Just months after the launch of the new James Webb Space Telescope, the experienced Hubble Space Telescope just proved that it’s not ready to rest on its laurels just yet, as a combination of both the older space telescope’s instruments and a little help from space’s “natural magnifying glass” just brought into Hubble’s view what may be the most distant star we’ve ever seen.
The supposed star, nicknamed “Earendel” by its discoverers from the Old English word for “morning star,” is so far away that the light that Hubble just spotted with its lenses took a whopping 12.9 billion years to travel from the innards of Earendel to us here on Earth.
Earendel was spotted using Hubble’s Reionization Lensing Cluster Survey (RELICS) program, with the paper reporting on the remarkable find published in the journal Nature. The paper about this very distant star was helmed by astronomer Brian Welch from Johns Hopkins University, together with co-author Dan Coe who leads RELICS.
“We almost didn’t believe it at first, it was so much farther than the previous most-distant, highest redshift star,” said Welch, describing the fact that distant stars get their light stretched as the space they travel in also expands with the expanding universe, making their wavelengths longer and thus shifting their colors into the red part of the spectrum, hence the term redshifting.
Welch continued in a press release from the Hubble team: “Normally at these distances, entire galaxies look like small smudges, with the light from millions of stars blending together. The galaxy hosting this star has been magnified and distorted by gravitational lensing into a long crescent that we named the Sunrise Arc.”
Welch and the team estimate Earendel to be around fifty (50) times the mass of our own Sun and is likely millions of times as bright. However, despite these staggering numbers, even the strongest of telescopes will struggle to even catch a glimpse of a star that’s so far away; luckily for Hubble, the galaxy cluster WHL0137-08 sat between us and Earendel.
WHL0137-08’s gravity caused the starlight from Earendel to pass as its immense mass warped the space around it, creating a natural “magnifying glass” known as gravitational lensing. This caused Earendel’s light to “pop out” of its host galaxy, magnifying its apparent brightness and enabling Hubble to spot it from so far away.
“Earendel existed so long ago that it may not have had all the same raw materials as the stars around us today,” Welch added. “Studying Earendel will be a window into an era of the universe that we are unfamiliar with, but that led to everything we do know. It’s like we’ve been reading a really interesting book, but we started with the second chapter, and now we will have a chance to see how it all got started.”
Welch and the team are positive that more findings will come from the spotting of Earendel; given its penchant for giving us images of itself in redshifted light, the sensitivity of the James Webb Space Telescope’s optics to infrared wavelengths makes the new space telescope the perfect candidate for studying Earendel further.
From there, scientists hope to ascertain the true identity of Earendel, as well as to measure its brightness and temperature. Additionally, given the extremely old age of the star, the research team expects to find both Earendel and its stellar neighbors to be quite lacking in heavy elements compared to newer stars like our own.
“With Webb, we may see stars even farther than Earendel, which would be incredibly exciting,” Welch concluded. “We’ll go as far back as we can. I would love to see Webb break Earendel’s distance record.”
References
- Record broken: Hubble spots farthest star ever seen. (2022, March 30). HubbleSite.Org. http://hubblesite.org/contents/news-releases/2022/news-2022-003
- Welch, B., Coe, D., Diego, J. M., Zitrin, A., Zackrisson, E., Dimauro, P., Jiménez-Teja, Y., Kelly, P., Mahler, G., Oguri, M., Timmes, F. X., Windhorst, R., Florian, M., de Mink, S. E., Avila, R. J., Anderson, J., Bradley, L., Sharon, K., Vikaeus, A., … Broadhurst, T. (2022). A highly magnified star at redshift 6.2. Nature, 603(7903), 815–818. https://doi.org/10.1038/s41586-022-04449-y
