Using the NASA/ESA Hubble Space Telescope, scientists have discovered that a giant extrasolar planet called 2MASSWJ 1207334-393254b has patchy clouds and rotates twice as fast as Earth.
This is an illustration of the super-Jupiter 2M1207b and the brown dwarf 2M1207A. The planet completes one rotation every 10 hours – about the same rate as Jupiter. Because the planet is young, it is still contracting under gravity and radiating heat. The atmosphere is so hot that it rains molten glass and, at lower altitudes, molten iron. Because the planet is only 170 light-years away, many of the bright background stars that can be seen from Earth can be seen from the planet’s location in our Galaxy, including Sirius, Fomalhaut, and Alpha Centauri. Our Sun is a faint star in the background, located midway between Procyon and Altair. Image credit: NASA / ESA / G. Bacon, STScI / Y. Zhou, University of Arizona.
2MASSWJ 1207334-393254b (2M1207b for short) was discovered in 2004 by Dr. Gaël Chauvin from the European Southern Observatory and co-authors.
This exoplanet is a so-called super-Jupiter with a mass four times that of Jupiter. It is only about five to seven times less massive than its host, the faint brown dwarf 2M1207A.
The planet orbits 2M1207A at a distance of 5 billion miles — by contrast, Jupiter is approximately 500 million miles from our Sun.
According to astronomers, this bizarre planetary system lies around 170 light-years from Earth.
2M1207b is a mere 10 million years old. Its days are short (less than 11 hours) and its temperature is very hot (2,600 degrees Fahrenheit). Its rain showers come in the form of liquid iron and glass.
Now, a team of scientists led by University of Arizona astronomer Yifan Zhou has been able to deduce the 2M1207b’s rotational period and better understand its atmospheric properties, including its patchy clouds, by taking 160 images of the target over the course of ten hours.
Their work was made possible by the high resolution and high contrast imaging capabilities of Hubble’s Wide Field Camera 3.
“Understanding the exoplanet’s atmosphere was one of the key goals for us. This can help us understand how its clouds form and if they are homogenous or heterogeneous across the planet,” said Zhou, who is the lead author of a paper in the Astrophysical Journal (arXiv.org preprint).
“The result is very exciting. It gives us a new technique to explore the atmospheres of exoplanets,” added co-author Dr. Daniel Apai, also of the University of Arizona.
“This new imaging technique provides a method to map exoplanets and is an important step for understanding and placing our planets in context.”
Brown dwarf 2M1207A and super-Jupiter 2M1207b. Left: Hubble near-infrared-light image of the brown dwarf. Right: when the glow of the brown dwarf is subtracted from the image, a smaller and fainter companion object — 2M1207b — becomes visible. Because 2M1207b is only 10 million years old, it is so hot it may rain molten glass and iron in its atmosphere. Hubble has measured fluctuations in the planet’s brightness that suggests the planet has patchy clouds as it completes one rotation every 10 hours. Image credit: NASA / ESA / Y. Zhou, University of Arizona.
“2M1207b is likely just the first of many exoplanets we will now be able to characterize and map,” said co-author Dr. Glenn Schneider from the University of Arizona.
“Do these exotic worlds have banded cloud patterns like Jupiter? How is the weather and climate on these extremely hot worlds similar to or different from that of the colder planets in our own Solar System? Observations like these are key to answering these questions,” said senior author Dr. Adam Showman from the University of Arizona.
Dr. Apai said: “our study demonstrates that Hubble and its successor, NASA’s James Webb Space Telescope, will be able to derive cloud maps for exoplanets, based on the light we receive from them.”
“Indeed, this super-Jupiter is an ideal target for the Webb telescope, an infrared space observatory scheduled to launch in 2018.”
“Webb will help astronomers better determine the exoplanet’s atmospheric composition and derive detailed maps from brightness changes with the new technique demonstrated with the Hubble observations,” he said.
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Yifan Zhou et al. 2016. Discovery of Rotational Modulations in the Planetary-Mass Companion 2M1207b: Intermediate Rotation Period and Heterogeneous Clouds in a Low Gravity Atmosphere. ApJ 818, 176; doi: 10.3847/0004-637X/818/2/176
