Hazardous NEO Technical Reviews

Position Statement

The IAU, recognizing its responsibility to encourage timely and responsible communication with the public and the press concerning possible impact hazards, has established the following procedures to be available to the members of the astronomical community in case of discovery and/or theoretical analysis leading to the prediction of impacts.

The accuracy of a prediction depends on both the observational data and the computational methods used. The IAU encourages its members to actively seek out and make available any observations that may help refine the orbit of a potentially threatening NEA. In addition, the following IAU review procedure of orbital computations and risk estimates is available on a voluntary basis to all scientists involved in any prediction of possible NEO impacts. This review procedure is encouraged for any prediction that is at a level equal to or greater than zero on the Palermo Technical Scale, a scale that compares the impact probability of the predicted event to the hazard posed by the background NEO population, taking into account the estimated size of the object and the time interval until the encounter. An object having the same or higher impact probability as that of the background population will have a Palermo Technical Scale value equal to or greater than zero. In most cases, such events will fall at a value of 1 or higher on the 0-10 point Torino Scale, a scale intended for public communication of impact hazard risks.

The procedure for technical review is as follows. Information leading to an impact prediction, consisting of an evaluation of the case and all data and computational details necessary to understand and reproduce the studies carried out by the authors, should be transmitted for confidential review to the chair of the IAU Working Group for Near Earth Objects (WGNEO), the President of IAU Division III, the General Secretary of the IAU, and the members of the NEO Technical Review Team (see below), before any announcement and/or written document on the subject be made public via any potentially nonprivate communication medium, including the World Wide Web. The individual members of the NEO Technical Review Committee shall review the work for technical accuracy and shall communicate under most circumstances within 72 hours the results of their reviews to the chair of the WGNEO and directly to the authors of the report or manuscript.

The authors of the work are encouraged to refer to this IAU review and may quote this review if and when they choose to make a public release of their conclusions. If the consensus of the above review supports the conclusion that there is a significant impact risk meriting an announcement by the IAU itself, such an announcement will be posted on the IAU webpage http://www.iau.org/ for public access as soon as possible after the information is released by the authors to the public. If the review disagrees with the original analysis or if there is not a consensus among the reviewers, the confidential results of the review will be given to the authors so they can revise or improve their work, as they see fit.

It is important to note that the WGNEO will review impact probabilities and reach conclusions based on the best observational information available at the time of the review. It is expected that new data that may be obtained during the period of the review and/or in the days, weeks, and months (in some cases years) that follow will provide sufficient new information for new probability calculations to be made. The most likely eventuality is that new calculations based on additional new data will ultimately yield impact probabilities that are effectively zero.

The news posted on the IAU webpage shall represent the official position of the IAU; further information will be provided by the WGNEO in case important updates become necessary. If so requested officially (e.g., by NASA or ESA), the IAU will also inform the responsible officials of relevant agencies of the results of the WGNEO review.