Name: Supernova SN2015F Optical Photometry and Spectroscopy
Creator: sne.space

Question 1

What type of supernova is SN2015F and what kind of star exploded?

Accepted Answer

SN2015F is spectroscopically classified as a Type Ia supernova, consistent with a thermonuclear explosion involving a carbon-oxygen white dwarf. Type Ia events are used as distance indicators via empirical relations such as the Phillips relation, but that cosmological utility does not identify which binary channel (single-degenerate accretion, double-degenerate merger, or sub-Chandrasekhar detonation) produced this object.

Question 2

What was the progenitor star doing in the millions of years leading up to SN2015F?

Accepted Answer

No unique progenitor history is established for SN2015F. Type Ia spectral classification is consistent with a thermonuclear explosion of a carbon-oxygen white dwarf, but it does not identify which binary pathway produced this event. Leading models include single-degenerate accretion toward the Chandrasekhar mass, double-degenerate white-dwarf mergers, and sub-Chandrasekhar helium-shell detonations. Distinguishing these requires population statistics, early-time spectra, or remnant searches that are not established for this individual object. Claims that this white dwarf accreted for millions of years, or that it approached 1.4 solar masses, are general theory—not documented facts about SN2015F.

Question 3

How far away is SN2015F from Earth and how old is the light reaching us?

Accepted Answer

SN2015F has a luminosity distance of approximately 78.4 Million Light-Years (redshift z = 0.00541, d_L = 24.04 Mpc). Under a flat ΛCDM cosmology (H₀≈70 km/s/Mpc, Ωₘ≈0.3), the corresponding lookback time is ≈75 Myr — when the light set out 75.3 million years ago during the Cretaceous period when Tyrannosaurus rex and Triceratops walked the planet. Luminosity distance is larger than the light-travel distance because cosmic expansion stretches the path; the two must not be equated.

Question 4

What does the cosmological redshift of SN2015F tell us about the expansion of space?

Accepted Answer

SN2015F exhibits a measured spectroscopic redshift of z = 0.0054. The cockpit reports a user-facing recession velocity of 1,617.5 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 (≈1,622 km/s) is a different low-z approximation and is not mixed here.

Question 5

How bright did SN2015F become at its peak, and how many Suns does that equal?

Accepted Answer

At peak brightness, SN2015F achieved an apparent magnitude of 13.1 around 2015/03/25. Corrected for cosmic distance and foreground interstellar dust, its intrinsic absolute magnitude was -18.8. At this peak, the exploding star radiated with the incandescent brilliance of approximately 2.8 billion Suns combined, briefly outshining the cumulative starlight of entire dwarf galaxies!

Question 6

How much total energy was released by SN2015F, and where did that energy go?

Accepted Answer

Type Ia events are typically associated with a kinetic energy scale of order 10⁵¹ ergs, with little neutrino emission compared to core-collapse. That is a class expectation—not a calorimetry measurement for SN2015F.

Question 7

How fast are the supernova ejecta and shockwave of SN2015F expanding through space?

Accepted Answer

Spectroscopic line blueshifts imply an ejecta velocity of approximately 1,399 km/s (~0.5% of c) for SN2015F. This is distinct from cosmological recession velocity inferred from redshift.

Question 8

What powers the prolonged glow of SN2015F weeks and months after detonation?

Accepted Answer

After peak, Type Ia light curves are generally powered by the radioactive chain ⁵⁶Ni → ⁵⁶Co → ⁵⁶Fe (half-lives ≈6.1 d and ≈77.2 d). Typical Type Ia events synthesize of order half a solar mass of freshly made Nickel-56 (which later decays into Iron-56); that is a class expectation, not a measured nickel mass for SN2015F. Estimating M(⁵⁶Ni) for this object requires a bolometric light-curve fit that is not published here.

Question 9

What chemical elements did SN2015F create and disperse into the universe?

Accepted Answer

Type Ia explosions are efficient producers of iron-peak elements via thermonuclear burning. Models typically yield substantial ⁵⁶Ni (which decays to stable ⁵⁶Fe), plus silicon, sulfur, calcium, and related species—consistent with the Si II features used in classification. No object-specific nucleosynthetic yield has been published for SN2015F; asserting that this event synthesized half a solar mass of iron would overstate the evidence.

Question 10

Did SN2015F leave behind a black hole, a neutron star, or nothing at all?

Accepted Answer

Nothing remains at the center. Because a Type Ia supernova involves the total thermonuclear disruption of the progenitor white dwarf, the entire star was incinerated and flung into space. There is no central neutron star, pulsar, or black hole left behind. The star's entire mass now exists as an expanding gaseous shell traveling through the host galaxy.

Question 11

What will SN2015F's explosion site look like in 1,000 to 10,000 years?

Accepted Answer

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 SN2015F. 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.

Question 12

In which galaxy did SN2015F explode, and where is it located relative to the galactic center?

Accepted Answer

SN2015F is associated with cataloged host NGC 2442 at an angular/physical offset of 97.16 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.

Question 13

Where is SN2015F located in the night sky and which constellation is it in?

Accepted Answer

In the celestial sphere, SN2015F is located at Right Ascension 07:36:15.76 and Declination -69:30:23.0, situated in the constellation Volans (The Flying Fish). Because its declination is -69:30:23.0, it is favorably placed for Southern Hemisphere observatories.

Question 14

How much Milky Way interstellar dust obscures our view of SN2015F?

Accepted Answer

Along this line of sight, the catalog records a Milky Way foreground color excess of E(B−V) = 0.1749 mag (source: 4,12), corresponding to roughly A_V ≈ 0.54 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.

Question 15

Across which photometric filter bands was SN2015F monitored?

Accepted Answer

SN2015F was tracked across 886 photometric observations across a baseline of 4306.3 days utilizing filter bands including 438, 555, 625, 814, B, H, I, J. Data were captured by observatories and survey networks including DuPont, GMOS, HST, LCO. Multi-color photometry tracks the temperature evolution of the fireball, verifying the rise time to peak and the rate of radioactive decline.

Question 16

What did astronomical spectroscopy reveal about SN2015F's chemical makeup?

Accepted Answer

Astronomers obtained 2 spectroscopic epochs for SN2015F from 1600.0 Å to 10229.5 Å. Optical spectroscopy provides the definitive physical fingerprint of the transient: P-Cygni line profiles reveal the expansion speed of the ejecta, while characteristic absorption features (such as hydrogen Balmer lines Hα/Hβ in Type II, or Si II λ6355 in Type Ia) identify the stellar composition and physical mechanism of the explosion.

Question 17

Who discovered SN2015F and how was it first detected?

Accepted Answer

SN2015F was officially reported on 2015/03/09 by Monard. 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.

Question 18

How many scientific publications and observatories have contributed data to SN2015F?

Accepted Answer

SN2015F is documented across 19 scientific references and archival data sources in the sne.space. These include discovery circulars and research datasets from Burns et al. (2018), 2017ApJ...850..111N, 2017arXiv171101275G, 2017ApJ...835...64G. All raw photometry and spectroscopy points are cross-indexed to their original bibliographic records for peer-reviewed verification.

Question 19

What other names and survey identifiers exist for SN2015F?

Accepted Answer

Throughout global alert streams and survey databases, SN2015F has also been designated as: OGLE15la, PSN J07361576-6930230. 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).

Question 20

How does SN2015F contribute to measuring the Hubble Constant and the scale of the cosmos?

Accepted Answer

Because SN2015F is a Type Ia supernova, it serves as an indispensable rung on the Cosmic Distance Ladder. Astrophysicists utilize the Phillips relation—a tight empirical correlation between peak absolute magnitude and light curve decline rate (Δm₁₅)—to standardize its luminosity. By comparing this calibrated intrinsic brightness with observed apparent magnitude, researchers calculate precise geometric distances across the universe, providing key empirical tests of the Hubble constant (H₀) and dark energy.

Question 21

Could gravitational waves or neutrinos from SN2015F be detected on Earth?

Accepted Answer

For thermonuclear explosions like SN2015F, gravitational wave and neutrino emissions are negligible compared to core-collapse events. However, multi-messenger radio and X-ray observations are crucial: detecting synchrotron radio emission would reveal circumstellar gas shed by a companion star, helping settle the century-old debate between single-degenerate and double-degenerate white dwarf progenitor channels.

Question 22

How does SN2015F compare to famous historical supernovae like SN 1987A or the Crab Supernova?

Accepted Answer

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), SN2015F occurred at a distance of 78.4 Million Light-Years. While historical naked-eye supernovae occurred within our Milky Way or its immediate satellites, modern discoveries like SN2015F allow astrophysicists to probe diverse galactic environments, metallicities, and stellar populations across the broader universe.

Question 23

Can I see SN2015F tonight with a backyard telescope or binoculars?

Accepted Answer

Unknown — no measured brightness. SN2015F was discovered 4268 days ago (2015/03/09), 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.

Question 24

Does the radiation or shockwave from SN2015F pose any threat to Earth?

Accepted Answer

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 78.4 Million Light-Years, the inverse-square law dilutes the radiation by quintillions of times, making SN2015F completely harmless to our biosphere and purely a fascinating spectacle for human exploration.

R.A. (J2000)	07:36:15.76 (114.06567°)
Dec. (J2000)	-69:30:23.0 (-69.50639°)
Spectral Type	Ia
Redshift (z)	0.00541
Recession Velocity	1399 km/s (redshift Doppler-equivalent)
Luminosity Distance	24.04 Mpc (~75.9 Million Light-Years, μ = 31.83)
Peak Apparent Mag	13.1 brightest multi-epoch detection (2015/03/25)
Peak Absolute Mag	-18.8
MW Dust E(B-V)	0.1749 mag derived from galactic coordinates (coordinate model), not a dust-map measurement
Host Galaxy	NGC 2442
Host Offset	97.16
Observations	852 detections, 34 upper limits, 2 spectra

ID	Source	Reference	NASA ADS Bibcode
[1]	Burns et al. (2018)	Burns et al. (2018)	`2018arXiv180906381B`
[2]	2017ApJ...850..111N	Nucita et al. (2017)	`2017ApJ...850..111N`
[3]	2017arXiv171101275G	Graur et al. (2017)	`2017arXiv171101275G`
[4]	2017ApJ...835...64G	Guillochon et al. (2017)	`2017ApJ...835...64G`
[5]	2017MNRAS.472.3437G	Graham et al. (2017)	`2017MNRAS.472.3437G`
[6]	2016A&A...594A..13P	Planck Collaboration et al. (2016)	`2016A&A...594A..13P`
[7]	2016arXiv160401021F	Foley et al. (2016)	`2016arXiv160401021F`
[8]	CBET 4081	Monard et al. (2015)	`2015CBET.4081....1M`
[9]	ATel 8484	Wyrzykowski et al. (2015)	`2015ATel.8484....1W`
[10]	2015ApJS..221...22I	Im et al. (2015)	`2015ApJS..221...22I`
[11]	SOUSA	Brown et al. (2014)	`2014Ap&SS.354...89B`
[12]	2011ApJ...737..103S	Schlafly & Finkbeiner (2011)	`2011ApJ...737..103S`
[13]	2008yCat....1.2024B	Barbon et al. (2008)	`2008yCat....1.2024B`
[14]	OGLE-IV Transient Detection System		`—`
[15]	Latest Supernovae		`—`
[16]	WISeREP	Yaron & Gal-Yam (2012)	`2012PASP..124..668Y`
[17]	SIMBAD astronomical database	Wenger et al. (2000)	`2000A&AS..143....9W`
[18]	NED-D v13.1.0	Helou et al. (1991)	`1991ASSL..171...89H`
[19]	Asiago Supernova Catalogue	Barbon, Cappellaro, & Turatto (1989)	`1989A&AS...81..421B`

SN2015F

Core Parameters

Interactive Sky Field (Aladin) ✨ DSS2 Optical (China-VO mirror)

Literature & Data Provenance

❓ Frequently Asked Questions About SN2015F

SN2015F

Core Parameters

Interactive Sky Field (Aladin) ✨ DSS2 Optical (China-VO mirror)

Literature & Data Provenance

❓ Frequently Asked Questions About SN2015F

BibTeX Citation Block