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WOCS Variability: Monitoring NGC6939

WOCS Variability: Monitoring NGC6939. S. Kafka (IUB) D. Gibbs II (Univ. of Wyoming) A. Henden (US Naval Obs.) R.K.Honeycutt (IUB). BGSU, April 3, 2004. W IYN O pen C luster S tudy. Establish a standard database of open clusters. Age Reddening Metallicity Abundances

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WOCS Variability: Monitoring NGC6939

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  1. WOCS Variability:Monitoring NGC6939 S. Kafka (IUB) D. Gibbs II (Univ. of Wyoming) A. Henden (US Naval Obs.) R.K.Honeycutt (IUB) BGSU, April 3, 2004

  2. WIYN Open Cluster Study Establish a standard database of open clusters • Age • Reddening • Metallicity • Abundances • Astrometric info • Variability http://www.astro.ufl.edu/~ata/wocs/

  3. Our motivation:Cataclysmic Variables • Interacting binaries • WD accretes H-rich material from its low-mass, Roche-lobe filling companion • Unique natural laboratories for studying • Accretion Physics • Classical Novae • SNe Ia progenitors ?

  4. Why Open Clusters? • Bonus: age, distance, metallicity • Not many CVs known in globular/open clusters • Only 3 CVs known in all open clusters!

  5. NGC 6939 • Age = 1.6 ± 0.3 Gyr • 0.29 < E(B-V) < 0.41 • 12.21 < m-M < 12.39 (Rosvick & Balam 2002) • [Fe/H] = -0.14±0.13 (Friel et al 2002) • Variability study : 6 vars (Robb & Cardinal 1998) Credit: J. Burkle, D. Gibbs, D. Hoffmann, S. Kafka, WIYN 0.9m, IU REU 2003

  6. Data

  7. E NGC 6939 WIYN 0.9m N NGC 6939 USNOFS 1.3m R- filter

  8. Data Reduction

  9. V R V-R B-V CMD

  10. P=0.3548d P=0.4511d P=0.2419d P=0.2946d R R P=0.3601d P=0.2951d P=0.11142d P=0.3379d R R 0 0.5 1 1.5 0 0.5 1 1.5 0 0.5 1 1.5 0 0.5 1 1.5 Phase Phase Results

  11. s28 s33 R V467Cep V470Cep V10 V466Cep V V2 Phase V1, V8 V7 V3 V9 V4 V6 V5 R B-V JD - 2452700 Results P=0.5668d P=1.143d P>95d

  12. Oddities

  13. NGC 6939 USNOFS 1.3m R- filter

  14. V4 NGC 6939 V9 µDe s28 V470 Cep V8 µRA Oddities Glushkova & Rastorguev 1991 Monet et al. 2003 (USNO-B)

  15. Conclusions:

  16. Conclusions: • No CVs found in the cluster • Cluster depleted of faint variables??? Future work: • X-rays? • More data! • More Clusters! Kafka et al, 2004, AJ, 127, 1622

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