Computational Astrophysics and Cosmology
Open Access Springer Journal
CompAC publishes paper on ● Astronomy, physics and cosmology● Computational and information science
The combination of these two disciplines leads to a wide range of topics which, from an astronomical point of view covers all scales and a rich palette of statistics, physics and chemistry. Computing is interpreted in the broadest sense and may include hardware, algorithms, software, networking, data management, visualization, modeling, simulation, visualization, high-performance computing and data intensive computing.
The Eta Carinae Riddle
Simon Portegies ZwartEdward P.J. van den Heuvel
Hamacker & Frew 2010
Collowgullouric War
M=80-120MSunm=30MSuna=15.5aue=0.9
The Great Eruption of 1838
The Eta Carinae Riddle
● What formed the complicated gaseous structures (Homunculus, skirt, S-knots, NN-knots, etc) of the Eta Carinae nebula.
● What caused the 1838 Great Eruption, and the 1843 eruption.
● Why did Eta Carinae brighten in the 200 years prior to the Great Eruption.
● How come that the NN-knots and the skirt are so Nitrogen richt.
Many researchers, including: Smith 2011-2015, Soker 2003-2013, Humphreys 1999-2013, etc..
Three step approach
1883 Great Eruption
Calculate forward Calculate backwardH
ydro
dyna
mic
sN-bodyStellar evolutionTidal evolutionStellar wind
MCMCof impulsive mass lossFrom a stellar marger In a triple system
Tidal brightening before the merger due to LK-effect
1838
Tidal evolution of a triple:
Conditions at birth:a = 0.9au, e=0.6, M=142MSun, m=30MsunA=95au, e=0.4, i=90o, m=30Msun
~0.1-1Myr after birth:a=1.0au, e=0.6, M=136MSun, m=30MsunA=100au, e=0.4, m=30MSun
time += 0.1Myr
After tidal interaction:A=0.4au, e=0.0, M=114MSun, m=30MsunA=100au, e=0.4, m=30
Spiral-in and merger of the inner two stars.
Runaway velocity of the merger product due to asymmetric mass outflow.
a=0.4au, M=114Msun, m=30Msun
1883 collision
M=90Msun m=30Msun24Msun is lost
1600--1838 1838 1843 2016
M=114MSuna=0.4-0.8AUdM = 24MSuni=91o
Vkick
= 53+/-8kms
M=136MSunm2=30MSuna=1-2AUA=20-100AUdM=22MSun
e<0.7
M=90MSunm=30MSuna=15.5AUe=0.9Vkick = 53+/-8kms
vwind
~ 200kms
v~ 500kms
vwind
~ 1000kms
Nitrogen richSkirt (S-ridge)
Bubble is blown Nitrogen rich skirt forms Homonculus forms
v~50km/sNN-knots
30MSun
Slow symmetric outflowDue to pre-1838 tidallyEnhanced wind
Slow symmetric outflow
Fast asymmetric wind
Due to merger
Colliflower nebulaDue to polar wind
Conclusions
● Hot bubble is blown by the Lidov-Kozai induced tidal wind of the pre-1938 triple star
● 1838: The Lidov-Kozai induced merger in the inner binary changed the outer orbit to the currently observed P=5.5yr, e=0.9 orbit. Skirt forms from the merger ejecta.
● 1843: the outer star plunges through the envelope of the rapidly rotating bloated primary star, leads to the formation of the ´Smurfette´ nebula.
● The rapidly rotating star has expelled mass loss perpendicular to the orbital plane, giving rise to the ´colliflower nebula´
Consequences
● The current orbital plane of the Eta Carina binary is perbendicular to the long axis of the Homonculus nebula.
● The skirt is Nitrogen enriched (by 2.9MSun) from the ejected surface layers of the primary star.
● The binary system is younger than 1Myr.● The long axis of the Homonculus nebula is
perpendicular to the orbital plane and aligned with the rotation axis of the primary star.