Texas astronomers revive idea for ‘eventually larger telescope’ on moon


Large telescopes eventually. Credit: University of Texas McDonald Observatory

A group of astronomers at the University of Texas at Austin have found that a telescope idea taken away by NASA a decade ago could solve a problem that no other telescope could: it would be able to study the first stars in the universe . Team led by NASA Hubble Fellow Anna Schauer will publish their results in the upcoming results The Astrophysical Journal.

“In astronomy history, the telescope has become more powerful, allowing us to sequentially examine sources closer to earlier cosmic times — the Big Bang,” said Professor and team member Volker Bromm, a Theorist who has studied stars for decades. . “Upcoming James Webb Space Telescope” [JWST] Would have reached the time when galaxies were first formed.

“But the theory predicts that there was also a time before, when galaxies were not yet present, but where individual stars first formed – the elusive Population III stars. This moment of ‘very first light’ was beyond the capabilities of the powerful JWST And an ‘ultimate’ telescope is needed instead.

These first stars formed about 13 billion years ago. They are unique, born from a mixture of hydrogen and helium gases, and possibly tens or 100 times larger than the Sun. Shehr’s new calculations show that a previously proposed facility, a liquid mirror telescope that operates from the lunar surface, can study these stars. Proposed in 2008 by a team led by Roger Angel of the University of Arizona, the facility was called the Lunar Liquid-Mirror Telescope (LLMT).

NASA conducted an analysis on the proposed facility a decade ago, but decided not to pursue the project. According to NV Dory, a senior research scientist at the McDonald Observatory at UT Austin, supporting science was not present at that point. “This telescope is perfect for that problem,” he said.

The proposed lunar liquid-mirror telescope, which Shaur has dubbed the “Ultimate Large Telescope”, will have a mirror diameter of 100 meters. It will operate autonomously from the lunar surface, receive power from the solar energy collection station on the moon, and relay data to the satellite in lunar orbit.

Instead of coated glass, the mirror of the telescope will be made of liquid, because it is lighter, and thus cheaper to transport to the moon. The mirror of the telescope will be a spinning vat of liquid, topped by a metallic – and thus reflective – liquid. (Previous liquid mirror telescopes have used mercury.) Vata will rotate continuously, keeping the surface of the liquid in the correct paraboloid shape to serve as a mirror.

The telescope will be stationary, located inside a pit at the north or south pole of the moon. To study the stars first, it would be to constantly stare at the same patch of sky, gathering as much light from them as possible.

“We live in a universe of stars,” Brom said. “This is an important question of how star formation was occurring early in cosmic history. The rise of the first stars indicates an important transition in the history of the universe, when the primordial conditions set by the Big Bang gave way to a growing cosmic Was. Complexity, eventually bringing life to planets, life and intelligent beings like us.

“This moment of first light is beyond the capabilities of current or near-future telescopes. It is therefore important to think of a ‘last’ telescope, which is able to directly observe those elusive first stars at the edge of time. “

The team proposes that the astronomical community revisit the plan of shelter for the lunar liquid mirror telescope, as a way to study these first stars in the universe.


Hubble makes amazing discoveries in early universe


more information:
Anna TP Shahaur et al, The Ultimate Large Telescope – What kind of facility do we need to detect Population III stars? Astrophysics of Galaxies arXiv: 2007.02946v2, arxiv.org/abs/2007.02946

Provided by the University of Texas Macdonald Observatory

Quotes: Astronomers in Texas revived the idea for an ‘ultimately large telescope’ on the moon (2020, 16 November). Retrieved 16 November 2020 from https://phys.org/news/2020-11-texas-astronomers-revive-idea-ultively.html.

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