What is IOTA/EA
IOTA/EA (International Occultation Timing Association – East Asia) was launched with its Establishment Meeting on August 27, 2023 (UTC). IOTA/EA is a joint organization of professional and amateur astronomers. IOTA/EA aims to promote and facilitate occultation observations in the East Asia region, and to help occultation observations become a useful partner in exploration missions and other studies of small solar bodies.
IOTA/EA publishes information on occultation event and observation results from this website. IOTA/EA also disseminates information about organized observation campaigns.
Inviting as many people as possible for occultation observations from different countries/regions will lead us to support the research and development on astronomy and planetary science fields (for more information, see the Purpose of Establishment below). In additions, being aware of the occultation phenomena that occur every day somewhere in the world is a new reminder that we live on Earth, a planet surrounded by a jumble of small bodies in a corner of the Universe.
We hope that many of you will join IOTA/EA and support us.
Main objectives of the IOTA/EA
The main objectives of the IOTA/EA are to carry out the following activities in the East Asian region
- To develop observations and research on astronomical occultations and eclipses for the advancement of astronomy and planetary science, and to conduct various activities to increase public and social awareness of occultation observations.
- To provide people and society with information on occultation phenomena, to organize a systematic observation group for scientific observations, to analyze the results of occultation and eclipse observations, and to publish the results and findings of these observations.
Purpose of Establishment
Necessity of organizing occultation observation in East Asia
Recently, the demand on occultation observations have increased dramatically.
This is likely driven by successful observations that support planetary exploration missions.
For example, it was organized occultation observations that led to the discovery of the snowball-like shape of a Kuiper Belt object (Arrokoth) earlier than the New Horizons’s flyby in 2019.
More recently, occultation observations revealed the size and shape (in 2019-2021) and orbital shift (in 2022) of Phaethon, the flyby target for Japan’s ongoing DESTINY+ mission, providing information that will certainly contribute to the mission planning.
Occultation observations of Didymos were conducted (in 2022) for supporting the DART/Hera mission, which aims to change the orbit of an asteroid by colliding the spacecraft with satellite of the Didymos asteroid system. This success of occultation observation provided valuable data to determine the extent to which the orbit of Didymos was affected by the impact on the satellite.
It was also through occultation observation that the Centaurs (Chariklo) was found to have a ring in 2013. Chariklo became the first Centaurs having ring. Even a small body can has/keeps a ring. It was a big discovery for the planetary science field. Occultation was also responsible for the discovery of rings on the outer solar system object Haumea (in 2017) and the double ring on Quaoar (in 2023). Occultation observations can also reveal the presence or absence of global atmospheres of small solar system bodies.
Thus, occultation observations have produced remarkable results in recent years.
This is because (1) the positional accuracy of stars has been dramatically improved by the Gaia catalogue, (2) the orbital accuracy of small objects is improving day by day with all-sky surveys such as PanSTARRS, and (3) inexpensive CMOS cameras with high time-resolution have been developed and are widely used among observers.
From this circumstance, the accuracy of occultation predictions has improved and also very short-duration phenomena have been observable.
In the future, the Vera C. Rubin Observatory, which is scheduled to begin science operations in 2025, will start an all-sky survey using the 8.4-meter telescope, which is expected to accurately determine the orbits of smaller small objects. Therefore, the number and accuracy of occultation predictions are expected to increase in near future. The higher the accuracy of the prediction, the more efficient the observational strategy will be realized.
The future of occultation observation is bright and full of hope for various scientific results. In East Asia, there are many excellent amateur astronomers who have been carrying out occultation observations. They have also developed observation methods and analysis tools to analyze the obtained data with high accuracy, and have succeeded in the mentioned occultation by Phaethon and the occultation by Didymos. These results not only contribute to planetary exploration missions, but also make it possible to accurately measure the dynamical evolution of small solar system bodies over short periods of time (a few years to a few decades) through observation.
Thus, occultation observations have become a very important tool for planetary science research. Occultation observations have always been an effective tool for studying the size of asteroids and the topography of the Moon, but now they have become much more powerful.
Until now, only a few professional researchers in Japan have been actively involved in occultation observation due to the low prediction accuracy and low observation efficiency of occultations. However, now, the enthusiasm for occultation observation is growing among not only amateur astronomer and also professional researchers.
Since 2021, a series of workshops on occultation observation has been held jointly by professionals and amateurs, and young researchers and university students are beginning to enter the field of occultation observation.
We are convinced that a new observation and research system can be established through the collaboration of amateurs with long experience in occultation observation and up-and-coming professional researchers.
Based on the above situation, we wanted to establish an organization for occultation observation in East Asia like the International Occultation Timing Association (IOTA). The occultation observations have been done by the free participation of amateur astronomers, but due to its significant contribution to planetary exploration and planetary science research, we would like to establish a center of excellence for occultation observations in East Asia, presenting occultation predictions, collecting and reporting observation results, archiving data, and making valuable observation data available to everyone for research.
Since the occultation zone will pass through broad areas, we will build a cooperative framework in China, Japan, Korea and Taiwan, which have experience in occultation observation and neighboring regions, in the occultation research. By doing so, we will be able to disperse the weather risk and observe occultation events with certainty.
In addition to amateur astronomers, professional researchers will also work together on an equal footing in terms of data archiving and international cooperation. In fact, “Research on sustainable archiving of stellar occultation observation by small solar-system objects” has been started in collaboration with the Aizu Research Center for Space Informatics in the University of Aizu in FY2023.
In order to obtain data of high scientific value from occultation observations, it is essential to conduct observations at multiple locations. The establishment of a center for occultation observation : IOTA/EA is expected to improve the accuracy of observation and analysis and to train observers.
For these reasons, IOTA/EA was established to organize the occultation observation in the East Asia region.
We look forward to your continued participation and support.
(2024.01.20)
Co-Chairpersons
Tsutomu Hayamizu [Saga Hoshizora Astronomy Center, Japan]
Fumi Yoshida [University of Occupational and Environmental Health, Japan / Chiba Institute of Technology]
(in alphabetical order)