Category: Exoplanet

Failed Star Presents Unique Opportunities

A rogue, planet-size object 20 light-years away from Earth has stunned astronomers with its incredibly powerful magnetic field.

The scientists found that the object’s magnetic field is more than 200 times stronger than Jupiter’s, which, in turn, is between 16 and 54 times stronger than Earth’s, according to NASA. How the object, which scientists call SIMP J01365663+0933473, can maintain a magnetic field so strong, as well as generate spectacular auroras, is still unclear.

“This particular object is exciting because studying its magnetic dynamo mechanisms can give us new insights on how the same type of mechanisms can operate in extrasolar planets — planets beyond our solar system,” lead study author Melodie Kao, an astrophysicist at Arizona State University, said in a statement from the National Radio Astronomy Observatory published Aug. 2.

It’s not just the magnetic mechanism that’s leaving scientists with questions right now — there are plenty of other mysteries about the object, which scientists first discovered in 2016.

The object is what scientists call a brown dwarf. Nicknamed “failed stars,” brown dwarfs are larger than planets, but not quite large enough to fuse hydrogen, the way stars do. The boundary line is still debated, but scientists tend to draw it at about 13 times the mass of Jupiter.

Originally, scientists thought SIMP J01365663+0933473 was a gigantic, old brown dwarf. But further study showed that it is instead relatively young, at 200 million years old, and is only 12.7 times the mass of Jupiter. That research also showed that the planet is on its own, not orbiting a star.

“This object is right at the boundary between a planet and a brown dwarf, or ‘failed star,’ and is giving us some surprises that can potentially help us understand magnetic processes on both stars and planets,” Kao said in the statement. “We think these mechanisms can work not only in brown dwarfs, but also in both gas giant and terrestrial planets.”
The team is particularly excited by the new research because it relies in part on radio observations of the object’s auroras — which means that radio telescopes may be able to identify new planets by their auroras.

The new research was described in an article published July 31 in the Astrophysical Journal.
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SpaceX Set To Launch Planet Hunter TESS On Monday

With the crippled Kepler orbital equipment almost out of fuel, NASA is preparing the launch of its newest planet-hunting spacecraft, TESS.

TESS, short for Transiting Exoplanet Survey Satellite, will be carried into space by SpaceX’s Falcon 9 rocket on April 16. With a little help from the moon’s gravity, the satellite will achieve a high Earth orbit, offering the probe wide, unobstructed views of the night sky. The probe will orbit Earth twice for every one lunar orbit.

While TESS’s scientific mission is largely the same as Kepler’s — image transiting exoplanets — the probe will use a different approach. Whereas Kepler focused on small fields of view for long periods of time, TESS will take a wider, more comprehensive view.

“TESS is designed to image almost all of the night sky — using four wide angle cameras — in long vertical strips called sectors,” Natalia Guerrero, MIT scientist and researcher on the TESS mission, told UPI.

TESS scientists have divided the sky into long strips called sectors. Each hemisphere contains 13 sectors, and over the next three years, TESS will survey, sector by sector, the Southern Hemisphere and then the Northern Hemisphere.

During each sector scan, TESS’s four cameras will capture 30-minute exposures. The four images will be stacked on top of each other by the satellite’s computer and transmitted back to Earth.

In addition to organizing the sky into sectors, TESS scientists have identified 200,000 especially bright stars likely to host transiting exoplanets. Each stellar target is highlighted by a so-called postage stamp.

Exposures of each postage stamp will be stacked on top of each other every two minutes and beamed back to Earth. These postage stamp observations are expected to identify planetary systems located much closer to Earth than those found by Kepler.

Data captured by TESS will go through the same image-processing pipeline used for Kepler observations. Basic algorithms will process images and identify the dimming patterns created when exoplanets pass across the face of their host star.

Scientists will review the transit events identified via computer analysis and highlight targets for follow-up observations.

“From the depth of the transit and the frequency light curve, we can back out the size of the planet and distance from its host star,” Guerrero said.

But, like Kepler, TESS is designed to survey the sky, not carry out in-depth investigations. Scientists will rely on other telescopes, both ground and space-based, to observe transiting objects in greater detail. Through follow-up investigations, astronomers will be able to estimate an exoplanet’s mass and the composition of its atmosphere, as well as its habitability.

TESS scientists will focus much of their analysis on the two-minute cadence of images of postage stamped targets, but the satellite’s biggest surprises may be more likely to be revealed by the full frame images. In addition to capturing transits, the full-frame images will record observations of thousands of stars.

“The full frame images will serve as really rich repositories of data,” Guerrero said. “They will be made public and will be a wonderful opportunity for the astronomical community and really any interested parties.”

“We’re very excited about the citizen science efforts that will be inspired by these images,” Guerrero said.