Thursday, April 5, 2018

Icarus: The Farthest Star From Earth



NASA's Hubble Space Telescope uncovers 'Icarus', the farthest star ever seen. A team of astrophysicists have reported the imaging of Icarus, a single star whose properties suggest that it is located approximately 9 billion light years away from Earth.

Discovery of Icarus

Working across a range of institutions in the UK, Spain, Denmark, Japan and the US, scientists used the gravitational-lens technique to image the star, which they initially termed MACS J1149 Lensed Star 1 (LS1). However, it also acquired the name of Icarus.

Gravitational lenses, which are partially conferred by other galactic clusters in the vicinity of the object, can magnify other galaxies. With these devices, the cosmos can be detected by telescopes on Earth despite being billions of light years away.

Imaging of Icarus

The latest images of Icarus were taken nearly two years ago (in late April to May 2016) using the Hubble Space Telescope (HST) Wide Field Camera 3 infrared (IR) camera.

The imaging session was, in fact, intended to assess the explosion of the Refsdal supernova. However, the team also noticed an anomaly in the red-shift of MACS J1149. It was found to be a single source of blue light coming from an individual super-giant - MACS J1149-LS1.


Icarus: What kind of star?

LS1 was also found to have a temperature of 11,000 to 14,000 kelvin and a characteristic SED profile. These properties were also consistent with MACS J1149’s red-shift (z=1.49). LS1 was also found to be relatively small (0.06 parsecs in width) suggesting that it was most likely a single star or a binary system, at best. The team also detected signs of a second body, which seemed to be extremely close to LS1. The images of this object, termed Lev16B, were found to have nearly identical properties in terms of colour and colour-magnitude.

References

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