J/A+A/600/A81 VLTS. 30Dor O giants and supergiants (Ramirez-Agudelo+, 2017)
The VLT-FLAMES Tarantula Survey.
XXIV. Stellar properties of the O-type giants and supergiants in 30 Doradus.
Ramirez-Agudelo O.H., Sana H., de Koter A., Tramper F., Grin N.J.,
Schneider F.R.N., Langer N., Puls J., Markova N., Bestenlehner J.M.,
Castro N., Crowther P.A., Evans C.J., Garcia M., Grafener G., Herrero A.,
van Kempen B., Lennon D.J., Maiz Apellaniz J., Najarro F.,
Sabin-Sanjulian C., Simon-Diaz S., Taylor W.D., Vink J.S.
<Astron. Astrophys. 600, A81 (2017)>
=2017A&A...600A..81R 2017A&A...600A..81R (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; Stars, O ; Stars, giant ; Stars, supergiant ;
Spectroscopy
Keywords: stars: early-type - stars: evolution -
stars: fundamental parameters - Magellanic Clouds -
galaxies: star clusters: individual: 30 Doradus
Abstract:
The Tarantula region in the Large Magellanic Cloud contains the
richest population of spatially resolved massive O-type stars known so
far. This unmatched sample offers an opportunity to test models
describing their main-sequence evolution and mass-loss properties.
Using ground-based optical spectroscopy obtained in the framework of
the VLT-FLAMES Tarantula Survey (VFTS), we aim to determine stellar,
photospheric and wind properties of 72 presumably single O-type
giants, bright giants and supergiants and to confront them with
predictions of stellar evolution and of line-driven mass-loss
theories.
We apply an automated method for quantitative spectroscopic analysis
of O stars combining the non-LTE stellar atmosphere model FASTWIND
with the genetic fitting algorithm PIKAIA to determine the following
stellar properties: effective temperature, surface gravity, mass-loss
rate, helium abundance, and projected rotational velocity. The latter
has been constrained without taking into account the contribution from
macro-turbulent motions to the line broadening.
We present empirical effective temperature versus spectral subtype
calibrations at LMC-metallicity for giants and supergiants. The
calibration for giants shows a +1kK offset compared to similar
Galactic calibrations; a shift of the same magnitude has been reported
for dwarfs. The supergiant calibrations, though only based on a
handful of stars, do not seem to indicate such an offset. The presence
of a strong upturn at spectral type O3 and earlier can also not be
confirmed by our data. In the spectroscopic and classical
Hertzsprung-Russell diagrams, our sample O stars are found to occupy
the region predicted to be the core hydrogen-burning phase by
state-of-the-art models. For stars initially more massive than
approximately 60M☉ the giant phase already appears relatively
early on in the evolution; the supergiant phase develops later. Bright
giants, however, are not systematically positioned between giants and
supergiants at Minit>25M_☉. At masses below 60M_☉ the dwarf
phase clearly precedes the giant and supergiant phases; however this
behavior seems to break down at $Minit<18M☉. Here, stars
classified as late O III and II stars occupy the region where
O9.5-9.7V stars are expected, but where few such late O V stars are
actually seen. Though we can not exclude that these stars represent a
physically distinct group, this behaviour may reflect an intricacy in
the luminosity classification at late O spectral subtype. Indeed, on
the basis of a secondary classification criterion, the relative
strength of SiIV to HeI absorption lines, these stars would have been
assigned a luminosity class IV or V. Except for five stars, the helium
abundance of our sample stars is in agreement with the initial LMC
composition. This outcome is independent of their projected spin
rates. The aforementioned five stars present moderate projected
rotational velocities (i.e., vrot<200km/s) and hence do not agree with
current predictions of rotational mixing in main-sequence stars. They
may potentially reveal other physics not included in the models such
as binary-interaction effects. Adopting theoretical results for the
wind velocity law, we find modified wind momenta for LMC stars that
are ∼0.3dex higher than earlier results. For stars brighter than
105L[sun, that is, in the regime of strong stellar winds, the
measured (unclumped) mass-loss rates could be considered to be in
agreement with line-driven wind predictions if the clump volume
filling factors were fV∼1/8 to 1/6.
Description:
Measured stellar and wind parameters of 72 presumably-single O-type
stars in the VLT-FLAMES Tarantula Survey, with luminosity class
identifiers III-I. Also included are the stellar and wind parameters
of 31 O-type stars without luminosity class identifier.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablec4.dat 244 72 Best fitting atmospheric and wind parameters of
the O-giants, bright giants, and supergiants
tablec5.dat 244 31 Best fitting atmospheric and wind parameters of
the O-stars without luminosity class
tablec1.dat 50 11 List of the hydrogen, helium, and nitrogen
diagnostic lines used in the determination of
the stellar and wind parameters of the
O-giants, bright giants, and supergiants
tablec2.dat 30 61 List of the hydrogen and helium diagnostic lines
used in the determination of the stellar and
wind parameters of the O-giants, bright giants,
and supergiants
tablec3.dat 30 31 List of the hydrogen and helium diagnostic lines
used in the determination of the stellar and
wind parameters of the O-stars without
luminosity class
--------------------------------------------------------------------------------
See also:
J/A+A/530/A108 : VLT-FLAMES Tarantula Survey (Evans+, 2011)
J/A+A/550/A107 : VFTS. RV catalogue of O stars in 30 Doradus (Sana+, 2013)
J/A+A/560/A29 : VFTS. O-stars rotational velocities (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/575/A70 : VFTS. B supergiants (McEvoy+, 2015)
J/A+A/600/A82 : VFTS. O giants & supergiants nitrogen abundances (Grin+, 2017)
Byte-by-byte Description of file: tablec4.dat tablec5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- VFTS VFTS identification number, [72/892] for
tablec4 and [31/892] for tablec5 (2)
5- 27 A23 --- SpType Spectral type and luminosity
classification by Walborn et al.,
(2014, Cat. J/A+A/564/A40)
29- 32 F4.1 mag KMAG Absolute K magnitude (3)
34- 38 F5.2 kK Teff Effective temperature
40 A1 --- nETeff [>] Note on E_Teff (4)
41- 44 F4.2 kK E_Teff ? Upper confidence interval of the
effective temperature
46 A1 --- neTeff [<] Note on e_Teff (5)
47- 50 F4.2 kK e_Teff ? Lower boundary confidence interval
of the effective temperature
52- 55 F4.2 [cm/s2] logg Surface gravity
57- 60 F4.2 [cm/s2] E_logg Upper boundary confidence interval of
the surface gravity
62- 65 F4.2 [cm/s2] e_logg Lower boundary confidence interval of
the surface gravity
67- 70 F4.2 [cm/s2] loggc Surface gravity corrected for rotation
72 A1 --- nEloggc [>] Note on E_loggc (4)
73- 76 F4.2 [cm/s2] E_loggc ? Upper boundary confidence interval of
the surface gravity corrected for
rotation
78 A1 --- neloggc [<] Note on e_loggc (5)
79- 82 F4.2 [cm/s2] e_loggc ? Lower boundary confidence interval of
the surface gravity corrected for
rotation
84- 88 F5.2 [Msun/yr] log(Mdot) Mass loss rate
90- 93 F4.2 [Msun/yr] E_log(Mdot) Upper boundary confidence interval of
the mass loss rate (4)
95 A1 --- nelog(Mdot) [<] Note on e_log(Mdot) (5)
96- 99 F4.2 [Msun/yr] e_log(Mdot) ? Lower boundary confidence interval of
the mass loss rate
101-104 F4.2 --- Y Surface Helium abundance in mass fraction
106-109 F4.2 --- E_Y Upper boundary confidence interval of the
surface helium abundance
111 A1 --- neY [<] Note on e_Y (5)
112-115 F4.2 --- e_Y ? Lower boundary confidence interval of
the surface helium abundance
117-118 I2 km/s vturb Micro-turbulent velocity
120 A1 --- nEvturb [>] Note on E_vturb (4)
121-122 I2 km/s E_vturb ? Upper boundary confidence interval of
the micro-turbulent velocity
124 A1 --- nevturb [<] Note on e_vturb (5)
125-126 I2 km/s e_vturb ? Lower boundary confidence interval of
the micro-turbulent velocity
128-130 I3 km/s vsini Projected rotational velocity
132 A1 --- nEvsini [>] Note on E_vsini (4)
133-135 I3 km/s E_vsini ? Upper boundary confidence interval
of the projected rotational
velocity (6)
137 A1 --- nevsini [<] Note on e_vsini (5)
138-140 I3 km/s e_vsini ? Lower boundary confidence interval
of the projected rotational
velocity (6)
142-145 I4 km/s vinf Terminal wind velocity
148-151 I4 km/s E_vinf Upper boundary confidence interval of
the terminal wind velocity
154-157 I4 km/s e_vinf Lower boundary confidence interval of the
terminal wind velocity
159-162 F4.2 [Lsun] logL Luminosity
164 A1 --- nElogL [>] Note on E_logL (4)
165-168 F4.2 [Lsun] E_logL ? Upper boundary confidence interval of
the luminosity
170 A1 --- nelogL [<] Note on e_logL (5)
171-174 F4.2 [Lsun] e_logL ? Lower boundary confidence interval of
the luminosity
176-180 F5.2 Rsun R Radius in solar units
182 A1 --- nER [>] Note on E_R (4)
183-186 F4.2 Rsun E_R ? Upper boundary confidence interval of
the radius
188 A1 --- neR [<] Note on e_R (5)
189-192 F4.2 Rsun e_R ? Lower boundary confidence interval of
the radius
194-198 F5.2 [g.cm/s2] log(Dmom) Modified wind-momentum
201-204 F4.2 [g.cm/s2] E_log(Dmom) Upper boundary confidence interval of
the modified wind-momentum
206 A1 --- nelog(Dmom) [<] Note on e_log(Dmom) (5)
207-210 F4.2 [g.cm/s2] e_log(Dmom) ? Lower boundary confidence interval of
the modified wind-momentum
212-216 F5.1 Msun Mspec Spectrocopic mass computed with
newtonian gravity
218 A1 --- nEMspec [>] Note on E_Mspec (4)
219-222 F4.1 Msun E_Mspec ? Upper boundary confidence interval
of the spectroscopic mass
224 A1 --- neMspec [<] Note on e_Mspec (5)
225-228 F4.1 Msun e_Mspec ? Lower boundary confidence interval
of the spectroscopic mass
230-233 F4.1 Msun Mevol Evolutionary mass
235 A1 --- nEMevol [>] Note on E_Mevol (4)
236-239 F4.1 Msun E_Mevol ? Upper boundary confidence interval of
the evolutionary mass
241 A1 --- neMevol [<] Note on e_Mevol (5)
242-244 F3.1 Msun e_Mevol ? Lower boundary confidence interval bar
the evolutionary mass
--------------------------------------------------------------------------------
Note (2): The last six entries of each table are excluded from the analysis.
They are newly detected binaries (i.e., tableC4) or their fits have been
rated as poor-quality (tableC5; see Sect. 3.6).
The stellar and wind parameters of the stars: VFTS 016, 087, 125, 178, 180,
259, 267, 518,566, 599, and 764 include nitrogen diagnostic lines.
Note (3): Values taken from Maiz-Apellaniz et al. (in prep).
Note (4): A '>' indicates that the upper boundary of the confidence interval
is not constrained (i.e., the lower boundary represents a lower limit).
Note (5): A '<' indicates that the lower boundary of the confidence interval
is not constrained (i.e., the upper boundary represents an upper limit).
Note (6): A '---' is adopted when no uncertainty is available. It means
that the parameter has been left fixed. This is the case for
VFTS 051 and 711.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablec1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- VFTS [11/892] VFTS identification number
5- 6 I2 --- Lines Number of diagnostic lines used
8 A1 --- delta [X0] Hdelta line used (G1)
10 A1 --- gamma [X0] Hgamma line used (G1)
12 A1 --- beta [X0] Hbeta line used (G1)
14 A1 --- alpha [X0] Halpha line used (G1)
16 A1 --- 4026 [X0] HeI+II 4026 line used (G1)
18 A1 --- 4387 [X0] HeI 4387 line used (G1)
20 A1 --- 4471 [X0] HeI 4471 line used (G1)
22 A1 --- 4713 [X0] HeI 4713 line used (G1)
24 A1 --- 4922 [X0] HeI 4922 line used (G1)
26 A1 --- 4200 [X0] HeII 4200 line used (G1)
28 A1 --- 4541 [X0] HeII 4541 line used (G1)
30 A1 --- 4686 [X0] HeII 4686 line used (G1)
32 A1 --- 3995 [X0] N III 3995 line used (G1)
34 A1 --- 4097 [X0] N III 4097 line used (G1)
36 A1 --- 4195 [X0] N III 4195 line used (G1)
38 A1 --- 4379 [X0] N III 4379 line used (G1)
40 A1 --- qua [X0] N III 4511, 4515, 4518 lines used (G1)
42 A1 --- 4523 [X0] N III 4523 line used (G1)
44 A1 --- trip [X0] N III 4634, 4640 lines used (G1)
46 A1 --- 4058 [X0] N IV 4058 line used (G1)
48 A1 --- 4603 [X0] N V 4603 line used (G1)
50 A1 --- 4619 [X0] N V 4619 line used (G1)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablec2.dat tablec3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- VFTS VFTS identification number,
[61/892] tablec2, [31/682] tablec3 (2)
5- 6 I2 --- Lines Number of diagnostic lines used
8 A1 --- delta [X0] Hdelta line used (G1)
10 A1 --- gamma [X0] Hgamma line used (G1)
12 A1 --- beta [X0] Hbeta line used (G1)
14 A1 --- alpha [X0] Halpha line used (G1)
16 A1 --- 4026 [X0] HeI+II 4026 line used (G1)
18 A1 --- 4387 [X0] HeI 4387 line used (G1)
20 A1 --- 4471 [X0] HeI 4471 line used (G1)
22 A1 --- 4713 [X0] HeI 4713 line used (G1)
24 A1 --- 4922 [X0] HeI 4922 line used (G1)
26 A1 --- 4200 [X0] HeII 4200 line used (G1)
28 A1 --- 4541 [X0] HeII 4541 line used (G1)
30 A1 --- 4686 [X0] HeII 4686 line used (G1)
--------------------------------------------------------------------------------
Note (2): The last six entries of each table are excluded from the analysis.
They are newly detected binaries (i.e., tableC4) or their fits have
been rated as poor-quality (tableC5; see Sect. 3.6).
For the star VFTS 125, the following Nitrogen lines have also been used:
N III 4634, 4640, N IV 4058, N V 4603, 4619.
--------------------------------------------------------------------------------
Global notes:
Note (G1): Flag as follows:
X = line has been used in the determination of the stellar and wind parameters
0 = line has not been used
--------------------------------------------------------------------------------
Acknowledgements:
Oscar Hernan Ramirez Agudelo, oscar.ramirez(at)stfc.ac.uk
References:
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Bestenlehner et al., Paper III 2011A&A...530L..14B 2011A&A...530L..14B
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Dunstall et al., Paper V 2012A&A...542A..50D 2012A&A...542A..50D
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Sana et al., Paper VIII 2013A&A...550A.107S 2013A&A...550A.107S, Cat. J/A+A/550/A107
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Evans et al., Paper XVIII 2015A&A...574A..13E 2015A&A...574A..13E
McEvoy et al., Paper XIX 2015A&A...575A..70M 2015A&A...575A..70M
Clark et al., Paper XX 2015A&A...579A.131C 2015A&A...579A.131C
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Grin et al., Paper XXV 2017A&A...600A..82G 2017A&A...600A..82G, Cat. J/A+A/600/A82
(End) Oscar Hernan Ramirez Agudelo [UK ATC], Patricia Vannier [CDS] 18-Jan-2017