Asteroidal occultation by (155140)2005 UD

【Remark】
■ 2023.１０.２７   １５ｈ１６ｍ ＵＴ (24h16m JST)
  Star  ：TYC 3313-00763-1    mag9.1
          RA 03h 35m 19.968s Dec +45°25' 47.30"(J2000)
  Asteroid：(155140)2005 UD  mag20.9  dia 1.1km
  Drop mag：aprox 11.8mag  Max duration 0.05sec
  Area    ：Kagoshima Japan, Hangzhou China
  Note    ：The candidate body of DESTINY+ mulch flyby

 Prediction by JPL-Horizons & Gaia EDR3 Occultation data map. (update 2023.10.22)

 Occultation area Map based on JPL#133 (update 2023.10.22)

■ the Importance of this event
Asteroid (155140) 2005 UD is the second flyby candidate for the DESTINY+ mission. Since we can only observe the object from the spacecraft for a very short time during the flyby mission, it is necessary to study the asteroid from the ground in advance. This occultation event is an excellent opportunity to determine the exact size and orbit of this asteroid before the spacecraft arrives.
2005 UD is very small, with a diameter of about 1.1 km. We have asked several places to observe its position, but the prediction of the occultation zone still has a large margin of error. Therefore many observers are needed to cover the error.
Note for observation
The target star is bright enough. However, the movie shutter speed must be less than 0.02 sec. Because the maximum duration of this event is only 0.05 sec. Before you consider participating in this observing campaign, please confirm that your telescope can detect the 9.1mag target star with the exposure time of 0.02 sec. Also, the movie should be accurately timed by the GPS time signal.
・ 観測で注意したいこと(渡部勇人さん提供) Sorry, this document is written by Japanese only.

Special note for cooperation
In Japan, we can only observe this event in a limited area in Kagoshima. Considering the weather risk, we hope that collaborators in China will observe this event with us, if possible. The occultation zone will pass south of Shanghai.
Restrictions on publication of observation results
This observation will only be scientifically meaningful when the results of the multi-site observations are collected. The PI will collect data from all participants in the observing campaign, check the data set and analysis results with IOTA/EA, and open the results as soon as possible; the results of the IOTA/EA analysis will be the official results.

Star :TYC 3313-00763-1  (mag9.1)
Asteroid : (155140)2005 UD  (mag20.9)



Wide Map
by The SKY 6


2deg square
by The SKY 6

If you observed...
If you observed, please send to

2005 UD observation(DESTINY+) or Tstutomu Hayamizu. Reported observations will be published to world and be utilized for Occultation study.
◆ for report Tsutomu Hayamizu／

Required Data are below;
1.Observers Name
2.Observed Place. longitude, latitude and altitude，Datum.
Longitude and latitude must have digits of 0.1"
Altitude must have digits of 1m
3.Observation start and end time (UTC)
4.Occultation occured or not.
5.The Disappearance and Disappearance time, if the occultation occured
6.The Equipments and methods, for example telscope type and appature, camera, exporse duration
7.Time signal

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Links...
IOTA/EA
JAXA / 深宇宙探査技術実証機 DESTINY+
千葉工業大学 惑星探査研究センター／深宇宙探査技術実証機 DESTINY+
PASJ／Multi-chord observation of stellar occultation by the near-Earth asteroid (3200) Phaethon on 2021 October 3 (UTC) with very high accuracy

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