HR 8799c – an exoplanet – has water and carbon monoxide in its atmosphere

Main Point:

Scientists have found water vapor and carbon monoxide in the atmosphere of a Jupiter-size extrasolar planet, dubbed as HR 8799c orbiting a star known as HR 8799.



Artist depiction of the planetary system of HR 8799 with HR 8799c and disk of gas and dust (Credit: Dunlap Institute for Astronomy & Astrophysics; Mediafarm)
Artist’s depiction of the planetary system of HR 8799 with HR 8799c and disk of gas and dust (Credit: Dunlap Institute for Astronomy & Astrophysics; Mediafarm)


Study Further:

HR 8799c is a gas-giant and has about seven times the mass of Jupiter. This planet is rotating around its star at a distance that is comparable to the distance between the Pluto and Sun.

Scientists, in this study, took high-resolution data on the chemistry, gravity and atmosphere of HR 8799c.

“The exoplanet has an ideal set of properties, being both fairly bright and located far enough away from the star to allow us to acquire this amazing spectral data,” Dr Konopacky said.

Scientists have found water and carbon monoxide in the atmosphere but there are no signs of methane.

“The fact that we don’t see methane tells us a lot about the chemical processes at work in the atmosphere of this young gas giant.” Dr Konopacky added.

Scientists are of the opinion that core accretion – multi-step planet-forming mechanism by which the gas accumulates onto a planetary core – was responsible for the planet’s formation.

“Our results are most consistent with the planets around HR8799 forming via core accretion, much in the same way we think the planets in our own Solar System formed,” said co-author Dr Quinn Konopacky from the Dunlap Institute for Astronomy and Astrophysics at the University of Toronto.

“By studying the HR8799 system, we can get a peek at how Jupiter-like planets look very shortly after they form.”

“Although we see a lot of water vapor in the atmosphere of HR 8799c, we actually detect slightly less than we would have expected if the planet had the same composition as its host star,” said Konopacky. “This tells us that the planet has a slightly elevated amount of carbon compared to oxygen.”

High carbon-to-oxygen ratio helps in studying the formation of the exoplanet. Researchers are of the opinion that grains of water ice condensed in the disc of the matter around the HR 8799 and depleted the oxygen.

“These ice grains stuck together to make bigger ice chunks, a few kilometers across, that kept colliding and building up the planet’s solid core,” Konopacky said. “The atmosphere came later — from gas that the planet attracted after it got big enough. By the time that happened, some of the ice grains were gone and the gas didn’t have as much water in it.”

“Since the planetary system surrounding HR8799 looks like a scaled up version of our Solar System, it would not come as a surprise to find Earth-like planets closer in,” according to the researchers.

Source: Eurekalert, Sci-news


Konopacky, Q., Barman, T., Macintosh, B., & Marois, C. (2013). Detection of Carbon Monoxide and Water Absorption Lines in an Exoplanet Atmosphere Science DOI: 10.1126/science.1232003

Usman Zafar Paracha

Usman Zafar Paracha is a sort of entrepreneur. He is the author of "Color Atlas of Statistics", and the owner of an Android game "Faily Rocket."

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