Astronomer finds star that never was
Even the best scientists sometimes make dumb mistakes. Andrew Masterson reports.
The Astronomer’s Telegram is an excellent rapid communication system set up in 1997 and used to disseminate time-critical information to a huge network of professional and amateur star-gazers around the world.
For properly credentialed astronomers, the service allows them to publish observations directly, ensuring that the information spreads without delay.
Sometimes, speed is critical in the field. Objects such as meteors suddenly transiting across the night sky, for instance, may only be visible for minutes. Supernova explosions, gravitational microlensing opportunities, and eclipses, to name a few phenomena, are sometimes limited in their duration.
Any one of these broad types of occurrence is known among astronomers as a “transient”, and is guaranteed to generate excitement. The chance to make observations about unusual events is generally a scientific opportunity not to be missed.
Thus it was that people rushed to refocus their telescopes on March 20 this year when the Astronomer’s Telegram broadcast a notification titled Very bright optical transient near the Trifid and Lagoon Nebulae.
The telegram, sent out by an astronomer at the University of Cape Town in South Africa, reported a bright object in the night sky, fully visible for two and three-quarter hours.
The bulletin provided coordinates for the object, and noted that it had “no obvious counterpart” in the Digital Sky Survey maps.
“The optical transient is the brightest star in the field,” the telegram reported, and “strongly urged” further observations to establish its nature.
The excitement of the global astronomical community was palpable. Had a new star suddenly burst into life? Was the bright object a supernova explosion, perhaps, or some other enormous and violent cosmological act?
Well, it didn’t take long for the mystery to be solved. Just 40 minutes after the first telegram, the same Cape Town astronomer sent out a second. It was much shorter.
“The object reported … has been identified as Mars,” it said. “Our sincere apologies for the earlier report and the inconvenience caused.”