VEGA/CHARA: Status and First Science SPIE 2010 San Diego M. Tallon, D. Mourard The VEGA and CHARA Teams

High Angular (0.3mas) and up to spectral resolution Mode 3T HD Differential measurements Fundamental parameters June 27th 20102VEGA SPIE San Diego Old GI2T Facility CHARA Array : Integration : First observations : Remote operation : First science papers

3 Summary of performances (Mourard et al, A&A ) Spectrograph Characteristics Instrumental visibility Limiting magnitude Polarisation behaviour Differential phase June 27th 2010VEGA SPIE San Diego R0=8cmR0=15cm  V² Cal ≈2%  ≈1-2°

Recent advances June 27th 2010VEGA SPIE San Diego4 1.Routine remote operations thanks to the CHARA staff 2.Blind recording with IR tracking (CLIMB, new IR CHARA instrument) 3.Simultaneous observations between visible VEGA and IR FLUOR 4.End of night automated pipeline for quality check 5.Off line data analysis compatible with the OI-FITS norm. 6.Standard use of the JMMC web-service like LITPro (model fitting)

5 Summary of the VEGA Science Programs First science papers – AB Aur: Perraut et al, A&A 516, L1 (2010) – A/B Supergiants: Chesneau et al, A&A in press (2010) Circumstellar environments – Kinematics study in the circumstellar environment of Be stars (Delaa et al.) – Interactive massive stars: ups Sgr (Chesneau et al.) and bet Lyr (Bonneau et al.) Fundamental parameters – 13 Cyg (exoplanet host star) – bet Cep (extended environnement and companion) – ro Ap stars (angular diameter and Teff) – sub giants radii and orbits (class IV stars) But also: eps Aur (famous eclipsing system), alp Cep (rotation), P Cyg (stellar wind), theta OriC (H  line forming region)… June 27th 2010VEGA SPIE San Diego

6 AB Aur is a prototype of Herbig Ae/Be stars and, as such, it has been fully observed in spectroscopy, in infrared interferometry (PTI, IOTA, …) – Spectral type : A0 – Magnitudes : V = 7.1 / K = 4.4 – Distance : 144 pc – Luminosity : 47 L  – Large infrared excess – No jets, no CO flow – Variability of the H  emission at a scale of a few hours  Stellar activity, link wind and disc, … Fukagawa, Subaru June 27th 2010VEGA SPIE San Diego

7 VEGA observations S1S2: Clear spatial resolution of AB Aur in H  W1W2: Fringes but SNR too poor S1S2: Tracking problem PCygni profile Wind modelling V² HH 1

X-Wind D-Wind 8 Interpretation Additional component

A wind only does not allow us to reproduce the spectrum AND the visibility curve, even if this wind is very extended.  Another component has to be considered. We assume a brightness assymetry in agreement with : - the spiral arms detected at few hundreds of AU - the non-null closure phase measured by Millan-Gabet et al. (2006) - the binarity signals recorded by spectro-astrometry by Baines et al. (2006)  7% of ~40mas (5.5 AU) Perspectives: - Observe AB Aur in 2010 with larger baselines to resolve its photosphere - Take benefit of IR fringe tracking 9 Interpretation

10 Interests in the visible of A/B supergiants (e.g. Deneb A2Ia, and Rigel B8Ia): - Very bright and used as stellar candles, - large diameters ( solar radii), Deneb and Rigel are 2-3mas sources - Variability in H  line (R>10000), sensitive to mass-loss and its perturbation, time scale weeks to months. Rigel, Kaufer et al. 1997, PhD thesis Deneb, Przybilla et al June 27th 2010 VEGA SPIE San Diego

11 VEGA/CHARA observations of Deneb: the H  line V  I  Time variability I June 27th 2010 VEGA SPIE San Diego Spatial variability

12 Full 1D modeling of the wind of Deneb June 27th 2010 VEGA SPIE San Diego Parameters from the model of Schiller et al Conclusions: The H  line is complex with subtle opacity effects, The visibility curve is a sensitive indicator of mass-loss rate. The current modeling succeeds in fitting the data by changing the mass-loss rate. The differential phase signals clearly indicates asymmetries in the wind, changing with time. Progresses in the modeling are necessary. Synthetic spectra for different mass-loss rates V I I

Fundamental stellar parameters Works in progress Angular diameters: 13 Cyg : F4V (Exoplanets)  Equ : A9p (roAp) Mass β Cep : B2IIIev (pulsating binary) 48 And : F5IVe (sub-giants) Rotation α Cep : A7IV (fast rotator) Be stars envelopes June 27th VEGA SPIE San Diego VEGA/CHARA high angular resolution allows the study of main sequence stars

Measurements of angular diameters 1% 2% 4000 stars brighter than mV=6.5 that can be detected by VEGA with accuracy better than 2% constraints on models (Creevey et al. 2007, Kervella et al. 2008) June 27th VEGA SPIE San Diego

Visible 3T observations and infrared FT June 27th 2010VEGA SPIE San Diego15 Cal: <0.4 Target:<1.0 O412 B35112 A7176 F243 G481 K501 M Cal: <0.4 Target:<1.0 O715 B A88321 F4487 G559 K504 M2 m K <4.5 m K <5.0

Conclusions VEGA/CHARA is now operational in routine and remote in 2T mode: – medium and high spectral resolution for circumstellar at atmosphere/chromosphere studies – Medium and low spectral resolution for fundamental stellar parameters – Mourard et al. A&A 2009, Perraut et al. A&A 2010, Chesneau et al. A&A 2010 (accepted) Development of the 3T mode  external fringe tracker. Publications submitted or in preparation:  Nardetto et al. A&A (environnement of beta Cephei)  Delaa et al. A&A (kinematics of Be stars)  Chesneau et al. A&A (environnement of ups Sgr)  Bonneau et al. A&A (environnement of beta Lyrae)  Perraut et al. A&A (ro Ap diameter and Teff determination)  Bério et al. A&A (chromospheres of K giant stars)  Mourard et al. (H  in  Aur)  Mourard et al. (characterization of exoplanets host stars) Thanks a lot to CHARA and VEGA colleagues! More detailed informations on June 27th 2010VEGA SPIE San Diego16