J/ApJ/688/1345 Differential photometry of the SB* BD+20 307 (Zuckerman+, 2008)
Planetary systems around close binary stars: the case of the very dusty,
Sun-like, spectroscopic binary BD+20 307.
Zuckerman B., Fekel F.C., Williamson M.H., Henry G.W., Muno M.P.
<Astrophys. J., 688, 1345-1351 (2008)>
=2008ApJ...688.1345Z 2008ApJ...688.1345Z
ADC_Keywords: Binaries, spectroscopic ; Photometry, uvby ; Radial velocities
Keywords: planetary systems: formation - stars: individual (BD+20 307) -
stars: rotation - X-rays: stars
Abstract:
Field star BD+20 307 is the dustiest known main-sequence star, based
on the fraction of its bolometric luminosity, ∼4%, that is emitted at
infrared wavelengths. The particles that carry this large infrared
luminosity are unusually warm, comparable to the temperature of the
zodiacal dust in the solar system, and their existence is likely to be
a consequence of a fairly recent collision of large objects such as
planets or planetary embryos. Thus, the age of BD+20 307 is
potentially of interest in constraining the era of terrestrial planet
formation. The present project was initiated with an attempt to derive
this age using the Chandra X-Ray Observatory to measure the X-ray flux
of BD+20 307 in conjunction with extensive photometric and
spectroscopic monitoring observations from Fairborn Observatory.
However, the recent realization that BD+20 307 is a short-period,
double-line, spectroscopic binary whose components have very different
lithium abundances vitiates standard methods of age determination. We
find the system to be metal-poor; this, combined with its measured
lithium abundances, indicates that BD+20 307 may be several to many
Gyr old. BD+20 307 affords astronomy a rare peek into a mature
planetary system in orbit around a close binary star (because such
systems are not amenable to study by the precision radial velocity
technique).
Description:
We observed BD+20 307 with the Chandra X-Ray Observatory Advanced CCD
Spectrometer Spectroscopic array (ACIS-S) starting on 2007 September
25 at 23:34:20 (UT), for a total of 4919s.
For optical photometry, we used the T12 0.8m Automatic Photometric
Telescope (APT) located at Fairborn Observatory in Arizona to collect
a total of 449 nightly brightness measurements of BD+20 307 between
2005 February and 2007 December.
From 2008 January through March we obtained 28 spectrograms of
BD+20 307 with the Tennessee State University 2m automatic
spectroscopic telescope (AST), fiber-fed echelle spectrograph, and a
2048x4096 SITe ST-002A CCD.
Objects:
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RA (2000) DE Designation(s)
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01 54 50.3 +21 18 22 BD+20 307 = 2MASS J01545034+2118225 = TYC 1212-207-1
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 60 449 Individual photometric observations of BD+20 307
table2.dat 40 28 Radial velocities of BD+20 307
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See also:
J/ApJS/162/207 : Radial velocities of solar-type stars (Abt+, 2006)
J/A+A/389/931 : uvby photometry + radial velocities of R 81 (Tubbesing+, 2002)
J/A+A/356/590 : The CORALIE survey for extrasolar planets II (Udry+, 2000)
J/A+A/319/481 : Radial velocities of 10 spectroscopic binaries (Mermilliod+
1997)
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 (HJD)
14- 20 F7.4 mag D-A Star D minus Star A differential mag in (b+y)/2
22- 28 F7.4 mag D-B Star D minus Star B differential mag in (b+y)/2
30- 36 F7.4 mag D-C Star D minus Star C differential mag in (b+y)/2
38- 44 F7.4 mag C-A Star C minus Star A differential mag in (b+y)/2
46- 52 F7.4 mag C-B Star C minus Star B differential mag in (b+y)/2
54- 60 F7.4 mag B-A Star B minus Star A differential mag in (b+y)/2
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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- 11 F11.3 d HJD Heliocentric Julian date
12 A1 --- f_HJD [a] Spectrum has blended components, velocities
given zero weight.
14- 18 F5.3 --- Phase Phase
20- 24 F5.1 km/s RVA Radial velocity for A component
26- 29 F4.1 km/s (O-C)A Radial velocity residual for A component
31- 35 F5.1 km/s RVB Radial velocity for B component
37- 40 F4.1 km/s (O-C)B Radial velocity residual for B component
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 18-Jan-2011