<p>The <code>3713011</code> object (that is the internal SPICE/SPK id) is a special trajectory computed by the New Horizons team at SwRI which included data which is not in the public domain. The other one for <code>(486958) 2014 MU69</code> (its official asteroid number and temporary discovery designation) is for the publicly available data.</p>

<p>Generating an ephemeris in HORIZONS for the former produces:</p>

<pre><code> Revised: Dec 29, 2018            486958 (2014 MU69)                    2486958
 *SPECIAL*

 This pre-computed trajectory is consistent with the New Horizons spacecraft
 Kuiper-Belt extended mission, with the planned 3500 km flyby of Ultima Thule
 on 2019-Jan-1 @ 05:33 UTC.

 Trajectories were provided by the New Horizons mission planning team at SWRI 
 and are fits to internal flight-project data that has not been made available 
 outside the flight project.

 To use this official mission trajectory to ...

  A) Generate ephemerides with respect TO the mission target:
      Specify the coordinate center in Horizons as "@2486958" 

  B) Generate ephemerides OF the mission target
      Specify the target in Horizons as "2486958". 

 To instead use the latest JPL ground-based orbit solution (based on the 
 publicly available data) and numerically integrate over an arbitrary 
 time-span with statistical uncertainties of that public dataset, do a 
 look-up in Horizons with syntax "2014 MU69;" or "486958;" or "DES= 2486958;" 
 or "DES= 2014 MU69" or "2486958;" (i.e., with a semi-colon). 

 Note: the object previously had a provisional SPK ID of 3713011.  It was 
 then assigned an IAU number of 486958 such that the primary SPK ID became
 the present 2486958 (2000000 + IAU number).

 Trajectory name                            Start (TDB)         Stop (TDB)
 ---------------------------------------  -----------------  -----------------
 20180601_20250101_od141_tcm30_burn_V0.1  1994-Jan-08 00:00  2033-Dec-21 00:00 
</code></pre>

<p>(486958) is 2014 MU69's official number and is used at e.g the <a href="https://minorplanetcenter.net/db_search/show_object?utf8=%E2%9C%93&amp;object_id=486958" rel="nofollow noreferrer">MPC</a>. 3713011 and 2486958 are the JPL SPK id's for the kernels with and without the extra trajectory information respectively; they are not used outside JPL's software such as HORIZONS, Small Body Browser or the SPICE toolkit. <a href="ftp://naif.jpl.nasa.gov/pub/naif/toolkit_docs/Tutorials/pdf/individual_docs/18_spk.pdf" rel="nofollow noreferrer">Tutorial 18</a> of the SPICE Tutorial covers SPK files if you want more details. </p>

<p>The JPL software system handles multiple versions of the trajectory and/or orbital elements by creating multiple "bodies" for the same object. This is most commonly seen with comets which have 1 or more orbital elements for each perihelion passage e.g. this screenshot for comet 46P (Wirtanen):
<a href="https://i.sstatic.net/p2y7T.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/p2y7T.png" alt="Screenshot of JPL HORIZONS showing multiple element sets/&quot;bodies&quot;"></a> </p>

CC BY-SA 4.0
2019-02-11T06:55:39.847Z
(486958) is 2014 MU69's official number and is used at e.g the [MPC](https://minorplanetcenter.net/db_search/show_object?utf8=✓&object_id=486958). 3713011 and 2486958 are the JPL SPK id's for with and without the extra trajectory information respectively; they are not used outside JPL's software such as HORIZONS, Small Body Browser or SPICE.
astrosnapper
CC BY-SA 4.0
2019-02-11T03:06:22.327Z
2019-02-11T17:26:33.487Z
2019-02-11T17:26:33.487Z
astrosnapper
<p><a href="https://space.stackexchange.com/a/34094/12102">In this answer</a> I show that the (now pretty famous) Kuiper Belt Object <code>2014-MU69</code> has two entries in JPL's ephemeris generating Horizons site; Major Body <code>3713011</code> and Small Body <code>486958</code>. I'm pretty sure these represent the same body, their trajectories differ by about a half-million kilometers only, and that difference is probably only because for one of them the trajectory is only based on a 118 day arc of it's ~100,000 day orbit at ~43 AU back in 2015.</p>

<p>Are both <code>3713011</code> and <code>486958</code> still official references to the same body, but in different catalogs or databases? Is there a disambiguation page linking the two numbers somewhere? How did 2014-MU69 (unofficially <em>Ultima Thule</em>) get promoted from SB to MB?</p>

<blockquote>
  <p><a href="https://i.sstatic.net/OuX4K.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/OuX4K.png" alt="enter image description here"></a></p>
</blockquote>

<asteroids><terminology><nasa><kbo>
Does the KBO 2014-MU69 have two numbers and entries in asteroid databases? How did it get promoted to Major Body designation?
uhoh
# Does the KBO 2014-MU69 have two numbers and entries in asteroid databases? How did it get promoted to Major Body designation?

(Asked by: username_0 on 2019-02-11)

[In this answer](https://space.stackexchange.com/a/34094/12102) I show that the (now pretty famous) Kuiper Belt Object `2014-MU69` has two entries in JPL's ephemeris generating Horizons site; Major Body `3713011` and Small Body `486958`. I'm pretty sure these represent the same body, their trajectories differ by about a half-million kilometers only, and that difference is probably only because for one of them the trajectory is only based on a 118 day arc of it's ~100,000 day orbit at ~43 AU back in 2015.

Are both `3713011` and `486958` still official references to the same body, but in different catalogs or databases? Is there a disambiguation page linking the two numbers somewhere? How did 2014-MU69 (unofficially *Ultima Thule*) get promoted from SB to MB?

> [![enter image description here](https://i.sstatic.net/OuX4K.png)](https://i.sstatic.net/OuX4K.png)

**Tags:** asteroids, terminology, nasa, kbo


---

## 1 answers

### Answer by username_1 on 2019-02-11. Score: 3 | Accepted answer

The `3713011` object (that is the internal SPICE/SPK id) is a special trajectory computed by the New Horizons team at SwRI which included data which is not in the public domain. The other one for `(486958) 2014 MU69` (its official asteroid number and temporary discovery designation) is for the publicly available data.

Generating an ephemeris in HORIZONS for the former produces:

```
 Revised: Dec 29, 2018            486958 (2014 MU69)                    2486958
 *SPECIAL*

 This pre-computed trajectory is consistent with the New Horizons spacecraft
 Kuiper-Belt extended mission, with the planned 3500 km flyby of Ultima Thule
 on 2019-Jan-1 @ 05:33 UTC.

 Trajectories were provided by the New Horizons mission planning team at SWRI 
 and are fits to internal flight-project data that has not been made available 
 outside the flight project.

 To use this official mission trajectory to ...

  A) Generate ephemerides with respect TO the mission target:
      Specify the coordinate center in Horizons as "@2486958" 

  B) Generate ephemerides OF the mission target
      Specify the target in Horizons as "2486958". 

 To instead use the latest JPL ground-based orbit solution (based on the 
 publicly available data) and numerically integrate over an arbitrary 
 time-span with statistical uncertainties of that public dataset, do a 
 look-up in Horizons with syntax "2014 MU69;" or "486958;" or "DES= 2486958;" 
 or "DES= 2014 MU69" or "2486958;" (i.e., with a semi-colon). 

 Note: the object previously had a provisional SPK ID of 3713011.  It was 
 then assigned an IAU number of 486958 such that the primary SPK ID became
 the present 2486958 (2000000 + IAU number).

 Trajectory name                            Start (TDB)         Stop (TDB)
 ---------------------------------------  -----------------  -----------------
 20180601_20250101_od141_tcm30_burn_V0.1  1994-Jan-08 00:00  2033-Dec-21 00:00 

```

(486958) is 2014 MU69's official number and is used at e.g the [MPC](https://minorplanetcenter.net/db_search/show_object?utf8=%E2%9C%93&object_id=486958). 3713011 and 2486958 are the JPL SPK id's for the kernels with and without the extra trajectory information respectively; they are not used outside JPL's software such as HORIZONS, Small Body Browser or the SPICE toolkit. [Tutorial 18](ftp://naif.jpl.nasa.gov/pub/naif/toolkit_docs/Tutorials/pdf/individual_docs/18_spk.pdf) of the SPICE Tutorial covers SPK files if you want more details.

The JPL software system handles multiple versions of the trajectory and/or orbital elements by creating multiple "bodies" for the same object. This is most commonly seen with comets which have 1 or more orbital elements for each perihelion passage e.g. this screenshot for comet 46P (Wirtanen):
[![Screenshot of JPL HORIZONS showing multiple element sets/"bodies"](https://i.sstatic.net/p2y7T.png)](https://i.sstatic.net/p2y7T.png)

> **Comments:**
> **username_1**: (486958) is 2014 MU69's official number and is used at e.g the [MPC](https://minorplanetcenter.net/db_search/show_object?utf8=✓&object_id=486958). 3713011 and 2486958 are the JPL SPK id's for with and without the extra trajectory information respectively; they are not used outside JPL's software such as HORIZONS, Small Body Browser or SPICE.  

---

