SN 2011fe

Discovery

The Palomar Transient Factory is an automated telescopic survey that scans the sky for transient and variable astronomical events. Information is fed to the National Energy Research Scientific Computing Center (NERSC) at Lawrence Berkeley National Lab, which computes the information to identify new star events. After the initial observation of the SN 2011fe event, telescopes were used in the Canary Islands (Spain) to identify the emission spectrum of light emitted at various stages of the event. Following this, the Hubble Space Telescope, the Lick Observatory in California, and the Keck Observatory in Hawaii were used to observe the event in greater detail.

Although SN 2011fe was initially very faint, it brightened rapidly. On the day it was first imaged, 24 August 2011, it was 1 million times too dim to be visible to the unaided eye. One day later, it was 10 thousand times too dim. The next day it was 6 times brighter than that. On 25 August, the EVLA radio telescope failed to detect radio emissions from SN 2011fe. While such emissions are common for other types of supernovae, they have never been observed for Type Ia's.

Two possible candidates were proposed for the precursor system; however, subsequent analysis appears to rule them out.

Importance of Type Ia supernovae and SN 2011fe

Type Ia supernova events occur when a white dwarf star accretes enough additional matter to exceed the Chandrasekhar limit and collapses, triggering runaway fusion and a supernova explosion. Because this collapse happens at a consistent mass, the resulting explosions have very uniform characteristics, and are used as "standard candles" to measure the distance to their host galaxies. The exact brightness and behavior of a Type Ia supernova depends on the metallicity of its parent star (the fraction of the star composed of elements heavier than hydrogen and helium before its evolution into a white dwarf). Because the SN 2011fe event was detected so early, astronomers can gain a more accurate measurement of its initial composition and of its evolution during the supernova explosion, and so refine their models of Type Ia supernova events, resulting in more precise distance estimates for other Type Ia supernova observations.

Type Ia supernova standard candles may help provide evidence to support the hypothesis of dark energy and the accelerating expansion of the universe. A better understanding of Type Ia supernova behavior may in turn allow theoretical models of dark energy to be improved.

References

References

1. Beatty, Kelly. (25 August 2011). "Supernova Erupts in Pinwheel Galaxy". [[Sky & Telescope]].
2. Templeton, Matthew. (24 August 2011). "Special Notice #250: Possible Type-Ia Supernova in M101". [[American Association of Variable Star Observers]].
3. [https://www.rochesterastronomy.org/sn2011/snmag.html List of supernovae sorted by Magnitude for 2011] (David Bishop)
4. (25 August 2011). "Berkeley Scientists Discover an "Instant Cosmic Classic" Supernova".
5. Hartmut Frommert. (15 Sep 2011). "Supernova 2011fe in M101".
6. "[vsnet-recent-sn 2676] SN2011ht recent (Cont'd)".
7. (March 2016). "Optical Observations of the Type Ia Supernova SN 2011fe in M101 for Nearly 500 Days". The Astrophysical Journal.
8. (December 2022). "The whisper of a whimper of a bang: 2400 d of the Type Ia SN 2011fe reveals the decay of 55Fe". Monthly Notices of the Royal Astronomical Society.
9. http://www.astronomerstelegram.org/?read=3597 EVLA Radio Observations of SN 2011fe
10. Weidong Li. (25 August 2011). "Further Analysis of the archival HST images of PTF11kly in M101". The Astronomer's Telegram.
11. S. J. Smartt. (1 Sep 2011). "No progenitor detection for PTF11kly/SN2011fe in Hubble Space Telescope pre-explosion images". The Astronomer's Telegram.
12. Perlmutter, S.. (1999). "Measurements of Omega and Lambda from 42 high redshift supernovae". Astrophysical Journal.