Planetary and exoplanetary Astronomy Lunch Seminar (PALS) for 2023-05-15

Series: Planetary and exoplanetary Astronomy Lunch Seminar (PALS)
Date: Monday 15-May-2023
Time: 11:15-12:15
Location: ATL 1250
Speaker: Richard Wainscoat
Title: The discovery of `Oumuamua - an insider's perspective

Abstract: In October 2017, the Pan-STARRS1 telescope on Haleakala, Hawaii, discovered the first interstellar object. It moved rapidly away from Earth, and was only easy to observe for one lunation, producing a worldwide frenzy of observations, including telescopes on Maunakea. I will describe how we realized that this object had a hyperbolic orbit, and some of our early efforts to characterize it, and the challenges that we encountered. As `Oumuamua departed from the Sun, it accelerated slightly, showing non-gravitational motion. This small acceleration was evident in published astrometry, producing a difficult waiting period to publish this while we continued to observe `Oumuamua as it departed using HST. Most likely, the acceleration is caused by low-level cometary activity, probably involving larger grains. Prospects for discovery of more interstellar objects will also be discussed.

For further information contact PALS coordinators Quanzhi Ye at and Tad Komacek at


Special accommodations for individuals with disabilities can be made by calling (301) 405-3001. It would be appreciated if we are notified at least one week in advance.


Directions and information about parking can be found here.

This page was automatically generated on: 08-May-2023.