95 research outputs found
trippy: TRailed Image Photometry in Python
No full text<p>This is the first official release with the code and mechanisms published in the Astronomical Journal, main author Wesley Fraser.</p>
A carefully characterised trans-neptunian survey
No full textThe Trans-Neptunian objects (TNOs) preserve evidence of planet building processes in their orbital and size distributions. While all populations show steep size distributions for large objects, recently a relative deficit of Neptunian Trojans and scattering objects with diameters D99% confidence. The fact that three independent samples of three different populations show this trend suggests that it is a real feature, possibly shared by all hot TNO populations as a remnant of ''born big'' planetesimal formation processes. We surmise the existence of 9000 ± 3000 Plutinos with absolute magnitude Hr ≤ 8.66 and estimate 37000 +12000/-10000 Plutinos with Hr ≤ 10.0 (95% confidence ranges). Our survey also discovered one temporary Uranian Trojan, one temporary Neptunian Trojan and one stable Neptunian Trojan.
With these discoveries, combined with our survey characteristics, we derive populations of 110 +500/-100, 210 +900/-200 and 150 +600/-140 for these populations, respectively, with Hr ≤ 10.0.
With such approximately equal numbers, the temporary Neptunian Trojans cannot be previously stable Trojans that happen to be escaping the resonance now; they must be captured from another reservoir. Our population estimate also reveals that the Neptunian Trojans are less numerous than the main belt asteroids (semi-major axis 2.06<a<3.65), which has 592 asteroids with Hr ≤ 10.0. As the bias against detection of objects grows with larger semi-major axis, our discovery of three 3:1 resonators and one 4:1 resonator adds to the growing evidence that the high-order resonances are far more populated than can currently be explained theoretically.Science, Faculty ofPhysics and Astronomy, Department ofGraduat
The Outer Solar System Origin Survey full data release orbit catalog and characterization.
No full textInternational audienceThe Outer Solar System Origin Survey (OSSOS) completed main data acquisition in February 2017. Here we report the release of our full orbit sample, which include 836 TNOs with high precision orbit determination and classification. We combine the OSSOS orbit sample with previously release Canada-France Ecliptic Plane Survey (CFEPS) and a precursor survey to OSSOS by Alexandersen et al. to provide a sample of over 1100 TNO orbits with high precision classified orbits and precisely determined discovery and tracking circumstances (characterization). We are releasing the full sample and characterization to the world community, along with software for conducting ‘Survey Simulations’, so that this sample of orbits can be used to test models of the formation of our outer solar system against the observed sample. Here I will present the characteristics of the data set and present a parametric model for the structure of the classical Kuiper belt
The absolute magnitude distribution of cold classical Kuiper belt objects
No full textInternational audienceWe report measurements of the low inclination component of the main Kuiper Belt showing a size freqency distribution very steep for sizes larger than H_r ~ 6.5-7.0 and then a flattening to shallower slope that is still steeper than the collisional equilibrium slope.The Outer Solar System Origins Survey (OSSOS) is ongoing and is expected to detect over 500 TNOs in a precisely calibrated and characterized survey. Combining our current sample with CFEPS and the Alexandersen et al. (2015) survey, we analyse a sample of ~180 low inclination main classical (cold) TNOs, with absolute magnitude H_r (SDSS r' like flter) in the range 5 to 8.8. We confirm that the H_r distribution can be approximated by an exponential with a very steep slope (>1) at the bright end of the distribution, as has been recognized long ago. A transition to a shallower slope occurs around H_r ~ 6.5 - 7.0, an H_r mag identified by Fraster et al (2014). Faintward of this transition, we find a second exponential to be a good approximation at least until H_r ~ 8.5, but with a slope significantly steeper than the one proposed by Fraser et al. (2014) or even the collisional equilibrium value of 0.5.The transition in the cold TNO H_r distribution thus appears to occur at larger sizes than is observed in the high inclination main classical (hot) belt, an important indicator of a different cosmogony for these two sub-components of the main classical Kuiper belt. Given the largish slope faintward of the transition, the cold population with ~100 km diameter may dominate the mass of the Kuiper belt in the 40 AU < a < 47 au region
Discovery of 128 New Saturnian Irregular Moons
No full textInternational audienceAbstract We highlight the announcement by the IAU Minor Planet Center of 128 new irregular moons of Saturn discovered in our CFHT imaging acquired in 2023. We were able to link 83 of the new moons to detections from our earlier 2019–2021 study. Of the 58 new retrograde moons with multiyear arcs, 46 are likely in the Mundilfari subgroup. This large fraction is in line with the steep size distribution of the subgroup and the idea that it was created by a recent collision. Also, by more than tripling the number of Kiviuq subgroup members, the new discoveries have confirmed that this subgroup is a very tightly grouped collisional family, although likely much older
FOSSIL. III. Lightcurves of 371 Trans-Neptunian Objects
No full textFrom the first phase of the high-cadence Formation of the Outer Solar System: an Icy Legacy (FOSSIL) survey, we analyzed lightcurves, ranging from one to four nights in length, of 371 trans-Neptunian objects (TNOs) for periodicity. We found 29 TNOs with periodic lightcurves, one of which is a good candidate for a close/contact binary. Another of the periodic FOSSIL TNOs could potentially have the fastest of all known TNO spin rates, with a period of 1.3 hr. We do not have total confidence in the period and thus plan to obtain a more detailed lightcurve for confirmation. The periodic TNOs have an average rotation period of 11.2 hr, close to the value obtained by Alexandersen et al., which had similar cadence, but different from other surveys. In regards to contention in the literature about whether smaller TNOs are more irregular in shape and thus have larger lightcurve amplitudes, we found that there is a weak correlation between absolute magnitude and lightcurve amplitude in a subset of 194 FOSSIL TNOs, even when using the more appropriate brightest (minimum) absolute magnitude instead of the time-averaged value
Col-OSSOS: Probing Ice Line/Colour Transitions within the Kuiper Belt's Progenitor Populations
No full textInternational audienceThe Colours of the Outer Solar System Origins Survey (Col-OSSOS, Schwamb et al., 2019) has examined the surface compositions of Kuiper Belt Objects (KBOs) by way of broadband g-, r- and J-band photometry, using the Gemini North Hawaii Telescope. This survey showed a bimodal distribution in the colours of the objects surveyed, consistent with previous colour surveys (Tegler et al., 2016). These broadband surface colours can be considered a proxy for surface composition of these KBOs, so this survey allows the frequency of different surface compositions within the outer Solar System to be explored. The bimodality of the observed colours suggests the presence of some sort of surface transition within the Kuiper belt, perhaps due to a volatile ice-line transition in the pristine planetesimal disk that existed before Neptune"s migration. The Outer Solar System Origins Survey (OSSOS, Bannister et al., 2018), from which Col-OSSOS selected objects brighter than 23.6 r-band magnitude, has well characterised and quantified biases, so allowing for comparisons between the observations and numerical models of the Kuiper belt.By applying different colour transitions to the primordial planetesimal disk, in this work we explore the possible positions for ice line/colour transitions within the planetesimal disk that existed before Neptune"s migration. Within Schwamb et al. (2019), a simplified toy model was used to investigate the possible position of this transition. Nesvorny et al. (2020) has investigated the primordial colour fraction, in particular how it can create the inclination distribution that we see in the colours of KBOs today. In this work we use a full dynamical model of the Kuiper belt to more precisely pinpoint the possible location of this transition. We make use of the model by Nesvorny & Vokrouhlicky (2016) of Neptune"s migration from 23 au to 30 au, and the consequent perturbation of the Kuiper belt into its current form. This model allows precise tracking of the objects from their pre-Neptune migration to post-Neptune migration positions, allowing various colour transition positions in the initial disk, an example of which is shown in Figure 1, to be compared with the Col-OSSOS observations of the modern day disk.Figure 1: An example red/neutral transition at 27 au. The left plots show the objects in the primordial disk, while the right plots show the objects post-Neptune migration from the model of Nesvorny & Vokrouhlicky (2016).The OSSOS survey simulator (Lawler et al., 2018) can then be used to calculate which of the simulated objects could have been observed by OSSOS, and so selected by Col-OSSOS for surface colour observations. The colour transition within the initial disk, shown in Figure 1, is moved radially outwards through the disk and the corresponding outputs are compared with the Col-OSSOS colour observations to see which initial disk colour transition positions are consistent with the modern day Kuiper belt. We will present results combing an accurate dynamical model of the Kuiper Belt"s evolution by Nesvorny & Vokrouhlicky (2016) with Col-OSSOS photometry. We will explore multiple radial colour distributions in the primordial planetesimal disk and implications for the the positions of ice line/colour transitions within the Kuiper Belt"s progenitor populations. ReferencesBannister, M. T., Gladman, B. J., Kavelaars, J. J., et al. 2018, ApJS, 236, 18Lawler, S. M., Kavelaars, J. J., Alexandersen, M., et al. 2018, Front. Astron. Space Sci., 5, 14Nesvorny, D., Vokrouhlicky, D., Alexandersen, M., et al. 2020, AJ, in pressNesvorny, D., & Vokrouhlicky, D. 2016, ApJ, 825Schwamb, M. E., Bannister, M. T., Marsset, M., et al. 2019, ApJS, 243, 12Tegler, S. C., Romanishin, W., Consolmagno, G. J., & J., S. 2016, AJ, 152, 21
A CAREFULLY CHARACTERIZED AND TRACKED TRANS-NEPTUNIAN SURVEY: THE SIZE DISTRIBUTION OF THE PLUTINOS AND THE NUMBER OF NEPTUNIAN TROJANS
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