J/AJ/151/104 Photometry and spectroscopy of LS V+44 17 (Yan+, 2016)
Long-term optical studies of the Be/X-ray binary RX J0440.9+4431/LS V+44 17.
Yan J., Zhang P., Liu W., Liu Q.
<Astron. J., 151, 104 (2016)>
=2016AJ....151..104Y 2016AJ....151..104Y (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, X-ray ; Stars, Be ; Photometry, UBVRI ; Spectroscopy ;
Equivalent widths ;
Keywords: binaries: general - stars: emission-line, Be -
stars: individual (RX J0440.9+4431) - X-rays: binaries
Abstract:
We present the spectroscopic and photometric observations on the
Be/X-ray binary RX J0440.9+4431 from 2001 to 2014. The short-term and
long-term variability of the Hα line profile indicates that
one-armed global oscillations existed in the circumstellar disk.
Several positive and negative correlations between the V-band
brightness and the Hα intensity were found from the long-term
photometric and spectroscopic observations. We suggest that the
monotonic increase of the V-band brightness and the Hα
brightness between our 2005 and 2007 observations might be the result
of a continuous mass ejection from the central Be star, while the
negative correlation in 2007-2010 should be caused by the cessation of
mass loss from the Be star just before the decline in V-band
brightness began (around our 2007 observations). With the extension of
the ejection material, the largest circumstellar disk during the last
two decades has been observed in our 2010 observations with an
equivalent width of approximately -12.88Å, which corresponds to a
circumstellar disk with a size of 12.9 times the radius of the central
Be star. Three consecutive X-ray outbursts peaking around MJD 55293,
55444, and 55591 might be connected with the largest circumstellar
disk around the Be star. We also use the orbital motion of the neutron
star as a probe to constrain the structure of the circumstellar disk
and estimate the eccentricity of the binary system to be ≥0.4. After
three years of the Hα intensity decline after the X-ray
outbursts, a new circumstellar disk was being formed around the Be
star after our 2013 observations.
Description:
Most of our spectra of RX J0440.9+4431 were obtained with the 2.16m
telescope at Xinglong Station of National Astronomical Observatories.
The optical spectroscopy with an intermediate resolution was made with
a CCD grating spectrograph at the Cassegrain focus of the telescope.
We took the red spectra covering from 5500 to 6700Å. Sometimes
low-resolution spectra (covering from 4300 to 6700Å) were also
obtained. In 2012 March and 2013 November, we also carried out the
spectroscopic observations with the Yunnan Faint Object Spectrograph
and Camera (YFOSC) instrument of the Lijiang 2.4m telescope in the
Yunnan Astronomical Observatory. The Grism #8 was used with a
resolution of 1.47Å/pixel, with a spectral range from 5050 to
9750Å. The journal of our observations is summarized in Table1.
Since 2007, we performed systematic photometric observations on a
sample of X-ray binaries with the 100cm Education and Science
Telescope (EST) and the 80cm Tsinghua-NAOC Telescope (TNT) at Xinglong
Station of NAOC. The EST, manufactured by EOS Technologies, is an
altazimuth-mounted reflector with Nasmyth foci at a focal ratio of
f/8. TNT is an equatorial-mounted Cassegrain system with a focal of
f/10, made by AstroOptik, funded by Tsinghua University in 2002 and
jointly operated with NAOC. Both telescopes are equipped with the same
type of Princeton Instrument 1340*1300 thin back-illuminated CCD. The
CCD cameras use standard Johnson-Cousins UBVRI filters made by Custom
Scientific. The BVRI differential magnitudes and their errors are
listed in Table2.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
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04 40 59.32 +44 31 49.3 LS V +44 17 = RX J0440.9+4431
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 62 65 Summary of the spectroscopic observations of
LSV+44 17 between our 2001 and 2014 observations
table2.dat 62 87 Summary of the BVRI photometric observations of
LSV+44 17 between our 2007 and 2014 observations
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See also:
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014)
J/A+A/590/A122 : Spectra of high-mass X-ray binaries (Reig+, 2016)
J/BaltA/24/395 : X-ray and radio sources in binaries (Malkov+, 2015)
J/A+A/574/A33 : BVRI photometry of high-mass X-ray binaries (Reig+, 2015)
J/A+A/462/1081 : BVRIJHK light curves of 4U 0115+63/V635 Cas (Reig+, 2007)
J/A+A/455/1165 : Catalogue of Galactic high-mass X-ray binaries (Liu+, 2006)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 "Y:M:D" Date Date of observation
13 A1 --- f_Date [b] Flag "b" on Date indicates data obtained
with the Lijiang 2.4m telescope
15- 18 I4 s Exp [100/1200] Exposure time
20- 28 F9.3 d MJD [52177/56930] Modified Julian Date
30- 33 F4.2 0.1nm/pix Disp [1/2.45] Dispersion (spectral resolution)
(in Å/pixels)
35- 39 F5.2 0.1nm EWHa [0.6/12.9] Hα equivalent width
41- 44 F4.2 0.1nm e_EWHa [0.03/0.51] Uncertainty in EWHa
46- 50 F5.2 [-] logV/R [-0.16/0.11]? Log V/R ratio of the Hα
line (2)
52- 57 A6 --- f_logV/R Flag on logV/R (single)
59- 62 F4.1 --- Rd/Rs [1.9/12.9]? Ratio of Hα emission region
radius to central star radius (Rd/R*)
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Note (2): V/R=(I(V)-Ic)/(I(R)-Ic), where I(V), I(R), and Ic are the
intensities of the violet peak, red peak, and continuum, respectively.
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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 F10.4 d MJD [54403.3/56929.3] Modified Julian Date
12- 17 F6.3 mag Bmag [-3.3/-3]? B band magnitude
19- 23 F5.3 mag e_Bmag [0.01/0.02]? Uncertainty in Bmag
25- 30 F6.3 mag Vmag [-3.6/-3.2]? V band magnitude
32- 36 F5.3 mag e_Vmag [0.009/0.023]? Uncertainty in Vmag
38- 43 F6.3 mag Rmag [-3.5/-3.1]? R band magnitude
45- 49 F5.3 mag e_Rmag [0.011/0.026]? Uncertainty in Rmag
51- 56 F6.3 mag Imag [-2.1/-1.7]? I band magnitude
58- 62 F5.3 mag e_Imag [0.009/0.013]? Uncertainty in Imag
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History:
From electronic version of the journal
(End) Sylvain Guehenneux [CDS] 06-Oct-2016