J/AJ/149/125 Iybvu photometry and CCD spectroscopy of RX Gem (Olson+, 2015)
RX Geminorum: photometric solutions, (nearly uniform) gainer rotation, donor
radial velocity solution, Non-LTE accretion disk models of Hα emission
profiles, and secular light curve changes in the 20th century.
Olson E.C., Etzel P.B.
<Astron. J., 149, 125 (2015)>
=2015AJ....149..125O 2015AJ....149..125O
ADC_Keywords: Binaries, eclipsing ; Photometry ; Radial velocities
Keywords: binaries: eclipsing - stars: individual: RX Gem
Abstract:
We obtained full-orbit Iybvu intermediate-band photometry and CCD
spectroscopy of the long-period Algol eclipsing binary RX Geminorum.
Photometric solutions using the Wilson-Devinney code give a gainer
rotation (hotter, mass-accreting component) about 15 times the
synchronous rate. We describe a simple technique to detect departures
from uniform rotation of the hotter component. These binaries radiate
double-peaked Hα emission from a low-mass accretion disk around
the gainer. We used an approximate non-LTE disk code to predict models
in fair agreement with observations, except in the far wings of the
emission profile, where the star-inner disk boundary layer emits extra
radiation. Variations in Hα emission derive from modulations in
the transfer rate. A study of times of minima during the 20th century
suggests that a perturbing third body is present near RX Gem.
Description:
Some 5300 differential Iybvu observations (see Table 1) of RX Gem were
made on parts of 46 nights from 1982 October 09 UT to 1989 December 08
UT, using the remotely controlled, pulse-counting PE photometer on the
1m reflector at the Mount Laguna Observatory of San Diego State
University. We added photometric observations for a new primary
eclipse time of minimum on four nights in late 2001 and early 2002.
Starting in late 1990, we obtained first-order CCD spectra of Hα
and OI λ7774 at 1Å resolution. We also exposed a few Hβ
and second-order MgII λ4481 spectra (resolution 0.5Å).
Objects:
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RA (ICRS) DE Designation(s) (Period)
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06 50 11.54 +33 14 20.7 V* RX Gem = HD 49521 (P=12.2)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 20 5280 Iybvu observations of RX Geminorum
table6.dat 20 37 Star 2 (donor) radial velocities
table7.dat 82 19 (O-C)s for RX Gem
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See also:
B/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)
J/AJ/138/1435 : Photometric observations of UX Monocerotis (Olson+, 2009)
J/AJ/109/1308 : H-alpha Emission Variations (Olson+ 1995)
J/AJ/109/1269 : Streams and Disks in Binary Stars (Etzel+ 1995)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 A1 --- Flt Filter used (I, y, b, v, u)
3- 13 F11.5 d HJD Heliocentric Julian Date (HJD-2400000)
15- 20 F6.4 mag Dmag [0.25/3.32] Differential magnitude in Filter
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 8 F8.5 d MJD Modified Julian Date (HJD-2451000)
10- 16 F7.5 --- Phase [0/1] Phase
18- 20 I3 km/s HRV [-93/145] Heliocentric radial velocity
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 10 F10.4 d MJD Modified Julian Date of observation
(HJD-2440000)
12- 18 F7.4 d O-CL [-0.1/0.1] Linear fit (O-C) residual (1)
20- 26 F7.4 d O-CS [-0.03/0.03] Sine fit (O-C) residual
28- 31 I4 --- Cycle [0/2812] Cycle number
33- 82 A50 --- Ref Reference
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Note (1): Light-time variations triggered by a third body in circular orbit
around the eclipsing pair could produce a sinusoidal (O-C)L versus time
plot, relative to a mean linear fit. See Section 9 for details.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 23-Apr-2015