In an earlier, astronomers detected an exoplanet using radio waves and a Wobbly star


Hunting for exoplanet in our galaxy is a profoundly important endeavor. The more exoplanets we get, the better we can understand our solar system – and how life emerges in the universe. To date, more than 4,000 exoplanets have been confirmed – but a new discovery may widen the search, enabling us to find exoplanets that have previously proven to be very difficult to detect.

The newly discovered exoplanet, which is equivalent to the mass of Saturn, is a very small, cool red dwarf at a low mass range for the main sequence stars, and is located about 35 light-years away. However, it is not just the planet, nor the star, it is such a landslide here.

Particularly special in this discovery is that astronomers used a radio telescope to track the star’s movement through the Milky Way, and identify the snaking wiggle in that movement as the star gravitated from a gravitational exoplanet Is impressed. This very difficult feat is called astrometric technology, and is the first time it has been successfully deployed using a radio telescope.

TVLM 513-46546 System artist’s impression. (Luis A. Curiel Ramirez)

Using orbital wobble to detect exoplanet is not a new idea. You see, the orbital center of a planetary system is not interstellar. Rather, all bodies of the system revolve around a reciprocal center of gravity, called the baricentre. For example, the barrier of the solar system is just outside the surface of the Sun, mainly due to the gravitational effects of Jupiter and Saturn.

When we are looking at other stars on a large scale, closely orbiting, this effect can be detected as the light wavelength is drawn or narrowed as the star rotates. This detection technique is called Doppler spectroscopy, or radial velocity method, and is one of the more common methods for finding exoplanet.

Astrometric technique is slightly different. The stars of the Milky Way are not stable in space; They revolve around the galaxy, and the study of this movement is called astronomy. Therefore, instead of using wavelength changes, astronomy techniques look for deviations from a straight line of movement.

This method can be used to detect exoplanets that Doppler spectroscopy cannot perform, such that exoplanets spin in large orbits around their stars.

“Our method is complementary to the radial velocity method, which is more sensitive to planets orbiting in close orbits, while we have farther than the mass of planets orbiting planets,” Astrophysicist Gisela Tittiz of the Max Planck Institute for Radio- Leon said. Astronomy in Germany.

“In fact, in these other techniques only a few planets have been found such as planetary mass, orbital shape and host star mass, such as the planet we found. We believe that VLBAs and astronomy techniques in general, may reveal many. Is. More equal planets. “

VLBA is a very long baseline array, with a network of 10 radio antennas distributed widely across the US. For 18 months starting in June 2018, the research team led by astronomer Salvador Curiel of the National Autonomous University of Mexico placed a small star called TVLM 513-46546 into space for a year and a half.

A painstaking and careful analysis of the data revealed that Tara was not traveling in a perfectly straight line, but rather traveling a snacking path. Wiggle’s periodicity and amplitude detected a planet in a 221-day orbit and between 38 and 46 percent of Jupiter’s mass – slightly heavier than Saturn, which is about 30 percent of Jupiter’s mass.

“Huge planets like Jupiter and Saturn are expected to be rare around such small stars, and astrological techniques are best for finding planets like Jupiter in wide orbits, so we were surprised at what a low-mass, Saturn-like appearance would look like Planets in a relatively compact orbit. We found a more massive planet similar to Jupiter in a wider orbit.

Astrometric techniques are commonly used to study binary stars, whose gravitational effects on each other are much more pronounced than the effects of a star planet. Astrometric technology has been used to search for an exoplanet only once before (although it has been used to study an already known exoplanet), and has never been radio telescoped before.

Earlier this year, however, another group of scientists announced the first use of a radio telescope to detect an exoplanet. This was not through astronomy, but by detecting the circular polarization of radio waves generated by the motion of the planet through the magnetic field of a red dwarf.

So, although it was quite challenging for Curiel’s team to find out, their ultimate success confirms the promise of both radio telescopes and astronomy techniques in finding planets that miss other techniques.

The Gaia Telescope is currently surveying the Milky Way, creating the most detailed and accurate astrometric map of the galaxy yet; It is expected that this data will comprehensively blow up astrometric exoplanet detection, with an estimated tens of thousands of exoplanet searches to come.

The research has been published in The Astronomical Journal.

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