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A Search for Superhumps in Possible SW Sextantis Stars

A Search for Superhumps in Possible SW Sextantis Stars. 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. 1. Discovery of U Gem. MNRAS Vol. 16. 2. 2.

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A Search for Superhumps in Possible SW Sextantis Stars

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  1. A Search for Superhumps in Possible SW Sextantis Stars 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 1

  2. Discovery of U Gem MNRAS Vol. 16 2 2

  3. 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’ 3

  4. Discs and Rapid Variability CVs - Unique Opportunity to Study Accretion Discs Changes on Short Time Scales 4

  5. 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 5

  6. 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 6

  7. Superhumps • Light curve feature • Period slightly longer than CV orbital period • Often triangular in shape • For DN superhumps are observed during superoutbursts Thought to be caused by energy dissipation of colliding disc orbits 7

  8. 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 8

  9. Observing • Seven REU observing nights • January 25 - January 31, 2005 • Observers: S. Aggarwal, C. Bendersky, B. 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 • V filter (5443Å peak 1060Å FWHM) 9

  10. 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 10

  11. V393 Hya Other Name: EC 10578-2935 RA: 11:00:17.45 DEC: -29:51:58.9 Galactic Longitude: 276 Galactic Latitude: 27 Object Type: NL Magnitude Range: 15.9V Outburst Year: Period: 0.135d (~3h 15m) 5’x5’ UK - F/70 11

  12. Night 3 V393 Hya Relative Magnitude vs Time UT 12

  13. Night 6 V393 Hya Relative Magnitude vs Time UT 13

  14. Night 7 V393 Hya Relative Magnitude vs Time UT 14

  15. V393 Hya Power Spectra (aov) 15

  16. V393 Hya Power Spectra (per) 16

  17. V393 Hya Power Spectra (aov) 17

  18. V393 Hya Power Spectra (per) 18

  19. AH Men Other Name: Men1; 1H 0551-819 RA: 06:11:44.07 DEC: -81:49:24.1 Galactic Longitude: 294 Galactic Latitude: -28 Object Type: NL/DQ: Magnitude Range: 13.2 V -14.0 V Outburst Year: Period: 0.12721d (~3h) 5’x5’ UK - F/70 19

  20. Night 2 AH Men Relative Magnitude vs Time UT 20

  21. Night 4 AH Men Relative Magnitude vs Time UT 21

  22. Night 2 AH Men Relative Magnitude vs Phase Phase 22

  23. Night 4 AH Men Relative Magnitude vs Phase Phase 23

  24. Night 2 AH Men Relative Magnitude vs Phase Phase 24

  25. Night 4 AH Men Relative Magnitude vs Phase Phase 25

  26. AH Men Power Spectra (aov) 26

  27. AH Men Power Spectra (per) 27

  28. AH Men Power Spectra (aov) 28

  29. AH Men Power Spectra (per) 29

  30. AH Men Power Spectra by Patterson 30

  31. AH Men Power Spectra (aov) 31

  32. AH Men Power Spectra (per) 32

  33. AH Men Power Spectra by Patterson 33

  34. 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 34

  35. 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! 35

  36. Thank You Alan Whiting & Linda Schmidtobreick Don McCarthy, Bob Morse, Ken Nordsieck, Cary Forest, Aaron Steffen, Mike Stamatikos, Stefan Gerhardt, Masaaki Yamada 36

  37. 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 37

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