J/other/Sci/359.69 Massive stars in 30 Dor (Schneider+, 2018)
An excess of massive stars in the local 30 Doradus starburst.
Schneider F.R.N., Sana H., Evans C.J., Bestenlehner J.M., Castro N.,
Fossati L., Grafener G., Langer N., Ramirez-Agudelo O.H.,
Sabin-Sanjulian C., Simon-Diaz S., Tramper F., Crowther P.A., de Koter A.,
de Mink S.E., Dufton P.L., Garcia M., Gieles M., Henault-Brunet V.,
Herrero A., Izzard R.G., Kalari V., Lennon D.J., Apellaniz J.M.,
Markova N., Najarro F., Podsiadlowski P., Puls J., Taylor W.D.,
van Loon J.T., Vink J.S., Norman C.
<Science, 359, 69-71 (2018)>
=2018Sci...359...69S 2018Sci...359...69S (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; Star Forming Region ; Effective temperatures ;
Stars, masses ; Rotational velocities ; Stars, ages
Abstract:
The 30 Doradus star-forming region in the Large Magellanic Cloud is a
nearby analog of large star-formation events in the distant universe.
We determined the recent formation history and the initial mass
function (IMF) of massive stars in 30 Doradus on the basis of
spectroscopic observations of 247 stars more massive than 15 solar
masses (M☉). The main episode of massive star formation began
about 8 million years (My) ago, and the star-formation rate seems to
have declined in the last 1My. The IMF is densely sampled up to 200
Embedded Image and contains 32±12% more stars above 30M☉ than
predicted by a standard Salpeter IMF. In the mass range of 15 to
200M☉, the IMF power-law exponent is 190+0.37-0.26,
shallower than the Salpeter value of 2.35.
Description:
Through the use of the Fibre Large Array Multi Element Spectrograph
(FLAMES) on the Very Large Telescope (VLT), the VLT-FLAMES Tarantula
Survey (VFTS) has obtained optical spectra of ∼800 massive stars in 30
Dor, avoiding the core region of the dense star cluster R136 because
of difficulties with crowding. Repeated observations at multiple
epochs allow determination of the orbital motion of potentially binary
objects. For a sample of 452 apparently single stars, robust stellar
parameters-such as effective temperatures, luminosities, surface
gravities, and projected rotational velocities-are determined by
modeling the observed spectra. Composite spectra of visual multiple
systems and spectroscopic binaries are not considered here because
their parameters cannot be reliably inferred from the VFTS data.
To match the derived atmospheric parameters of the apparently single
VFTS stars to stellar evolutionary models, we use the Bayesian code
Bonnsai.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tables3.dat 267 572 Stellar parameters for our sample stars
tables4.dat 26 601 Inferred best-fit star formation history
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See also:
J/A+A/530/A108 : VLT-FLAMES Tarantula Survey (Evans+, 2011)
J/A+A/550/A107 : RV catalogue of O stars in 30 Doradus (Sana+, 2013)
J/A+A/550/A108 : DIB in VLT-FLAMES Tarantula Survey (van Loon+, 2013)
J/A+A/550/A109 : VLT-FLAMES Tarantula Survey: vsini measures (Dufton+ 2013)
J/A+A/560/A29 : O-stars in VLT-FLAMES Tarantula Survey (Ramirez-Agudelo+ 2013)
J/A+A/564/A39 : VFTS. OVz stars in 30 Dor (Sabin-Sanjulian+, 2014)
J/A+A/564/A40 : VFTS. O-type stellar content of 30 Dor (Walborn+, 2014)
J/A+A/564/L7 : VLT-FLAMES Tarantula Survey: VFTS 822 (Kalari+, 2014)
J/A+A/574/A13 : VFTS. B-type stars classification and RV (Evans+, 2015)
J/A+A/575/A70 : VLT-FLAMES Tarantula Survey: B supergiants (McEvoy+, 2015)
J/A+A/600/A81 : VLTS. 30Dor O giants and supergiants (Ramirez-Agudelo+, 2017)
J/A+A/600/A82 : VLTS. O giants & supergiants nitrogen abundances (Grin+, 2017)
Byte-by-byte Description of file: tables3.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- VFTS VFTS Identifier
6- 28 A23 --- SpType Spectral type (1)
30- 33 F4.2 [Lsun] logL Bolometric luminosity (2)
35- 38 F4.2 [Lsun] E_logL Error on logL (upper value)
40- 43 F4.2 [Lsun] e_logL Error on logL (lower value)
45- 48 F4.1 % CIlogL Confidence interval for logL errors
50- 57 F8.2 K Teff ?=- Effective temperature (2)
59- 65 F7.2 K E_Teff ?=- Error on Teff (upper value)
67- 73 F7.2 K e_Teff ?=- Error on Teff (lower value)
75- 78 F4.1 % CITeff ?=- Confidence interval for Teff errors
80- 83 F4.2 [cm/s2] logg ?=- Surface gravity (2)
85- 88 F4.2 [cm/s2] E_logg ?=- Error on logg (upper value)
90- 93 F4.2 [cm/s2] e_logg ?=- Error on logg (lower value)
95- 98 F4.1 [cm/s2] CIlogg ?=- Confidence interval for logg errors
100 A1 --- l_vsini Limit flag on vsini
101-106 F6.2 km/s vsini ?=- Projected rotational velocity (2)
108-112 F5.2 km/s E_vsini ?=- Error on vsini (upper value)
114-118 F5.2 km/s e_vsini ?=- Error on vsini (lower value)
120-124 F5.1 % CIvsini ?=- Confidence interval for vsini errors
126-129 F4.2 --- Y ?=- Surface helium mass fraction (2)
131-134 F4.2 --- E_Y ?=- Error on Y (upper value)
136-139 F4.2 --- e_Y ?=- Error on Y (lower value)
141-144 F4.1 --- CIY ?=- Confidence interval for Y errors
147-149 A3 --- Ref Reference (3)
152 A1 --- l_Mini Limit flag on Mini
153-157 F5.1 Msun Mini ?=- Initial mass or
lower limit of initial mass interval
158 A1 --- --- [-]
159-162 F4.1 Msun BMini ?=- Upper limit of initial mass interval
163-166 F4.1 Msun E_Mini ?=- Error on Mini (upper value)
168-171 F4.1 Msun e_Mini ?=- Error on Mini (lower value)
173-177 F5.1 % CIMini ?=- Confidence interval for Mini errors
179-181 I3 km/s vini ?=- Initial rotational velocity
183-185 I3 km/s E_vini ?=- Error on vini (upper value)
187-189 I3 km/s e_vini ?=- Error on vini (lower value)
191-194 F4.1 % CIvini ?=- Confidence interval for vini errors
197-200 F4.1 Myr Age ?=- Age or lower limit of age interval
201 A1 --- --- [-]
202-205 F4.1 Myr BAge ?=- Upper limit of age interval
207-209 F3.1 Myr E_Age ?=- Error on Age (upper value)
211-214 F4.1 Myr e_Age ?=- Error on Age (lower value)
216-220 F5.1 % CIAge ?=- Confidence interval for Age errors
222-226 F5.1 Msun Mpres ?=- Present-day mass or
lower limit of present-day mass interval
227 A1 --- --- [-]
228-231 F4.1 Msun BMpres ?=- Upper limit of present-day mass interval
232-235 F4.1 Msun E_Mpres ?=- Error on Mpres (upper value)
237-240 F4.1 Msun e_Mpres ?=- Error on Mpres (lower value)
242-246 F5.1 % CIMpres ?=- Confidence interval for Mpres errors
248-252 F5.1 Rsun R ?=- Radius
254-257 F4.1 Rsun E_R ?=- Error on R (upper value)
259-262 F4.1 Rsun e_R ?=- Error on R (lower value)
264-267 F4.1 % CIR ?=- Confidence interval for R errors
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Note (1): Spectral types are from Evans et al., 2011, Cat. J/A+A/530/A108,
Walborn et al., 2014, Cat. J/A+A/564/A40 and
Dias et al., 2015, Cat. J/A+A/573/A13.
Note (2): Observables used to determine fundamental stellar parameters
(Mini, vini, Age, Mpresent, R) from stellar models (Brott et al., 2011,
Cat. J/A+A/530/A115),Koehler et al., 2015, Cat. J/A+A/573/A71)) using BONNSAI.
Note (3): References as follows:
1 = Ramirez-agudelo et al., 2017, Cat. J/A+A/600/A81
2 = Bestenlehner et al. (2014A&A...570A..38B 2014A&A...570A..38B
3 = Sabin-sanjulian et al., 2014, Cat. J/A+A/564/A39
4 = Sabin-sanjulian et al., 2017, Cat. J/A+A/601/A79
5 = McEvoy et al., 2015, Cat. J/A+A/575/A70
6 = For the determination of atmospheric parameters of B-type stars,
see supplementary materials section S3.2.
7 = For the determination of atmospheric parameters of A-type and
later-type stars, see supplementary materials section S3.3.
8 = For the determination of atmospheric parameters of classical Wolf-Rayet
stars, see supplementary materials section S3.1.
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Byte-by-byte Description of file: tables4.dat
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Bytes Format Units Label Explanations
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1- 5 F5.2 Myr Age Age
7- 15 F9.7 --- PDF Probability density function (PDF)
of stellar ages (dp/dt)
17- 26 F10.7 --- PDF*N Age PDF multiplied by number of stars (dN/dt)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 20-Feb-2018