WHL0137-LS, also known as Earendel, is a

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

in the constellation of

Cetus Cetus () is a constellation, sometimes called 'the whale' in English. The Cetus (mythology), Cetus was a sea monster in Greek mythology which both Perseus and Heracles needed to slay. Cetus is in the region of the sky that contains other water- ...

. Discovered in 2022 by the

Hubble Space Telescope The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most versa ...

, it is the earliest and most distant known star, at a

comoving distance In standard cosmology, comoving distance and proper distance are two closely related distance measures used by cosmologists to define distances between objects. ''Proper distance'' roughly corresponds to where a distant object would be at a spec ...

of . The previous furthest known star,

MACS J1149 Lensed Star 1 MACS J1149 Lensed Star 1, also known as Icarus,Other names include ''LS1'', ''MACS J1149 LS1'', ''MACS J1149 Lensed Star 1 (LS1)'' and ''MACS J1149+2223 Lensed Star 1'' is a blue supergiant star observed through a gravitational lens. It is the ...

, also known as Icarus, at a comoving distance of , was discovered by Hubble in 2018. Stars like Earendel can be observed at cosmological distances thanks to the large magnification factors involved, that can exceed 1000. Other stars have been observed through this technique, such as

Godzilla is a fictional monster, or '' kaiju'', originating from a series of Japanese films. The character first appeared in the 1954 film ''Godzilla'' and became a worldwide pop culture icon, appearing in various media, including 32 films produc ...

Observation

Earendel's discovery by the

was reported on 30 March 2022. The star was detectable due to

gravitational lens A gravitational lens is a distribution of matter (such as a cluster of galaxies) between a distant light source and an observer that is capable of bending the light from the source as the light travels toward the observer. This effect is known ...

ing caused by the presence of the galaxy cluster WHL0137-08 between it and the Earth, concentrating the light from the star. Computer simulations of the lensing effect suggest that Earendel's brightness was magnified between one thousand and forty thousand times. The dates of Hubble's exposure to the star's light were 7 June 2016, 17 July 2016, 4 November 2019, and 27 November 2019.

The star was nicknamed '' Earendel'' by the discoverers, derived from the

Old English Old English (, ), or Anglo-Saxon, is the earliest recorded form of the English language, spoken in England and southern and eastern Scotland in the early Middle Ages. It was brought to Great Britain by Anglo-Saxon settlement of Britain, Anglo ...

name for 'morning star' or 'rising light'. Eärendil is also the name of a half-elven character in one of

J. R. R. Tolkien John Ronald Reuel Tolkien (, ; 3 January 1892 – 2 September 1973) was an English writer and philology, philologist. He was the author of the high fantasy works ''The Hobbit'' and ''The Lord of the Rings''. From 1925 to 1945, Tolkien was ...

's books, ''

The Silmarillion ''The Silmarillion'' () is a collection of myths and stories in varying styles by the English writer J. R. R. Tolkien. It was edited and published posthumously by his son Christopher Tolkien in 1977, assisted by the fantasy author Guy Gavriel ...

,'' who travelled through the sky with a radiant jewel that appeared as bright as a star. NASA astronomer

Michelle Thaller Dr. Michelle Lynn Thaller is an American astronomer and research scientist. Thaller is the assistant director for Science Communication at NASA's Goddard Space Flight Center. From 1998 to 2009 she was a staff scientist at the Infrared Processin ...

confirmed that the reference to Tolkien was intentional. The star's host galaxy, WHL0137-zD1, was nicknamed "Sunrise Arc", because gravitational lensing distorted its light into a long crescent. Further observations by Hubble and the

James Webb Space Telescope The James Webb Space Telescope (JWST) is a space telescope which conducts infrared astronomy. As the largest optical telescope in space, its high resolution and sensitivity allow it to view objects too old, distant, or faint for the Hubble Spa ...

have been proposed to better define the properties of the star. James Webb's higher sensitivity is expected to allow the analysis of Earendel's

stellar spectra Astronomical spectroscopy is the study of astronomy using the techniques of spectroscopy to measure the spectrum of electromagnetic radiation, including visible light, ultraviolet, X-ray, infrared and radio waves that radiate from stars and othe ...

and determine whether it is actually a single star. The spectral analysis would reveal the presence of elements heavier than hydrogen and helium, if any. On 30 July 2022, an image of Earendel was captured by the

during its first imaging campaign of the star.

Physical properties

The light detected from Earendel was emitted 900 million years after the

Big Bang The Big Bang event is a physical theory that describes how the universe expanded from an initial state of high density and temperature. Various cosmological models of the Big Bang explain the evolution of the observable universe from the ...

. The star has been determined to have a

redshift In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and simultaneous increase in f ...

, meaning the light from Earendel reached

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

12.9 billion years later. However, due to the

expansion of the universe The expansion of the universe is the increase in distance between any two given gravitationally unbound parts of the observable universe with time. It is an intrinsic expansion whereby the scale of space itself changes. The universe does not exp ...

, the star's observed position is now 28 billion

light-years A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

away. The previous most distant star,

, has a redshift of 1.49, and is now 14.4 billion light-years away. As observed, Earendel is likely to have a mass of between 50 and 100

solar masses The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass of ...

, and an effective surface temperature of at least . Stars this large usually explode as a

supernova A supernova is a powerful and luminous explosion of a star. It has the plural form supernovae or supernovas, and is abbreviated SN or SNe. This transient astronomical event occurs during the last evolutionary stages of a massive star or when ...

just a few million years after forming. Although unlikely, Earendel has a small probability of being a

population III star During 1944, Walter Baade categorized groups of stars within the Milky Way into stellar populations. In the abstract of the article by Baade, he recognizes that Jan Oort originally conceived this type of classification in 1926: Baade noticed th ...

, meaning it would contain almost no elements other than primordial hydrogen and helium.

Notes

References

{{DEFAULTSORT:WHL0137-LS 20220330 Cetus (constellation) Hubble Space Telescope Intergalactic stars Things named after Tolkien works

Observation

Physical properties

See also

Notes

References