Ereandel
The Most Distant Individual Star Ever Detected
Quick Reader
| Attribute | Details |
|---|---|
| Name | Earendel (formally: WHL0137-LS) |
| Meaning | “Morning Star” in Old English (named after a character in Tolkien’s lore) |
| Type | Possibly a massive Population III or very metal-poor B-type star |
| Discovered | 2022, announced by NASA and Hubble Space Telescope team |
| Distance from Earth | ~12.9 billion light-years (light-travel distance) |
| Redshift (z) | ~6.2 |
| Apparent Magnitude | ~28.7 (very faint) |
| Host Galaxy | WHL0137-zD1 (a star-forming galaxy behind a galaxy cluster) |
| Lens | Gravitational lensing by galaxy cluster WHL0137-08 |
| Telescope | Hubble Space Telescope (later confirmed by JWST) |
| Size and Mass Estimate | Estimated mass ≥ 50 solar masses (likely more) |
| Temperature | Possibly >20,000 K |
| Significance | Farthest individual star ever observed |
| Previous Record Holder | Icarus (z ~1.49) |
Introduction – A Single Star from the Dawn of Time
We’ve seen galaxies billions of light-years away. But to detect a single star from the early universe? That was once thought impossible — until the discovery of Earendel, the most distant individual star ever detected.
Named after the Old English word for “morning star”, Earendel is a beacon from a time when the universe was less than 7% of its current age. Its light traveled across 12.9 billion years of cosmic history before reaching the Hubble Space Telescope.
This discovery wasn’t just a technological marvel — it was a profound glimpse into the universe’s infancy, offering insights into:
The first generations of stars
The nature of gravitational lensing
The capabilities of next-gen observatories like JWST
How Was Earendel Discovered?
The Role of Gravitational Lensing
Earendel was not detected through brightness alone. It was revealed thanks to a perfect alignment between:
A foreground galaxy cluster (WHL0137-08)
A background galaxy (WHL0137-zD1, where Earendel resides)
The Hubble Space Telescope’s deep-field imaging
This alignment created a gravitational lens, magnifying the light of distant background objects.
In Earendel’s case, the lensing was so strong that it produced a critical curve, boosting the star’s brightness by a factor of thousands — enough to be picked up by Hubble.
Why Was Earendel So Special?
Unlike galaxies, which are made of billions of stars, individual stars are much harder to detect at extreme distances. Before Earendel, the farthest known star was Icarus (z ~1.49). Earendel shattered that record with z ~6.2.
Key reasons Earendel stood out:
Extreme magnification made the single star detectable
It was not blended into its host galaxy
The lensing model matched a point source, not a star cluster
Follow-up data confirmed no movement or multiple sources, supporting the single-star scenario
Characteristics of Earendel
Though unresolved even by Hubble, modeling allows astronomers to infer several properties:
Likely a B-type or O-type star, very hot and massive
Possibly 50–100 times the mass of the Sun
Surface temperature could exceed 20,000 Kelvin
Lifetime likely short — only a few million years
May be part of a binary system (JWST is investigating this)
There’s even speculation that Earendel could be a Population III star, one of the first stars formed in the universe — though this remains unconfirmed.
Gravitational Lensing – Nature’s Telescope
Earendel’s detection wouldn’t have been possible without a phenomenon predicted by Einstein’s theory of general relativity: gravitational lensing.
How It Works:
A massive foreground object (in this case, galaxy cluster WHL0137-08) bends space-time.
This distortion bends and magnifies light from a background source.
When the alignment is precise, a caustic (extreme magnification zone) forms.
If a star crosses that zone, it can be magnified thousands of times — briefly making it visible to our telescopes.
This is how Earendel — a single star at 12.9 billion light-years away — appeared in Hubble’s image, amplified by a factor of 1000–4000×.
The Role of Hubble and JWST
Hubble Space Telescope (HST):
Hubble’s Deep Field imaging with the WFC3/IR camera was key.
The image was part of the RELICS (Reionization Lensing Cluster Survey) program.
The star was detected near a critical curve, showing traits of a lensed point source.
James Webb Space Telescope (JWST):
After Hubble’s discovery, JWST confirmed Earendel’s existence in 2023.
JWST’s NIRCam and NIRSpec instruments provided:
Higher-resolution imaging
Better constraints on spectral energy distribution (SED)
Potential insights into the star’s temperature, mass, and metallicity
JWST will help determine whether Earendel is:
A binary system
A Population III candidate
Representative of normal star formation at z > 6
Could Earendel Be a Population III Star?
What Are Population III Stars?
The first stars ever formed, ~100–250 million years after the Big Bang
Composed entirely of hydrogen and helium — no metals
Extremely hot, massive, and short-lived
Theoretical, never directly observed
Why Earendel Is a Candidate:
It’s at redshift z ~6.2, meaning it formed <900 million years after the Big Bang
JWST spectral data may reveal zero metallicity, which would support Pop III classification
Its luminosity and temperature are consistent with massive early stars
However, Earendel’s host galaxy shows signs of metal enrichment, making a Pop III origin less likely, though not impossible — it may be a Population II star (second generation) instead.
What Makes Earendel Different from Icarus?
| Feature | Icarus (2018) | Earendel (2022) |
|---|---|---|
| Redshift (z) | ~1.49 | ~6.2 |
| Distance | ~9.4 billion light-years | ~12.9 billion light-years |
| Telescope | Hubble | Hubble + JWST |
| Lens Type | Galaxy cluster | Galaxy cluster |
| Magnification | ~2000× | ~4000× (peak) |
| Stellar Type | B-type supergiant | Possibly O/B-type (unknown) |
Earendel extends the frontier of stellar detection by over 3 billion light-years.
Frequently Asked Questions (FAQ)
Q: What is Earendel?
A: Earendel (formally WHL0137-LS) is the most distant individual star ever detected. Discovered by the Hubble Space Telescope in 2022 and confirmed by JWST, it lies about 12.9 billion light-years away at a redshift of z ~6.2, from a time when the universe was under a billion years old.
Q: How was a single star seen from so far away?
A: Thanks to gravitational lensing by a massive foreground galaxy cluster, Earendel’s light was magnified up to 4000 times, briefly making it visible to Hubble. This rare alignment placed the star on a caustic line, where extreme magnification can occur.
Q: Could Earendel be a Population III star?
A: It’s possible, but not confirmed. If Earendel has no heavy elements (metals) in its atmosphere, it could be one of the universe’s first stars. However, its host galaxy shows signs of metal enrichment, so it may more likely be a Population II (early second-generation) star.
Q: What instruments confirmed Earendel?
A:
Hubble Space Telescope (HST) first detected Earendel in 2016–2019 images as part of the RELICS survey
James Webb Space Telescope (JWST) confirmed it in 2023 using NIRCam and other near-infrared instruments
Q: How long will Earendel remain visible?
A: The lensing effect that revealed Earendel is temporary — caused by relative motion between the lensing cluster and the background galaxy. Eventually, Earendel may fade below detection limits as the magnification alignment shifts.
Final Thoughts – A Star from the Edge of Time
Earendel is not just the most distant individual star we’ve ever seen — it’s a symbol of human ingenuity, technological achievement, and the power of natural cosmic lenses.
Why Earendel Matters:
It expands the limits of stellar observation
Offers rare clues about early star formation
Provides a unique opportunity to study metallicity, stellar evolution, and binarity in the early universe
Proves that individual stars can now be studied at cosmic dawn — once thought impossible
Earendel is a gateway — showing that with tools like JWST, and the help of gravitational lensing, we may soon detect even older, fainter, and more exotic stars, including the elusive Population III generation.
