Quick search Find article
Quick search
Find article

Observations of the SW Sextantis Star BH Lyncis in a High State

FREE

D. W. Hoard1 and Paula Szkody1

Show affiliations


We present time-resolved photometry and medium resolution (2 Å) spectroscopy of the SW Sextantis star BH Lyncis obtained during a high state of the system. Previous detailed observations have been obtained only during low and intermediate states. In addition, we present the first International Ultraviolet Explorer low-resolution (6 Å) spectrum of BH Lyn. A revised photometric ephemeris, HJD(min) = 2,447,180.3366(2) + 0.15587535(6)E, is derived based on new and previously published eclipse timings. The amplitude of the pre-eclipse hump in light curves of BH Lyn is shown to vary, suggesting that the degree to which the incoming accretion stream impacts the edge of the disk changes over time. We estimate system parameters using the V-band eclipse width and He II λ4686 emission-line radial velocity (i ≈ 79°, q ≈ 0.45, MWD ≈ 0.7 Msun, M2 ≈ 0.3 Msun, R2 ≈ 0.4 Rsun, a ≈ 1.2 Rsun). Doppler tomograms constructed for the prominent emission lines in BH Lyn show a lack of emission at the expected locations of the bright spot and accretion stream trajectories. The differences between the low and high states of BH Lyn are discussed, along with the possible origin of a significant amount of the emission-line flux in a wind from the disk and/or white dwarf primary star. Finally, a model involving the presence of vertically extended bulges in the accretion disk is introduced to explain the characteristic phase-dependent absorption feature found in emission lines of the SW Sex stars.


Subject headings

accretion, accretion disks; binaries: close; novae, cataclysmic variables; stars: individual (BH Lyncis)


Dates

Issue 1 (1997 May 20)

Received 1996 September 17, accepted for publication 1996 December 18



View by subject




Export








Please login to access our web services, or create an account if you don't yet have one.

You must have cookies enabled in your web browser to be able to login.

Username
Password

Forgotten your password? Get a new one here.