At 2pm, she used her cellphone to take a snapshot of her friends, who were seated on the grandstand opposite.
In addition to her friends, the high-schooler found that she had snapped a photo of a flying saucer.
Incredulous about her find, Thidarat attempted to take a second photo of the coconut tree behind which the UFO had appeared, but the saucer failed to make a second appearance.
Weerayos Yuttarin, an English teacher at the school, said that Thidarat was a well-behaved student who was unlikely to fabricate the story.
"I heard many teachers talking about their UFO experience on the same day, but I did not believe since there was no concrete evidence," said Weerayos.
Weerayos added that behind the row of coconut trees were townhouses that should not have a height of more than three stories.
Curiously, today's alien visitors to earth appear to have reverted to vintage spacecraft: the UFO looks uncannily like the flying saucer in the famous Adamski photograph taken in California in the 1950s - later revealed to be a truck hubcap.