- 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.
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- ID:
- ivo://CDS.VizieR/J/A+AS/115/295
- Title:
- Astrometry of outer Jovian satellites
- Short Name:
- J/A+AS/115/295
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the course of The Uppsala-ESO Survey of Asteroids and Comets astrometric positions of the faint outer Jovian satellites J VI-XIII were obtained from photographic plates and films taken at the European Southern Observatory, La Silla, Chile and at the Anglo-Australian Observatory, Siding Spring, Australia
- ID:
- ivo://CDS.VizieR/J/A+A/383/1054
- Title:
- Astrometry of Pluto and Saturn in 1995-2001
- Short Name:
- J/A+A/383/1054
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work, we publish astrometric positions of Pluto and satellites of Saturn obtained with the Bordeaux and Valinhos CCD meridian circles. These observations are used to test the DE403 and DE405 ephemerides.
- 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/A+AS/130/77
- Title:
- Astrometry of Satellites of Uranus
- Short Name:
- J/A+AS/130/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Table7 contains standard Co-ordinates (J2000.0) in arcseconds relative to the reference satellite. The numbers of the satellites 1-5 correspond to the conventional designation of the satellites I-V.
- 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/other/PSS/210.1
- Title:
- Astrometry of the 5 largest Uranian sat.
- Short Name:
- J/other/PSS/210.
- Date:
- 14 Dec 2021 08:12:44
- Publisher:
- CDS
- Description:
- We present the astrometry of the five largest satellites of Uranus from observations spread over almost three decades with photographic plates and CCDs (mainly), taken at the Pico dos Dias Observatory - Brazil. All positions presented here are obtained from the reanalysis of measurements and images used in previous publications. Reference stars are those from the Gaia Early Data Release 3 (Gaia EDR3) allowing, in addition to a higher accuracy, a larger number of positions of the largest satellites as compared to our previous works. From 1982 to 1987, positions were obtained from photographic plates. From 1989 to 2011, CCDs were used. On average, we obtained {Delta}{alpha}cos{delta}=-11(+/-52) milli-arcseconds and {delta}{delta}=-14 (+/-43) milli-arcseconds for the differences in the sense observation minus ephemerides (DE435+ura111). Comparisons with different ephemerides (DE440, INPOP21a, INPOP19a and NOE-7-2013-MAIN) and results from stellar occultations indicate a possible offset in the (Solar System) barycentric position of the Uranian system barycenter. Overall, our results are useful to improve dynamical models of the Uranian largest satellites as well as the orbit of Uranus.
- ID:
- ivo://CDS.VizieR/J/A+A/582/A8
- Title:
- Astrometry of the main satellites of Uranus
- Short Name:
- J/A+A/582/A8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We determine accurate positions of the main satellites of Uranus: Miranda, Ariel, Umbriel, Titania, and Oberon. Positions of Uranus, as derived from those of these satellites, are also determined. The observational period spans from 1992 to 2011. All runs were made at the Pico dos Dias Observatory, Brazil. We used the software called Platform for Reduction of Astronomical Images Automatically (PRAIA) to perform a digital coronography to minimise the influence of the scattered light of Uranus on the astrometric measurements and to determine accurate positions of the main satellites. The positions of Uranus were then indirectly determined by computing the mean differences between the observed and ephemeris positions of these satellites. A series of numerical filters was applied to filter out spurious data. These filters are mostly based on (a) the comparison between the positions of Oberon with those of the other satellites and on (b) the offsets as given by the differences between the observed and ephemeris positions of all satellites. We have, for the overall offsets of the five satellites, -29mas (+/-63mas) in right ascension and -27mas (+/-46mas) in declination. For the overall difference between the offsets of Oberon and those of the other satellites, we have +3mas (+/-30mas) in right ascension and -2mas (+/-28mas) in declination. Ephemeris positions for the satellites were determined from DE432+ura111.
- ID:
- ivo://CDS.VizieR/J/A+A/575/A73
- Title:
- Astrometry of the Saturnian satellites 2004-12
- Short Name:
- J/A+A/575/A73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Cassini spacecraft has been orbiting Saturn since 2004 returning images of satellites with astrometric resolution as high as few hundreds of meters. The images that were taken by the Narrow Angle Camera (NAC) of Image Science Subsystem (ISS) instrument on board Cassini, were used in this work for the purpose of astrometry. We applied the same method that was previously developed to reduce Cassini NAC images of Mimas and Enceladus. We provide 5240 astrometric positions in right ascension and declination of the satellites: Tethys, Dione, Rhea, Iapetus, and Phoebe, using images that were taken by Cassini NAC between 2004 and 2012. Mean residuals compared to the JPL ephemeris SAT365 are of the order of hundreds of meters with standard deviations of the order of few kilometers. Frequency analysis of the residuals shows the remaining non-modeled effects of satellites on others.
