2014 PN70, imaged by the Hubble Space Telescope in May 2015
|Discovered by||Hubble Space Telescope|
|Discovery site||Earth's orbit|
|Discovery date||6 August 2014|
(first observed only)
|MPC designation||2014 PN70|
|g12000JZ · g1 · PT3 |
|TNO  · cubewano |
|Orbital characteristics |
|Epoch 4 September 2017 (JD 2458000.5)|
|Uncertainty parameter 5|
|Observation arc||yr (77 days)|
|295.37 yr (107,886 d)|
|0° 0m 11.88s / day|
39 km (estimate)
44 km (est. at 0.07)
2014 PN70, internally designated g12000JZ, g1 and PT3, is a trans-Neptunian object from the cold classical Kuiper belt located in the outermost region of the Solar System. It measures approximately 40 kilometers in diameter. The object was first observed by the Hubble Space Telescope on 6 August 2014, and was a proposed flyby target for the New Horizons probe until 2015, when the alternative target 2014 MU69 was definitively selected.
Discovery and designations
2014 PN70 was discovered during an observation campaign intended to search for KBO flyby targets for the New Horizons probe. The observations started in June 2014, and more intensive ones continued in July and August. They were conducted with the help of the Hubble Space Telescope; the object's apparent magnitude of 26.4 is too faint to be observed by ground-based telescopes. 2014 PN70 was first discovered in observations on August 6, 2014, and it was designated g12000JZ at the time, nicknamed g1 for short. Its existence as a potential target of the New Horizons probe was revealed by NASA in October 2014 and it was designated PT3; its official provisional designation, 2014 PN70, was not assigned by the Minor Planet Center until March 2015 after better orbit information was available.
Orbit and classification
2014 PN70 is a trans-Neptunian object. More specifically, it is a non-resonant classical Kuiper belt object, also known as "cubewano". It orbits the Sun at a distance of 42.1–46.6 AU once every 295 years and 4 months (107,886 days; semi-major axis of 44.4 AU). Its orbit has an eccentricity of 0.05 and an inclination of 4° with respect to the ecliptic. This makes it a typical member of the "cold population" among the cubewanos in the Kuiper belt.
The body's observation arc begins with a precovery taken by the New Horizons KBO Search team with the Subaru Telescope at Mauna Kea Observatory on Hawaii, six week prior to its official first observation by Hubble.
2014 PN70, has a diameter approximately 35–55 km (22–34 mi), based on an estimated albedo between 0.04 and 0.10. Astronomer Marc Buie gives a similar estimate of 30–55 km (19–34 mi), and the Johnston's archive calculated a diameter of 39 km. Based on generic magnitude-to-diameter conversion, the object measures 44 km, for an absolute magnitude of 10.3 and an assumed albedo of 0.07.
Having completed its flyby of Pluto, the New Horizons space probe will be maneuvered to a flyby of at least one Kuiper belt object. Several potential targets were under consideration. 2014 PN70 (PT3) was considered a second choice after 2014 MU69 (PT1), because more fuel was required to carry out a flyby. 2014 OS393 (PT2) was already no longer under consideration as a potential target. On 28 August 2015, the New Horizons team announced the selection of 2014 MU69 as the next flyby target.
2014 PN70 is one of the objects that New Horizons will observe from greater distances, as part of its extended Kuiper belt mission. The spacecraft will pass 2014 PN70 in March 2019, at a distance of approximately 0.1 AU (15 million km, 9.3 million miles). This will make 2014 PN70 the third closest KBO observed by New Horizons, after 2014 MU69 and 2014 OS393. New Horizons will not come close enough to resolve either 2014 PN70 or 2014 OS393, but the observations can be used to determine the rotation periods and surface properties of these objects, and look for possible satellites. The distant KBO observations provide an important context for the data collected during the close flyby of 2014 MU69. At its closest approach, 2014 PN70 will appear to be between 0.4 and 0.75 arcseconds across, roughly the apparent size of Ceres from Earth.
Numbering and naming
- "2014 PN70". Minor Planet Center. Retrieved 9 February 2018.
- Zangari, Amanda (March 28, 2015). "Postcards from Pluto". Tumblr.
- "JPL Small-Body Database Browser: (2014 PN70)" (2014-10-22 last obs.). Jet Propulsion Laboratory. Retrieved 9 February 2018.
- Marc W. Buie. "Orbit Fit and Astrometric record for 14PN70". SwRI (Space Science Department). Retrieved 2018-02-18.
- Johnston, Wm. Robert (30 December 2017). "List of Known Trans-Neptunian Objects". Johnston's Archive. Retrieved 9 February 2018.
- Buie, Marc (October 15, 2014). "New Horizons HST KBO Search Results: Status Report" (PDF). Space Telescope Science Institute. p. 23.
- Lakdawalla, Emily (October 15, 2014). "Finally! New Horizons has a second target". Planetary Society blog. Planetary Society. Archived from the original on October 15, 2014.
- "Asteroid Size Estimator". CNEOS NASA/JPL. Retrieved 9 February 2018.
- J. R. Spencer; M. W. Buie; et al. (2015). "The Successful Search for a Post-Pluto KBO Flyby Target for New Horizons Using the Hubble Space Telescope" (PDF). European Planetary Science Congress (EPSC) Abstract. Copernicus Office.
- "Hubble to Proceed with Full Search for New Horizons Targets". HubbleSite news release. Space Telescope Science Institute. July 1, 2014.
- "NASA's Hubble Telescope Finds Potential Kuiper Belt Targets for New Horizons Pluto Mission". HubbleSite. 15 October 2014.
- Wall, Mike (October 15, 2014). "Hubble Telescope Spots Post-Pluto Targets for New Horizons Probe". Space.com. Archived from the original on October 15, 2014.
- Powell, Corey S. (March 29, 2015). "Alan Stern on Pluto's Wonders, New Horizons' Lost Twin, and That Whole "Dwarf Planet" Thing". Discover.
- Cofield, Calla (28 August 2015). "Beyond Pluto: 2nd Target Chosen for New Horizons Probe". Space.com.
- S. A. Stern; H. A. Weaver; J. R. Spencer; H. A. Elliott (2016). "The New Horizons Kuiper Belt Extended Mission" (PDF). arXiv.org.
- Alan Stern (14 April 2016). "To Boldly Go On, In the Service of Exploration". pluto.jhuapl.edu. Retrieved 22 September 2018.
- OPAG: We Did It!, p.33, Presentation to the Outer Planets Assessment Group, Alan Stern
- 2014 PN70 at the JPL Small-Body Database