Fields containing Uranus and Neptune and their moons were observed during normal survey operations by the southern 2MASS facility on 980607 and 980611. Both planets were "rediscovered" by Adam Burgasser as part of the campaign to locate methane brown dwarfs. Both planets were also correctly identified and flagged by the 2MASS processing software.
Following the same procedure used to locate Jupiter's moons in the 2MASS data, I easily picked up the five major moons of Uranus as well as Neptune's large moon Triton. None of the other minor moons were detected, which is consistent with their small sizes and low albedos. These calculations suggest that the remaining 10 moons of Uranus range from 6 to 10 magnitudes fainter than Ariel, or about 19th magnitude at best; and that (with the exception of Nereid) the last 6 moons of Neptune should be 6.7 to 11 magnitudes fainter than Triton, or again about 19th magnitude at brightest. Considering that the 5-sigma detection limits at JHK are about 17.4, 16.6 and 15.8 respectively, it is no surprise that they are not visible.
Neptune's moon Nereid is predicted to have a J magnitude of 17.4, which could be bright enough to detect. However, neither the point source list nor the atlas image show any object within ten arcsec of the predicted position.
The following table lists the observations of Uranus and Neptune's moons
as observed by 2MASS. Positions are from the 2MASS point source lists.
Images of each field are available by clicking on the planet name.
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21 01 00.27 | -17 39 44.8 | 980607s | 062 | 257 |
| Ariel | 21 00 59.73 | -17 39 38.9 | 980607s | 062 | 257 |
| Umbriel | 21 01 00.52 | -17 39 28.1 | 980607s | 062 | 257 |
| Titania | 21 00 59.37 | -17 40 04.2 | 980607s | 062 | 257 |
| Oberon | 21 01 01.13 | -17 39 12.4 | 980607s | 062 | 257 |
| Miranda | 21 01 00.31 | -17 39 36.3 | 980607s | 062 | 257 |
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20 15 56.45 | -19 24 35.4 | 980611s | 092 | 068 |
| Triton | 20 15 56.68 | -19 24 22.6 | 980611s | 092 | 068 |
