Not so cool… red supergiants and the Hayashi-limit of massive stars

Rolf Kudritzki in collaboration with

Ben Davies Liverpool John Moores University in collaboration with

Bertrand Plez University Montpellier 2 in collaboration with

Maria Bergemann MPIA Heidelberg in collaboration with

Zach Gazak IfA our nearest RSG neighbors… our nearest RSG neighbors…

Maniakalani – the Maui fish hook southern cross

Lehua-kona Antares

Keawaula Beach, June 24, 2012

Davies, Kudritzki et al., ApJ 767, 3, (2013) Spring 2016 Brightest stars red supergiants red

at infrared light: infrared at K–M K–M core core collapse supernovae of Progenitors (TMT and E-ELT) Coma cluster galaxies out to the RSGs in individual studies: abundance Infrared beacons for of of fullystars convective at star evolution phaseofmassive Final

-8 ≥ M Hayashi – limit J -11 mag -11 ≥ Spring 2016 MARCS model atmosphere,MARCS Gustafsson Plez, et al., 2011 2008;

RSG – SED: T J H eff K = 3400K 3400K = Spring 2016 Why T eff of Hayashi-limit important? important? Hayashi-limit of K–M K–M • • • • • • • • SN progemitors SN progemitors extinction reddening, studies abundance age of populations age of clusters mass luminosity correction bolometric Phil Massey Phil Emily Levesque & T on work Pioneering eff by by Spring 2016 T eff from BVRI SED and TiO-bands TiO-bands and SED BVRI from T Levesque et al, 2005, ApJ 628, 973 Levesque et al, 973 ApJ 628, 2005, eff = 3500 K 3500 = et al. 2008 Gustafsson Atmospheres Model MARCS Spring 2016 T eff from BVRI SED and TiO-bands TiO-bands and SED BVRI from T Levesque et al, 2005, ApJ 628, 973 Levesque et al, 973 ApJ 628, 2005, eff = 3625 K 3625 = Spring 2016 T eff from BVRI SED and TiO-bands TiO-bands and SED BVRI from T Levesque et al, 2005, ApJ 628, 973 Levesque et al, 973 ApJ 628, 2005, eff = 3750 K 3750 = Spring 2016 T eff from BVRI SED and TiO-bands TiO-bands and SED BVRI from T Levesque et al, 2005, ApJ 628, 973 Levesque et al, 973 ApJ 628, 2005, eff = 4000 K 4000 = Spring 2016 T eff vs. spectral type type spectral vs. Levesque et al, 2005, ApJ 628, 973 Levesque et al, 973 ApJ 628, 2005, new old old • • •

our J-band spectroscopy our J-band gives higher Teff does thegive NIR same ???answer Spring TiO-method 2016 However …. misses important part of SED – – SED of part important J, H, K Spring 2016 TiO TiO B,V,R,I J H K The Temperatures of Red Supergiants

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© Ben Davies spectroscopy test J-band at low metallicity check Teff for TiO-method 2.4 to 0.35 from XShooter VLT ESO • • •

our J-band spectroscopy our J-band gives higher Teff does thegive NIR same ???answer Spring TiO-method 2016 However …. : simultaneous spectral coverage (R ~ 6000) XShooter misses spectra of 25 LMC/SMC RSGs RSGs LMC/SMC 25 of spectra important part of SED – – SED of part important µ (U-band to K-band) K-band) to (U-band J, H, K

Galaxy (Solar metallicity)

Large Magellanic Cloud (0.4x Solar)

XSHOOTER (VLT instrument)

Small Magellanic Cloud (0.2x Solar)

22 J H

K

XShooter SED observation model

TiO - fit

Teff = 3560 K E(B-V) = 0.10 mag TiO - fit

Teff = 3560 K E(B-V) = 0.10 mag 700 K hotter !!! SED - fit

Teff = 4280 K E(B-V) = 0.47 mag SED - fit

Teff = 4280 K E(B-V) = 0.47 mag

TiO - fit

Teff = 3620 K E(B-V) = 0.10 mag TiO - fit

Teff = 3620 K E(B-V) = 0.10 mag 600 K hotter !!! SED - fit

Teff = 4200 K E(B-V) = 0.40 mag Spring 2016 - fails with TiO features mag 0.4 ~ E(B-V) high with • - fails at JHK with flux low BVRI ~ 0.1 magE(B-V) • Khotter 500 ~ • SED-fit – reproduces flux – reproduces BVRIJHK SED-fit and TiO features – reproduces TiO-fit T T eff eff from full SED-fit full from SED-fit discrepancy of MARCS model fits fits model MARCS of discrepancy than TiO-fit Spring 2016 A more model independent approach…. definition of T atmosphere model of independent T yields over integral observed if if is known eff

observed flux flux observed

eff

Spring 2016 T eff for large use model fluxes only at longest wavelength from flux integration method (FIM) integration flux from method converges for x < 4 4 x< for converges method

use at and

and

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normalization λ0 Spring 2016 T eff for large use model fluxes only at longest wavelength from flux integration method (FIM) integration flux from method converges for x < 4 4 x< for converges method

use at and

and

Spring 2016 reddening interstellar reddening and FIM

use at and de-redden minimum minimum

and

J H

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XShooter SED FIM à Teff E(B-V)=0.4mag Spring 2016 reddening interstellar reddening and FIM

use at and de-redden minimum minimum

and

0.0

E(B-V)

0.1

0.2

0.3 TiO Teff FIM - fit

Teff = 4200 K E(B-V) = 0.36 mag FIM - fit

Teff = 4020 K E(B-V) = 0.32 mag 0.0

E(B-V)

0.1

0.2

0.3

TiO Teff Spring 2016 low E(B-V) E(B-V) low • R/d and E(B-V) constrain to wavelengths • •

Model independent lower Teff limits at at limits Teff lower independent Model model but fluxes used only at two FIM result FIM is result also model dependent Flux integration method - FIM Flux integration T(TiO) vs T(FIM)

LMC

SMC

500K !!! Spring 2016 HRD in change

Spring 2016 3D convection simulation Betelgeuze simulation Betelgeuze 3D convection 2 AU

2011 al. et Chiavassa cells huge convective à scale height Large pressure

48 Spring 2016 49 Spring 2016 Temperature structure: 3D structure: vs.Temperature MARCS Chiavassa et al.2011 et Chiavassa MARCS

3D

50

Spring 2016 the near-IR model 1-D which visual fits spectrum fails of 3D-model in 3D effects on à consequences for al., 2013, al., 2013, et Davies,from Kudritzki TiO Teff determination !!! determination and SED SED and ApJ 767, 3 3 767,

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