CorotWeek8 May 2005 Hubert/Neiner Corot Be stars group Be stars: Secondary targets candidates for the Core Programme of asteroseismology Targets for the Additional Programme The team: 11 members (Belgium, Brazil, France and Spain) People interested in joining our group are welcome! Contact: [email protected]Website: http://www.ster.kuleuven.ac.be/~coralie/corotbe.h tml
Corot Be stars group. Be stars: Secondary targets candidates for the Core Programme of asteroseismology Targets for the Additional Programme The team: 11 members (Belgium, Brazil, France and Spain) People interested in joining our group are welcome! Contact: [email protected] - PowerPoint PPT Presentation
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CorotWeek8 May 2005 Hubert/Neiner
Corot Be stars groupBe stars:
Secondary targets candidates for the Core Programmeof asteroseismology
Targets for the Additional Programme
The team: 11 members (Belgium, Brazil, France and Spain)
People interested in joining our group are welcome!
- assumes: Rigid rotator (Roche model) log g Von Zeipel law Teff
Local model atmospheres- LTE temperature and pressure distribution
(ATLAS9, Kurucz)
- NLTE level populations (TLUSTY, Hubeny & Lanz)
CS envelope veiling effect
Fastrot
Assumes:
-Rigid rotator (Roche model)‡ log g
-von Zeipel law‡ Teff
Local model atmospheres
- LTE temperature and pressure distributions (ATLAS 9, Kurucz)
- NLTE level populations (TLUSTY, Hubeny & Lanz)
CorotWeek8 May 2005 Hubert/Neiner
From modeling of different spectral domains Teff, logg, Vsin i and i for a given /c
Without correction for rotational effects:Teff = 25450° 1000°K,log g = 3.87 0.10V sini = 310 30 km/s
With corrections for /c= 0.9 (value adopted from Frémat, Zorec et al., in press): Teff = 26000° 1000°K,log g = 4.10 0.10V sini = 325 30 km/s, i ~ 60°
: observed spectrum: fitted spectrum
CorotWeek8 May 2005 Hubert/Neiner
With corrections for/c=0.9
Without correction for rotational effects
Location of Be stars in the HRdiagram
CorotWeek8 May 2005 Hubert/Neiner
Be star’s spectral-type distributionin the cones of COROT
(Frémat, Neiner, Hubert, Floquet, Zorec, Janot-Pacheco, de Medeiros, 2005, submitted)
Different Be star spectral distributions between the Galactic Centre and Anticentre to be related to the insterstellar absorption, more important towards the Galactic Centre (Lucke 1978)
CorotWeek8 May 2005 Hubert/Neiner
Detection of Be stars in the exoplanet fields
Spectroscopy at ESO with VLT/GIRAFFEPart of a programme on the Guaranteed Time Observations of the Observatoire de Paris devoted to spectral classification and precise type identification in exoplanet fields of COROT (G. Alecian: P.I., Hubert, Deleuil, Neiner, Martayan, Floquet):
To validate the method of spectral classification for exoplanet stellar database
(Deleuil et al.)
To determine fundamental parameters
To identify specific groups of stars, Hg-Mn, Be…for Additional Programmes of COROT
Preparatory programmes for faint Be stars
CorotWeek8 May 2005 Hubert/Neiner
Giraffe: a multi-object spectrograph
CorotWeek8 May 2005 Hubert/Neiner
VLT-GIRAFFE: a multi-object spectrograph
In Medusa mode: 132 fibers
R=7500 and 25000
Required astrometric precision : 0.2”
Field =25’
Fibers: Minimal separation ~ 12”
CorotWeek8 May 2005 Hubert/Neiner
Anticentre direction
2 GIRAFFE fields observed (=26’)next to HD 49933+HD 49434
About 35 B0-A5 candidates in each field (exodat catalog by Deleuil et al.)
2 Be
31 B0-A0 (Teff ≥ 9500°K) H
(Alecian, Martayan et al. in preparation)
CorotWeek8 May 2005 Hubert/Neiner
Fundamental parametersB stars:
-LTE temperature and pressure distributions (ATLAS9, Kurucz)
-NLTE level populations (TLUSTY, Hubeny & Lanz)
Example of fit for a B star: : observed spectrum: fitted spectrum
Teff=13615°K, log g=3.95
V sini=65 km/s, RV=49 km/s
CorotWeek8 May 2005 Hubert/Neiner
Be stars:
Teff=20860°K, log g=3.93 V sini=260 km/s; RV=55 km/s
Teff=15100°K, log g=3.40 V sini=297 km/s; RV=59 km/s