“Rains Liquid Iron and Glass” –Hubble Reveals 1st Images of an Exoplanet Atmosphere

 

 

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Using NASA's Hubble Space Telescope, astronomers at the University of Arizona have taken the first direct, time-resolved images of an exoplanet, a young, gaseous exoplanet known as 2M1207b, shown below, located some 160 light-years from Earth. The planet is four times the mass of Jupiter and orbits a failed star, known to astronomers as a brown dwarf. And while our solar system is 4.5 billion years in the making, 2M1207b is a mere ten million years old. Its days are short–less than 11 hours–and its temperature is hot–a blistering 2,600 degrees Fahrenheit. Its rain showers come in the form of liquid iron and glass.


The researchers, led by UA Department of Astronomy graduate student Yifan Zhou, were able to deduce the exoplanet'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.

Before now, nobody had ever used 26-year-old Hubble to create time-resolved images of an exoplanet. Even the largest telescope on Earth could not snap a sharp photo of a planet as far away as 2M1207b, so the astronomers created an innovative, new way to map its clouds without actually seeing them in sharp relief: They measured its changing brightness over time.

Daniel Apai, UA assistant professor of astronomy and planetary sciences, is the lead investigator of this Hubble program. He said, "The result is very exciting. It gives us a new technique to explore the atmospheres of exoplanets."

According to Apai, this new imaging technique provides a "method to map exoplanets" and is "an important step for understanding and placing our planets in context." Our Solar System has a relatively limited sampling of planets, and there is no planet as hot or as massive as 2M1207b within it.

 

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"2M1207b is likely just the first of many exoplanets we will now be able to characterize and map," said Steward Observatory Astronomer Glenn Schneider who co-authored the study with  Lunar and Planetary Laboratory's Adam Showman.

"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 Showman.

Zhou and his collaborators began collecting  data for this project in 2014. It began as a pilot study to demonstrate that space telescopes like Hubble and the James Webb Space Telescope, which NASA will launch in late 2018, can be used to map clouds on other planets.

The success of this study lead to a new, larger program: Hubble's Cloud Atlas program for which Apai is also the lead investigator. As one of Hubble's largest exoplanet-focused programs, Cloud Atlas represents a collaboration between 14 experts from across the globe, who are now creating more time-resolved images of other planets using the space telescope.

The composite image at the top of the page shows an exoplanet 2M1207b (the red spot on the lower left), orbiting the brown dwarf 2M1207 (center), the first exoplanet directly imaged and the first discovered orbiting a brown dwarf. It was imaged the first time by the VLT in 2004. Its planetary identity and characteristics were confirmed after one year of observations in 2005. 2M1207b is a Jupiter-like planet, 5 times more massive than Jupiter. It orbits the brown dwarf at a distance 55 times larger than the Earth to the Sun, nearly twice as far as Neptune is from the Sun. The system 2M1207 lies at a distance of 230 light-years, in the constellation of Hydra. The photo is based on three near-infrared exposures (in the H, K and L wavebands) with the NACO adaptive-optics facility at the 8.2-m VLT Yepun telescope at the ESO Paranal Observatory.

The Daily Galaxy via University of Arizona and ESO

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