Post on 06-Jan-2016
description
Corot Week 6 1
Targets selection
Be stars
Paris-Meudon Observatory: A.-M. Hubert, M. Floquet, C. Neiner
Univ. of Valencia: J. Fabregat, J. Gutierrez-Soto, J. Suso
Univ. of Sao Paulo: E. Janot-Pacheco, L. Andrade, S. Daflon
Royal Observatory of Belgium: Y. Frémat
ESA, Estec, RSSD: C. Neiner
Corot Week 6 2
Early and late Be stars: 2 science goals
Early Be stars (B0-B3): pulsations and multiperiodicity already detected from the ground
Is the beating effect of close pulsation periods the cause of the Be phenomenon i.e. the presence of a disk around Be stars?
Effects of fast rotation and magnetic field on the pulsations
Late Be stars (B4-B9): pulsations predicted by theory but the amplitude is too small to be detected from the ground
detection of pulsations with Corot!
Corot Week 6 3
Photometric variability: Hipparcos(Hubert & Floquet )
Some of the targets observed by Hipparcos: periodicity found!
Corot Week 6 4
Ground-based photometry + variability(Fabregat, Gutierrez-Soto, Suso)
Stromgren photometry at the 0.9m in Granada (6 weeks) for variability: detection of variability, periodicity and even multiperiodicity for HD 168797 and HD 179405
uvby photometry + narrow filters (H, H) at the 1.5m in Calar Alto (3 weeks) to search for faint Be stars in the exoplanet fields
See Gutierrez-Soto et al. 2003 and posters!
Corot Week 6 5
Spectroscopy: GAUDI
for 6 < V < 8 spectra in GAUDI
17 new Be stars discovered in GAUDI (Neiner, Hubert & Catala, 2004)
But:
No spectrum if V > 8
Does not allow variability study
Corot Week 6 6
Additional spectroscopy + variability(Hubert, Janot-Pacheco, Andrade)
Spectroscopic observations at the 1.5m at OHP (6 weeks)
Spectroscopic observations at the 1.6m at LNA (1 week)
Spectrum for Be stars with V > 8
Detection of variability
Corot Week 6 7
Determination of stellar parameters( Frémat, Neiner, Daflon, Andrade)
Data : GAUDI + OHP + LNA
2 independent determinations: Frémat & Neiner + Daflon & Andrade
~70 Be stars in the eyes of Corot
(See Frémat, Neiner et al. 2004)
26000 3.75 253
Corot Week 6 8
CentreMain target Be target Type V vsini Teff log g Variability
HD 171234+170580 HD 171219 B8e 7.65 300 13590 3.07
HD 171834 HD 171219 B8e 7.65 300 13590 3.07
HD 175726 HD 175869 B9IIIe 5.56 164 11810 3.25
HD 177552 -
HD 181555+180642 HD 181231 B9Ve 8.58 250 13658 3.73
HD 181367 B8e 9.36 279 13500 3.65
Only late Be stars in these primary targets fields.
Results for primary fields
Corot Week 6 9
Anticentre
Main target Be target Type V vsini Teff log g Variability
HD 43318 -
HD 43587 HD 43285 B6Ve 6.07 240 14000 3.78 0.45 d
HD 43913 A0e 7.88
HD 45067 -
HD 46558 HD 45901 B2Ve 8.8 164 26518 3.73 phot
HD 46484 B1Ve 7.74 120 27000 3.60 3.29 d
HD 47359 B0.5Ve 8.87
HD 49933+49434 HD 49330 B0e 8.92 300 27000 3.82 0.28 d
HD 49585 B0.5Ve 9.13 253 26042 3.75 0.61 d
HD 50209 B9Ve 8.33 180 11809 3.62 0.66 + 0.59 d
HD 50696 B1Ve 8.83 350 21300 3.45 0.31 d
HD 52265 HD 50891 B0pe 8.88 0.54 d
HD 51193 B1Vnne 8.06 215 22994 3.62 0.61 + 5.5 d
HD 51404 B3e 9.3 342 22500 4.2 0.37 d
HD 51452 B0IIIne 8.08 298 29887 3.88 spec
Corot Week 6 10
Centre: 5 possible late Be stars including 3 well positioned next to the primary targets
no early Be stars
Anticentre: 3 possible late Be stars including 3 well positioned next to the primary targets
10 possible early Be stars including 3 well positioned next to HD 52265
TOTAL:
18 possible Be stars (8 late, 10 early) including 9 well positioned (6 late and 3 early)
Corot Week 6 11
Field HD 171234 + HD 170580
171219
Corot Week 6 12
Field HD 175726
175869
Corot Week 6 13
Field 181555 + HD 180642
181367
181231
Corot Week 6 14
Field HD 43587
43285
43913
+ HD 43913
Corot Week 6 15
Field HD 46558
+ HD 4735946484
45901
47359
46484
Corot Week 6 16
Field HD 49933 + HD 49434
50209
49330
49585
50696
3 early Be stars outside the CCDs with this position of the CCDs
Corot Week 6 17
Field HD 52265
+ HD 50891
51404
51193
51452
50891
Corot Week 6 18
HR diagram of Be secondary targets
Apparent Location
+ 4 Be stars
Corot Week 6 19
HR diagram of Be secondary targets
Rotation effect
c = 0.95
+ 4 Be stars
Corot Week 6 20
+ 2 Be stars in the CCDs+ 2 Be stars
HR diagram of Be secondary targets
Real Location
= in the CCDs
Corot Week 6 21
Results for exploratory fields
~ 60 possible Be targets for exploratory fields
It is better to concentrate on early Be stars, since we have very few early Be stars as secondary targets
2 already detected with multiperiodicity (Fabregat et al.) : HD 168797 (B3e) and HD 179405 (B5e)
Targets in non-selected primary fields have been well studied easier candidates
Corot Week 6 22
Conclusions We need early and late Be stars as secondary targets: 2 different science goals
We found variability, periodicity and even multiperiodicity in most of the Be stars, in spectroscopy and in photometry
We plan to search for magnetic fields with Espadons (CFHT) for the Be secondary targets (starting Feb. 2005)
We have 9 out of 18 Be stars (possible secondary targets) which are well positioned in the CCDs, but 6 late and only 3 early
We need to concentrate on early Be stars for the exploratory fields
We already have 2 very interesting exploratory candidates