NASA scientists discovered a strange ice giant that cannot be explained by the above theory using the exoplanet detective transit exoplanet recognition satellite (TESS, which had “first light” on August 7, 2018). The planet, TOI-849 b, is the most massive Neptune-sized planet detected to date, and the first to have a density comparable to that of Earth. The strange proportions of the planet orbit a star about 750 light years from Earth every 18 hours, and are 40 times more massive.
“We are really puzzled about how this planet formed,” says Chelsea Huang, a postdoctoral fellow at MIT’s Kavli Institute for Astrophysics and Space Research, and a member of the TESS science team. “All current theories do not fully explain why it is so massive at its current location. We don’t expect planets to grow to 40 land masses and then just stop there. Instead, it should continue to grow and end up being a gas giant, like a hot Jupiter, to several hundred land masses. It’s crazy to think what happens at the center of a planet with that kind of pressure. “
Since launching on April 18, 2018, the TESS satellite has been scanning the heavens for planets beyond our solar system. The project is one of NASA’s Astrophysics Explorer missions and is managed and operated by MIT. TESS, which is predicted to discover a handful of habitable alien planets, is designed to examine almost the entire sky by rotating your view each month to focus on a different patch of the sky as it orbits Earth. TESS uses the “transit method,” which looks for small drops in the star’s brightness caused when an orbiting planet crosses the star’s face from TESS’s perspective, similar to NASA’s Kepler space telescope, which roughly discovered the 70% of the more than 4,000 more or less known strange worlds
“Object of interest to Tess”
Data taken by TESS, in the form of a star’s light curve, or measurements of brightness, are made available to the TESS scientific team, an international group of researchers from various institutes led by MIT scientists. These researchers get a first look at the data to identify promising planetary candidates, or TESS Objects of Interest (TOI). These are shared publicly with the general scientific community along with the TESS data for analysis.
Hidden in the data
For the most part, astronomers focus their planet hunt on the closest, brightest stars TESS has observed. However, Huang and his team at MIT recently had additional time to review the data during September and October 2018, and wondered if anything could be found among the weaker stars. Indeed, they discovered a significant number of dives similar to the transit of a star 750 light years away, and soon after, confirmed the existence of TOI-849 b.
NASA “TESS Mission Objects” Probe – Alien Civilization Target Probe
“Stars like this are generally not carefully examined by our team, so this discovery was a happy coincidence,” says Huang. Follow-up observations of the faint star with a series of ground-based telescopes further confirmed the planet and also helped determine its mass and density.
Previous theories cannot explain this planet
One hypothesis that scientists have put forward to explain the mass and density of the new planet is that it was perhaps once a much larger gas giant, similar to Jupiter and Saturn, planets with more massive gas envelopes that envelop nuclei that are considered so dense as the Earth.
As the TESS team proposes in the new study, over time, much of the planet’s gas envelope may have been removed by radiation from the star, which is not an unlikely scenario, since TOI-849 b orbits extremely close to its host star. Its orbital period is only 0.765 days, or just over 18 hours, which exposes the planet to about 2,000 times the solar radiation that Earth receives from the sun. According to this model, the Neptune-sized planet that TESS discovered may be the remnant nucleus of a much more massive giant, the size of Jupiter.
“If this scenario is true, TOI-849 b is the only remaining planet nucleus and the largest known gas giant nucleus that exists,” says Huang. “This is something that scientists are excited about because previous theories cannot explain this planet.”
The Daily Galaxy, Max Goldberg, via MIT
