AT2023bji: What Happened, Distance & Viewing Guide

Q: What type of supernova is AT2023bji and what kind of star exploded?

AT2023bji is cataloged as a Type Nova transient. Mechanism-specific claims (progenitor mass, nickel yield, remnant type) require more than this label and are not asserted here as object-specific measurements.

Q: How far away is AT2023bji from Earth and how old is the light reaching us?

The distance to AT2023bji has not been measured. No spectroscopic redshift or luminosity distance is published for this transient, so neither its distance from Earth nor its lookback time can be stated. A redshift requires a spectrum, and a photometric redshift requires multi-band imaging that has not been reported. Without a distance, its intrinsic luminosity and total energy release are also undetermined. Check the sources below for follow-up spectroscopy or host-galaxy identification.

Q: What does the cosmological redshift of AT2023bji tell us about the expansion of space?

No spectroscopic redshift has been measured for AT2023bji. Without a published z, its place in the Hubble flow, recession velocity, and lookback time cannot be stated. A redshift requires a spectrum (or a well-calibrated photometric redshift from multi-band imaging). Check the sources below for follow-up spectroscopy.

Q: How fast are the supernova ejecta and shockwave of AT2023bji expanding through space?

No ejecta velocity is measured for AT2023bji. 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.

          🔭 Deep Field (~2.1′ FOV) · DSS2 Optical (China-VO mirror)
        

● AT2023bji Explosion Site

High-magnification deep optical view into AT2023bji'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

Millions of Light-Years

Lookback Cosmic Time

✨ Peak Brightness

Mag 16.33

Astro Camera (CCD)

☀️ 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

Camelopardalis

The Giraffe

💥 Explosion Physics

Type Nova

Core-Collapse Supergiant

📅 Discovered On

2023/02/05

S.T. Hodgkin, E. Breedt, A. Delgado, D.L. Harrison, M. van Leeuwen, G. Rixon, T. Wevers, A. Yoldas (IoA Cambridge), N. Ihanec, K. Kruszyńska, K.A. Rybicki, Ł. Wyrzykowski (Warsaw University Astronomical Observatory), Z. Kostrzewa-Rutkowska (Leiden Observatory), D. Eappachen (SRON/RU), G. Marton (Konkoly Observatory), on behalf of the Gaia Alerts team

CHAPTER I

A Core-Collapse Class Transient

On 2023/02/05, astronomers scanning the heavens flagged a sudden, violent pinpoint of light that had flared into visibility. Designated AT2023bji, it represents a catastrophic stellar explosion classified as a Type Nova supernova.

AT2023bji 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 AT2023bji.

Astrophysical Mechanism Summary

Type: Type Nova • Progenitor: Massive Red/Stripped Supergiant Star • Velocity: Not measured

CHAPTER II

A Message Across Deep Cosmic Time

AT2023bji has a luminosity distance of approximately Millions of Light-Years . Lookback time is unavailable without a usable redshift; do not equate luminosity distance with travel time.

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

CHAPTER III

Brightness Record

At the height of the outburst around 2023/02/08, AT2023bji surged to a peak apparent magnitude of 16.33.

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 Nova light curves; an object-specific nickel mass for AT2023bji 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 AT2023bji'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 AT2023bji.

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 Camelopardalis

No host galaxy is identified for AT2023bji in this catalog record . In our terrestrial sky, it resides in the constellation Camelopardalis (The Giraffe) at Right Ascension 05:43:48.270 and Declination +62:58:41.66.

CHAPTER VII

The Scientific Surveillance Campaign

Following its discovery by S.T. Hodgkin, E. Breedt, A. Delgado, D.L. Harrison, M. van Leeuwen, G. Rixon, T. Wevers, A. Yoldas (IoA Cambridge), N. Ihanec, K. Kruszyńska, K.A. Rybicki, Ł. Wyrzykowski (Warsaw University Astronomical Observatory), Z. Kostrzewa-Rutkowska (Leiden Observatory), D. Eappachen (SRON/RU), G. Marton (Konkoly Observatory), on behalf of the Gaia Alerts team, observatories worldwide swung their lenses toward AT2023bji. In the Open Supernova Catalog, AT2023bji is documented across 17 photometric measurements in passbands such as g, r 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? No reliable current brightness estimate.

Discovered 1369 days ago (2023/02/05). Cataloged peak 2023/02/08 (1366d ago; rest-frame phase +1366.0d). Cataloged/observed peak: m = 16.33 on 2023/02/08. Latest observed: m = 17.73 on 2023/02/19 (MJD 59994.4).

No reliable current brightness estimate — no event-specific brightness fit with documented uncertainty is published for this object. Class-average decay templates are not used as object-specific predictions. Latest observed magnitude: m = 17.73 on 2023/02/19 (MJD 59994.4). Published upper limits (nondetections) exist in the photometry record. Current brightness trend is unknown (last observation 2023/02/19 (MJD 59994.4); same-band recent pair unavailable or stale).

Instrument Class & Aperture	Sensitivity Limit	Cataloged Peak (m=16.33 on 2023/02/08)	Current Brightness Tonight
Naked Eye Dark sky site (Bortle 1–3) with no optical aid	m ≤ 6.0	Requires larger aperture (limit m ≤ 6.0)	No reliable estimate
Binoculars (50mm) Standard 7x50 or 10x50 handheld binoculars	m ≤ 9.5	Requires larger aperture (limit m ≤ 9.5)	No reliable estimate
Small Backyard Scope (4" / 100mm) Entry 4-inch (100mm) refractor / reflector	m ≤ 12.0	Requires larger aperture (limit m ≤ 12.0)	No reliable estimate
Medium Amateur Scope (8"–12") 8-inch to 12-inch Dobsonian or Schmidt-Cassegrain	m ≤ 14.5	Requires larger aperture (limit m ≤ 14.5)	No reliable estimate
Amateur CMOS Rig Cooled monochrome/color CMOS camera with multi-hour stack	m ≤ 19.5	✅ Reachable	No reliable estimate
2m–3m Research Telescope University or regional observatory (e.g. Palomar 60", Calar Alto)	m ≤ 22.0	✅ Reachable	No reliable estimate
Giant 8m–10m Observatories Keck (10m), VLT (8.2m), Gemini, Subaru optical imaging	m ≤ 25.0	✅ Reachable	No reliable estimate
Space Observatories Only Hubble Space Telescope (WFC3) / JWST (NIRCam deep stack)	m ≤ 30.0	✅ Reachable	No reliable estimate

Planetary Safety Note: Even though AT2023bji was a titanic explosion, our planet sits safely outside the lethal 50–100 light-year kill zone. At a distance of Millions of Light-Years, the blast poses zero physical hazard to Earth's biosphere.

🌌 Cosmic Neighbors & Contemporaries 105,768+ transients indexed

Cataloged transients closest to AT2023bji in discovery time, spatial sky neighborhood, and cosmological redshift:

⏱️ Closest in Time

FRB20230205A Exploded same day

Type FRB 2023/02/05

FRB20230204B 1d before

Type FRB 2023/02/04

FRB20230204C 1d before

Type FRB 2023/02/04

🔭 Closest on the Sky

AT2019shc 11.2′ away

Type Candidate Discovered 2019/10/08

SN2025buw 13.8′ away

Type Ia Discovered 2025/02/17

GRB 920419B 22.1′ away

Type LGRB Discovered 1992/04/19

🌌 Same Cosmic Era (Redshift)

No redshift match available (target z missing or no comparable redshifts in index).

❓ Frequently Asked Questions About AT2023bji

Scientific & observational Q&As indexed from astronomical databases & the Open Supernova Catalog

What type of supernova is AT2023bji and what kind of star exploded? Astrophysics & Progenitor

AT2023bji is cataloged as a Type Nova 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 AT2023bji? Astrophysics & Progenitor

The specific progenitor of AT2023bji 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 AT2023bji.

How far away is AT2023bji from Earth and how old is the light reaching us? Cosmic Distance & Time

The distance to AT2023bji has not been measured. No spectroscopic redshift or luminosity distance is published for this transient, so neither its distance from Earth nor its lookback time can be stated. A redshift requires a spectrum, and a photometric redshift requires multi-band imaging that has not been reported. Without a distance, its intrinsic luminosity and total energy release are also undetermined. Check the sources below for follow-up spectroscopy or host-galaxy identification.

What does the cosmological redshift of AT2023bji tell us about the expansion of space? Cosmic Distance & Time

No spectroscopic redshift has been measured for AT2023bji. Without a published z, its place in the Hubble flow, recession velocity, and lookback time cannot be stated. A redshift requires a spectrum (or a well-calibrated photometric redshift from multi-band imaging). Check the sources below for follow-up spectroscopy.

How bright did AT2023bji become at its peak, and how many Suns does that equal? Explosion Energetics

At peak brightness, AT2023bji achieved an apparent magnitude of 16.33 around 2023/02/08.

How much total energy was released by AT2023bji, 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 AT2023bji.

How fast are the supernova ejecta and shockwave of AT2023bji expanding through space? Explosion Energetics

No ejecta velocity is measured for AT2023bji. 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 AT2023bji 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 AT2023bji. 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 AT2023bji create and disperse into the universe? Nucleosynthesis & Elements

The nucleosynthetic products of AT2023bji 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 AT2023bji leave behind a black hole, a neutron star, or nothing at all? Cosmic Remnant

A core-collapse explosion associated with AT2023bji'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 AT2023bji'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 AT2023bji. 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 AT2023bji explode, and where is it located relative to the galactic center? Galactic Environment

No host galaxy is identified for AT2023bji 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 AT2023bji located in the night sky and which constellation is it in? Sky Coordinates

In the celestial sphere, AT2023bji is located at Right Ascension 05:43:48.270 and Declination +62:58:41.66, situated in the constellation Camelopardalis (The Giraffe). Because its declination is +62:58:41.66, it is primarily placed in the Northern celestial hemisphere.

How much Milky Way interstellar dust obscures our view of AT2023bji? Interstellar Dust

Along this line of sight, the catalog records a Milky Way foreground color excess of E(B−V) = 0.1274 mag (source: 5), corresponding to roughly A_V ≈ 0.39 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 AT2023bji monitored? Astronomical Observations

AT2023bji was tracked across 17 photometric observations across a baseline of 43.2 days utilizing filter bands including g, r. Data were captured by observatories and survey networks including ZTF. Multi-color photometry tracks the temperature evolution of the fireball, verifying the rise time to peak and the rate of radioactive decline.

What did astronomical spectroscopy reveal about AT2023bji's chemical makeup? Astronomical Observations

No spectrum has been published for AT2023bji. 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 AT2023bji and how was it first detected? Discovery & History

AT2023bji was officially reported on 2023/02/05 by S.T. Hodgkin, E. Breedt, A. Delgado, D.L. Harrison, M. van Leeuwen, G. Rixon, T. Wevers, A. Yoldas (IoA Cambridge), N. Ihanec, K. Kruszyńska, K.A. Rybicki, Ł. Wyrzykowski (Warsaw University Astronomical Observatory), Z. Kostrzewa-Rutkowska (Leiden Observatory), D. Eappachen (SRON/RU), G. Marton (Konkoly Observatory), on behalf of the Gaia Alerts team. 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 AT2023bji? Scientific Research

AT2023bji is documented across 5 scientific references and archival data sources in the Open Supernova Catalog. These include discovery circulars and research datasets from Transient Name Server, 2023TNSTR.304....1H, The Open Supernova Catalog, ALeRCE / ZTF. All raw photometry and spectroscopy points are cross-indexed to their original bibliographic records for peer-reviewed verification.

What other names and survey identifiers exist for AT2023bji? Cross-Identifications

Throughout global alert streams and survey databases, AT2023bji has also been designated as: 2023bji, Gaia23apb, SN2023bji, AT 2023bji, ZTF23aabvpgb. 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 AT2023bji contribute to measuring the Hubble Constant and the scale of the cosmos? Cosmology & Distance Ladder

AT2023bji 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 AT2023bji be detected on Earth? Multi-Messenger Astronomy

No neutrino or gravitational-wave counterpart has been reported for AT2023bji, 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 AT2023bji 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 AT2023bji is not measured, so no such comparison can be drawn. While historical naked-eye supernovae occurred within our Milky Way or its immediate satellites, modern discoveries like AT2023bji allow astrophysicists to probe diverse galactic environments, metallicities, and stellar populations across the broader universe.

Can I see AT2023bji tonight with a backyard telescope or binoculars? Backyard Observation

Unknown — no measured brightness. AT2023bji was discovered 1369 days ago (2023/02/05), 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 AT2023bji pose any threat to Earth? Planetary Safety

Earth is in no danger from AT2023bji. The astrophysical 'lethal kill zone' for a supernova to damage our ozone layer is roughly 50 to 100 light-years. This transient is far outside the solar neighbourhood: it was discovered by a wide-field survey at a magnitude only reachable for an extragalactic object, and any transient in our own galaxy within that radius would have appeared far brighter than the ~18th magnitude reported here. Its exact distance is unmeasured, but the detection brightness alone rules out any nearby threat.

Data sourced from IAU TNS, ALeRCE, WISeREP, and the Open Supernova Catalog. View All General Astrophysics FAQs →

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The Story of Supernova AT2023bji