J/AJ/147/10 Light curve of V794 Aql over 1990-2012 (Honeycutt+, 2014)
The long-term light curve of the cataclysmic variable V794 Aquilae.
Honeycutt R.K., Kafka S., Robertson J.W.
<Astron. J., 147, 10 (2014)>
=2014AJ....147...10H 2014AJ....147...10H
ADC_Keywords: Stars, variable ; Binaries, cataclysmic ; Photometry
Keywords: cataclysmic variables - stars: individual: V794 Aql
Abstract:
The 1990-2012 light curve of the nova-like (NL) cataclysmic variable
V794 Aql is studied in order to characterize and better understand the
transitions to and from the faint state, and the variations within the
bright state. Investigations of earlier portions of this data had
concluded that the transitions to the low state were much slower than
the rapid recovery, giving a sawtoothed appearance to the light curve.
This behavior differs from that of most other VY Scl stars, which led
to an interpretation of the large amplitude sawtooths as being due to
an accretion disk (AD) instability. However, more recent photometry
strongly suggests that the bright state itself has transitions of
1-1.5mag, and that earlier studies had intermixed these bright state
variations with the transitions to the low state. These newly
recognized variations within the bright state sometimes appear as
small outbursts (OBs) with typical amplitudes of 0.5-1.5mag and
spacings of ∼15-50days. The rise times of the OBs are 2-3 times
faster than the decline times. We argue that the V794 Aql bright state
variations are due to AD behavior similar to that seen in dwarf novae,
but with varying degrees of stability. Similar regular small OBs have
also been reported in other NL CVs, which we compare with V794 Aql.
The true deep low states in V794 Aql appear to be normal, having
transition speeds and shapes very similar to the transitions in other
VY Scl stars.
Description:
All of the V794 Aql photometry was acquired from unattended telescopes
at the Morgan-Monroe Observatory (MMO) of Indiana University. MMO is
located 17km north of campus, near the center of the Morgan-Monroe
State Forest. The telescopes at the MMO are a 0.4m Cassegrain
reflector and a 1.25m Ritchey-Chretien reflector. A full description
of the facility can be found in Honeycutt et al. (2013, cat.
J/PASP/125/126).
The telescopes employed, the CCD used, and the data reduction
procedures varied somewhat over the 22yr interval 1990-2012, leading
us to divide the data into five campaigns (Table1).
Objects:
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RA (ICRS) DE Designation(s)
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20 17 33.91 -03 39 50.9 V794 Aql = 2MASS J20173391-0339509
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 52 5 V794 Aql photometry by observing campaign
table2.dat 28 1798 V794 Aql light curve data
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See also:
J/PASP/125/126 : Light curve of CR Boo over 1990-2012 (Honeycutt+, 2013)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 A1 --- C [A-E] Campaign code (1)
3- 6 F4.2 m Tel [0.41/1.25] Telescope size (0.41 or 1.25)
7 A1 --- --- [m]
9- 18 A10 --- Cam CCD camera type
20- 23 I4 yr Year0 Year of observation (start)
24 A1 --- --- [-]
25- 28 I4 yr Year1 Year of observation (end)
30- 33 I4 --- Nexp [61/1194] Number of usable exposures
35- 37 I3 --- Nstar [78/171] Number of field stars in the
ensemble solution
39- 43 F5.3 mag <Err> [0.02/0.024] Mean error of the variable
45- 46 I2 --- Nstd [9/10] Number of secondary standards used (2)
48- 52 F5.3 mag Err [0.004/0.005] Error in the light curve zero
point using the secondary standards
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Note (1): Defined more fully in Honeycutt et al. (2013, cat. J/PASP/125/126):
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Campaign Tel Range Duration CCD
(yr)
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A 0.41-m 1990.87-1991.98 1.11 TI 800
B 0.41-m 1992.08-2005.17 13.09 Tek 512
C 1.25-m 2006.58-2009.42 2.84 PXL Tek 1024
D 1.25-m 2010.75-2012.88 2.13 SBIG Kodak 1024
E 0.41-m 2011.65-2012.88 1.23 SBIG Kodak 1024
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Note (2): From Henden & Honeycutt (1995, cat. J/PASP/107/324).
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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- 13 F13.5 d JD [2448208/2456252] Julian Date of the observation
15- 20 F6.3 mag Vmag The V band magnitude
22- 26 F5.3 mag e_Vmag Error in Vmag
28 A1 --- C [A-E] Campaign code (see Table1)
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History:
From electronic version of the journal
References:
Honeycutt et al., Paper I, 1994ApJ...425..835H 1994ApJ...425..835H
Honeycutt & Robertson, Paper II, 1998AJ....116.1961H 1998AJ....116.1961H
Honeycutt & Kafka, Paper III, 2004AJ....128.1279H 2004AJ....128.1279H
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 27-Aug-2014