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Type Supernova

The Story of Supernova SN2023pgr

An extraordinary stellar explosion that occurred 1.18 Billion Light-Years away in deep space.

⏱️ ~6 min deep read 🔬 24 Astrophysical Q&As 🔭 Viewing Guide Included 🪐 Constellation Pisces
🔭 Deep Field (~2.1′ FOV) · DSS2 Optical (China-VO mirror)
● SN2023pgr Explosion Site

High-magnification deep optical view into SN2023pgr'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
1.18 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
Pisces
The Fishes
💥 Explosion Physics
Type
Core-Collapse Supergiant
📅 Discovered On
2023/08/13
M. Pursiainen, D. Coppejans, D. Steeghs, D. K. Galloway, V. Dhillon, P. O'Brien, G. Ramsay, D. Pollacco, S. Poshyachinda, R. Kotak, L. Nuttall, E. Pallé, J. Lyman, D. O'Neill, K. Ulaczyk, K. Ackley, M. Dyer, T. Killestein, A.Kumar, on behalf of GOTO collaboration
CHAPTER I

An Unclassified Astronomical Transient

On 2023/08/13, astronomers scanning the heavens flagged a sudden, violent pinpoint of light that had flared into visibility. Designated SN2023pgr, it is an unclassified astronomical transient whose physical nature is not yet established.

SN2023pgr was reported as a changing source, but it has not been spectroscopically classified. Without a spectrum, the progenitor cannot be identified: a thermonuclear white-dwarf detonation and a core-collapse of a massive star are mutually exclusive histories that produce different spectra and light curves. No progenitor, explosion mechanism, or remnant outcome is established for this object.

Astrophysical Mechanism Summary
Type: Unclassified (no spectrum) • Progenitor: Unknown • Velocity: Not measured
CHAPTER II

A Message Across Deep Cosmic Time

SN2023pgr has a luminosity distance of approximately 1.18 Billion Light-Years (redshift z = 0.08). That figure is not the light-travel time: under flat ΛCDM the lookback time is ≈1056 Myr, when the light set out 1055.6 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 SN2023pgr, so neither its apparent brightness nor an equivalent solar luminosity can be stated.

The total energy release is unknown without a spectroscopic classification.

CHAPTER IV

The Radioactive Furnace: Why Supernovae Glow for Months

Without a classification, the power source of SN2023pgr cannot be identified; radioactive ⁵⁶Ni decay powers many supernovae but is not established for this transient.

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 SN2023pgr'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 SN2023pgr.

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 Pisces

No host galaxy is identified for SN2023pgr in this catalog record . In our terrestrial sky, it resides in the constellation Pisces (The Fishes) at Right Ascension 23:47:33.204 and Declination +16:58:16.91.

CHAPTER VII

The Scientific Surveillance Campaign

Following its discovery by M. Pursiainen, D. Coppejans, D. Steeghs, D. K. Galloway, V. Dhillon, P. O'Brien, G. Ramsay, D. Pollacco, S. Poshyachinda, R. Kotak, L. Nuttall, E. Pallé, J. Lyman, D. O'Neill, K. Ulaczyk, K. Ackley, M. Dyer, T. Killestein, A.Kumar, on behalf of GOTO collaboration, observatories worldwide swung their lenses toward SN2023pgr. In the Open Supernova Catalog, SN2023pgr 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 3.2 years ago (2023/08/13). No reliable current brightness estimate — no photometry has been published.

Planetary Safety Note: Even though SN2023pgr was a titanic explosion, our planet sits safely outside the lethal 50–100 light-year kill zone. At a distance of 1.18 Billion Light-Years, the blast poses zero physical hazard to Earth's biosphere.

🌌 Cosmic Neighbors & Contemporaries 105,768+ transients indexed

Cataloged transients closest to SN2023pgr in discovery time, spatial sky neighborhood, and cosmological redshift:

⏱️ Closest in Time
FRB20230813A Exploded same day
Type FRB 2023/08/13
SN2023pem Exploded same day
Type Ia 2023/08/13
SN2023pel Exploded same day
Type Ic-BL 2023/08/13
🔭 Closest on the Sky
AT2021wbh 18.9′ away
Type Candidate Discovered 2021/08/14
MLS170924:234856+171231 24.4′ away
Type Candidate Discovered 2017/09/24
CSS141024:234726+163142 26.6′ away
Type Transient Discovered 2014/10/24
🌌 Same Cosmic Era (Redshift)
SN1999ah z = 0.08
Type Ic ~1095.9 Mly (approx.)
GRB 051109B z = 0.08
Type LGRB ~1095.9 Mly (approx.)
SN1999eo z = 0.08
Type Ia ~1095.9 Mly (approx.)

❓ Frequently Asked Questions About SN2023pgr

Scientific & observational Q&As indexed from astronomical databases & the Open Supernova Catalog
🔍 24 of 24
What type of supernova is SN2023pgr and what kind of star exploded? Astrophysics & Progenitor
SN2023pgr has not been spectroscopically classified. It was reported as an astronomical transient, which means an object was detected changing in brightness, but its nature is not yet established. Classification requires a spectrum: the presence or absence of hydrogen lines separates Type II from Type I, and Type Ia is identified by silicon absorption near 6150 Å combined with the absence of hydrogen. Until such a spectrum is published, claims about the progenitor star or explosion mechanism would be speculation. Check the sources below for follow-up spectroscopy.
What was the progenitor star doing in the millions of years leading up to SN2023pgr? Astrophysics & Progenitor
The progenitor of SN2023pgr cannot be identified without a classification. Stellar evolutionary history depends entirely on the explosion type: a Type Ia event would require a carbon-oxygen white dwarf in a binary system, whereas a core-collapse event would require a massive star exhausting its fuel within tens of millions of years. These are mutually exclusive histories that produce different spectra and light curves. No progenitor or precursor has been reported for this transient in the available literature.
How far away is SN2023pgr from Earth and how old is the light reaching us? Cosmic Distance & Time
SN2023pgr has a luminosity distance of approximately 1.18 Billion Light-Years (redshift z = 0.08, d_L = 363.26). Under a flat ΛCDM cosmology (H₀≈70 km/s/Mpc, Ωₘ≈0.3), the corresponding lookback time is ≈1056 Myr — when the light set out 1055.6 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 SN2023pgr tell us about the expansion of space? Cosmic Distance & Time
SN2023pgr exhibits a measured spectroscopic redshift of z = 0.0800. The cockpit reports a user-facing recession velocity of 23,026.9 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 (≈23,983 km/s) is a different low-z approximation and is not mixed here.
How bright did SN2023pgr become at its peak, and how many Suns does that equal? Explosion Energetics
The peak brightness of SN2023pgr 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 SN2023pgr, and where did that energy go? Explosion Energetics
The total energy released by SN2023pgr is unknown. Energy budgets differ by orders of magnitude depending on mechanism: a thermonuclear Type Ia liberates ~10⁵¹ ergs mostly as kinetic energy, while a core-collapse event liberates ~10⁵³ ergs of which ~99% escapes as neutrinos. Without a spectroscopic classification, neither figure applies to this transient.
How fast are the supernova ejecta and shockwave of SN2023pgr expanding through space? Explosion Energetics
No ejecta velocity is measured for SN2023pgr. 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 SN2023pgr weeks and months after detonation? Radioactive Engine
The power source sustaining SN2023pgr cannot be identified without a classification. Classified supernovae are typically powered after peak by the radioactive decay of ⁵⁶Ni → ⁵⁶Co → ⁵⁶Fe, but nickel yields and whether a shock-breakout flash occurred depend on the explosion mechanism. No spectrum is published for this transient, so no ⁵⁶Ni mass or decay-powered light-curve narrative applies.
What chemical elements did SN2023pgr create and disperse into the universe? Nucleosynthesis & Elements
The nucleosynthetic products of SN2023pgr 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 SN2023pgr leave behind a black hole, a neutron star, or nothing at all? Cosmic Remnant
Whether SN2023pgr left a remnant is unknown. A thermonuclear Type Ia leaves no compact remnant (the white dwarf is fully disrupted), whereas a core-collapse event leaves a neutron star or black hole depending on progenitor mass. Without a spectroscopic classification, none of these outcomes can be asserted for this transient.
What will SN2023pgr'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 SN2023pgr. 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 SN2023pgr explode, and where is it located relative to the galactic center? Galactic Environment
No host galaxy is identified for SN2023pgr 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 SN2023pgr located in the night sky and which constellation is it in? Sky Coordinates
In the celestial sphere, SN2023pgr is located at Right Ascension 23:47:33.204 and Declination +16:58:16.91, situated in the constellation Pisces (The Fishes). Because its declination is +16:58:16.91, it is primarily placed in the Northern celestial hemisphere.
How much Milky Way interstellar dust obscures our view of SN2023pgr? Interstellar Dust
Along this line of sight, the catalog records a Milky Way foreground color excess of E(B−V) = 0.0483 mag (source: Analytical Galactic Disk Model (IAU)), corresponding to roughly A_V ≈ 0.15 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 SN2023pgr monitored? Astronomical Observations
No calibrated photometry is published for SN2023pgr. 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 SN2023pgr's chemical makeup? Astronomical Observations
No spectrum has been published for SN2023pgr. 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 SN2023pgr and how was it first detected? Discovery & History
SN2023pgr was officially reported on 2023/08/13 by M. Pursiainen, D. Coppejans, D. Steeghs, D. K. Galloway, V. Dhillon, P. O'Brien, G. Ramsay, D. Pollacco, S. Poshyachinda, R. Kotak, L. Nuttall, E. Pallé, J. Lyman, D. O'Neill, K. Ulaczyk, K. Ackley, M. Dyer, T. Killestein, A.Kumar, on behalf of GOTO collaboration. 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 SN2023pgr? Scientific Research
Data for SN2023pgr 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 SN2023pgr? Cross-Identifications
Throughout global alert streams and survey databases, SN2023pgr has also been designated as: 2023pgr, PS23hly, AT2023pgr, GOTO23aan, ATLAS23qtl, SN 2023pgr. 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 SN2023pgr contribute to measuring the Hubble Constant and the scale of the cosmos? Cosmology & Distance Ladder
SN2023pgr 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 SN2023pgr be detected on Earth? Multi-Messenger Astronomy
No neutrino or gravitational-wave counterpart has been reported for SN2023pgr, 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 SN2023pgr 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), the distance to SN2023pgr is not established for a historical comparison (unclassified; redshift z = 0.08 is published but no luminosity distance is derived). While historical naked-eye supernovae occurred within our Milky Way or its immediate satellites, modern discoveries like SN2023pgr allow astrophysicists to probe diverse galactic environments, metallicities, and stellar populations across the broader universe.
Can I see SN2023pgr tonight with a backyard telescope or binoculars? Backyard Observation
Unknown — no measured brightness. SN2023pgr was discovered 1180 days ago (2023/08/13), 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 SN2023pgr 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 1.18 Billion Light-Years, the inverse-square law dilutes the radiation by quintillions of times, making SN2023pgr completely harmless to our biosphere and purely a fascinating spectacle for human exploration.
Data sourced from IAU TNS, ALeRCE, WISeREP, and the Open Supernova Catalog. View All General Astrophysics FAQs →
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