RT Journal Article
T1 BK Lyncis: the oldest old nova?...  and a Bellwether for cataclysmic variable evolution
A1 Patterson, Joseph
A1 Uthas, Helena
A1 Kemp, Jonathan
A1 Miguel Agustino, Enrique de
A1 Krajci, Thomas
A1 Foote, Jerry
A1 Hambsch, Franz-Josef
A1 Campbell, Tut
A1 Roberts, George
A1 Cejudo, David
A1 Dvorak, Shawn
A1 Vanmunster, Tonny
A1 Koff, Robert
A1 Skillman, David
A1 Harvey, David
A1 Martin, Brian
A1 Rock, John
A1 Boyd, David
A1 Oksanen, Arto
A1 Morelle, Etienne
A1 Ulowetz, Joseph
A1 Kroes, Anthony
A1 Sabo, Richard
A1 Jensen, Lasse
AB We summarize the results of a 20-year campaign to study the light curves ofBK Lyncis, a nova-like star strangely located below the 2-3 hour orbital period gap inthe family of cataclysmic variables. Two apparent “superhumps” dominate the nightlylight curves – with periods 4.6% longer, and 3.0% shorter, than Porb. The first appearsto be associated with the star's brighter states (V~14), while the second appears to bepresent throughout and becomes very dominant in the low state (V~15.7). It'splausible that these arise, respectively, from a prograde apsidal precession and aretrograde nodal precession of the star's accretion disk.Starting in the year 2005, the star's light curve became indistinguishablefrom that of a dwarf nova – in particular, that of the ER UMa subclass. No such cleartransition has ever been observed in a cataclysmic variable. Reviewing all the star'soddities, we speculate: (a) BK Lyn is the remnant of the probable nova on 30December 101, and (b) it has been fading ever since, but has taken ~2000 years forthe accretion rate to drop sufficiently to permit dwarf-nova eruptions. If such behavioris common, it can explain other puzzles of CV evolution. One: why the ER UMa classeven exists (because all members can be remnants of recent novae). Two: why ERUMa stars and short-period novalikes are rare (because their lifetimes, which areessentially cooling times, are short). Three: why short-period novae all decline toluminosity states far above their true quiescence (because they're just getting startedin their postnova cooling). Four: why the orbital periods, accretion rates, and whitedwarftemperatures of short-period CVs are somewhat too large to arise purely fromthe effects of gravitational radiation (because the unexpectedly long interval ofenhanced postnova brightness boosts the mean mass-transfer rate). And maybeeven five: why very old, post-period-bounce CVs are hard to find (because the highermass-loss rates have “burned them out”). These are substantial rewards in return forone investment of hypothesis: that the second parameter in CV evolution, besidesPorb, is time since the last classical-nova eruption.
PB Oxford University Press
SN 0035-8711
SN 1365-2966 (electrónico)
YR 2013
FD 2013
LK http://hdl.handle.net/10272/9516
UL http://hdl.handle.net/10272/9516
LA eng
NO Patterson, J., Uthas, H., Kemp, J., Miguel Agustino, E., Krajci, T., Foote, J., Hambsch, F.J., Campbell, T., Roberts, G., Cejudo, D., Dvorak, S., Vanmunster, T., Koff, R., Skillman, D., Harvey, D., Martin, B., Rock, J., Boyd, D., Oksanen, A., Morelle, E., Ulowetz, J., Kroes, A., Sabo, R., Jensen, L.: "BK Lyncis: the oldest old nova?...  and a Bellwether for cataclysmic variable evolution". Monthly Notices of the Royal Astronomical Society. Vol. 43, n. 3, págs. 1902-1919, (2013). ISSN 0035-8711
DS Repositorio Institucional de la Universidad de Huelva
RD 30 may 2026