British Astronomical Association
Supporting amateur astronomers since 1890

Secondary menu

Main menu

Home Forums Neptune
Terms of use

Triton's diameter from occultation timings

4 posts / 0 new
Last post
A R Pratt's picture
Offline
Last seen: 1 week 2 days ago
Joined: 04/03/2014 - 14:01
Triton's diameter from occultation timings
On 2017 October 5 a number of observers successfully recorded the occultation of a magnitude 12.7 star by Neptune’s largest moon, Triton. Tim Haymes and I wrote a provisional report for the 2017 December BAA Journal which included a profile of Triton displaying the UK observers' chords.
Eric Frappa (FR) has added a more comprehensive shape profile to the Euraster website using data from 17 stations (ranging from Yorkshire to Algeria) submitted to Planoccult
Because Triton has a significant atmosphere, producing gradual rather than instantaneous occultations, most observers reported D and R timings at the 50% flux level. The resultant estimated diameter of Triton (2,850 km) is within about 5% of the official figure (2,707 km).
Although it's pleasing, this result is of no great scientific value. The real interest is in the light curve data that will be analysed by the professional researchers of Bruno Sicardy and his Lucky Star Project team (Paris) to monitor any changes in Triton’s atmosphere, 20 years after an earlier study.
Clear skies,
     Alex.
Jeremy's picture
Offline
Last seen: 6 hours 12 min ago
Joined: 04/03/2014 - 22:00
Triton's atmosphere

Many thanks for the update on this fascinating piece of work, Alex. Do keep us posted on what Bruno Sicardy finds out about the atmosphere.

Jeremy

A R Pratt's picture
Offline
Last seen: 1 week 2 days ago
Joined: 04/03/2014 - 14:01
Triton's atmosphere

Jeremy, in due course all contributing observers should receive a copy of the Lucky Star team's paper, perhaps a preprint. Depending on where it's published we'll have to see if general readers have to negotiate a paywall, although the key results should wend their way into the public domain.

Ray, I'm just summarising the results of many observers. The real science will come from the work of Bruno's team, hopefully revealing any changes in Triton's atmosphere since 1989.

Cheers,

     Alex.

Ray Emery's picture
Offline
Last seen: 1 week 4 days ago
Joined: 05/03/2014 - 08:54
Triton

Wonderful work Alex! Your modesty does you even more credit - super genuine science!