From Type Ia Supernova Remnants to Binary Love Stories in Their Previous Life

    Type Ia Supernovae (SNe Ia) have been used as standardizable candles to discover the accelerated expansion of the universe, leading to the revelation of dark energy and the award of 2011 Nobel Prize in Physics to astronomers. However, important as they are, SNe Ia are not fully understood yet. 

    Generally speaking, two contrasting origins of SNe Ia have been suggested: a single degenerate (SD) origin in which a white dwarf (WD) accretes too much material from a normal star companion, and a double degenerate (DD) origin that results from the merger of two WDs. 

    In the SD scenario, the interaction between the WD and the normal star companion strips the mass of the companion to form a circumstellar medium, and the companion can survive the SN explosion and be detected. In the DD scenario, both WDs are destroyed and no dense circumstellar medium or detectable stellar remnant is expected. Therefore, if a surviving companion or a dense circumstellar medium is detected near the explosion center of a Type Ia SN remnant (SNR Ia), the SD origin of this SN can be affirmed. 

    Large Magellanic Cloud

    The Large Magellanic Cloud (LMC) is an ideal galaxy where we can study SNRs and search for surviving companions of SN progenitors because it has a large sample of SNRs all at a known moderate distance, ∼50 kpc, near enough for stars and SNRs to be easily resolved by the Hubble Space Telescope (HST). Furthermore, confusion and extinction along the lines of sight are minimized by the LMC disk’s nearly face-on orientation. 

    Ground-based Telescopes versus the Hubble Space Telescope 

in the Large Magellanic Cloud