Low State, Phase-Resolved IR Spectroscopy of VV Puppis
Steve B. Howell, Thomas E. Harrison, Ryan K. Campbell, France A. Cordova, Paula Szkody
Abstract
We present phase-resolved low resolution
JHK
and higher resolution
K
-band spectroscopy of the polar VV Pup. All observations were obtained when VV Pup was in a low accretion state having a K magnitude near 15. The low resolution observations reveal cyclotron emission in the
J
band during some phases, consistent with an origin near the active 30.5 MG pole on the white dwarf. The secondary in VV Pup appears to be a normal M7V star and we find that the
H
and
K
band fluxes are entirely due to this star at all orbital phases during the low accretion state. We use our higher resolution Keck spectroscopy to produce the first
K
-band radial velocity curve for VV Pup. Our orbital solution yields
K
2
=414
±27
km sec
−1
and leads to mass estimates of M
1
=0.73
±
0.05 M
⊙
and M
2
=0.10
±
0.02 M
⊙
. We find that the mass accretion rates during the normal low states of the polars VV Pup, EF Eri, and EQ Cet are near 10
−13
M
⊙
yr
−1
. The fact that M is not zero in low state polars indicates active secondary stars in these binary systems, including the sub-stellar donor star present in EF Eri.