What type of supernova is SN2007ig and what kind of star exploded?
Astrophysics & Progenitor
SN2007ig 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 SN2007ig?
Astrophysics & Progenitor
The progenitor of SN2007ig 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 SN2007ig from Earth and how old is the light reaching us?
Cosmic Distance & Time
SN2007ig has a luminosity distance of approximately 619.4 Million Light-Years (redshift z = 0.0416, d_L = 189.9). Under a flat ΛCDM cosmology (H₀≈70 km/s/Mpc, Ωₘ≈0.3), the corresponding lookback time is ≈564 Myr — when the light set out 564.0 million years ago during the Neoproterozoic, hundreds of millions of years before complex animal life diversified. 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 SN2007ig tell us about the expansion of space?
Cosmic Distance & Time
SN2007ig exhibits a measured spectroscopic redshift of z = 0.0416. The cockpit reports a user-facing recession velocity of 12,212.2 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 (≈12,471 km/s) is a different low-z approximation and is not mixed here.
How bright did SN2007ig become at its peak, and how many Suns does that equal?
Explosion Energetics
At peak brightness, SN2007ig achieved an apparent magnitude of 18.6 around 2007/09/09. Corrected for cosmic distance and foreground interstellar dust, its intrinsic absolute magnitude was -17.75. At this peak, the exploding star radiated with the incandescent brilliance of approximately 1.1 billion Suns combined, briefly outshining the cumulative starlight of entire dwarf galaxies!
How much total energy was released by SN2007ig, and where did that energy go?
Explosion Energetics
The total energy released by SN2007ig 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 SN2007ig expanding through space?
Explosion Energetics
Spectroscopic line blueshifts imply an ejecta velocity of approximately 12,469 km/s (~4.2% of c) for SN2007ig. This is distinct from cosmological recession velocity inferred from redshift.
What powers the prolonged glow of SN2007ig weeks and months after detonation?
Radioactive Engine
The power source sustaining SN2007ig 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 SN2007ig create and disperse into the universe?
Nucleosynthesis & Elements
The nucleosynthetic products of SN2007ig 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 SN2007ig leave behind a black hole, a neutron star, or nothing at all?
Cosmic Remnant
Whether SN2007ig 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 SN2007ig'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 SN2007ig. 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 SN2007ig explode, and where is it located relative to the galactic center?
Galactic Environment
SN2007ig is associated with cataloged host MCG -01-05-02 at an angular/physical offset of 17.77″ (15.05 kpc) from the reported galactic center. That offset places the transient in the host's projected light distribution; it does not by itself prove which stellar population produced the progenitor.
Where is SN2007ig located in the night sky and which constellation is it in?
Sky Coordinates
In the celestial sphere, SN2007ig is located at Right Ascension 01:32:19.81 and Declination -07:51:35.8, situated in the constellation Cetus (The Sea Monster). Because its declination is -07:51:35.8, it is favorably placed for Southern Hemisphere observatories.
How much Milky Way interstellar dust obscures our view of SN2007ig?
Interstellar Dust
Along this line of sight, the catalog records a Milky Way foreground color excess of E(B−V) = 0.0263 mag (source: published extinction estimate), corresponding to roughly A_V ≈ 0.08 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 SN2007ig monitored?
Astronomical Observations
No calibrated photometry is published for SN2007ig. 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 SN2007ig's chemical makeup?
Astronomical Observations
No spectrum has been published for SN2007ig. 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 SN2007ig and how was it first detected?
Discovery & History
SN2007ig was officially reported on 2007/09/10 by Naito. 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 SN2007ig?
Scientific Research
Data for SN2007ig are compiled from international astronomical notices, the IAU Transient Name Server (TNS), and peer-reviewed astrophysical journals.
How does SN2007ig contribute to measuring the Hubble Constant and the scale of the cosmos?
Cosmology & Distance Ladder
SN2007ig 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 SN2007ig be detected on Earth?
Multi-Messenger Astronomy
No neutrino or gravitational-wave counterpart has been reported for SN2007ig, 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 SN2007ig 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 SN2007ig is not established for a historical comparison (unclassified; redshift z = 0.0416 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 SN2007ig allow astrophysicists to probe diverse galactic environments, metallicities, and stellar populations across the broader universe.
Can I see SN2007ig tonight with a backyard telescope or binoculars?
Backyard Observation
Unknown — no measured brightness. SN2007ig was discovered 6994 days ago (2007/09/10), 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 SN2007ig 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 619.4 Million Light-Years, the inverse-square law dilutes the radiation by quintillions of times, making SN2007ig completely harmless to our biosphere and purely a fascinating spectacle for human exploration.
