July 23, 2020
from CosmosMagazine Website

Credit: Y Stein (CDS), NRAO, SDSS, KPNO 0.9m,

J English (U Manitoba), R-J Dettmar and A Miskolczi (Ruhr U),

RJ Rand (UNM), and J Irwin (Queen's U).


 

Two new images from space inform and intrigue

Here are two more images from space that have astronomers pretty excited.

Above is a radio/optical composite image of the edge-on spiral galaxy NGC 4217 showing the huge and unexpected extent of its magnetic field, which provides more pieces to the puzzle of how magnetic structures form in galaxies such as our own.

Below is the first ever image of a young, Sun-like star accompanied by two giant exoplanets, which may help astronomers understand how planets formed and evolved around the Sun.

 

The star TYC 8998-760-1

accompanied by two giant exoplanets.

Credit: ESO/Bohn et al.

NGC 4217, which is a star-forming galaxy similar to the Milky Way, is 67 million light-years from Earth in the constellation Ursa Major.
 

This visible-light image is from the Kitt Peak National Observatory in Arizona, while the magnetic field lines - which extend up to 22,500 light-years beyond the galaxy's disc - are revealed (and shown in green) by the Karl G Jansky Very Large Array (VLA) radio telescope in New Mexico.

Scientists know that magnetic fields play an important role in many processes within galaxies, such as star formation, but it is not clear how such huge magnetic fields are generated and maintained.

An international team led by Yelena Stein from Germany's Ruhr-Universität Bochum analyzed data from NGC 4217, which has an X-shaped magnetic structure, and found a helix structure and two large bubble structures, called superbubbles.

The latter originate from places where many massive stars explode as supernovae and where stars are formed that emit stellar winds in the process, they say, leading them to suspect a connection between these phenomena.

Analysis also revealed large loop structures in the magnetic fields along the entire galaxy.

"This has never been observed before," says Stein.

 

"We suspect that the structures are caused by star formation, because at these points matter is ejected outward."

The findings are described in a paper (Transport processes and the X-shaped magnetic field of NGC 4217) in the journal Astronomy & Astrophysics.

The second image, taken by the European Southern Observatory's Very Large Telescope (VLT), shows the star TYC 8998-760-1 about 300 light-years away and is,

"a snapshot of an environment that is very similar to our Solar System but at a much earlier stage of its evolution", says Alexander Bohn from Leiden University in the Netherlands, lead author of a paper (Two directly-imaged, wide-orbit giant planets around the young, solar analogue TYC 8998-760-1) in the Astrophysical Journal Letters.

The two exoplanets orbit their host star at distances of around 160 and 320 times the distance between Earth and the Sun.

This places then much further away from their star than two other gas giants, Jupiter and Saturn, are from their host.

Alexander Bohn and colleagues also found the two exoplanets are much heavier than the ones in our Solar System, the inner planet having 14 times Jupiter's mass and the outer one six times.

"Even though astronomers have indirectly detected thousands of planets in our galaxy, only a tiny fraction of these exoplanets have been directly imaged.

 

Direct observations are important in the search for environments that can support life," says Leiden's Matthew Kenworthy, a co-author.