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- ID:
- ivo://CDS.VizieR/J/AJ/156/20
- Title:
- Astrometry of (486958) 2014 MU_69_ with HST
- Short Name:
- J/AJ/156/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NASA's New Horizons spacecraft will conduct a close flyby of the cold-classical Kuiper Belt Object (KBO) designated (486958) 2014 MU69 on 2019 January 1. At a heliocentric distance of 44 au, "MU69" will be the most distant object ever visited by a spacecraft. To enable this flyby, we have developed an extremely high-precision orbit fitting and uncertainty processing pipeline, making maximal use of the Hubble Space Telescope's Wide Field Camera 3 (WFC3) and pre-release versions of the ESA Gaia Data Release 2 (DR2) catalog. This pipeline also enabled successful predictions of a stellar occultation by MU69 in 2017 July. We describe how we process the WFC3 images to match the Gaia DR2 catalog, extract positional uncertainties for this extremely faint target (typically 140 photons per WFC3 exposure), and translate those uncertainties into probability distribution functions for MU69 at any given time. We also describe how we use these uncertainties to guide New Horizons, plan stellar occultions of MU69, and derive MU69's orbital evolution and long-term stability.
- ID:
- ivo://CDS.VizieR/J/AJ/152/80
- Title:
- Astrometry of Pluto and trans-Neptunian objects
- Short Name:
- J/AJ/152/80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use astrometry of Pluto and other trans-neptunian objects to constrain the sky location, distance, and mass of the possible additional planet (Planet Nine) hypothesized by Batygin & Brown. We find that over broad regions of the sky, the inclusion of a massive, distant planet degrades the fits to the observations. However, in other regions, the fits are significantly improved by the addition of such a planet. Our best fits suggest a planet that is either more massive or closer than argued for by Batygin & Brown based on the orbital distribution of distant trans-neptunian objects (or by Fienga et al. based on range measured to the Cassini spacecraft). The trend to favor larger and closer perturbing planets is driven by the residuals to the astrometry of Pluto, remeasured from photographic plates using modern stellar catalogs, which show a clear trend in decl. over the course of two decades, that drive a preference for large perturbations. Although this trend may be the result of systematic errors of unknown origin in the observations, a possible resolution is that the decl. trend may be due to perturbations from a body, in addition to Planet Nine, that is closer to Pluto but less massive than Planet Nine.
- ID:
- ivo://CDS.VizieR/J/AJ/149/22
- Title:
- Astrometry of Pluto from 1930-1951 observations
- Short Name:
- J/AJ/149/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new analysis of 843 photographic plates of Pluto taken by Carl Lampland at Lowell Observatory from 1930-1951. This large collection of plates contains useful astrometric information that improves our knowledge of Pluto's orbit. This improvement provides critical support to the impending flyby of Pluto by New Horizons. New Horizons can do inbound navigation of the system to improve its targeting. This navigation is capable of nearly eliminating the sky-plane errors but can do little to constrain the time of closest approach. Thus the focus on this work was to better determine Pluto's heliocentric distance and to determine the uncertainty on that distance with a particular eye to eliminating systematic errors that might have been previously unrecognized. This work adds 596 new astrometric measurements based on the USNO CCD Astrograph Catalog 4. With the addition of these data the uncertainty of the estimated heliocentric position of Pluto in Developmental Ephemerides 432 (DE432) is at the level of 1000km. This new analysis gives us more confidence that these estimations are accurate and are sufficient to support a successful flyby of Pluto by New Horizons.
- ID:
- ivo://CDS.VizieR/J/ApJ/743/1
- Title:
- Astrometry of seven wide trans-Neptunian binaries
- Short Name:
- J/ApJ/743/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The low-inclination component of the Classical Kuiper Belt is host to a population of extremely widely separated binaries. These systems are similar to other trans-Neptunian binaries (TNBs) in that the primary and secondary components of each system are of roughly equal size. We have performed an astrometric monitoring campaign of a sample of seven wide-separation, long-period TNBs and present the first-ever well-characterized mutual orbits for each system. The sample contains the most eccentric (2006 CH_69_, e_m_=0.9) and the most widely separated, weakly bound (2001 QW_322_, a/R_H_~0.22) binary minor planets known, and also contains the system with lowest-measured mass of any TNB (2000 CF_105_, M_sys_~1.85x10^17^kg). Four systems orbit in a prograde sense, and three in a retrograde sense. They have a different mutual inclination distribution compared to all other TNBs, preferring low mutual-inclination orbits. These systems have geometric r-band albedos in the range of 0.09-0.3, consistent with radiometric albedo estimates for larger solitary low-inclination Classical Kuiper Belt objects, and we limit the plausible distribution of albedos in this region of the Kuiper Belt. We find that gravitational collapse binary formation models produce an orbital distribution similar to that currently observed, which along with a confluence of other factors supports formation of the cold Classical Kuiper Belt in situ through relatively rapid gravitational collapse rather than slow hierarchical accretion. We show that these binary systems are sensitive to disruption via collisions, and their existence suggests that the size distribution of TNOs at small sizes remains relatively shallow.
- ID:
- ivo://CDS.VizieR/J/AJ/152/111
- Title:
- A 2011-2013 survey of trans-Neptunian objects
- Short Name:
- J/AJ/152/111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 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, a relative deficit of Neptunian trojans and scattering objects with diameters of D<100km has been detected. We investigated this deficit with a 32 square degree survey, in which we detected 77 TNOs that are brighter than a limiting r-band magnitude of 24.6. Our plutino sample (18 objects in 3:2 mean-motion resonance with Neptune) shows a deficit of D<100km objects, rejecting a single power-law size distribution at >99% confidence. Combining our survey with the Canada-France Ecliptic Plane Survey, we perform a detailed analysis of the allowable parameters for the plutino size distribution, including knees and divots. We surmise the existence of 9000+/-3000 plutinos with an absolute magnitude of H_r_{<=}8.66 and 37000_-10000_^+12000^ with H_r_{<=}10.0 (95% confidence). Our survey also discovered one temporary Uranian trojan, one temporary Neptunian trojan, and one stable Neptunian trojan, for which we estimate populations of 110_-100_^+500^, 210_-200_^+900^, and 150_-140_^+600^ with H_r_{<=}10.0, respectively. All three populations are thus less numerous than the main belt asteroids (592 asteroids with H_r_{<=}10.0). With such population sizes, the temporary Neptunian trojans cannot be previously stable trojans diffusing out of the resonance now; they must be recently captured Centaurs or scattering objects. As the bias against the detection of objects grows with larger semimajor axes, 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 is typically predicted.
- ID:
- ivo://CDS.VizieR/J/ApJS/247/13
- Title:
- ATLAS c-o colors and classification of asteroids
- Short Name:
- J/ApJS/247/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present here the c-o colors for identified Flora, Vesta, Nysa-Polana, Themis, and Koronis family members within the historic data set (2015-2018) of the Asteroid Terrestrial-impact Last Alert System (ATLAS). The Themis and Koronis families are known to be relatively pure C- and S-type Bus-DeMeo taxonomic families, respectively, and the extracted color data from the ATLAS broadband c- and o-filters of these two families are used to demonstrate that the ATLAS c-o color is a sufficient parameter to distinguish between the C- and S-type taxonomies. The Vesta and Nysa-Polana families are known to display a mixture of taxonomies possibly due to Vesta's differentiated parent body origin and Nysa-Polana actually consisting of two nested families with differing taxonomies. Our data show that the Flora family also displays a large degree of taxonomic mixing and the data reveal a substantial H-magnitude dependence on color. We propose and exclude several interpretations for the observed taxonomic mix. Additionally, we extract rotation periods of all of the targets reported here and find good agreement with targets that have previously reported periods.
- ID:
- ivo://CDS.VizieR/J/A+A/646/A132
- Title:
- beta Pictoris debris disk image
- Short Name:
- J/A+A/646/A132
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The nearby young star beta Pictoris hosts a rich and complex planetary system, with at least two giant planets and a nearly edge-on debris disk that contains several dynamical subpopulations of planetesimals. While the inner ranges of the debris disk have been studied extensively, less information is known about the outer, fainter parts of the disk. Here we present an analysis of archival FORS V-band imaging data from 2003-2004, which have previously not been explored scientifically because the halo substructure of the bright stellar point spread function is complex. Here we present the deepest imaging yet for the outer range of the beta Pic disk.
- ID:
- ivo://CDS.VizieR/J/A+A/380/347
- Title:
- BVRI photometry of 27 Kuiper Belt Objects
- Short Name:
- J/A+A/380/347
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present visible (BVRI) photometric measurements of 27 Trans-Neptunian objects, obtained with the FORS2 instrument on the ESO/8m Very Large Telescope (Unit 2) from runs during September and November 2000. The objects display a broad and continuous range of colors from neutral-bluish to very red. Most of the objects also have a linear reflectivity spectrum over the VRI range. There is no evidence of a bimodal color distribution as has been previously reported by other groups. Several objects (1994 TB, 1995 SM_55_, 1998 UR_43_, 1999CF_119_ and 2000 OK_67_) show evidence of changing color, and should be investigated further. The object 1995 SM_55_ deserves a more complete study since its neutral-blue colors suggest it could be a good candidate for hosting cometary activity.
- ID:
- ivo://CDS.VizieR/J/AJ/149/27
- Title:
- Cassini ISS astrometry of Saturnian satellites
- Short Name:
- J/AJ/149/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present numerically derived orbits and mass estimates for the inner Saturnian satellites, Atlas, Prometheus, Pandora, Janus, and Epimetheus from a fit to 2580 new Cassini Imaging Science Subsystem astrometric observations spanning 2004 February to 2013 August. The observations are provided as machine-readable and Virtual Observatory tables. We estimate GM_Atlas_=(0.384+/-0.001)x10^-3^km^3^/s^2^, a value 13% smaller than the previously published estimate but with an order of magnitude reduction in the uncertainty. We also find GM_Prometheus_=(10.677+/-0.006)x10^-3^km^3^/s^2^, GM_Pandora_=(9.133+/-0.009)x10^-3^km^3^/s^2^, GM_Janus_=(126.51+/-0.03)x10^-3^km^3^/s^2^, and GM_Epimetheus_=(35.110+/-0.009)x10^-3^km^3^/s^2^, consistent with previously published values, but also with significant reductions in uncertainties. We show that Atlas is currently librating in both the 54:53 co-rotation-eccentricity resonance (CER) and the 54:53 inner Lindblad (ILR) resonance with Prometheus, making it the latest example of a coupled CER-ILR system, in common with the Saturnian satellites Anthe, Aegaeon, and Methone, and possibly Neptune's ring arcs. We further demonstrate that Atlas's orbit is chaotic, with a Lyapunov time of ~10years, and show that its chaotic behavior is a direct consequence of the coupled resonant interaction with Prometheus, rather than being an indirect effect of the known chaotic interaction between Prometheus and Pandora. We provide an updated analysis of the second-order resonant perturbations involving Prometheus, Pandora, and Epimetheus based on the new observations, showing that these resonant arguments are librating only when Epimetheus is the innermost of the co-orbital pair, Janus and Epimetheus. We also find evidence that the known chaotic changes in the orbits of Prometheus and Pandora are not confined to times of apse anti-alignment.
