From NASA:
NASA Schedules News Briefing About Unusual Solar Object
The discovery of a mysterious object in our solar system is the topic of a listen-and-log-on news briefing on Monday, March 15, at 1 p.m. EST.
Dr. Michael Brown, associate professor of planetary astronomy, California Institute of Technology, Pasadena, Calif. will present his discovery of the most distant object ever detected orbiting the sun. He and colleagues made the discovery as part of a NASA-funded research project.
A radio report says this object is smaller than Pluto.