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Type removed Supernova

The Story of Supernova AT2020ild

An extraordinary stellar explosion that occurred 151.5 Million Light-Years away in deep space.

⏱️ ~6 min deep read 🔬 24 Astrophysical Q&As 🔭 Viewing Guide Included 🪐 Constellation Leo
🔭 Deep Field (~2.1′ FOV) · DSS2 Optical (China-VO mirror)
● AT2020ild Explosion Site

High-magnification deep optical view into AT2020ild's host environment. Pan and scroll to explore the cosmic neighborhood where this star exploded.

⚡ Quick Observer Facts & Telemetry

IAU Transients DB
🌐 Distance to Earth
151.5 Million Light-Years
Lookback Cosmic Time
✨ Peak Brightness
Mag 19.8
Large Observatory
☀️ Peak Radiance
21.9 million Suns
Combined Stellar Energy
🚀 Shock Velocity
~3,105 km/s
~1.0% Speed of Light
🌌 Host Galaxy
NGC 3690
Center Coincident
🧭 Constellation
Leo
The Lion
💥 Explosion Physics
Type removed
Core-Collapse Supergiant
📅 Discovered On
2020/02/12
ZTF
CHAPTER I

A Core-Collapse Class Transient

On 2020/02/12, astronomers scanning the heavens flagged a sudden, violent pinpoint of light that had flared into visibility. Designated AT2020ild, it represents a catastrophic stellar explosion classified as a Type removed supernova.

AT2020ild is classified in a core-collapse spectroscopic family. Events of this class are generally linked to the death of a massive star after successive nuclear burning stages, but no unique progenitor mass, lifetime, or pre-explosion identification is established for this object. The narrative of onion-shell fusion ending in iron-core collapse describes the class model, not a measured biography of AT2020ild.

Astrophysical Mechanism Summary
Type: Type removed • Progenitor: Massive Red/Stripped Supergiant Star • Velocity: ~3,105 km/s (~1.0% c)
CHAPTER II

A Message Across Deep Cosmic Time

AT2020ild has a luminosity distance of approximately 151.5 Million Light-Years (redshift z = 0.010411). That figure is not the light-travel time: under flat ΛCDM the lookback time is ≈144 Myr, when the light set out 144.3 million years ago during the Cretaceous period when Tyrannosaurus rex and Triceratops walked the planet.

Luminosity distance incorporates cosmic expansion and exceeds the light-travel distance. The two quantities must be reported separately.

CHAPTER III

Incandescence of 21.9 million Suns

At the height of the outburst around 2020/02/12, AT2020ild surged to a peak apparent magnitude of 19.8 and an intrinsic absolute magnitude of -13.5233. At that instant, this single dying star radiated with the collective power of approximately 21.9 million Suns combined, outshining whole dwarf galaxies.

The total energy released by the cataclysm was on the order of 10⁵¹ to 10⁵³ ergs. Over 99% of this energy was emitted within the first 10 seconds as a dense burst of trillions of neutrinos, with only 1% driving the visible blast wave.

CHAPTER IV

The Radioactive Furnace: Why Supernovae Glow for Months

After peak, many supernovae are powered by the radioactive chain ⁵⁶Ni → ⁵⁶Co → ⁵⁶Fe. That is the standard model for Type removed light curves; an object-specific nickel mass for AT2020ild is not published here.

Nickel-56 decays to Cobalt-56 (half-life ≈6.1 days), then to stable Iron-56 (half-life ≈77.2 days), heating the ejecta from within. Typical class yields must not be quoted as measured values for this event.

CHAPTER V

Cosmic Kiln: Seeding the Elements of Life

Supernovae enrich galaxies with heavy elements. Events of AT2020ild's class are associated with oxygen-group and intermediate-mass products (O, C, Ne, Mg, Si) in galactic chemical-evolution models. No measured elemental yields are published for AT2020ild.

As Carl Sagan observed, "We are made of star-stuff" — a statement about nucleosynthesis in general, not a claim that atoms from this specific remnant are identified in the Solar System.

CHAPTER VI

Galactic Setting in Leo

AT2020ild is associated with cataloged host NGC 3690 . In our terrestrial sky, it resides in the constellation Leo (The Lion) at Right Ascension 11:20:28.011 and Declination +26:57:13.47.

CHAPTER VII

The Scientific Surveillance Campaign

Following its discovery by ZTF, observatories worldwide swung their lenses toward AT2020ild. In the sne.space, AT2020ild is documented across 0 photometric measurements and 0 spectroscopic epochs. These multi-wavelength observations allow astrophysicists to model the expanding photosphere, measure shock velocities, and probe circumstellar interactions.

CHAPTER VIII

Stargazer's Field Guide: Can You See It Tonight?

Can I see it tonight? Unknown — no measured brightness.

Discovered 6.8 years ago (2020/02/12). No reliable current brightness estimate — no photometry has been published.

Planetary Safety Note: Even though AT2020ild was a titanic explosion, our planet sits safely outside the lethal 50–100 light-year kill zone. At a distance of 151.5 Million Light-Years, the blast poses zero physical hazard to Earth's biosphere.

🌌 Cosmic Neighbors & Contemporaries 105,868+ transients indexed

Cataloged transients closest to AT2020ild in discovery time, spatial sky neighborhood, and cosmological redshift:

⏱️ Closest in Time
AT2020adje Exploded same day
Type Candidate 2020/02/12 · Mag 18.9
AT2020cgz Exploded same day
Type Candidate 2020/02/12 · Mag 19.2
AT2020cha Exploded same day
Type Candidate 2020/02/12 · Mag 19
🔭 Closest on the Sky
AT2020ayx 0.1′ away
Type Candidate Discovered 2020/01/26
AT2020dbf 0.4′ away
Type Candidate Discovered 2020/02/21
CSS160227:111946+270019 9.8′ away
Type Transient Discovered 2016/02/27
🌌 Same Cosmic Era (Redshift)
SN2020fkb z = 0.01041
Type Ib/c ~142.6 Mly (approx.)
SN2019yxp z = 0.010417
Type Ib ~142.7 Mly (approx.)
SN2016bfv z = 0.010404
Type II ~142.5 Mly (approx.)

❓ Frequently Asked Questions About AT2020ild

Scientific & observational Q&As indexed from astronomical databases & the sne.space
🔍 24 of 24
What type of supernova is AT2020ild and what kind of star exploded? Astrophysics & Progenitor
AT2020ild is cataloged as a Type removed transient. Mechanism-specific claims (progenitor mass, nickel yield, remnant type) require more than this label and are not asserted here as object-specific measurements.
What was the progenitor star doing in the millions of years leading up to AT2020ild? Astrophysics & Progenitor
The specific progenitor of AT2020ild has not been observed. Events of this spectroscopic class are generally associated with massive-star core collapse after successive nuclear burning stages (hydrogen → helium → carbon → neon → oxygen → silicon → iron). Typical lifetimes of such progenitors are tens of millions of years, but that is a class expectation—not a measured age or evolutionary track for this star. No pre-explosion imaging identification is cited in the available record for AT2020ild.
How far away is AT2020ild from Earth and how old is the light reaching us? Cosmic Distance & Time
AT2020ild has a luminosity distance of approximately 151.5 Million Light-Years (redshift z = 0.010411, d_L = 46.4424). Under a flat ΛCDM cosmology (H₀≈70 km/s/Mpc, Ωₘ≈0.3), the corresponding lookback time is ≈144 Myr — when the light set out 144.3 million years ago during the Cretaceous period when Tyrannosaurus rex and Triceratops walked the planet. Luminosity distance is larger than the light-travel distance because cosmic expansion stretches the path; the two must not be equated.
What does the cosmological redshift of AT2020ild tell us about the expansion of space? Cosmic Distance & Time
AT2020ild exhibits a measured spectroscopic redshift of z = 0.0104. The cockpit reports a user-facing recession velocity of 3,104.9 km/s, computed as the redshift Doppler-equivalent v = c·((1+z)²−1)/((1+z)²+1). Cosmological redshift is not generally equivalent to special-relativistic motion through space; this number is a convenient velocity label for z, not a measured peculiar velocity and not supernova ejecta speed. Bare c·z (≈3,121 km/s) is a different low-z approximation and is not mixed here.
How bright did AT2020ild become at its peak, and how many Suns does that equal? Explosion Energetics
At peak brightness, AT2020ild achieved an apparent magnitude of 19.8 around 2020/02/12. Corrected for cosmic distance and foreground interstellar dust, its intrinsic absolute magnitude was -13.5233. At this peak, the exploding star radiated with the incandescent brilliance of approximately 21.9 million Suns combined, briefly outshining the cumulative starlight of entire dwarf galaxies!
How much total energy was released by AT2020ild, and where did that energy go? Explosion Energetics
Core-collapse events of this broad class are often discussed with a ~10⁵³ erg gravitational binding energy of which ~99% may escape as neutrinos—again a class scale, not a measured budget for AT2020ild.
How fast are the supernova ejecta and shockwave of AT2020ild expanding through space? Explosion Energetics
Spectroscopic line blueshifts imply an ejecta velocity of approximately 3,105 km/s (~1.0% of c) for AT2020ild. This is distinct from cosmological recession velocity inferred from redshift.
What powers the prolonged glow of AT2020ild weeks and months after detonation? Radioactive Engine
Classified core-collapse light curves are often sustained after peak by radioactive ⁵⁶Ni → ⁵⁶Co → ⁵⁶Fe decay, with typical nickel yields of order 0.05–0.15 solar masses—again a class scale, not a measured yield for AT2020ild. Shock-breakout heating may dominate the earliest optical flash; without a published bolometric fit, neither nickel mass nor the dominant power source is established for this event.
What chemical elements did AT2020ild create and disperse into the universe? Nucleosynthesis & Elements
The nucleosynthetic products of AT2020ild are unknown because its type is unresolved. Element yields depend directly on the explosion mechanism: a thermonuclear Type Ia produces mostly iron-peak elements such as 56Ni and 56Fe, whereas a core-collapse event produces large quantities of oxygen, neon, magnesium and silicon from successive burning shells. No spectrum has been published for this transient, so which of these occurred is not established.
Did AT2020ild leave behind a black hole, a neutron star, or nothing at all? Cosmic Remnant
A core-collapse explosion associated with AT2020ild's class forges an ultra-dense compact stellar remnant at the center of the detonation. If the progenitor had an initial mass under ~20 solar masses, it left behind a neutron star (pulsar)—packing the mass of our entire Sun into a city-sized sphere barely 20 kilometers wide, spinning dozens or hundreds of times per second. If the progenitor exceeded ~25–30 solar masses, gravity overcame neutron degeneracy pressure, creating a permanent stellar-mass black hole.
What will AT2020ild's explosion site look like in 1,000 to 10,000 years? Cosmic Remnant
Supernova remnants in general evolve through free-expansion, Sedov–Taylor, and radiative phases over centuries to millennia, sometimes becoming bright X-ray shells and occasionally compressing nearby molecular clouds. These are standard remnant-evolution models, not forecasts measured for AT2020ild. Whether this site will trigger star formation, reach particular X-ray temperatures, or match Cassiopeia A depends on local density and magnetic field—none of which are constrained by the data shown here.
In which galaxy did AT2020ild explode, and where is it located relative to the galactic center? Galactic Environment
AT2020ild is cataloged with host galaxy NGC 3690. No secure nuclear offset is published in this record.
Where is AT2020ild located in the night sky and which constellation is it in? Sky Coordinates
In the celestial sphere, AT2020ild is located at Right Ascension 11:20:28.011 and Declination +26:57:13.47, situated in the constellation Leo (The Lion). Because its declination is +26:57:13.47, it is primarily placed in the Northern celestial hemisphere.
How much Milky Way interstellar dust obscures our view of AT2020ild? Interstellar Dust
Along this line of sight, the catalog records a Milky Way foreground color excess of E(B−V) = 0.0358 mag (source: Analytical Galactic Disk Model (IAU)), corresponding to roughly A_V ≈ 0.11 mag for R_V = 3.1. Band-specific corrections (e.g. A_r) differ from A_V and should be applied when available. Map-based values (IRSA / Schlafly & Finkbeiner 2011) must not be claimed unless that map was actually queried.
Across which photometric filter bands was AT2020ild monitored? Astronomical Observations
No calibrated photometry is published for AT2020ild. Without multi-epoch flux measurements, neither a light curve nor a peak magnitude can be established. Follow-up imaging from survey alert streams would be required to map its brightness evolution.
What did astronomical spectroscopy reveal about AT2020ild's chemical makeup? Astronomical Observations
No spectrum has been published for AT2020ild. Without spectroscopy, its chemical composition, expansion velocity, and physical classification cannot be established. Classification spectra from follow-up observatories would be required to identify diagnostic absorption and emission lines.
Who discovered AT2020ild and how was it first detected? Discovery & History
AT2020ild was officially reported on 2020/02/12 by ZTF. Discoveries are typically flagged by high-cadence robotic survey telescopes (such as ATLAS, ZTF, Pan-STARRS, ASAS-SN, or Gaia) and worldwide amateur astronomers scanning the night sky, followed by rapid spectroscopic classification by international observatories.
How many scientific publications and observatories have contributed data to AT2020ild? Scientific Research
Data for AT2020ild are compiled from international astronomical notices, the IAU Transient Name Server (TNS), and peer-reviewed astrophysical journals.
What other names and survey identifiers exist for AT2020ild? Cross-Identifications
Throughout global alert streams and survey databases, AT2020ild has also been designated as: ZTF20aaozbix. These cross-matched identifiers allow astronomers to cross-reference observations across the Zwicky Transient Facility (ZTF), the Asteroid Terrestrial-impact Last Alert System (ATLAS), Pan-STARRS, Gaia Photometric Science Alerts, and the IAU Transient Name Server (TNS).
How does AT2020ild contribute to measuring the Hubble Constant and the scale of the cosmos? Cosmology & Distance Ladder
AT2020ild cannot currently be used for cosmological distance work because its classification is unresolved. The distance ladder relies on type-specific techniques: Type Ia supernovae use the Phillips relation between peak absolute magnitude and decline rate, while Type II events use the Expanding Photosphere Method or SCM-II. An unclassified transient fits neither, so no Hubble-constant constraint can be derived from it until a spectrum establishes its type.
Could gravitational waves or neutrinos from AT2020ild be detected on Earth? Multi-Messenger Astronomy
No neutrino or gravitational-wave counterpart has been reported for AT2020ild, and none is expected to be identifiable without a classification. The multi-messenger signature differs sharply by type: core-collapse events emit a neutrino burst at shock breakout (detected once, for SN 1987A), while thermonuclear Type Ia events produce negligible neutrinos and gravitational waves. Searching for a counterpart before knowing which mechanism applies would be unfocused.
How does AT2020ild compare to famous historical supernovae like SN 1987A or the Crab Supernova? Historical Comparison
Compared to historical landmarks like SN 1987A in the Large Magellanic Cloud (168,000 light-years away, naked-eye peak m = 2.9) or the Crab Supernova of 1054 (6,500 light-years away), AT2020ild occurred at a distance of 151.5 Million Light-Years. While historical naked-eye supernovae occurred within our Milky Way or its immediate satellites, modern discoveries like AT2020ild allow astrophysicists to probe diverse galactic environments, metallicities, and stellar populations across the broader universe.
Can I see AT2020ild tonight with a backyard telescope or binoculars? Backyard Observation
Unknown — no measured brightness. AT2020ild was discovered 2468 days ago (2020/02/12), but no calibrated photometry is published for it, so its current apparent magnitude cannot be stated. Without a magnitude there is no basis for a telescope-aperture recommendation. Use the coordinates and airmass chart above to plan a follow-up observation and report what you measure.
Does the radiation or shockwave from AT2020ild pose any threat to Earth? Planetary Safety
No, Earth is in zero danger. Supernovae are violent events emitting powerful gamma rays, X-rays, and cosmic rays; however, the astrophysical 'lethal kill zone' for our planet's protective ozone layer is estimated at 50 to 100 light-years. At a distance of 151.5 Million Light-Years, the inverse-square law dilutes the radiation by quintillions of times, making AT2020ild completely harmless to our biosphere and purely a fascinating spectacle for human exploration.
Data sourced from IAU TNS, ALeRCE, WISeREP, and the sne.space. View All General Astrophysics FAQs →
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