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White Dwarfs in Nova-Like Variables: A Census Study with Insights into Low States

This study focuses on the detection and census of white dwarfs in nova-like variable systems above the period gap, emphasizing luminous disks, outflowing winds, and the rarity of low states. The project includes detailed analyses of specific Nova-Like Variables such as V794 Aql, V442 Oph, KR Aur, IX Vel, VY Scl, BB Dor, MV Lyr, DW UMa, TT Ari, and RW Tri. The research also delves into archival IUE spectra of some systems along with insightful findings on BK Lyn-type systems and V3885 Sgr as a representative of the UX UMa-type. Conclusions highlight the increasing number of white dwarfs with specific temperature ranges in nova-like variables, emphasizing the importance of HST observations to capture systems in low states.

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White Dwarfs in Nova-Like Variables: A Census Study with Insights into Low States

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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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