VLA detects possible extrasolar planetary-mass magnetic powerhouse 

Posted: August 4, 2018 by oldbrew in Astrophysics
Tags: ,

Very Large Array, New Mexico [image credit: NASA]


This was ‘the first radio detection and the first measurement of the magnetic field of a possible planetary mass object beyond our Solar System.’ It’s even bigger than Jupiter. Plenty of puzzles for scientists to investigate.

Astronomers have used the VLA to detect a possible planetary-mass object with a surprisingly powerful magnetic field some 20 light-years from Earth.

It can help scientists better understand magnetic processes on stars and planets, says the National Radio Astronomy Observatory.

Astronomers using the National Science Foundation’s Karl G. Jansky Very Large Array
(VLA) have made the first radio-telescope detection of a planetary-mass object beyond our Solar System. The object, about a dozen times more massive than Jupiter, is a surprisingly strong magnetic powerhouse and a “rogue,” traveling through space unaccompanied by any parent 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,” said Melodie Kao, who led this study while a graduate student at Caltech, and is now a Hubble Postdoctoral Fellow at Arizona State University.

Brown dwarfs are objects too massive to be considered planets, yet not massive enough to sustain nuclear fusion of hydrogen in their cores — the process that powers stars. Theorists suggested in the 1960s that such objects would exist, but the first one was not discovered until 1995. They originally were thought to not emit radio waves, but in 2001 a VLA discovery of radio flaring in one revealed strong magnetic activity.

Subsequent observations showed that some brown dwarfs have strong auroras, similar to those seen in our own Solar System’s giant planets. The auroras seen on Earth are caused by our planet’s magnetic field interacting with the solar wind. However, solitary brown dwarfs do not have a solar wind from a nearby star to interact with. How the auroras are caused in brown dwarfs is unclear, but the scientists think one possibility is an orbiting planet or moon interacting with the brown dwarf’s magnetic field, such as what happens between Jupiter and its moon Io.

The strange object in the latest study, called SIMP J01365663+0933473, has a magnetic field more than 200 times stronger than Jupiter’s. The object was originally detected in 2016 as one of five brown dwarfs the scientists studied with the VLA to gain new knowledge about magnetic fields and the mechanisms by which some of the coolest such objects can produce strong radio emission. Brown dwarf masses are notoriously difficult to measure, and at the time, the object was thought to be an old and much more massive brown dwarf.

Last year, an independent team of scientists discovered that SIMP J01365663+0933473 was part of a very young group of stars. Its young age meant that it was in fact so much less massive that it could be a free-floating planet — only 12.7 times more massive than Jupiter, with a radius 1.22 times that of Jupiter.

At 200 million years old and 20 light-years from Earth, the object has a surface temperature of about 825 degrees Celsius, or more than 1500 degrees Fahrenheit. By comparison, the Sun’s surface temperature is about 5,500 degrees Celsius.

Continued here.

Comments
  1. JB says:

    Very interesting. By my estimation of the mass increase of our sun to shift the earth’s orbit from 360 to 365¼ days, the amount was equivalent to 14x that of Jupiter. That mass was primarily formed of the “wandering” star known as Phaeton/Marduk, etc. as outlined in Allan & Delair’s 1995 book When the Earth Nearly Died. Released State side as Cataclysm in ’97.

    My supposition is that the planet was an ejected exoplanet from the sun’s companion binary system, as modeled by Nickolas Moeckel and Dimitri Veras in their 2012 paper.

    The strength of SIMP’s magnetic field also nests well with the proffered orbital trajectory-destruction scenario in the book. My exercise was driven by the question of how large a planet orbiting in the asteroid belt would have to be, and was based on magnifying Ceres until the gravity was between 1 & 2 times that of Earth. That also proved to fit well within the plot of various mass, velocity, density, and inertia parameters of the solar system bodies.

  2. oldbrew says:

    the object has a surface temperature of about 825 degrees Celsius, or more than 1500 degrees Fahrenheit.

    Not much of that can be due to a local star 😐
    a “rogue,” traveling through space unaccompanied by any parent star.

  3. JB says:

    “The strange object in the latest study, called SIMP J01365663+0933473, has a magnetic field more than 200 times stronger than Jupiter’s.”

    Magnetic induction heating seems the likely source of its high surface temp. That implies the SIMP is a dense object. Such a surface temp is not likely to come from star radiation, but if it is in the vicinity of high magnetic field(s) it would explain the observation.

  4. oldbrew says:

    The report says: 12.7 times more massive than Jupiter, with a radius 1.22 times that of Jupiter.

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