J/ApJ/869/37 Optical interferometry of 6 O-type HD stars (Gordon+, 2018)
Angular sizes and effective temperatures of O-type stars from optical
interferometry with the CHARA Array.
Gordon K.D., Gies D.R., Schaefer G.H., Huber D., Ireland M., Hillier D.J.
<Astrophys. J., 869, 37 (2018)>
=2018ApJ...869...37G 2018ApJ...869...37G
ADC_Keywords: Interferometry; Stars, O; Optical
Keywords: stars: early-type ; stars: fundamental parameters ; stars: massive ;
techniques: interferometric
Abstract:
We present interferometric observations of six O-type stars that were
made with the Precision Astronomical Visible Observations beam
combiner at the Center for High Angular Resolution Astronomy (CHARA)
Array. The observations include multiple brackets for three targets,
λ Ori A, ζ Oph, and 10 Lac, but there are only
preliminary, single observations of the other three stars, ξ Per,
α Cam, and ζ Ori A. The stellar angular diameters range
from 0.55mas for ζ Ori A down to 0.11mas for 10 Lac, the smallest
star yet resolved with the CHARA Array. The rotational oblateness of
the rapidly rotating star ζ Oph is directly measured for the
first time. We assembled ultraviolet to infrared flux measurements for
these stars, and then derived angular diameters and reddening
estimates using model atmospheres and an effective temperature set by
published results from analysis of the line spectrum. The model-based
angular diameters are in good agreement with those observed. We also
present estimates for the effective temperatures of these stars,
derived by setting the interferometric angular size and fitting the
spectrophotometry.
Description:
Observations of our targets were made using the Precision Astronomical
Visible Observations (PAVO) beam combiner at the CHARA Array, located
at Mount Wilson Observatory in California. The CHARA Array is an
optical interferometer composed of six 1m telescopes. We were able to
achieve an extremely high angular resolution for our targets of about
0.2mas.
Observations of our targets with CHARA were accomplished from 2013
November to 2017 June. For all observations only one baseline, or two
telescopes, was used at a time. Observing data are given in Table 5.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 78 6 Parameters of target stars
table5.dat 69 605 Calibrated visibilities
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See also:
II/224 : Catalogue of Stellar Diameters (CADARS) (Pasinetti- Fracassini+ 2001)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
I/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)
II/297 : AKARI/IRC mid-IR all-sky Survey (ISAS/JAXA, 2010)
III/274 : Galactic O-Star Spectroscopic Survey (GOSSS) (Sota+, 2014)
II/346 : JMMC Stellar Diameters Catalogue - JSDC. Version 2 (Bourges+, 2017)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/AJ/117/354 : OB associations from Hipparcos (de Zeeuw+, 1999)
J/A+A/438/1163 : Catalogue of Open Cluster Data (COCD) (Kharchenko+, 2005)
J/A+A/457/637 : UBVJHK synthetic photom. of Galactic O stars (Martins+, 2006)
J/A+A/507/833 : Interstellar CaII lines for 290 stars (Megier+, 2009)
J/ApJS/191/301 : Spitzer Atlas of Stellar Spectra (SASS) (Ardila+, 2010)
J/other/A+ARV/18.67 : Accurate masses and radii of normal stars (Torres+, 2010)
J/A+A/529/A75 : Limb-darkening coefficients (Claret+, 2011)
J/A+A/562/A135 : Northern Galactic OB stars vsini (Simon-Diaz+, 2014)
J/AJ/153/16 : Calibrator stars catalog for interferometers (Swihart+, 2017)
J/A+A/613/A65 : Spectroscopic parameters of O-type stars (Holgado+, 2018)
J/A+A/613/A9 : Extinction towards Galactic O stars (Maiz Apellaniz +, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 A1 --- ID Internal identifier
3- 14 A12 --- Name Star name
16- 21 I6 --- HD [24912/214680] HD number
23- 38 A16 --- SpT Spectral type (1)
40- 43 F4.2 mag Vmag [1.8/4.9] V-band magnitude
45- 49 F5.2 mag B-V [-0.3/0.05] B-V color index
51- 55 F5.2 mag V-K [-0.7/0.2] V-K color index
57- 60 F4.1 kK Teff [29.4/35.5] Effective temperature (2)
62- 64 F3.1 kK e_Teff [0.5/1.3] Teff uncertainty
66- 69 F4.2 [cm/s2] logg [3/4] log of surface gravity (2)
71- 74 F4.2 [cm/s2] e_logg [0.08/0.3] logg uncertainty
76- 78 I3 km/s vsini [16/311] Projected rotational velocity
from Simon-Diaz+ 2014, J/A+A/562/A135
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Note (1): Spectral types are from the Galactic O-Star Spectroscopic Survey
(Sota+ 2011, III/274).
Note (2): Effective temperatures and gravities are average values taken from
the sources listed in Table 2:
Bouret et al. (2008MNRAS.389...75B 2008MNRAS.389...75B);
Herrero et al. (2002A&A...396..949H 2002A&A...396..949H);
Holgado et al. (2018, J/A+A/613/A65);
Marcolino et al. (2009A&A...498..837M 2009A&A...498..837M);
Markova et al. (2004A&A...413..693M 2004A&A...413..693M);
Martins et al. (2012A&A...538A..29M 2012A&A...538A..29M);
Martins et al. (2015A&A...575A..34M 2015A&A...575A..34M);
Martins et al. (2017A&A...599A..30M 2017A&A...599A..30M);
Mokiem et al. (2005A&A...441..711M 2005A&A...441..711M);
Najarro et al. (2011A&A...535A..32N 2011A&A...535A..32N);
Puls et al. (2006A&A...454..625P 2006A&A...454..625P);
Repolust et al. (2004A&A...415..349R 2004A&A...415..349R);
Repolust et al. (2005A&A...440..261R 2005A&A...440..261R);
Simon-Diaz et al. (2006A&A...448..351S 2006A&A...448..351S).
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- HD [24912/214680] HD number
8- 12 I5 d MJD [56602/57934] Modified Julian Date of
observation, JD-2400000.5
14- 17 A4 --- TPair Telescope pair
19- 25 F7.3 rad-1 SFreq [200.02/505.62] Spatial frequency (1)
27- 35 F9.3 arcsec-1 u [-2254.67/2253.56] u-coordinate
37- 45 F9.3 arcsec-1 v [-2450.3/2174.94] v-coordinate
47- 53 F7.3 m B [158.72/330.47] Baseline
55- 60 F6.4 --- V2 [0.016/1.246] Visibility squared
62- 69 F8.6 --- e_V2 [0.004/0.464] Uncertainty in visibility squared
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Note (1): The spatial frequency of the observation is the baseline, B,
divided by the wavelength B/λ*10-6.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 31-Oct-2019