# List of unnumbered minor planets: 2004 Y

This is a partial list of unnumbered minor planets for principal provisional designations assigned during 16–31 December 2004. As of February 2022, a total of 156 bodies remain unnumbered for this period. Objects for this year are listed on the following pages: A–B · C · D–E · F · G–H · J–O · P–Q · R$_i$ · R$_{ii}$ · R$_{iii}$ · S · T$_i$ · T$_{ii}$ · T$_{iii}$ · T$_{iv}$ · U–V · W–X and Y. Also see previous and next year.
| Near-Earth obj. | MBA (inner) | MBA (outer) | Centaur |
| Mars-crosser | MBA (middle) | Jupiter trojan | Trans-Neptunian obj. |
| Unclassified | | | |

## Y

| U | Designation | Class | Physical | Physical | Observations | Observations | Observations | Observations | Description and notes | Ref |
| U | Designation | Class | H | D | Opp. | Arc | Last | Used | Description and notes | Ref |
| 8 | 2004 YA | APO | 24.9 | 37 m | single | 2 days | 18 Dec 2004 | 19 | Disc.: LINEAR | MPC · JPL |
| 8 | 2004 YC | ATE | 25.6 | 27 m | single | 5 days | 19 Dec 2004 | 35 | Disc.: LINEAR | MPC · JPL |
| 8 | 2004 YD | ATE | 24.0 | 56 m | single | 9 days | 26 Dec 2004 | 22 | Disc.: LONEOS | MPC · JPL |
| 6 | 2004 YE | AMO | 24.9 | 37 m | single | 19 days | 03 Jan 2005 | 21 | Disc.: LINEAR | MPC · JPL |
| 1 | 2004 YL | HUN | 18.3 | 650 m | multiple | 2004–2019 | 05 Jul 2019 | 43 | Disc.: LINEAR Alt.: 2014 NP49 | MPC · JPL |
| 8 | 2004 YQ | APO | 24.4 | 47 m | single | 2 days | 20 Dec 2004 | 18 | Disc.: LINEAR | MPC · JPL |
| 1 | 2004 YR | APO | 20.3 | 310 m | multiple | 2004–2014 | 01 Jul 2014 | 134 | Disc.: LINEAR | MPC · JPL |
| 2 | 2004 YG1 | APO | 21.4 | 190 m | multiple | 2004–2013 | 02 Aug 2013 | 94 | Disc.: LINEAR | MPC · JPL |
| 0 | 2004 YH1 | MCA | 17.55 | 920 m | multiple | 2004–2022 | 06 Jan 2022 | 58 | Disc.: LINEAR | MPC · JPL |
| 5 | 2004 YJ1 | AMO | 20.7 | 260 m | single | 15 days | 02 Jan 2005 | 51 | Disc.: LINEAR | MPC · JPL |
| 1 | 2004 YK1 | AMO | 21.3 | 200 m | multiple | 2004–2018 | 20 Mar 2018 | 47 | Disc.: LINEAR | MPC · JPL |
| 0 | 2004 YX1 | MCA | 17.90 | 1.1 km | multiple | 2004–2021 | 28 Nov 2021 | 116 | Disc.: MLS | MPC · JPL |
| 0 | 2004 YX4 | MBA-M | 16.94 | 2.3 km | multiple | 2004–2021 | 09 Sep 2021 | 64 | Disc.: KLENOT Alt.: 2010 KR65 | MPC · JPL |
| 9 | 2004 YA5 | ATE | 22.6 | 110 m | single | 13 days | 31 Dec 2004 | 30 | Disc.: LINEAR | MPC · JPL |
| – | 2004 YB5 | MCA | 18.0 | 1.4 km | single | 2 days | 21 Dec 2004 | 28 | Disc.: LINEAR | MPC · JPL |
| 6 | 2004 YD5 | APO | 29.3 | 5 m | single | 1 day | 21 Dec 2004 | 21 | Disc.: Spacewatch | MPC · JPL |
| 0 | 2004 YW5 | MCA | 19.12 | 450 m | multiple | 2004–2022 | 08 Jan 2022 | 79 | Disc.: Spacewatch | MPC · JPL |
| 0 | 2004 YE8 | MBA-O | 16.4 | 2.9 km | multiple | 2004–2020 | 20 Dec 2020 | 83 | Disc.: MLS | MPC · JPL |
| 0 | 2004 YN11 | MBA-O | 17.4 | 1.8 km | multiple | 2004–2019 | 24 Sep 2019 | 35 | Disc.: MLS | MPC · JPL |
| 0 | 2004 YU12 | MBA-O | 17.5 | 1.8 km | multiple | 2004–2020 | 14 Nov 2020 | 62 | Disc.: MLS | MPC · JPL |
| 0 | 2004 YD13 | MBA-I | 18.4 | 620 m | multiple | 2004–2018 | 10 Dec 2018 | 25 | Disc.: MLS | MPC · JPL |
| 0 | 2004 YZ13 | MBA-O | 17.42 | 1.8 km | multiple | 2004–2022 | 12 Jan 2022 | 59 | Disc.: MLS Added on 21 August 2021 Alt.: 2010 BH46, 2015 XP371 | MPC · JPL |
| 5 | 2004 YF15 | JT | 13.8 | 9.7 km | multiple | 2004–2017 | 31 Jan 2017 | 24 | Disc.: MLS Trojan camp (L5) Alt.: 2017 BN37 | MPC · JPL |
| 0 | 2004 YK15 | JT | 14.2 | 8.0 km | multiple | 2004–2020 | 21 Jun 2020 | 54 | Disc.: MLS Added on 17 January 2021 Trojan camp (L5) | MPC · JPL |
| 0 | 2004 YS15 | MBA-O | 16.87 | 2.4 km | multiple | 2004–2021 | 17 Apr 2021 | 71 | Disc.: MLS | MPC · JPL |
| 0 | 2004 YU15 | MBA-O | 17.5 | 1.8 km | multiple | 2002–2021 | 13 Feb 2021 | 35 | Disc.: MLS Added on 11 May 2021 | MPC · JPL |
| 0 | 2004 YC17 | MBA-M | 17.01 | 1.7 km | multiple | 2004–2022 | 27 Jan 2022 | 183 | Disc.: MLS Alt.: 2010 LG101 | MPC · JPL |
| 0 | 2004 YD17 | MBA-M | 17.2 | 1.5 km | multiple | 2004–2020 | 12 Sep 2020 | 86 | Disc.: MLS | MPC · JPL |
| 0 | 2004 YX17 | MBA-M | 17.50 | 940 m | multiple | 1999–2022 | 26 Jan 2022 | 98 | Disc.: MLS Alt.: 2012 XC157 | MPC · JPL |
| 0 | 2004 YX18 | MBA-M | 17.59 | 1.7 km | multiple | 2004–2021 | 11 Sep 2021 | 61 | Disc.: MLS Alt.: 2013 YE106 | MPC · JPL |
| 4 | 2004 YY23 | AMO | 19.4 | 470 m | single | 44 days | 04 Feb 2005 | 157 | Disc.: CSS | MPC · JPL |
| 2 | 2004 YN24 | MBA-M | 17.8 | 820 m | multiple | 2000–2021 | 09 Jan 2021 | 77 | Disc.: Spacewatch Added on 17 January 2021 Alt.: 2009 AG34 | MPC · JPL |
| 0 | 2004 YY24 | MBA-M | 17.41 | 1.4 km | multiple | 2004–2022 | 04 Jan 2022 | 94 | Disc.: MLS | MPC · JPL |
| 0 | 2004 YJ25 | MBA-I | 18.28 | 660 m | multiple | 2004–2021 | 07 Oct 2021 | 47 | Disc.: MLS | MPC · JPL |
| 0 | 2004 YT25 | MBA-M | 17.8 | 1.2 km | multiple | 2004–2020 | 16 Oct 2020 | 67 | Disc.: MLS Alt.: 2012 VS45 | MPC · JPL |
| 0 | 2004 YD26 | MBA-M | 17.1 | 1.1 km | multiple | 2004–2021 | 11 Jan 2021 | 126 | Disc.: MLS Alt.: 2010 MR50 | MPC · JPL |
| 0 | 2004 YX26 | MBA-O | 16.72 | 2.5 km | multiple | 2004–2022 | 27 Jan 2022 | 61 | Disc.: MLS Alt.: 2010 DO90 | MPC · JPL |
| 0 | 2004 YB28 | MBA-I | 18.2 | 680 m | multiple | 2004–2021 | 02 Jan 2021 | 150 | Disc.: LINEAR Alt.: 2007 TW377 | MPC · JPL |
| 0 | 2004 YF28 | HUN | 19.03 | 460 m | multiple | 2004–2022 | 06 Jan 2022 | 23 | Disc.: Spacewatch Added on 24 December 2021 | MPC · JPL |
| 0 | 2004 YB29 | MBA-O | 16.6 | 2.7 km | multiple | 2004–2020 | 14 Dec 2020 | 87 | Disc.: Spacewatch Alt.: 2014 WM32, 2016 AL142 | MPC · JPL |
| 0 | 2004 YX29 | MBA-M | 17.2 | 1.1 km | multiple | 2004–2021 | 14 Jan 2021 | 69 | Disc.: Spacewatch | MPC · JPL |
| 0 | 2004 YE32 | MCA | 17.58 | 1.3 km | multiple | 2001–2022 | 13 Jan 2022 | 108 | Disc.: LONEOS | MPC · JPL |
| 0 | 2004 YS34 | MBA-O | 16.7 | 3.5 km | multiple | 2004–2020 | 16 Oct 2020 | 80 | Disc.: MLS Alt.: 2010 AP123 | MPC · JPL |
| 1 | 2004 YY34 | MBA-O | 17.14 | 2.1 km | multiple | 2004–2021 | 26 Nov 2021 | 59 | Disc.: MLS Added on 5 November 2021 | MPC · JPL |
| 0 | 2004 YS36 | MBA-O | 17.2 | 2.0 km | multiple | 2004–2021 | 07 Jan 2021 | 68 | Disc.: MLS Alt.: 2004 YC15, 2016 CS152 | MPC · JPL |
| 1 | 2004 YR37 | MBA-M | 17.9 | 1.1 km | multiple | 2004–2020 | 10 Nov 2020 | 79 | Disc.: MLS | MPC · JPL |
| 0 | 2004 YT37 | MBA-M | 16.95 | 1.2 km | multiple | 2004–2022 | 27 Jan 2022 | 147 | Disc.: MLS | MPC · JPL |
| 0 | 2004 YW37 | MBA-I | 18.22 | 670 m | multiple | 2004–2021 | 02 Dec 2021 | 121 | Disc.: Spacewatch | MPC · JPL |
| 0 | 2004 YX37 | MBA-I | 17.0 | 1.2 km | multiple | 2004–2020 | 18 Jul 2020 | 152 | Disc.: Spacewatch | MPC · JPL |
| 0 | 2004 YY37 | MBA-I | 18.23 | 670 m | multiple | 2004–2022 | 26 Jan 2022 | 92 | Disc.: Spacewatch | MPC · JPL |
| 0 | 2004 YD38 | MBA-M | 17.35 | 1.4 km | multiple | 2004–2021 | 28 Dec 2021 | 81 | Disc.: Spacewatch | MPC · JPL |
| 0 | 2004 YK38 | MBA-I | 18.7 | 540 m | multiple | 2004–2020 | 16 Mar 2020 | 64 | Disc.: MLS | MPC · JPL |
| 0 | 2004 YM38 | MBA-I | 18.82 | 510 m | multiple | 2004–2022 | 27 Jan 2022 | 56 | Disc.: Spacewatch | MPC · JPL |
| 2 | 2004 YN38 | MBA-I | 18.6 | 570 m | multiple | 2004–2018 | 06 Oct 2018 | 57 | Disc.: MLS | MPC · JPL |
| 1 | 2004 YO38 | MBA-M | 16.9 | 1.2 km | multiple | 2002–2021 | 16 Jan 2021 | 123 | Disc.: Spacewatch Alt.: 2013 AJ195 | MPC · JPL |
| 0 | 2004 YQ38 | MBA-M | 17.5 | 940 m | multiple | 2004–2020 | 20 Oct 2020 | 69 | Disc.: Spacewatch | MPC · JPL |
| 0 | 2004 YS38 | MBA-M | 17.92 | 1.1 km | multiple | 2004–2022 | 22 Jan 2022 | 73 | Disc.: Spacewatch | MPC · JPL |
| 0 | 2004 YU38 | MBA-M | 17.40 | 1.4 km | multiple | 2004–2022 | 04 Jan 2022 | 127 | Disc.: Spacewatch | MPC · JPL |
| 0 | 2004 YV38 | MBA-M | 17.17 | 2.0 km | multiple | 2004–2021 | 04 Oct 2021 | 64 | Disc.: Spacewatch | MPC · JPL |
| 0 | 2004 YW38 | MBA-O | 15.9 | 3.7 km | multiple | 2004–2020 | 16 Nov 2020 | 70 | Disc.: Spacewatch | MPC · JPL |
| 0 | 2004 YY38 | MBA-M | 17.74 | 1.2 km | multiple | 2004–2021 | 04 Dec 2021 | 50 | Disc.: Spacewatch | MPC · JPL |
| 0 | 2004 YA39 | MBA-O | 16.5 | 2.8 km | multiple | 2004–2021 | 09 Jan 2021 | 60 | Disc.: MLS Alt.: 2016 BC3 | MPC · JPL |
| 0 | 2004 YB39 | MBA-M | 17.7 | 860 m | multiple | 1991–2021 | 06 Jan 2021 | 135 | Disc.: Spacewatch Alt.: 1995 SB44 | MPC · JPL |
| 0 | 2004 YD39 | MBA-O | 16.6 | 2.7 km | multiple | 2004–2021 | 17 Jan 2021 | 73 | Disc.: Spacewatch Alt.: 2010 BT124 | MPC · JPL |
| 0 | 2004 YE39 | MBA-O | 16.43 | 2.9 km | multiple | 2004–2022 | 27 Jan 2022 | 114 | Disc.: MLS Alt.: 2010 CU193 | MPC · JPL |
| 0 | 2004 YF39 | MBA-I | 18.4 | 620 m | multiple | 2004–2020 | 26 Apr 2020 | 47 | Disc.: Spacewatch | MPC · JPL |
| 0 | 2004 YG39 | MBA-I | 19.02 | 470 m | multiple | 2004–2021 | 31 Aug 2021 | 33 | Disc.: Spacewatch | MPC · JPL |
| 3 | 2004 YJ39 | MBA-M | 18.0 | 1.1 km | multiple | 2004–2018 | 18 Feb 2018 | 28 | Disc.: MLS | MPC · JPL |
| 0 | 2004 YK39 | MBA-M | 17.7 | 1.2 km | multiple | 2004–2020 | 25 Jul 2020 | 36 | Disc.: MLS | MPC · JPL |
| 1 | 2004 YL39 | MBA-M | 17.6 | 900 m | multiple | 2004–2021 | 14 Jan 2021 | 179 | Disc.: CSS | MPC · JPL |
| 0 | 2004 YM39 | MBA-O | 16.93 | 2.3 km | multiple | 2002–2022 | 06 Jan 2022 | 73 | Disc.: MLS Alt.: 2010 CW214 | MPC · JPL |
| 0 | 2004 YQ39 | MBA-O | 16.7 | 2.5 km | multiple | 2004–2021 | 17 Jan 2021 | 79 | Disc.: Spacewatch | MPC · JPL |
| 0 | 2004 YT39 | MBA-I | 19.0 | 470 m | multiple | 2004–2019 | 03 Dec 2019 | 58 | Disc.: MLS | MPC · JPL |
| 1 | 2004 YU39 | MBA-I | 18.7 | 540 m | multiple | 2004–2018 | 15 Oct 2018 | 52 | Disc.: Spacewatch | MPC · JPL |
| 0 | 2004 YW39 | MBA-M | 17.5 | 940 m | multiple | 2004–2020 | 15 Dec 2020 | 69 | Disc.: MLS | MPC · JPL |
| 0 | 2004 YA40 | MBA-M | 18.09 | 1.0 km | multiple | 2004–2021 | 28 Sep 2021 | 56 | Disc.: MLS | MPC · JPL |
| 0 | 2004 YB40 | MBA-M | 17.84 | 1.1 km | multiple | 2004–2021 | 09 Dec 2021 | 90 | Disc.: Spacewatch | MPC · JPL |
| 0 | 2004 YD40 | MBA-I | 19.16 | 440 m | multiple | 2004–2021 | 13 Jul 2021 | 48 | Disc.: MLS | MPC · JPL |
| 0 | 2004 YF40 | MBA-O | 16.8 | 2.4 km | multiple | 2004–2021 | 18 Jan 2021 | 39 | Disc.: MLS | MPC · JPL |
| 1 | 2004 YG40 | HUN | 19.1 | 450 m | multiple | 2004–2020 | 23 Jan 2020 | 55 | Disc.: MLS | MPC · JPL |
| 1 | 2004 YH40 | MBA-I | 18.1 | 710 m | multiple | 2004–2020 | 24 Mar 2020 | 38 | Disc.: MLS | MPC · JPL |
| 0 | 2004 YJ40 | MBA-M | 17.51 | 1.3 km | multiple | 2004–2021 | 11 Nov 2021 | 40 | Disc.: Spacewatch | MPC · JPL |
| 0 | 2004 YL40 | MBA-O | 16.41 | 2.9 km | multiple | 2004–2022 | 25 Jan 2022 | 134 | Disc.: Spacewatch Alt.: 2010 BW130 | MPC · JPL |
| 0 | 2004 YN40 | MBA-O | 16.18 | 3.2 km | multiple | 2004–2021 | 10 Sep 2021 | 73 | Disc.: MLS | MPC · JPL |
| 0 | 2004 YU40 | MBA-I | 18.7 | 540 m | multiple | 2004–2020 | 12 Sep 2020 | 33 | Disc.: MLS | MPC · JPL |
| 0 | 2004 YX40 | MBA-M | 18.02 | 1.0 km | multiple | 2004–2021 | 27 Nov 2021 | 57 | Disc.: Spacewatch | MPC · JPL |
| 0 | 2004 YA41 | MBA-I | 18.75 | 530 m | multiple | 2004–2022 | 05 Jan 2022 | 34 | Disc.: MLS | MPC · JPL |
| 0 | 2004 YB41 | MBA-I | 18.7 | 540 m | multiple | 2004–2018 | 06 Oct 2018 | 33 | Disc.: Spacewatch | MPC · JPL |
| 0 | 2004 YD41 | MBA-O | 16.8 | 2.4 km | multiple | 2004–2020 | 18 Nov 2020 | 56 | Disc.: Spacewatch | MPC · JPL |
| 1 | 2004 YE41 | HUN | 18.9 | 490 m | multiple | 2004–2021 | 07 Jun 2021 | 51 | Disc.: MLS | MPC · JPL |
| 0 | 2004 YF41 | MBA-I | 18.7 | 540 m | multiple | 2004–2020 | 23 Jan 2020 | 46 | Disc.: Spacewatch | MPC · JPL |
| 0 | 2004 YH41 | MBA-I | 18.6 | 570 m | multiple | 2004–2020 | 30 Jan 2020 | 51 | Disc.: Spacewatch Added on 22 July 2020 | MPC · JPL |
| 0 | 2004 YJ41 | MBA-I | 18.2 | 680 m | multiple | 2004–2019 | 29 Apr 2019 | 46 | Disc.: MLS Added on 22 July 2020 | MPC · JPL |
| 0 | 2004 YL41 | MBA-M | 17.40 | 1.4 km | multiple | 2004–2021 | 20 Nov 2021 | 71 | Disc.: MLS Added on 22 July 2020 | MPC · JPL |
| 1 | 2004 YN41 | MBA-I | 18.8 | 520 m | multiple | 2004–2020 | 22 Mar 2020 | 35 | Disc.: MLS Added on 22 July 2020 | MPC · JPL |
| 1 | 2004 YO41 | MBA-I | 18.6 | 570 m | multiple | 2004–2020 | 21 Mar 2020 | 33 | Disc.: MLS Added on 22 July 2020 | MPC · JPL |
| 2 | 2004 YP41 | MBA-M | 17.4 | 980 m | multiple | 2004–2020 | 21 Dec 2020 | 76 | Disc.: MLS Added on 19 October 2020 | MPC · JPL |
| 0 | 2004 YR41 | MBA-M | 17.34 | 1.0 km | multiple | 2001–2022 | 12 Jan 2022 | 88 | Disc.: CSS Added on 17 January 2021 Alt.: 2020 MK7 | MPC · JPL |
| 0 | 2004 YS41 | MBA-M | 17.3 | 1.5 km | multiple | 2004–2020 | 10 Sep 2020 | 43 | Disc.: MLS Added on 17 January 2021 | MPC · JPL |
| 2 | 2004 YU41 | MBA-M | 17.9 | 780 m | multiple | 2004–2020 | 11 Oct 2020 | 52 | Disc.: MLS Added on 17 January 2021 | MPC · JPL |
| 0 | 2004 YW41 | MBA-M | 17.6 | 900 m | multiple | 2004–2020 | 14 Dec 2020 | 68 | Disc.: MLS Added on 17 January 2021 | MPC · JPL |
| 0 | 2004 YY41 | MBA-O | 17.29 | 1.9 km | multiple | 2004–2022 | 06 Jan 2022 | 23 | Disc.: Spacewatch Added on 11 May 2021 | MPC · JPL |
| 0 | 2004 YA42 | MBA-M | 18.06 | 1.0 km | multiple | 2004–2021 | 09 Dec 2021 | 71 | Disc.: MLS Added on 21 August 2021 | MPC · JPL |
| 0 | 2004 YB42 | MBA-O | 17.64 | 1.7 km | multiple | 2004–2021 | 18 Jan 2021 | 38 | Disc.: MLS Added on 5 November 2021 | MPC · JPL |