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A Search for Superhumps in Possible
SW Sextantis Stars
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A.J. Carver
2005 CTIO REU Student
University of Wisconsin-Madison
Mentors: Alan Whiting (CTIO) & Linda Schmidtobreick (ESO)
March 24, 2005
acarver@wisc.edu or ajcarver@u.washington.edu
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Discovery of U Gem
MNRAS Vol. 16
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Cataclysmic Variables (CVs)
• Close Binary Systems
• Red Dwarf (RD) and White Dwarf (WD)
• RD fills its Roche lobe and loses matter to WD
• Matter often forms a disc around WD
• Matter hitting disc creates ‘hot spot’
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Discs and Rapid Variability
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CVs - Unique Opportunity to Study Accretion
Changes on Discs Time Scales
Short
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CV Classifications
• Classical Nova (CN) - One observed outburst,
outbursts of 6 - 19 magnitudes
• Recurrent Nova (RN) - Multiple observed outbursts
• Dwarf Nova (DN) - Outbursts with smaller change
in magnitude, typical outbursts of 2 - 5 magnitudes
• Nova-Like variables (NL) - non-eruptive CVs
possibly pre-novae, post-novae
• Polars - have the strongest magnetic fields
• Intermediate Polars (IP) - weaker magnetic fields
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SW Sextantis Stars
• Subset of NLs
• Typically eclipsing
• High velocity emission line wings
• Line core absorption near phase 0.5
• Orbital periods of 3-4hrs
• Thought to have large discs and high mass transfer
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Superhumps
• Light curve feature
• Period slightly longer than CV orbital period
• Often triangular in shape
• For DN superhumps are observed during
superoutbursts
caused by energy
Thought to be Quic kTime™ and a dissipation of
colliding disc orbits
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The Project
• Search for Superhumps in possible SW Sextantis
Stars
• Selected four stars to observe: AH Men, V1193 Ori,
IM Eri, and V393 Hya
• Searching for new systems to observe that can help
constrain disc models
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Observing
• Seven REU observing nights
• January 25 - January 31, 2005
• Observers: S. Aggarwal, C. Bendersky, B. QuickTime™ and a
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Brandvig, A.J. Carver, B. Mills, L. Pérez, S.
Points, D. Semler, O. Valdivia, & A. Whiting
• .9m (36”) Cassegrain Telescope
• 2048x2046 CCD w/ quad
readout
• 1024x1024 ROI used (ROI bias &
flats taken)
• 30 second exposures
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Reduction
• Data reduced using IRAF
• Reduced Image = (Raw Image - Bias)/Flat Field
• Averaged 43 dome flats (from nights 2, 4, 5, 6, 7)
• Averaged 63 biases (from nights 2, 4, 5, 6, 7)
• IRAF tasks: imexam, phot, txdump, imcopy, imdel,
quadproc, zerocombine, flatcombine
• Telescope drift slowed reduction process
• Determined bins of five successive image successfully
kept star in aperture
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V393 Hya
Other Name: EC 10578-2935
RA: 11:00:17.45
DEC: -29:51:58.9
Galactic Longitude: 276
Galactic Latitude: 27 QuickTime™ and a
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Object Type: NL
Magnitude Range: 15.9V
Outburst Year:
Period: 0.135d (~3h 15m)
5’x5’ UK - F/70
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Night 3 V393 Hya Relative Magnitude vs
-0.4
Time
-0.3
-0.2
Relative Magnitude
-0.1
0
0.1
0.2
0.3
0.4
05:45 06:15 06:45 07:15 07:45 08:15 08:45
UT
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Night 6 V393 Hya Relative Magnitude vs
-0.4
Time
-0.3
-0.2
Relative Magnitude
-0.1
0
0.1
0.2
0.3
0.4
04:45 05:15 05:45 06:15 06:45 07:15 07:45 08:15
UT
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Night 7 V393 Hya Relative Magnitude vs
-0.4
Time
-0.3
-0.2
Relative Magnitude
-0.1
0
0.1
0.2
0.3
0.4
04:30 05:00 05:30 06:00 06:30 07:00 07:30 08:00 08:30
UT
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V393 Hya Power Spectra (aov)
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V393 Hya Power Spectra (per)
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V393 Hya Power Spectra (aov)
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V393 Hya Power Spectra (per)
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AH Men
Other Name: Men1; 1H 0551-819
RA: 06:11:44.07
DEC: -81:49:24.1
Galactic Longitude: 294
Galactic Latitude: -28
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Object Type: NL/DQ:
Magnitude Range: 13.2 V -14.0 V
Outburst Year:
Period: 0.12721d (~3h)
5’x5’ UK - F/70
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Night 2 AH Men Relative Magnitude vs Time
-0.8
-0.6
Relative Magnitude
-0.4
-0.2
0
0.2
0.4
01:15 02:15 03:15 04:15 05:15 06:15 07:15
UT
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Night 4 AH Men Relative Magnitude vs Time
-0.8
-0.6
Relative Magnitude
-0.4
-0.2
0
0.2
0.4
01:30 02:30 03:30 04:30 05:30 06:30 07:30 08:30
UT
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Night 2 AH Men Relative Magnitude vs Phase
-0.4
-0.3
-0.2
Relative Magnitude
-0.1
0
0.1
0.2
0.3
0.4
0 0.5 1 1.5 2 2.5
Phase
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Night 4 AH Men Relative Magnitude vs Phase
-0.4
-0.3
-0.2
Relative Magnitude
-0.1
0
0.1
0.2
0.3
0.4
0 0.5 1 1.5 2 2.5
Phase
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Night 2 AH Men Relative Magnitude vs Phase
-0.4
-0.3
-0.2
Relative Magnitude
-0.1
0
0.1
0.2
0.3
0.4
0 0.2 0.4 0.6 0.8 1
Phase
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Night 4 AH Men Relative Magnitude vs Phase
-0.4
-0.3
-0.2
Relative Magnitude
-0.1
0
0.1
0.2
0.3
0.4
0 0.2 0.4 0.6 0.8 1
Phase
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AH Men Power Spectra (aov)
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AH Men Power Spectra (per)
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AH Men Power Spectra (aov)
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AH Men Power Spectra (per)
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AH Men Power Spectra by Patterson
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AH Men Power Spectra (aov)
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AH Men Power Spectra (per)
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AH Men Power Spectra by Patterson
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Summary & Conclusions
• Flickering observed in V393 Hya light curve
• Superhumps not observed in V393 Hya light curve
• Flickering observed in AH Men light curve
• Broad features observe in AH Men light curve
• Superhump candidates in AH Men
• AH Men has been observed before
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Future & Recommendations
• Observe V1193 Ori and IM Eri
• If an interesting system is found,
take synchronous spectral and
photometric data
• Double check for star aliases
• Observe target continuously for as
long as possible (for at least two
complete periods)
• Help the reducer - make sure
tracking is working!
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Thank You
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Alan Whiting & QuickTime™ a nd a
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Linda Schmidtobreick
Quic kT ime™ and a
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Don McCarthy, Bob Morse, Ken Nordsieck, Cary
Forest, Aaron Steffen, Mike Stamatikos, Stefan
Gerhardt, Masaaki Yamada
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For More Information
acarver@wisc.edu
ajcarver@u.washington.edu
lschmidt@eso.org
whiting@ctiosz.ctio.noao.edu
http://www.ctio.noao.edu/REU/ctioreu_2005/Projects2005/acarver/index.html
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