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Exploration of White Dwarfs in Nova-Like Variables: Insights and Discoveries

This study presents an in-depth exploration of white dwarfs (WDs) in nova-like variables, highlighting key findings on systems, luminosity, and wind dynamics. The observations reveal that many nova-like systems are viewed at high inclination angles, obscuring the WDs. A census of WDs in various nova-like variables such as V794 Aql, KR Aur, and BB Dor is conducted, discussing their characteristics including masses, outflow rates, and effective temperatures. The significant increase in WD temperatures over time suggests a potential for further observational studies targeting low states of these systems.

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Exploration of White Dwarfs in Nova-Like Variables: Insights and Discoveries

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  1. WHITE DWARFS IN NOVA-LIKE VARIABLES Edward M.Sion Department of Astronomy & Astrophysics, Villanova University

  2. Collaborators • Patrick Godon, Villanova University • Al Linnell, University of Washington • Paula Szkody, University of Washington • Ivan Hubeny, University of Arizona • Current and Former Villanova Students Ryan Hamilton, Joel Urban, Trisha Mizusawa, Ronald-Louis Ballouz

  3. Detection of WDs in Nova-Likes • Systems (except BK Lyn) Above the Gap • Luminous Disks • Outflowing Wind • Low states relatively rare & shorter than high states Many nova-likes are viewed at high inclination (obscures WD and BL) Low Inclination NLs (WD hidden?)

  4. CENSUS of WDs in Nova-Likes V794 Aql {BK Lyn } {V442 Oph} {KR Aur} IX Vel {V3885 Sgr} VY Scl {BB Dor} MV Lyr DW UMa TT Ari

  5. RW Tri (Mizusawa et al.2009, PASP in preparation) d = 341 + 38/-41 pc M_wd = 0.4 Msun, Mdot = 6.3 x 10^-9 Msun/yr 7 Archival IUE Spectra from Feb.1980 to Aug.1982

  6. KR Aur Mizusawa et al.2009, PASP, in prep.

  7. V442 Oph Ballouz & Sion, 2009, ApJ, in press

  8. BB Dor Mdot = 1 x 10^-9 Msun/yr T_wd ~ 32000K (T_wd =37,000K) i = 8 degrees (80 degrees) Godon et al. 2008, ApJ, 687, 532

  9. BK Lyn • VY Scl-type Nova-Like Variable • Only Nova-Like below the Period Gap • P_orb = 108 min • i < 80 degrees; i > 20 degrees • M_wd = 0.3 +0.35 /- 0.12 Msun (Dobrzycka & Howell 1992) • d = 116 to 1.5 kpc? • HST STIS G140L Obs (4/13/03) B.Gaensicke, PI • No P Cygni features, strong emission, sharp LyA • Spectroscopic Twin of V794 Aql (P_orb = 221min)

  10. BK Lyn Ballouz, Sion, Gaensicke, Long, 2009, in preparation

  11. BK Lyn Disk Fitting Results (Ballouz et al. 2009, in preparation) Mwd    Mdot     i        chi^2       d (pc)  1.2       -9/-9.5   75-81   1.84-1.9      300-5501.0        -9.0      75-81    1.94         400-7000.8        -8.5      75-81    1.97         560-940 0.55      -8.0     75-81   1.97-2.00    730-12200.40      -8.0      75       2.07         860

  12. V3885 Sgr • UX UMa-type Nova-Like • P_orb = • Luminous Disk, Wind • Mdot = 5 x 10^-9 Msun/yr • M_wd = 0.8 Msun • i = 40 – 60 degrees • d = 500 pc

  13. V3885 Sgr T_wd = 57,000 +/- 5000K Linnell et al. 2009, ApJ, submitted

  14. Conclusions • # of NL WDs with Teff’s slowly increasing • All (so far) have Teff > 30,000K • All are hottest WDs at their P_orb • V3885 Sgr has T_wd = 57,000 +/- 5000K • We must have TOO program with HST to Catch NL Systems in Low States

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