New insights into Eta Carinae with PIONIER

Transcription

1 New insights into Eta Carinae with PIONIER Image credits: Montage (J. Groh), VLTI (ESO), Eta Car (N. Smith + NASA) Jose Groh (Geneva Observatory, Switzerland) Collaborators O. Absil (Liege), JP Berger (ESO), M. de Becker (Liege), JB Le Bouquin (Grenoble), H. Sana (STScI)

2 Location of stars in the HR diagram

3 Location of stars in the HR diagram Initial Mass ~250 MSun Eta Carinae A

4 Eta Carinae and the Homunculus nebula Ejected mass: ~10 to 20 M from high-res MIR imaging (Smith+ 03) 18

5 Eta Carinae and the Homunculus nebula Central Source: L ~ 5 x 10 6 L M > 100 M. M ~ 8 x10-4 M /yr vinf ~ 420 km/s (Hillier+ 01, Groh+ 12) Needs interferometry to probe the inner 20 mas: mass loss rotation binarity

6 Mass loss and extension of the photosphere Strong stellar wind causes the photosphere to be formed in the wind Sun rhydr = rphot Atmosphere

7 Mass loss and extension of the photosphere Strong stellar wind causes the photosphere to be formed in the wind Eta Car Sun rphot (set by free-free emission) rhydr = rphot rhydr Atmosphere Atmosphere Stellar Wind

8 Mass loss and extension of the photosphere Strong stellar wind causes the photosphere to be formed in the wind. Eta Car (M/2) Sun rhydr = rphot rphot (set by free-free emission) rhydr Atmosphere Atmosphere Stellar Wind

9 Mass loss and extension of the photosphere Strong stellar wind causes the photosphere to be formed in the wind. Eta Car (M/2) Sun rhydr = rphot rphot (set by free-free emission) rhydr Atmosphere Atmosphere Stellar Wind

10 Eta Carinae mass loss (van Boekel+03; Weigelt+07; Kervella 07; Groh+10, 12) Observations NLTE 1D model NLTE 1D model image VINCI AMBER Weigelt+07 Groh+12

11 Eta Carinae mass loss (van Boekel+03; Weigelt+07; Kervella 07; Groh+10, 12) Observations NLTE 1D model NLTE 1D model image VINCI AMBER Weigelt+07 Groh+12 Mass-loss rate in : ~ 8.4 x 10-4 Msun/yr Groh+12

12 Variability in Eta Carinae mass loss? (Mehner+10, 12, Corcoran+10, Gull+11, Groh+12, Teodoro+12, Madura+13) Mass-loss rate reduction by a factor of 2 in the last 10 yr? Mehner+12

13 Eta Car PIONIER data Data taken by O. Absil on 2012 Mar and 2013 Feb 7 spectral channels across the H band 1.0 ETA_CAR PIONIER all data: (red) / (green) / (blue) 1.0 V2 0.1 V spat.freq [m/µm] spat.freq [m/µm] V [m/µm] 0 50 T3phi [deg] U [m/µm] spat.freq [m/µm]

14 Probing changes in mass loss with PIONIER Data taken by O. Absil on 2012 Mar and 2013 Feb 1.00 Visibility squared 0.10 NLTE 1D model Mdot=8.4x10-4 Msun/yr Spatial frequency (m/micron)

15 Probing changes in mass loss with PIONIER Data taken by O. Absil on 2012 Mar and 2013 Feb 1.00 Visibility squared 0.10 NLTE 1D model Mdot=8.4x10-4 Msun/yr NLTE 1D model Mdot=4.2x10-4 Msun/yr Spatial frequency (m/micron) PIONIER data do NOT support a noticeable change in Eta Car s mass-loss rate.

16 Rotation: elongation of the K-band photosphere (van Boekel+ 03; Kervella 07; Weigelt+07; Groh+10) van Boekel+03

17 Rotation: elongation of the K-band photosphere (van Boekel+ 03; Kervella 07; Weigelt+07; Groh+10) Homunculus i=41 o ; PA=131 o Geometric model PA~134 o ; b/a=1.25 b a x500 Eta Car A rapid rotator: rot. axis aligned with the Homunculus polar axis

18 Rotation: elongation of the K-band photosphere (van Boekel+ 03; Kervella 07; Weigelt+07; Groh+10) Homunculus i=41 o ; PA=131 o Geometric model PA~134 o ; b/a=1.25 Rad. Transf. VINCI+AMBER vrot/vcrit=0.77 to 0.92 i=60 o to 90 o PA=108 o to 142 o b a x500 Eta Car A rapid rotator: rot. axis aligned with the Homunculus polar axis Eta Car A rapid rotator: rotation axis misaligned with the Homunculus Groh+10

19 Binarity of Eta Carinae: effects are time dependent Orbit: i=139 o, ω=243 o, PA=312 o, e=0.9, P=5.54 years (Damineli 96; Madura 12) apastron B A x100

20 Binarity of Eta Carinae: effects are time dependent Orbit: i=139 o, ω=243 o, PA=312 o, e=0.9, P=5.54 years (Damineli 96; Madura 12) apastron B A x100

21 Binarity of Eta Carinae: effects are time dependent Orbit: i=139 o, ω=243 o, PA=312 o, e=0.9, P=5.54 years (Damineli 96; Madura 12) apastron B A Eta Car A x100

22 Binarity of Eta Carinae: effects are time dependent Orbit: i=139 o, ω=243 o, PA=312 o, e=0.9, P=5.54 years (Damineli 96; Madura 12) apastron B A Eta Car A x100 Eta Car B

23 Binarity of Eta Carinae: effects are time dependent Orbit: i=139 o, ω=243 o, PA=312 o, e=0.9, P=5.54 years (Damineli 96; Madura 12) apastron B A Eta Car A x100 Eta Car B Around periastron A B

24 Binarity of Eta Carinae: effects are time dependent Orbit: i=139 o, ω=243 o, PA=312 o, e=0.9, P=5.54 years (Damineli 96; Madura 12) apastron B A Eta Car A x100 Eta Car B Around periastron A B wind-wind collision zone

25 Effects due to the companion star around periastron bore hole and free-free emission from the wind-wind collision 3-D isodensity surface Groh+10,12

26 Effects due to the companion star around periastron bore hole and free-free emission from the wind-wind collision 3-D isodensity surface carving of the wind, exposing the hotter, inner parts ( bore hole effect, Madura & Owocki 2010) Groh+10,12

27 Effects due to the companion star around periastron bore hole and free-free emission from the wind-wind collision 3-D isodensity surface carving of the wind, exposing the hotter, inner parts ( bore hole effect, Madura & Owocki 2010) free-free emission from the dense postshocked primary wind compressed along the shock cone walls Groh+10,12

28 Effects due to the companion star around periastron bore hole and free-free emission from the wind-wind collision 3-D isodensity surface KKK-band continuum image carving of the wind, exposing the hotter, inner parts ( bore hole effect, Madura & Owocki 2010) free-free emission from the dense postshocked primary wind compressed along the shock cone walls Groh+10,12

29 Effects due to the companion star around periastron bore hole and free-free emission from the wind-wind collision 3-D isodensity surface Fit to the visibilities 2D model VINCI data (Groh et al. 2010a) carving of the wind, exposing the hotter, inner parts ( bore hole effect, Madura & Owocki 2010) free-free emission from the dense postshocked primary wind compressed along the shock cone walls Groh+10,12

30 Both rotation and binary effects explain the previous data Near-infrared: geometry of the K-band continuum emitting region Binary model fits data as well as single, rapid-rotating star Rapid rotator Wind-wind collision model Fit to the visibilities models VINCI data (Groh et al. 2010a) B A

31 Rotation as seen by PIONIER Data taken by O. Absil on 2012 Mar (close to apastron) at micron Variation of visibility as a function of PA PA 150 Visibility squared PA Spatial frequency (m/micron)

32 Rotation as seen by PIONIER Data taken by O. Absil on 2012 Mar (close to apastron) at micron Variation of visibility as a function of PA PA 150 Visibility squared 0.1 rapid rotator model PA Spatial frequency (m/micron)

33 PIONIER data reveals a rapid rotator Data taken by O. Absil on 2012 Mar -- only spectral channel 6 (1.875 micron) Variation of visibility as a function of PA PA 150 Visibility squared 0.1 rapid rotator model PA Spatial frequency (m/micron)

34 Binary effects not enough to fit PIONIER data Data taken by O. Absil on 2012 Mar (close to apastron) at micron Variation of visibility as a function of PA PA 150 apastron B Visibility squared 0.1 wind-wind collision model A PA Spatial frequency (m/micron)

35 Preliminary image reconstruction: all data by JB Le Bouquin DEC offset (mas) RA offset (mas) I/I max

36 Preliminary image reconstruction: all data by JB Le Bouquin DEC offset (mas) RA offset (mas) I/I max

37 Preliminary image reconstruction: short+inter by JB Le Bouquin beam nearly circular e e 03 relative δ (milliarcseconds) e e e e e e e e e+00 relative α (milliarcseconds)

38 Preliminary image reconstruction: short+inter by JB Le Bouquin beam nearly circular e e 03 relative δ (milliarcseconds) e e e e e e e e e+00 relative α (milliarcseconds)

39 Preliminary image reconstruction Wind-wind collision model Image reconstruction Rotation model DEC offset (mas) I/I max RA offset (mas)

40 Preliminary image reconstruction Wind-wind collision model Image reconstruction Rotation model DEC offset (mas) I/I max RA offset (mas) no changes in Mdot over last 15 years; - rapidly-rotating primary star (~80% critical speed) seem at i~70-90deg (misaligned with Homunculus); - no strong binary effects (WWC) around apastron.

41 IAU SYMPOSIUM 307 NEW WINDOWS ON MASSIVE STARS ASTEROSEISMOLOGY, INTERFEROMETRY AND SPECTROPOLARIMETRY GENEVA SWITZERLAND JUNE 2014 SOC Dave Arnett (USA) Lydia Cidale (Argentina) Emily Levesque (USA) Marco Limongi (Italy) Phil Massey (USA) André Maeder (Switzerland) Georges Meynet (Chair, Switzerland) Coralie Neiner (France) Arlette Noels (Belgium) Stan Owocki (USA) Raphael Hirschi (U.K.) Thomas Rivinius (Chile) Hideyuki Saio (Japan) Philippe Stee (co-chair, France) Rich Townsend (USA) Gregg Wade (Canada) LOC Patrick Eggenberger Sylvia Ekström Anahí Granada José Groh Lionel Haemmerlé Georges Meynet Giovanni Privitera Gilles Simond Chantal Taçoy