WHITE DWARFS IN NOVA-LIKE VARIABLES

Edward M.Sion

Department of Astronomy & Astrophysics, Villanova University

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

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?)

{BK Lyn }

{V442 Oph}

{KR Aur}

IX Vel

{V3885 Sgr}

VY Scl

{BB Dor}

MV Lyr

DW UMa

TT Ari

V794 Aql

CENSUS of WDs in Nova-Likes

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

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

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

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

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)

BK Lyn Ballouz, Sion, Gaensicke, Long, 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

BK Lyn Disk Fitting Results

(Ballouz et al. 2009, in preparation)

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

V3885 Sgr

T_wd = 57,000 +/- 5000K

Linnell et al. 2009, ApJ, submitted

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