Table 1.
Parameters of the occulted star and Triton, and results of the atmospheric fits.
| Occulted star | |
|---|---|
| Identification (Gaia DR3) | 2639239368824994944 |
| ICRS position at occultation epoch | α = 23h36m52.45142s ± 0.7 mas, δ = −03° 50′09.7952″ ± 0.9 mas |
| Triton’s parameters | |
| Mass, radius (1) | GMT = 1.4279 × 1012 m3 sec−2, RT = 1353 km |
| Geocentric distance | 4.33409 × 109 km |
| Pole position (2) (ICRS) | αp = 20h 13m 52.4s, δp = 20° 32′38.2″ |
| Sub-solar latitude, sub-observer latitude, longitude | 34.2° S, 34.6° S, 115.0° E |
| North pole position angle (3) | 298.2° |
| Reconstructed geometry | |
| Half-light layer in Triton’s atmosphere, in shadow plane | 1442 km, 1420 km |
| Geocentric closest approach distance and time for shadow center | ρC/A, G = 4067 ± 3 km, tC/A, G= 14:39:46.26 ± 0.04 s UT |
| Atmospheric results | |
| This work | |
| Pressure at reference radius 1400 km, at surface (4) | p1400 = 1.211 ± 0.039 μbar, psurf = 14.54 ± 0.47 μbar |
| Other works | |
| 25 August 1989 (RSS occultation) (5) | psurf = 14.1 ± 1 μbar |
| 25 August 1989 (RSS occultation) (6) | p1400 = 1.0 ± 0.2 μbar |
| 14 August 1995 (ground-based occultation) (7) | p1400 = 1.4 ± 0.1 μbar |
| 18 July 1997 (ground-based occultation) (8) | p1400 = 2.23 ± 0.28 μbar |
| 18 July 1997 (ground-based occultation) (6) |
 μbar |
| 4 November 1997 (HST occultation) (9) | p1400 = 1.759 ± 0.016 μbar |
| 21 May 2008 (ground-based occultation) (6) |
 μbar |
| 5 October 2017 (ground-based occultation) (6) | p1400 = 1.18 ± 0.03 μbar |
Notes. The error bars are given at the 1σ level.
McKinnon et al. (1995), where G is the constant of gravitation.
On 6 October 2022, using Archinal et al. (2018).
Position angle of the Triton north pole projected in the sky plane. Counted positively from celestial north to celestial east.
HST: Hubble Space Telescope, Elliot et al. (2003).
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