J/ApJ/783/35 VRI light curves of TT Her (Terrell+, 2014)
The double contact nature of TT Herculis.
Terrell D., Nelson R.H.
<Astrophys. J., 783, 35 (2014)>
=2014ApJ...783...35T 2014ApJ...783...35T (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Photometry, VRI ; Radial velocities
Keywords: binaries: close - binaries: eclipsing - stars: individual: TT Her
Abstract:
We present new radial velocities and photometry of the short-period
Algol TT Herculis. Previous attempts to model the light curves of the
system have met with limited success, primarily because of the lack of
a reliable mass ratio. Our spectroscopic observations are the first to
result in radial velocities for the secondary star, and thus provide a
spectroscopic mass ratio. Simultaneous analysis of the radial
velocities and new photometry shows that the system is a double
contact binary, with a rapidly rotating primary that fills its
limiting lobe.
Description:
In April of 2005, 2006, and 2007 R.H.N. took a total of nine medium
resolution (reciprocal dispersion=10Å/mm, R=10000) spectra at the
Dominion Astrophysical Observatory (DAO) in Victoria, BC using the
1.8m Plaskett Telescope. The exposure time was usually 1hr and the
spectral coverage was approximately 5000-5260Å. The log of the
spectroscopic observations is given in Table1.
Photometric observations in the VRCIC photometric passbands were
undertaken by R.H.N. at his private observatory in Prince George, BC,
Canada in May and June of 2008. A total of 392 frames in V, 413 in
RC, and 393 in IC were taken. Standard reduction techniques (bias
subtraction, dark subtraction, and flat-fielding) were done and
aperture photometry performed. Differential photometry was then
performed with GSC 1525-0805 (V=9.82±0.03 and B-V=0.72±0.03 from
the Tycho-2 catalog; Hog et al. 2000, cat. I/259) as the comparison
star and GSC 1525-0939 (V=11.73±0.07 and B-V=0.82±0.07 from Data
Release 7 of the APASS survey; Henden et al., 2012JAVSO..40..430H 2012JAVSO..40..430H; see
DR9 in Henden et al. 2016, cat. II/336) as the check star. No
variation in the comparison and check stars greater than 0.01mag was
detected, and the precision of the differential magnitudes for TT Her
was about 0.005mag in each filter. The instrumental magnitude
differences are given in Table2.
Objects:
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RA (ICRS) DE Designation(s) (Period)
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16 54 22.97 +16 50 13.1 TT Herculis = GSC 01521-00071 (P=0.912099)
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 47 8 Log of spectroscopic observations
table2.dat 27 1198 Photometry of TT Herculis
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See also:
II/336 : AAVSO Photometric All Sky Survey (APASS) DR9 (Henden+, 2016)
I/259 : The Tycho-2 Catalogue (Hog+ 2000)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- DAO Image number from Dominion Astrophysical
Observatory (DAO)
6- 15 F10.4 d HJD Mid time Heliocentric Julian Date (HJD-2400000)
17- 21 F5.3 --- Phase Orbital phase
23- 26 I4 s Exp Exposure time
28- 32 F5.1 km/s RV1 Primary radial velocity
34- 36 F3.1 km/s e_RV1 Uncertainty in RV1
38- 43 F6.1 km/s RV2 ? Secondary radial velocity
45- 47 F3.1 km/s e_RV2 ? Uncertainty in RV2
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- Flt Filter (V, Rc, or Ic)
4- 14 F11.5 d HJD ? Heliocentric Julian Day (HJD-2400000.0)
16- 20 F5.3 -- Phase ? Orbital phase
22- 27 F6.3 mag Dmag ? Instrumental magnitude difference in Flt
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 06-Apr-2016