J/ApJ/766/119 Radial velocities of δ Sco (Miroshnichenko+, 2013)
The 2011 periastron passage of the Be binary δ Scorpii.
Miroshnichenko A.S., Pasechnik A.V., Manset N., Carciofi A.C.,
Rivinius TH., Stefl S., Gvaramadze V.V., Ribeiro J., Fernando A.,
Garrel T., Knapen J.H., Buil C., Heathcote B., Pollmann E., Mauclaire B.,
Thizy O., Martin J., Zharikov S.V., Okazaki A.T., Gandet T.L.,
Eversberg T., Reinecke N.
<Astrophys. J., 766, 119 (2013)>
=2013ApJ...766..119M 2013ApJ...766..119M
ADC_Keywords: Stars, Be ; Binaries, spectroscopic ; Radial velocities
Keywords: binaries: spectroscopic; stars: emission-line, Be;
stars: individual: * del Sco
Abstract:
We describe the results of the world-wide observing campaign of the
highly eccentric Be binary system δ Scorpii 2011 periastron
passage which involved professional and amateur astronomers. Our
spectroscopic observations provided a precise measurement of the
system orbital period at 10.8092±0.0005yr. Fitting of the HeII
4686Å line radial velocity curve determined the periastron passage
time on 2011 July 3, UT 9:20 with a 0.9-day uncertainty. Both these
results are in a very good agreement with recent findings from
interferometry. We also derived new evolutionary masses of the binary
components (13 and 8.2M☉) and a new distance of 136pc from the
Sun, consistent with the HIPPARCOS parallax. The radial velocity and
profile variations observed in the Hα line near the 2011
periastron reflected the interaction of the secondary component and
the circumstellar disk around the primary component. Using these data,
we estimated a disk radius of 150R☉. Our analysis of the radial
velocity variations measured during the periastron passage time in
2000 and 2011 along with those measured during the 20th century, the
high eccentricity of the system, and the presence of a bow shock-like
structure around it suggest that δ Sco might be a runaway triple
system. The third component should be external to the known binary and
move on an elliptical orbit that is tilted by at least 40° with
respect to the binary orbital plane for such a system to be stable and
responsible for the observed long-term radial velocity variations.
Description:
Spectroscopic monitoring of δ Sco began shortly after its
brightening discovery in 2000 (Fabregat et al. 2000IAUC.7461....1F 2000IAUC.7461....1F)
and has been ongoing since that time. While only a few spectra of
δ Sco were obtained by amateurs in 2000, this number grew to 200
spectra in 83 nights in 2010 and over 300 spectra in 149 nights in
2011.
The main instruments that contributed to the campaign from the
professional side were the 3.6m Canada-France-Hawaii Telescope (CFHT)
with the spectropolarimeter ESPaDOnS, which covers a region
∼3600-10500Å with a spectral resolving power R∼70000, and the 2.2m
Max-Planck-Gesellschaft (MPG) telescope at ESO/La Silla with the FEROS
spectrograph, which covers a region ∼3600-9200Å with R=48000. Over
300 individual spectra of δ Sco were obtained at these
facilities during 40 nights in 2011.
An important feature of the campaign was a 10-night observing run at
the 0.8m IAC80 telescope of the Instituto de Astrofisica de Canarias
at the Teide Observatory on the Canary Island of Tenerife in Spain.
The run took place between 2011 June 28 and 2011 July 8, was centered
on the periastron time predicted by Tycner et al. (2011,
Cat. J/ApJ/729/L5), and accomplished by a team of five authors of this
paper (A. Miroshnichenko, J. Ribeiro, A. Fernando, T. Garrel, and J.
Knapen). We used a private LhiresIII spectrograph with R∼17000 in the
Hα region and R∼21000 in the HeII 4686Å line region.
Objects:
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RA (ICRS) DE Designation(s) Period (d)
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16 00 20.01 -22 37 18.1 * del Sco = HD 143275 (P=3948)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 31 148 Radial velocities for the Hα line
table2.dat 34 115 Radial velocities for the HeII4686Å line
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See also:
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "MM/DD/YYYY" Date Date of the observation
12- 19 F8.3 d JD Julian date; JD-2450000
21- 25 F5.1 km/s HRV Heliocentric radial velocity
27- 29 F3.1 km/s e_HRV Error in HRV (1)
31 I1 --- Source Source of the spectrum (G1)
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Note (1): The error of the mirrored fit to the line profile.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "MM/DD/YYYY" Date Date of the observation
12- 19 F8.3 d JD Julian date; JD-2450000
21- 25 F5.1 km/s HRV Heliocentric radial velocity
27- 32 F6.4 --- RMS r.m.s error of Gaussian fit to line profile
34 I1 --- Source Source of the spectrum (G1)
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Global notes:
Note (G1): Source as follows:
1 = ESPaDOnS (CFHT);
2 = FEROS at the 1.52m ESO telescope;
3 = IAC80 telescope of the Teide Observatory;
4 = C. Buil;
5 = T. Garrel;
6 = B. Heathcote;
7 = J. Ribeiro;
8 = E. Pollmann;
9 = O. Thizy.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 13-Nov-2014