Jupiter’s Red Spot Jr

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Jupiter’s Great Red Spot(GRS), an atmospheric storm, is the most prominent feature on the planet. It is being rivaled by a storm officially named Oval BA, but colloquially referred to as Jupiter’s Red Spot Jr.

Jr is nearly half the size of the GRS and is about the same color. The storm started when three smaller white storms collided in 2000. Many astronomers think that the GRS may have started in the same way. Since the GRS has been observed for at least 400 years, there is no way to verify that theory.

Oval BA is in Jupiter’s southern hemisphere, located in the South Temperate Belt(STB). The three white oval storms that created Oval BA can be traced to 1939, when the South Temperate Zone(STZ) was torn into three long pieces by dark features. Elmer Reese labeled the dark sections AB, CD, and EF. As the rifts expanded, they shrunk the remaining segments of the STZ into the white ovals FA, BC, and DE. Ovals BC and DE merged in 1998, forming Oval BE. In March 2000, BE and FA joined together, forming Oval BA. Oval BA(Jr.) slowly began to turn red in August 2005. By February 2006, the color had changed to nearly match reached the GRS. Observations with the Hubble Space Telescope in 2007 indicate that Jr is getting stronger. Wind speeds have reached 618 km/h. As of July 2008, the storm was large enough to engulf the Earth.

A group of astronomers theorized that the new storm and the GRS might combine sometime in 2006, so they began using the Hubble Space Telescope to track the storms. The storms pass each other about every two years. Dr. Amy Simon-Miller, of the Goddard Space Flight Center predicted the storms would make their closest approach to each other on July 20, 2006. The storms did not converge, but the Gemini spacecraft returned some of the best images at the time.

Scientists do not understand why the GRS and Jupiter’s Great Red Spot Jr. have turned red. One of the most commonly suspected mechanisms is ”an upward and inward diffusion of either a colored compound or a coating vapor that may interact later with high energy solar photons at the upper levels of Oval BA.” The most likely suspects are complex organic molecules, red phosphorus, or other sulfur compounds.

Jupiter’s Red Spot Jr. should not be confused with another storm called the Baby Red Spot. This storm was torn to pieces, then absorbed by the GRS in 2008. Scientist think that the Jr will eventually collide with the GRS. Only time will prove this theory one way or the other.

Universe Today has covered Oval BA on many occasions. Here’s one article when the storms were about to pass one another, and another article about a third big storm in the making.

Here’s a NASA Science article about Oval BA, and an image from the Hubble Space Telescope.

We’ve also recorded an entire show just on Jupiter for Astronomy Cast. Listen to it here, Episode 56: Jupiter, and Episode 57: Jupiter’s Moons.

Source:
NASA