J/AJ/145/142 Differential BV photometry of δ Sco (Jones+, 2013)
Using photometry to probe the circumstellar environment of δ Scorpii.
Jones C.E., Wiegert P.A., Tycner C., Henry G.W., Cyr R.P., Halonen R.J.,
Muterspaugh M.W.
<Astron. J., 145, 142 (2013)>
=2013AJ....145..142J 2013AJ....145..142J
ADC_Keywords: Stars, Be ; Stars, double and multiple ; Photometry, UBV
Keywords: binaries: general - circumstellar matter - stars: emission-line, Be -
stars: individual: delta Sco - stars: mass-loss
Abstract:
We acquired Johnson BV photometry of the binary Be disk system δ
Scorpii during its 2009, 2010, 2011, and 2012 observing seasons and
used it to probe the innermost regions of the disk. We found that
several disk building events have occurred during this time, resulting
in an overall brightening in the V band and reddening of the system.
In addition to these long-term trends, we found cyclical variability
in each observing season on timescales between 60 and 100days. We were
able to reproduce the changes in the magnitude and color of δ
Sco using our theoretical models and found that variable mass-loss
rates in the range 2.5-7.0*10-9M☉/yr over ∼35days can
reproduce the observed increase in brightness.
Description:
The T3 0.4m APT (Automatic Photoelectric Telescope) at Fairborn
Observatory in southern Arizona acquired several hundred observations
of δ Scorpii during the 2009, 2010, 2011, and 2012 observing
seasons. T3 is one of eight automatic telescopes operated by Tennessee
State University (TSU) at Fairborn for automated photometry,
spectroscopy, and imaging. Photometry is in the Johnson system
(Table1).
Objects:
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RA (ICRS) DE Designation(s)
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16 00 20.01 -22 37 18.1 * del Sco = HD 143275
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 38 480 Photometric observations of δ Sco (2009-2012)
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See also:
J/ApJ/729/L5 : The revised orbit of the δ Sco system (Tycner+, 2011)
J/AJ/127/1727 : Differential magnitudes of binary stars (Horch+, 2004)
J/A+A/408/305 : Spectroscopic observations of delta Sco (Miroshnichenko+, 2003)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 F10.4 d RJD [54857/56102] Reduced Julian Date
12- 17 F6.3 mag DBmag [-2.199/-1.811]?=99.999 Variable-Comparison
differential B-band magnitude (1)
19- 24 F6.3 mag DVmag [-2.253/-1.753]?=99.999 Variable-Comparison
differential V-band magnitude (1)
26- 31 F6.3 mag DBmag2 [-1.497/-1.445]?=99.999 Check-Comparison
differential B-band magnitude (1)
33- 38 F6.3 mag DVmag2 [-1.466/-1.41]?=99.999 Check-Comparison
differential V-band magnitude (1)
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Note (1): We programmed the automatic photoelectric Telescope (APT) to make one
or two observations of δ Scorpii each clear nigh in the following
sequence, termed a group observation: Check, S, Comparison, δ Sco,
Comparison, δ Sco, Comparison, δ Sco, Comparison, S, Check. The
Comparison star is HD 144470, the Check star is HD 144217, and S is a sky
reading taken near the center of the group). Each group observation is
reduced to form three bracketed Variable-Comparison and two unbracketed
Check-Comparison differential magnitudes, which are averaged together to
create group means for both B and V bands. Differential magnitudes with
standard deviation greater than 0.01mag were discarded. The surviving group
means were corrected for differential extinction, and transformed to the
Johnson system.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 27-May-2014