WASHINGTON, May 9 (Xinhua) -- A team of researchers using NASA's Spitzer Space Telescope have found that the distant gas planet HD 149026b may be the hottest yet discovered, NASA announced on Wednesday.

Astronomers led by Joseph Harrington of the University of Central Florida in Orlando discovered that HD 149026b is a scorching 3,700 F (2,040 Celsius), even hotter than some low-mass stars.

"This planet is like a chunk of hot coal in space," said Harrington. "Because this planet is so hot, we believe its heat is not being spread around. The day side is very hot, and the night side is probably much colder."

HD 149026b is located 279 light-years away in the constellation Hercules. It is the smallest and densest known transiting planet, with a size similar to Saturn's and a core suspected to be 70 to 90 times the mass of Earth. It speeds around its star every 2.9 days.

According to Harrington and his team, the oddball planet probably reflects almost no starlight, instead absorbing all of the heat into its fiery body. That means HD 149026b might be the blackest planet known, in addition to the hottest.

"This planet is off the temperature scale that we expect for planets," said Drake Deming, one of Harrington's teammates from NASA's Goddard Space Flight Center.

Their findings will appear in the May 9 issue of the journal Nature.

HD 149026b is a "hot Jupiter" -- a sizzling, gas giant planet that zip closely around their star. Roughly 50 of more than 200 known planets outside our solar system, called exoplanets, are hot Jupiters.

Visible-light telescopes can detect these strange worlds and determine certain characteristics, such as their sizes and orbits, but not much is known about their atmospheres or what they look like.

Since 2005, Spitzer has been revolutionizing the study of exoplanets' atmospheres by examining their infrared light, or heat.

Spitzer was able to calculate the temperature of this transiting planet by observing the drop in infrared light that occurs as it dips behind its star.