A complete massive star census of R136/NGC 2070: the core of 30 Doradus

Joachim M. Bestenlehner1, Paul A. Crowther1, Saida M. Caballero-Nieves2, Sergio Simon-D´ ´ıaz3, Fabian R.N. Schneider4

10 September 2019

1University of Sheffield, 2Florida Institute of Technology, 3Instituto de Astrof´ısica de Canarias, 4University of Heidelberg 1 Outline

R136

Data and analysis

Masses and Ages

Feedback

He abundances and stellar winds

Future massive star surveys

(Stellar wind theory)

2 30 Doradus, NGC 2070 and R136

3 The star cluster R136

Stellar mass of 105 M ∼ Metallicity of 50% Z ∼ WNh, Of/WN and O stars

7.0 WNh-stars 6.5

6.0 O-stars !

L 5.5 / WR-stars L log

5.0

4.5

4.0

5.0 4.9 4.8 4.7 4.6 4.5 log Teff

4 R136: HST/STIS programme

Crowther et al. 2016 39 HST orbits during Cycles 19-20 (17 STIS 52 0.2” slits) × 5 R136: HST/STIS programme

Spectroscopic data (stellar parameters and chemical abundances):

UV: HST/STIS 1180 to 1700 A˚ (G140L)

blue-optical: HST/STIS 3800 to 4800 A˚ (G430M)

Hα: HST/STIS 6300 to 6865 A˚ (G750M)

Photometric data (luminosity and reddening):

HST/WFC3: B-band (F438W) and V-band (F555W), de Marchi et al. (2011) VLT/SPHERE: K-band, Khorrami et al. (2017) HST/WFPC2: U (F336W) and V (F555W) photometry, Hunter et al. (1995)

6 Spectroscopic analysis: HSH95-31

FASTWIND analysis (Puls et al. (1995)) to be comparable with VLT/Flames Tarantula Survey (Evans et al. (2011))

CMFGEN analysis (Hillier & Miller (1998)) for R136a1, a2, a3

Reddening law from Ma´ız Apellaniz´ et al. (2014)

UV-spectra from Crowther et al. (2016)

7 Spectroscopic analysis: HSH95-31 O2V((f*))

IACOB-GBAT: S. Simon-D´ ´ıaz et al. (2011), Puls et al. (2005), Sab´ın-Sanjulian´ et al. (2014) + Nitrogen lines 8 HR-diagram

7.0 ZAMS

200M

150M 6.5 R136b 100M

70M

6.0 50M 2.5My

L/L 5.5 30M

log 20M 5.0

15M

4.5 single SB? low S/N 4.0 crowding

4.75 4.70 4.65 4.60 4.55 4.50 4.45 log Teff Evolutionary tracks are from Yusof et al. (2013), Brott et al. (2011) and Kohler¨ et al. (2015). 9 Masses and ages

BONNSAI (Schneider et al. (2014)) evolutionary tracks from Brott et al. (2011) and Kohler¨ et al. (2015)

Median age 1.6 My (similar to Crowther et al. (2016) from UV calibration)' Cluster age peaks 1.2 Myr low mass stars: star-formation∼ rate peaked between 1 and 2 Myr ago (Cignoni et al. 2015) 10 Masses and ages

7 stars > 100M

Top-heavy IMF with γ 2 < 2.35 (Salpeter (1955)) ≈ 30 Dor γ = 1.9 (Schneider et al. (2018)) Abundances can be better reproduce with a top-heavy IGIMF (Palla et al. submitted) 11 Masses and ages

age < 2.5 My, age > 2.5 My 12 Ionising fluxes and mechanical feedback

Within 0.5 pc around R136a1:

Ionising flux Q = 2.75 1051 ph/s 0 × 1 ˙ 2 39 Stellar wind luminosity Lsw = 2 Mv = 1.17 10 erg/s ∞ × (7 stars > 100M ) / R136:

57% of ionising flux and 90% of mechanical feedback ∼ ∼ Doran et al. (2013) estimated the output of the Tarantula Nebula (within in a radius of 150 pc)

R136 / Tarantula Nebula: 27% of ionising flux and 60% of mechanical feedback ∼ ∼ (7 stars > 100M ) / Tarantula Nebula:

15% of ionising flux and 54% of mechanical feedback ∼ ∼

13 Cumulative ionizing output

Crowther (2019), review of massive stars in the Tarantula Nebula 14 HRD of the Tarantula Nebula

Crowther (2019), review of massive stars in the Tarantula Nebula 15 Helium enrichment

R136a2 0.55 R136a3 R136a1 0.50

0.45

0.40 R136a5

in mass0 fraction .35 R136a7 R136b Y 0.30

0.25

9.0 8.5 8.0 7.5 7.0 6.5 6.0 − − − − − − − log (M/M˙ evo)

16 Helium enrichment

R136a3 0.55 R136a2 R136a1 0.50

0.45

0.40 R136a5

in mass0 fraction .35 R136b H121 R136a7 Y 0.30

0.25

100 150 200 250 300 vbroad R136a7, age ∼ 0.8 Myr, binary interaction or binary merger product ??? 17 Wind momuentum – luminosity relation

31 fit through our targets Vink et al. (2000, 2001)

) Sab´ın-Sanjuli´anet al. (2017) 30 R/R p

∞ 29 v v f √

˙ 28 M/ single

log ( SB? 27 low S/N crowding

5.0 5.5 6.0 6.5 7.0 log L/L

18 Summary

Young and older population in R136 Star formation peaked 1.2 Myr ago ∼ Top-heavy IMF? Most massive stars dominate ionsing and mechanical output R136 accounts for 1/4 of ionsing flux and 2/3 of mechanical feedback∼ of the Tarantula Nebula∼

Helium enrichment as a result of core-overshoot and mass loss? Good agreement between observed and predicted mass-loss rates for the most massive stars Mass-loss rates for O stars are over-predicted

19 Future surveys: 4MOST and ULLYSES

1001 MC survey (Cioni et al. 2019, Eso Messenger):

10 000 to 15 000 WR, OB and Y/RSG Mini & 15M

Hubble UV Legacy Library of Young Stars as Essential Standards (ULLYSES): 150 OB and WR stars in the Magellanic Clouds ∼ 180 existing archival data ∼ 20