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Type TDE-He Supernova

The Story of Supernova 13Z3-H

An extraordinary stellar explosion that occurred 2.24 Billion Light-Years away in deep space.

⏱️ ~6 min deep read 🔬 24 Astrophysical Q&As 🔭 Viewing Guide Included 🪐 Constellation Draco
🔭 Deep Field (~2.1′ FOV) · DSS2 Optical (China-VO mirror)
● 13Z3-H Explosion Site

High-magnification deep optical view into 13Z3-H'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
2.24 Billion Light-Years
Lookback Cosmic Time
✨ Peak Brightness
Mag —
Research Scope
☀️ Peak Radiance
Hundreds of Millions of Suns
Combined Stellar Energy
🚀 Shock Velocity
Not measured
No spectral ejecta velocity
🌌 Host Galaxy
Field Transient Host
Center Coincident
🧭 Constellation
Draco
The Dragon
💥 Explosion Physics
Type TDE-He
Core-Collapse Supergiant
📅 Discovered On
2025/04/21
Robert Stein (UMD) on behalf of ZTF
CHAPTER I

A Core-Collapse Class Transient

On 2025/04/21, astronomers scanning the heavens flagged a sudden, violent pinpoint of light that had flared into visibility. Designated 13Z3-H, it represents a catastrophic stellar explosion classified as a Type TDE-He supernova.

13Z3-H 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 13Z3-H.

Astrophysical Mechanism Summary
Type: Type TDE-He • Progenitor: Massive Red/Stripped Supergiant Star • Velocity: Not measured
CHAPTER II

A Message Across Deep Cosmic Time

13Z3-H has a luminosity distance of approximately 2.24 Billion Light-Years (redshift z = 0.145). That figure is not the light-travel time: under flat ΛCDM the lookback time is ≈1830 Myr, when the light set out 1829.5 million years ago in deep Precambrian time, well before multicellular animals dominated Earth.

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

CHAPTER III

Brightness Record

No calibrated peak magnitude is published for 13Z3-H, so neither its apparent brightness nor an equivalent solar luminosity can be stated.

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 TDE-He light curves; an object-specific nickel mass for 13Z3-H 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 13Z3-H'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 13Z3-H.

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 Draco

No host galaxy is identified for 13Z3-H in this catalog record . In our terrestrial sky, it resides in the constellation Draco (The Dragon) at Right Ascension 15:49:37.195 and Declination +52:19:15.53.

CHAPTER VII

The Scientific Surveillance Campaign

Following its discovery by Robert Stein (UMD) on behalf of ZTF, observatories worldwide swung their lenses toward 13Z3-H. In the sne.space, 13Z3-H 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 1.6 years ago (2025/04/21). No reliable current brightness estimate — no photometry has been published.

Planetary Safety Note: Even though 13Z3-H was a titanic explosion, our planet sits safely outside the lethal 50–100 light-year kill zone. At a distance of 2.24 Billion Light-Years, the blast poses zero physical hazard to Earth's biosphere.

🌌 Cosmic Neighbors & Contemporaries 105,868+ transients indexed

Cataloged transients closest to 13Z3-H in discovery time, spatial sky neighborhood, and cosmological redshift:

⏱️ Closest in Time
SN2025hwp Exploded same day
Type Ia 2025/04/21
SN2025hyu Exploded same day
Type Ia 2025/04/21
SN2025hxf Exploded same day
Type II 2025/04/21
🔭 Closest on the Sky
TDE2025lxx 0.0′ away
Type TDE-He Discovered 2025/04/21
SN2019xbu 22.8′ away
Type Ia Discovered 2019/12/19
AT2020jmn 30.5′ away
Type Candidate Discovered 2020/04/27
🌌 Same Cosmic Era (Redshift)
SN1992ar z = 0.145
Type Ic ~2001.0 Mly (approx.)
LSQ12fzr z = 0.145
Type Ia ~2001.0 Mly (approx.)
iPTF14gtp z = 0.145
Type Ia ~2001.0 Mly (approx.)

❓ Frequently Asked Questions About 13Z3-H

Scientific & observational Q&As indexed from astronomical databases & the sne.space
🔍 24 of 24
What type of supernova is 13Z3-H and what kind of star exploded? Astrophysics & Progenitor
13Z3-H is classified as a tidal disruption event (TDE): a star was torn apart by a supermassive black hole's tidal field. This is not a stellar core-collapse or thermonuclear supernova; radioactive ⁵⁶Ni-powered light-curve models for supernovae do not apply by default.
What was the progenitor star doing in the millions of years leading up to 13Z3-H? Astrophysics & Progenitor
The specific progenitor of 13Z3-H 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 13Z3-H.
How far away is 13Z3-H from Earth and how old is the light reaching us? Cosmic Distance & Time
13Z3-H has a luminosity distance of approximately 2.24 Billion Light-Years (redshift z = 0.145, d_L = 687.24). Under a flat ΛCDM cosmology (H₀≈70 km/s/Mpc, Ωₘ≈0.3), the corresponding lookback time is ≈1830 Myr — when the light set out 1829.5 million years ago in deep Precambrian time, well before multicellular animals dominated Earth. 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 13Z3-H tell us about the expansion of space? Cosmic Distance & Time
13Z3-H exhibits a measured spectroscopic redshift of z = 0.1450. The cockpit reports a user-facing recession velocity of 40,347.0 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 (≈43,470 km/s) is a different low-z approximation and is not mixed here.
How bright did 13Z3-H become at its peak, and how many Suns does that equal? Explosion Energetics
The peak brightness of 13Z3-H is not recorded. No peak apparent magnitude and no calibrated photometry are published for this transient, so neither its apparent brightness nor its intrinsic luminosity can be stated. Any figure quoted here would be an estimate from a template rather than a measurement of this object. Follow-up photometry would establish the light curve and the peak.
How much total energy was released by 13Z3-H, and where did that energy go? Explosion Energetics
No object-specific energy budget is published for 13Z3-H. Tidal disruption events are powered by accretion onto a supermassive black hole, not by the neutrino burst or ⁵⁶Ni decay that dominate supernova energy discussions. Class-scale estimates must not be quoted as measurements of this event.
How fast are the supernova ejecta and shockwave of 13Z3-H expanding through space? Explosion Energetics
No ejecta velocity is measured for 13Z3-H. Blast-wave speed is obtained from Doppler shifts of spectral absorption features (e.g. Si II λ6355 for Type Ia), not from cosmological redshift. Any recession velocity derived from z describes Hubble flow, not the explosion debris.
What powers the prolonged glow of 13Z3-H weeks and months after detonation? Radioactive Engine
Radioactive ⁵⁶Ni decay is not the default power source for 13Z3-H. As a tidal disruption event, the optical light curve is generally discussed in terms of accretion and circularization physics, not the supernova ⁵⁶Ni → ⁵⁶Co → ⁵⁶Fe chain. No object-specific nickel mass applies.
What chemical elements did 13Z3-H create and disperse into the universe? Nucleosynthesis & Elements
13Z3-H is a TDE, not a nucleosynthesis factory in the supernova sense. Observed abundances reflect debris from the disrupted star and accretion-flow physics; no supernova-style elemental yield is published for this object.
Did 13Z3-H leave behind a black hole, a neutron star, or nothing at all? Cosmic Remnant
A core-collapse explosion associated with 13Z3-H'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 13Z3-H'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 13Z3-H. 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 13Z3-H explode, and where is it located relative to the galactic center? Galactic Environment
No host galaxy is identified for 13Z3-H in this catalog record. A blank host field means the association is unresolved here—it does not establish that the host is uncataloged, resolved in imaging, or securely linked by astrometry. Possible states (unidentified, hostless candidate, imaging detection without a catalog name, or a securely matched cataloged galaxy) require separate evidence that is not present in this field.
Where is 13Z3-H located in the night sky and which constellation is it in? Sky Coordinates
In the celestial sphere, 13Z3-H is located at Right Ascension 15:49:37.195 and Declination +52:19:15.53, situated in the constellation Draco (The Dragon). Because its declination is +52:19:15.53, it is primarily placed in the Northern celestial hemisphere.
How much Milky Way interstellar dust obscures our view of 13Z3-H? Interstellar Dust
Along this line of sight, the catalog records a Milky Way foreground color excess of E(B−V) = 0.0444 mag (source: Analytical Galactic Disk Model (IAU)), corresponding to roughly A_V ≈ 0.14 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 13Z3-H monitored? Astronomical Observations
No calibrated photometry is published for 13Z3-H. 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 13Z3-H's chemical makeup? Astronomical Observations
No spectrum has been published for 13Z3-H. 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 13Z3-H and how was it first detected? Discovery & History
13Z3-H was officially reported on 2025/04/21 by Robert Stein (UMD) on behalf of 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 13Z3-H? Scientific Research
Data for 13Z3-H 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 13Z3-H? Cross-Identifications
Throughout global alert streams and survey databases, 13Z3-H has also been designated as: 2025lxx, TDE2025lxx, ZTF25aaplxiz. 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 13Z3-H contribute to measuring the Hubble Constant and the scale of the cosmos? Cosmology & Distance Ladder
13Z3-H 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 13Z3-H be detected on Earth? Multi-Messenger Astronomy
No neutrino or gravitational-wave counterpart has been reported for 13Z3-H, 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 13Z3-H 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), 13Z3-H occurred at a distance of 2.24 Billion Light-Years. While historical naked-eye supernovae occurred within our Milky Way or its immediate satellites, modern discoveries like 13Z3-H allow astrophysicists to probe diverse galactic environments, metallicities, and stellar populations across the broader universe.
Can I see 13Z3-H tonight with a backyard telescope or binoculars? Backyard Observation
Unknown — no measured brightness. 13Z3-H was discovered 573 days ago (2025/04/21), 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 13Z3-H 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 2.24 Billion Light-Years, the inverse-square law dilutes the radiation by quintillions of times, making 13Z3-H 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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