J/A+A/672/A31 Triple star delta Ori radial velocities (Oplistilova+, 2023)
Spectrum of the secondary component and new orbital elements of the massive
triple star delta Ori A.
Oplistilova A., Mayer P., Harmanec P., Broz M., Pigulski A., Bozic H.,
Zasche P., Slechta M., Pablo H., Kolaczek-Szymanski P.A., Moffat A.,
Lovekin C.C., Wade G.A., Zwintz K., Popowicz A., Weiss W.W.
<Astron. Astrophys. 672, A31 (2023)>
=2023A&A...672A..31O 2023A&A...672A..31O (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Stars, O ; Radial velocities
Keywords: binaries: close - stars: massive - stars: individual: Delta Ori -
binaries: eclipsing - stars: fundamental parameters -
techniques: spectroscopic
Abstract:
Delta Orionis is the closest massive multiple stellar system and one
of the brightest members of the Orion OB association. The primary
(Aa1) is a unique evolved O star. In this work, we applied a two-step
disentangling method to a series of spectra in the blue region (430 to
450 nm), and we detected spectral lines of the secondary (Aa2). For
the first time, we were able to constrain the orbit of the tertiary
(Ab) -- to 55450d or 152yr -- using variable gamma velocities and
new speckle interferometric measurements, which have been published in
the Washington Double Star Catalogue. In addition, the Gaia DR3
parallax of the faint component (Ca+Cb) constrains the distance of the
system to (381±8)pc, which is just in the centre of the Orion OB1b
association, at (382±1)pc. Consequently, we found that the
component masses according to the three-body model are 17.8, 8.5, and
8.7 solar masses, for Aa1, Aa2, and Ab, respectively, with the
uncertainties of the order of 1 solar mass. We used new photometry
from the BRITE satellites together with astrometry, radial velocities,
eclipse timings, eclipse duration, spectral line profiles, and
spectral energy distribution to refine radiative properties. The
components, classified as O9.5 II + B2 V + B0 IV, have radii of 13.1,
4.1, and 12.0 solar radii, which means that Delta Ori A is a
pre-mass-transfer object. The frequency of 0.478 cycles per day, known
from the Fourier analysis of the residual light curve and X-ray
observations, was identified as the rotation frequency of the
tertiary. Delta Ori could be related to other bright stars in Orion,
in particular, Zeta Ori, which has a similar architecture, or Epsilon
Ori, which is a single supergiant, and possibly a post-mass-transfer
object.
Description:
Radial velocities of all components and details about spectra of the
triple star Delta Ori (HR 1852, HD 36486, HIP 25930, ADS 4134) from
the coude focus of the Ondrejov 2m reflector and the ELODIE and FEROS
echele spectrographs in the blue region. The RVs of all three
components were determined during the spectral disentangling
(three-step method) in KOREL.
Objects:
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RA (2000) DE Designation(s)
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05 32 00.40 +00 17 56.7 delta Ori = HD 36486
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tableb1.dat 71 65 Delta Ori data measured from spectra from the
coude focus of the Ondrejov 2m reflector
tableb2.dat 71 9 Delta Ori data measured from spectra from the
ELODIE and FEROS spectrographs
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See also:
J/A+A/520/A89 : Multi-epoch photometry of δ Ori (Mayer+, 2010)
Byte-by-byte Description of file: tableb1.dat tableb2.dat
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Bytes Format Units Label Explanations
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1- 12 F12.4 d HJD Heliocentric Julian date
14- 20 F7.2 s ExpT Exposure time
22- 26 F5.1 --- SN Signal to noise ratio
28- 35 F8.4 km/s HelC Heliocentric correction
37- 42 F6.2 km/s RV1 Radial velocity of the primary
44- 47 F4.2 km/s e_RV1 Error of the RV of the primary
49- 55 F7.2 km/s RV2 Radial velocity of the secondary
57- 60 F4.2 km/s e_RV2 Error of the RV of the secondary
62- 66 F5.2 km/s RV3 Radial velocity of the tertiary
68- 71 F4.2 km/s e_RV3 Error of the RV of the tertiary
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Acknowledgements:
Alzbeta Oplistilova, Alzbeta.Oplistilova(at)eso.org
(End) A. Oplistilova [AU UK, Czech Republic], P. Vannier [CDS] 19-Jan-2023