# Presentation: 631438

## 20,040 Years of SN1987A

- (in 25 minutes)

- Dick McCray
- University of Colorado

## The Explosion

- Energy: 1051 ergs (Victor Utrobin)
- Why did it explode? (Adam Burrows, Thomas Janka)
- Asymmetries: Craig Wheeler, Nick Chugai, Sergey Moiseenko

## Neutrinos

- Temperature: ~ 4 MeV
- Decay time: ~ 4 s
- Just about right for neutron star formation

## Why don’t we see a compact object?

- Optical, near IR: obscured by black cloud?
- X-rays: < cooling neutron star.  Debris may be opaque at 1 keV.
- Absorbed luminosity should emerge as far IR.
- 	Manchester, Aschenbach, Kirshner, Werner

## Progenitor Star

- Why blue giant, not red giant? (Wheeler)
- How massive? Utrobin
- 	Single star models: Woosley
-    Binary star models: Podsiadlowski

## Triple Ring system

- Radius: R ~ 0.6 lt yr
- Expanding: V ~ 10 km s-1
- Density ~ 3 x 103 – 3 x 104 cm-3
- Glowing mass ~ 0.1 MSun
- Nitrogen-rich

-  Rings were ejected by progenitor
-      t ~ R/V ~ 20,000 years before explosion
-  Then photoionized by soft X-rays from SN
-      flash (Lundqvist, Pun)
- But why three rings?
- (Podsiadlowski, Dwarkadas, Smith)

## Light Echoes

- Distant echoes: interstellar clouds
- (courtesy Patrick Tisserand)

- Nearby echoes: Napoleon’s Hat etc.
-  few solar masses ejected by progenitor (Sugerman, Crotts, et al.)

**10 Ly**

## Inner Debris

- Glowing: 44Ti decay
- Expanded to ~ 0.5 inner ring radius
- Interior dust clouds
- Cold!  < 300 K
- Stirred, not blended

- Fe bubbles: ~1% of mass, ~50% of interior volume
- Abundances: Don’t know! – except radioactive elements

- :

## Debris Light curve

- Woosley, Hartmann, Fransson, Kozma

- 56Fe = 0.07 MSun
- 57Fe = 3.3 x 10-3 MSun
- 44Ti  = 1 x 10-4 MSun

## CRASH!

## Slide 11

## Hotspots!

- 2006 – 2003 difference

- Ring has brightened by factor ~ 3
- Hotspots still unresolved
- Have not fully merged
- (Kjaer, Pun, Kirshner, Iping, Smith, Fransson)
- What caused fingers?
- Why so regularly spaced?

## Radio & X-ray Emission(Gaensler, Staveley-Smith, Aschenbach, Park)

-  X-rays and radio turned on at 1200 d
-  Radio, X-ray rings expanded with radial velocity ~  3000 km/s, then slowed down
- ratio [hard (> 3keV) X-rays/radio] remains nearly constant
-  Soft (~0.5 – 2 keV) X-rays increased rapidly after hotspots appeared)
- Soft X-ray image resembles optical image
- Radio and hard X-rays come from relatively low density gas between blast wave and reverse shock
- Optical and soft X-rays come from blast waves overtaking hotspots

- How (where) are relativistic electrons accelerated?

## Reverse shock(Kevin Heng, Nathan Smith)

- LyMichael 1996)

- H(Smith 2005)

- Reverse shock is the piston
- Doppler velocities ~ 104 km s-1
- Can measure shape of reverse shock
- No cylindrical symmetry
- Flux of H atoms is increasing

## Dust and IR

- IR comes from collisional heating of dust grains in X-ray emitting gas
- Dust/gas ratio is low
- IR/X-rays decreasing  dust destruction
- Dwek, Polomski, Danziger, Suntzeff

- 11.7 m

- 0.5 – 2 keV

## Forecasting SN1987A

- 2017 celebration:
- X-ray, optical ring: ~ 10 x brighter than today
- Hotspots will merge
- Reverse shock emission will vanish
- Interior debris will begin to brighten
- Circumstellar matter will begin to glow
- Spectacular images of NT radio emission from ALMA
- Compact Object: JWST?, ALMA?
- 2027 celebration:
- X-rays, optical: ~ 100 x brighter than today
- Will clearly see interior debris and circumstellar matter
- Newly synthesized elements will begin to cross reverse shock