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The VLT-FLAMES Survey of Massive StarsChris Evans (ING, La
Palma)Tartu August 2005
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Main collaboratorsSteve Smartt, Philip Dufton, Ian Hunter
(Belfast)
Danny Lennon (ING)
Carrie Trundle, Artemio Herrero (IAC)
Alex de Koter, Rohied Mokiem (Amsterdam)
Mike Irwin (Cambridge)
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FLAMES survey of massive starsESO Large Programme (PI: S.
Smartt)
112hrs on the VLT with FLAMES
FLAMES has 137 fibres which feed the Giraffe spectrograph
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Target fieldsFields chosen to sample a range of Z and ages:
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Some of our motivationsObtain CNO abundances for a large,
homogenous OB sample
Determine vsini distributions, evidence for Z-dependence?
Armed with vsini, explore CNO cf. evolutionary models
Tests of the Z-dependence of O star mass-loss rates
Un-planned, but interesting: Binary detection!
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Target fieldsFields chosen to sample a range of Z and ages:
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Target fieldsFields chosen to sample a range of Z and ages:Evans
et al. (2005)
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Target fieldsFields chosen to sample a range of Z and ages:
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Observational informationHigh resolution: R~20,000
800 stars observed over the 7 fields:@ 6 -settings, coverage
from 3850-4750, 6400-6650 LMC/SMC fields observed 6 times at each
-setting
Obtained in service mode, often different observational
epochsfor each -settingfor repeat observations at each -setting
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Observational informationHigh resolution: R~20,000
800 stars observed over the 7 fields:@ 6 -settings, coverage
from 3850-4750, 6400-6650 LMC/SMC fields observed 6 times at each
-setting
Obtained in service mode, often different observational
epochs:for each -settingfor repeat observations at each
-settingO9.5 VV = 15.29
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Targets in NGC 346V-band DSS
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Targets in NGC 346ACS (HST/Nota)V-band DSS
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Targets in N11NIR (from R. Barba)V-band DSS
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Targets in N11NIR (from R. Barba)V-band DSSLH 10LH 9
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Census of young MC clusters
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Census of young MC clusters
Incidence of Be-stars: there is a selection effects for the
Be-stars, one cannot simply take the above numbers at face
value!
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Be-type spectra in NGC346
H
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Census of young MC clusters
62 O-type stars, ~half of them previously unknown
Analysis now underway in Amsterdam [more in Alex de Koters talk
later today]
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New O2-type star
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New O2-type starO2-2.5 III(f*)
Still small number statistics at earlier than O3 (~10 stars)
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N11 field
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N11 field
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N11 field
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N11 fieldO2 star
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Binary detectionService observations @ multiple epochs checks
for binarity
Single/double-lined binaries found from simple methods:from
visual inspection when classifying the spectrafrom radial velocity
measurements of the H, He & Si lines [accurate to ~10 km/s]
More sophisticated methods now being used to cross-correlate the
individual spectra at each -setting [accurate to ~5 km/s, which
will no doubt find further binaries]
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Binaries in the young MC clusters
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Binaries in the young MC clustersNote that these numbers do not
include those found from cross-correlation methods expect them to
go up slightly
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Binaries in the young MC clustersNote that these numbers do not
include those found from cross-correlation methods expect them to
go up slightly26%37%
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Binaries in the young MC clustersNote that these numbers do not
include those found from cross-correlation methods expect them to
go up slightly29%36%
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Binary detection: time samplingNGC 346N1157 days84 daysJulian
Date
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Binaries in the young MC clustersFirm lower limits on binary
fraction, to then compare with different star formation scenarios
(eg Bally & Zinnecker, 2005) 29%36%
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N abundances in B stars in NGC 346Provisional results from
TLUSTY analysis, (Ian Hunter, Belfast)
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N abundances in B stars in NGC 346Provisional results from
TLUSTY analysis, (Ian Hunter, Belfast)Binaries
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SummaryLots of interesting objects in these young clusters!
Overview paper of LMC/SMC data, binary detection, radial
velocities, etc: Evans et al., in prep.
Parallel studies:LMC/SMC O-star analysis: AmsterdamGalactic
vsini paper: BelfastAnalysis of narrow-lined stars: Ian Hunter
(Belfast)Analysis of O stars in NGC 6611: Herrero/Villamariz
(IAC)
