J/AJ/134/179 Light minimum times of TY Boo (Yang+, 2007)
Orbital period changes for the weak-contact binary TY Bootis.
Yang Y.-G., Dai J.-M., Yin X.-G., Xiang F.-Y.
<Astron. J., 134, 179-184 (2007)>
=2007AJ....134..179Y 2007AJ....134..179Y
ADC_Keywords: Binaries, eclipsing ; Photometry
Keywords: binaries: close - binaries: eclipsing - stars: evolution -
stars: individual (TY Bootis)
Abstract:
We present a detailed period analysis of TY Bootis, based on all
available light minimum times covering about 80 years. We discovered
that there exists a cyclic variation overlaying a secular period
decrease from the distorted (O-C) diagram. A long-term decrease with
a sinusoidal oscillation (i.e., eq. (2)) or with a light-time effect
(i.e., eq. (3)) may be reasonable due to the smaller difference
between their sum of residuals. The sinusoidal change with a period of
59.7 yr for equation (2) can be attributed to either a light-time
effect or cyclic magnetic activity of both components. For the assumed
third body, the period and eccentricity of the light-time orbit are
P3=58.6yr and e'=0.1744, respectively. If the existence of an
additional unseen body is true, this binary may be a tertiary system.
The long-term orbital period decrease suggests that TY Boo is
undergoing a mass transfer from the primary component to the secondary
component at a rate of dm/dt=-3.15x10-8M☉/yr for equation (2)
or dm/dt=-2.90x10-8M☉/yr for equation (3). As its mass
transfers, accompanied by angular momentum loss due to mass outflow
L2, this binary will evolve into a deep contact configuration.
Description:
CCD observations in the R band for TY Boo were performed using the 1 m
telescope at Yunnan Observatory in China on 2006 June 3.
Objects:
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RA (2000) DE Designation(s)
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15 00 46.9 +35 07 55 TY Boo = V* TY Boo
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 55 292 All available light minimum times for TY Bootis
refs.dat 72 84 References
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 12 F12.4 d HJD Heliocentric Julian Date of minimum
14- 21 F8.1 --- Epoch Epoch E (in periods)
23- 25 A3 --- Method Method used (1)
27- 28 A2 --- Min [I II] Primary (I) or secondary (II) minimum
30- 36 F7.4 --- (O-C) (O-C) residual with Kreiner ephemeris 2001:
2447612.6035+0.31714910E (Eq.1)
38- 44 F7.4 --- (O-C)1 (O-C)1 residual with parabolic curve (Eq.2)
46- 52 F7.4 --- (O-C)2 (O-C)2 residual with 3rd body (Eq.3)
54- 55 I2 --- Ref Reference, in refs.dat file
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Note (1): Method used as follows:
pg = photographic measurement
vi = visual observation
pe = photoelectric data
CCD = charge-coupled device
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Code Reference code
4- 72 A69 --- Ref Reference
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 22-Aug-2009