar wind ions. The electronic dose is also very high for an irradiation time of several Gyr (> 100 eV.atom−1), leading to the formation of reddish disordered solids, provided that the surface contains a minimum abundance of carbonaceous species. Finally, sp2-rich amorphous carbons produced in the laboratory (e.g. the ACAR compound from Zubko et al., 1996) are fair analogues of the darkening agent produced by radiolysis.

The Conductive Cooling of Planetesimals With Temperature‐Dependent Properties

AbstractModeling the planetary heat transport of small bodies in the early Solar System allows us to understand the geological context of meteorite samples. Conductive cooling in planetesimals is controlled by thermal conductivity, heat capacity, and density, which are functions of temperature (T). We investigate if the incorporation of the T‐dependence of thermal properties and the introduction of a nonlinear term to the heat equation could result in different interpretations of the origin of different classes of meteorites. We have developed a finite difference code to perform numerical models of a conductively cooling planetesimal with T‐dependent properties and find that including T‐dependence produces considerable differences in thermal history, and in turn the estimated timing and depth of meteorite genesis. We interrogate the effects of varying the input parameters to this model and explore the nonlinear T‐dependence of conductivity with simple linear functions. Then we apply non‐monotonic functions for conductivity, heat capacity, and density fitted to published experimental data. For a representative calculation of a 250 km radius pallasite parent body, T‐dependent properties delay the onset of core crystallization and dynamo activity by ∼40 Myr, approximately equivalent to increasing the planetary radius by 10%, and extend core crystallization by ∼3 Myr. This affects the range of planetesimal radii and core sizes for the pallasite parent body that are compatible with paleomagnetic evidence. This approach can also be used to model the T‐evolution of other differentiated minor planets and primitive meteorite parent bodies and constrain the formation of associated meteorite samples.