High-magnification deep optical view into AT2018cov's host environment. Pan and scroll to explore the cosmic neighborhood where this star exploded.
⚡ Quick Observer Facts & Telemetry
IAU Transients DBThe Thermonuclear Obliteration of a White Dwarf
On 2018/06/17, astronomers scanning the heavens flagged a sudden, violent pinpoint of light that had flared into visibility. Designated AT2018cov, it represents a catastrophic stellar explosion classified as a Type Ia supernova.
In a binary star system located deep within an uncataloged host galaxy, a dense carbon-oxygen white dwarf—the dead stellar corpse of an ancient sun—orbited its stellar companion for millions of years. As it siphoned material across the gravitational saddle point, its mass relentlessly climbed toward the Chandrasekhar limit of 1.4 solar masses. At that fateful tipping point, uncontrollable carbon fusion ignited in the degenerate core, ripping the entire star apart in a thermonuclear detonation that left behind zero remnant.
A Message Across Deep Cosmic Time
The light from AT2018cov is a dispatch from an ancient past. Located approximately 771.6 Million Light-Years away
(redshift z = 0.051456), the photons detected by telescopes today began their journey
771.6 million years ago during the Paleozoic era, long before the first dinosaurs appeared on Earth.
While this burst of electromagnetic radiation traversed the cold void of intergalactic space at 299,792 kilometers per second, continents on Earth drifted, mountain ranges rose, and entire ecosystems rose and fell. To look into a telescope at AT2018cov is to gaze directly into prehistoric cosmic time.
Incandescence of 5.0 billion Suns
At the height of the outburst around 2018/06/16, AT2018cov surged to a peak apparent magnitude of 17.4 and an intrinsic absolute magnitude of -19.4152. At that instant, this single dying star radiated with the collective power of approximately 5.0 billion Suns combined, outshining whole dwarf galaxies and illuminating the surrounding interstellar medium.
The total energy released by the cataclysm was on the order of 10⁵¹ to 10⁵³ ergs. Virtually all of this was deposited into the kinetic shockwave and radioactive nucleosynthesis.
The Radioactive Furnace: Why Supernovae Glow for Months
Unlike a conventional terrestrial explosion that cools and goes dark in seconds, AT2018cov shone brightly for weeks and months. The secret behind this prolonged celestial glow is nuclear physics: the extreme heat and pressure of detonation synthesized vast quantities of radioactive Nickel-56 (⁵⁶Ni).
With a half-life of 6.075 days, Nickel-56 decays into Cobalt-56 (⁵⁶Co), emitting gamma rays and high-energy positrons that heat the expanding ejecta from within. Cobalt-56 in turn decays with a half-life of 77.2 days into stable Iron-56 (⁵⁶Fe), powering the steady exponential radioactive tail observed in the light curve.
Cosmic Kiln: Seeding the Elements of Life
Supernovae are the premier chemical foundries of our universe. AT2018cov forged and liberated tons of newly synthesized elements: rich supplies of iron, silicon, calcium, and sulfur that will one day seed the formation of rocky terrestrial worlds.
As Carl Sagan famously observed, "We are made of star-stuff." The iron atoms that carry oxygen in human hemoglobin and the calcium in our bones were originally forged in explosions identical to AT2018cov billions of years ago.
Galactic Setting in Sculptor
AT2018cov detonated inside an uncataloged host galaxy.
In our terrestrial sky, it resides in the constellation Sculptor (The Sculptor) at Right Ascension 23:49:48.323
and Declination -14:07:10.76.
The Scientific Surveillance Campaign
Following its discovery by ASAS-SN, observatories worldwide swung their lenses toward AT2018cov. In the Open Supernova Catalog, AT2018cov is documented across 1 photometric measurements and 0 spectroscopic epochs. These multi-wavelength observations allow astrophysicists to model the expanding photosphere, measure shock velocities, and probe circumstellar interactions.
Stargazer's Field Guide: Can You See It Tonight?
Can I see it tonight? No — this supernova is physically extinguished.
Supernovae are brief, explosive cosmic catastrophes. They brighten over days to weeks and then permanently fade into darkness as their radioactive nickel-56 and cobalt-56 fuel decays. This explosion occurred 8.3 years ago (2018/06/16). Accounting for cosmological time dilation at redshift z = 0.0515, the rest-frame age is +2882.7 days. By standard radioactive decay templates, its optical brightness has decayed by Δm ≈ 44.6 magnitudes to an estimated magnitude 62.0, rendering the transient undetectable to all ground-based observatories.
Instrument Breakdown: At its maximum brightness in 2018/06/16, it reached magnitude 17.40 (Amateur CMOS Rig). Tonight, pointing a telescope at these coordinates will reveal only the background host galaxy.
| Instrument Class & Aperture | Sensitivity Limit | At Peak Maximum (m=17.40) | Tonight (Est. m≈62.0) |
|---|---|---|---|
| Naked Eye Dark sky site (Bortle 1–3) with no optical aid |
m ≤ 6.0 | ❌ Below limit | ❌ Below limit |
| Binoculars (50mm) Standard 7x50 or 10x50 handheld binoculars |
m ≤ 9.5 | ❌ Below limit | ❌ Below limit |
| Small Backyard Scope (4" / 100mm) Entry 4-inch (100mm) refractor / reflector |
m ≤ 12.0 | ❌ Below limit | ❌ Below limit |
| Medium Amateur Scope (8"–12") 8-inch to 12-inch Dobsonian or Schmidt-Cassegrain |
m ≤ 14.5 | ❌ Below limit | ❌ Below limit |
| Amateur CMOS Rig Cooled monochrome/color CMOS camera with multi-hour stack |
m ≤ 19.5 | ✅ Detectable | ❌ Below limit |
| 2m–3m Research Telescope University or regional observatory (e.g. Palomar 60", Calar Alto) |
m ≤ 22.0 | ✅ Detectable | ❌ Below limit |
| Giant 8m–10m Observatories Keck (10m), VLT (8.2m), Gemini, Subaru optical imaging |
m ≤ 25.0 | ✅ Detectable | ❌ Below limit |
| Space Observatories Only Hubble Space Telescope (WFC3) / JWST (NIRCam deep stack) |
m ≤ 30.0 | ✅ Detectable | ❌ Below limit |
Planetary Safety Note: Even though AT2018cov was a titanic explosion, our planet sits safely outside the lethal 50–100 light-year kill zone. At a distance of 771.6 Million Light-Years, the blast poses zero physical hazard to Earth's biosphere.
Cataloged supernovae closest to AT2018cov in discovery time, spatial sky neighborhood, and cosmological lookback epoch: