J/ApJ/809/134 delta Orionis Aa. III. Radial velocities (Pablo+, 2015)
A coordinated X-ray and optical campaign of the nearest massive eclipsing
binary, δ Orionis Aa.
III. Analysis of optical photometric (MOST) and spectroscopic (ground-based)
variations.
Pablo H., Richardson N.D., Moffat A.F.J., Corcoran M., Shenar T.,
Benvenuto O., Fuller J., Naze Y., Hoffman J.L., Miroshnichenko A.,
Apellaniz J.M., Evans N., Eversberg T., Gayley K., Gull T., Hamaguchi K.,
Hamann W.-R., Henrichs H., Hole T., Ignace R., Iping R., Lauer J.,
Leutenegger M., Lomax J., Nichols J., Oskinova L., Owocki S., Pollock A.,
Russell C.M.P., Waldron W., Buil C., Garrel T., Graham K., Heathcote B.,
Lemoult T., Li D., Mauclaire B., Potter M., Ribeiro J., Matthews J.,
Cameron C., Guenther D., Kuschnig R., Rowe J., Rucinski S., Sasselov D.,
Weiss W.
<Astrophys. J., 809, 134 (2015)>
=2015ApJ...809..134P 2015ApJ...809..134P (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Radial velocities ; Stars, OB
Keywords: binaries: close; binaries: eclipsing; stars: early-type;
stars: individual: delta Ori A;
stars: mass-loss; stars: variables: general
Abstract:
We report on both high-precision photometry from the Microvariability
and Oscillations of Stars (MOST) space telescope and ground-based
spectroscopy of the triple system δ Ori A, consisting of a
binary O9.5II+early-B (Aa1 and Aa2) with P=5.7days, and a more distant
tertiary (O9IV P>400 years). This data was collected in concert with
X-ray spectroscopy from the Chandra X-ray Observatory. Thanks to
continuous coverage for three weeks, the MOST light curve reveals
clear eclipses between Aa1 and Aa2 for the first time in non-phased
data. From the spectroscopy, we have a well-constrained radial
velocity (RV) curve of Aa1. While we are unable to recover RV
variations of the secondary star, we are able to constrain several
fundamental parameters of this system and determine an approximate
mass of the primary using apsidal motion. We also detected second
order modulations at 12 separate frequencies with spacings indicative
of tidally influenced oscillations. These spacings have never been
seen in a massive binary, making this system one of only a handful of
such binaries that show evidence for tidally induced pulsations.
Description:
Our optical photometry was obtained with the MOST microsatellite that
houses a 15cm Maksutov telescope through a custom broadband filter
covering 3500-7500Å. δ Ori A was observed for roughly half of
each MOST orbit from 2012 December through 2013 January 7.
We initiated a professional-amateur campaign in order to obtain a
large number of high-quality optical spectra simultaneously with our
MOST and Chandra campaigns. This resulted in more than 300 moderate
resolution (R≳10000) spectra obtained over the three-week period.
Details of the telescopes and spectrographs used are given in Table 1.
A typical signal-to-noise ratio (S/N) for any observation is ∼100-150.
Objects:
------------------------------------------------------------------------
RA (2000) DE Designation(s) (Period)
------------------------------------------------------------------------
05 32 00.40 -00 17 56.7 δ Ori = HD 36486 (P=5.73244)
05 32 00.40 -00 17 56.7 δ Ori A = NAME del Ori Aa1
05 32 00.41 -00 17 56.9 δ Ori B = NAME del Ori Aa2
------------------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 91 15 δ Ori observing log
table2.dat 24 289 Radial velocity light curve
--------------------------------------------------------------------------------
See also:
III/274 : Galactic O-Star Spectroscopic Survey (Sota+, 2014)
II/7 : UBVRIJKLMNH Photoelectric Catalogue (Morel+ 1978)
J/ApJS/215/15 : SMaSH+: observations and companion detection (Sana+, 2014)
J/AJ/147/123 : Speckle interferometry with SOAR, 2012-2013 (Tokovinin+, 2014)
J/A+A/563/A59 : KIC 3858884: list of pulsation frequencies (Maceroni+, 2014)
J/MNRAS/433/1300 : HD 165052 radial-velocity measurements (Ferrero+, 2013)
J/A+A/533/A4 : CoRoT photometry of three O-type stars (Blomme+, 2011)
J/A+A/520/A89 : Multi-epoch photometry of δ Ori (Mayer+, 2010)
J/A+A/518/A1 : Galactic massive stars with AstraLux (Maiz Apellaniz, 2010)
J/AJ/137/3358 : Speckle interferometry of massive stars (Mason+, 2009)
J/A+A/485/931 : Young stars and brown dwarfs in Ori OB1b (Caballero+, 2008)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 28 A28 --- Obs Observer
30- 32 I3 --- Nobs [2/201] Number of observations
34- 55 A22 --- Tel Telescope
57- 72 A16 --- Spec Spectrograph
74- 85 A12 --- CCD CCD
87- 91 I5 --- R [11000/65000] Resolution
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.4 d HJD [6245.5/6300.7] Heliocentric Julian Date;
HJD-2450000
11- 18 F8.4 km/s RVel [-97.8/113.8] Radial velocity
20- 24 F5.2 km/s e_RVel [0.7/25] Error in RVel
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
Corcoran et al. Paper I. 2015ApJ...809..132C 2015ApJ...809..132C
Nichols et al. Paper II. 2015ApJ...809..133N 2015ApJ...809..133N
Shenar et al. Paper IV. 2015ApJ...809..135S 2015ApJ...809..135S
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 10-Dec-2015