Fresh images obtained by ALMA or Atacama Large Millimeter/submillimeter Array radio telescope in Chile exposed a turtle-shaped object on the solar surface indicating a sunspot in the making with a size double that of Earth.
The upcoming sunspot has been captured by ALMA when it was commissioned for the first ever study of the sun under a campaign by international astronomers that lasted for more than two years with a focus on chromospheres – the hotter area above the visible surface of the sun.
Ideally, ALMA, as a telescope is used for probing radio waves emitted by the distant galaxies of the universe that appear as faint objects.
Millimeter Wavelength Imaging
The researchers decided to tap ALMA for its capabilities in capturing images of millimeter-wavelength light in studying the sun's chromosphere.
Factoring in the brightness of the sun, which is billions of times higher than the faint objects generally tracked by ALMA, the team opted for many new procedures in making the imaging safe.
The 30-month campaign was initiated in 2014, with the team using ALMA's single-antenna and array capabilities to target the millimeter-wavelength light emitted by the chromosphere.
"To fully understand the Sun, we need to study it across the entire electromagnetic spectrum, including the millimeter and the submillimeter portion that ALMA can observe," said Tim Bastian, an astronomer with the National Radio Astronomy Observatory in Charlottesville.
Stunning Details
Finally, the telltale images brought out vivid details about the evolving sunspot. Taken at a wavelength of 1.25 millimeters on Dec. 18, 2015, the images of the sunspot revealed the inner workings of the molten hot chromosphere and the darker areas. It should be noted that sunspots are relatively cooler areas.
The different depths in the chromosphere became evident in the images returned by radio waves at 2.5 and 3 millimeters. ALMA took the whole of the sun's image at a wavelength of 617.3 nanometers.
Formation Of Sun Spots
The formation of sunspots happens when magnetic field lines warp and start jutting out through the plasma's surface with a cooler area. Such magnetic activity also accelerates solar flares and coronal mass ejections with the sun's material fuming outwards.
Explaining the importance of the new solar study, Bastian noted that a broader focus on the electromagnetic spectrum of the sun is very essential.
The images have certainly reinforced ALMA's capability to study solar activity at longer wavelengths than normally observed with regular solar telescopes on Earth.
ESO Tribute
Meanwhile, the European Southern Observatory in a statement noted that this was ALMA's first attempt at measuring radio emissions of the orb and for ESO this was the first observatory where it is a partner in investigating the sun.
