The Most Distant Star Ever Seen

Detection of Star Icarus (formally, MACS J1149 Lensed Star 1). Credit: NASA, ESA, and P. Kelly (University of Minnesota)

Using the Hubble Space Telescope and gravitational lensing, astronomers have set a new distance record for the farthest individual star ever seen: 9 billion light years! One of those astronomers includes Dr. Brenda Frye from the University of Arizona Department of Astronomy, and blogger for the Catholic Astronomer!
Tucson News Now

What is Gravitational Lensing?

Massive objects in space have gravitational fields associated with them⁽¹⁾; the more massive the object, the stronger its gravitational field. Galaxies are massive objects with large gravitational fields – galaxy clusters even more so. Strong gravitational fields can bend light – much like the lens of a refracting telescope.

Bending light around a massive object from a distant source. The orange arrows show the apparent position of the background source. The white arrows show the path of the light from the true position of the source. Credit: Public Domain

If a distant galaxy is lined up just right with a galaxy cluster and the Earth, light from the distant galaxy will be bent and magnified by the gravity of the galaxy cluster. Astronomers have found numerous examples of this type of gravitational lensing – many examples appearing as smears or odd elliptical shapes.

An Einstein Ring. Credit: ESA/Hubble & NASA

Cosmic Snake. Credit: ESA/NASA

For the first time, astronomers have identified a magnified individual star in a distant galaxy. The star is named “MACS J1149+2223 Lensed Star 1” nicknamed Icarus – a blue supergiant about 9 billion light years distant. Previously, the most distant individual stars astronomers could identify were millions of light years away – this discovery has pushed that limit well past several billions of light years.

“This technique with its high magnification factors of 1000 or more  may offer a viable route to detect not just distant stars, but also distant galaxies, or even the first galaxies. We will hope to develop this new technique in time for the launch of JWST in May, 2020.” – Dr. Brenda Frye

The James Webb Space Telescope, now scheduled to launch in May of 2020, could potentially find many more examples of distant gravitationally lensed stars.

Artist’s concept of the James Webb Space Telescope. Image credit: Northrop Grumman

Read More:

University of Arizona News: Hubble Telescope Sights Most Distant Star Ever Seen
Tucson News Now: UA astronomer announces discovery of star 9 billion light years away

(1): “In general relativity, the presence of matter (energy density) can curve spacetime, and the path of a light ray will be deflected as a result. This process is called gravitational lensing and in many cases can be described in analogy to the deflection of light by (e.g. glass) lenses in optics. Many useful results for cosmology have come out of using this property of matter and light.” From: http://w.astro.berkeley.edu/~jcohn/lens.html