BK Lyncis: The Oldest Old Nova?... And a Bellwether for Cataclysmic-Variable Evolution

Dec, 2012
46 pages
Published in:
  • Mon.Not.Roy.Astron.Soc. 434 (2013) 1902
e-Print:

Citations per year

20132016201920222025012345
Abstract: (arXiv)
We summarize the results of a 20-year campaign to study the light curves of BK Lyncis, a nova-like star strangely located below the 2-3 hour orbital period gap in the family of cataclysmic variables. Two apparent 'superhumps' dominate the nightly light curves - with periods 4.6% longer, and 3.0% shorter, than P_orb. The first appears to be associated with the star's brighter states (V~14), while the second appears to be present throughout and becomes very dominant in the low state (V~15.7). Starting in the year 2005, the star's light curve became indistinguishable from that of a dwarf nova - in particular, that of the ER UMa subclass. Reviewing all the star's oddities, we speculate: (a) BK Lyn is the remnant of the probable nova on 30 December 101, and (b) it has been fading ever since, but has taken ~2000 years for the accretion rate to drop sufficiently to permit dwarf-nova eruptions. If such behavior is common, it can explain other puzzles of CV evolution. One: why the ER UMa class even exists (because all members can be remnants of recent novae). Two: why ER UMa stars and short-period novalikes are rare (because their lifetimes, which are essentially cooling times, are short). Three: why short-period novae all decline to luminosity states far above their true quiescence (because they're just getting started in their postnova cooling). Four: why the orbital periods, accretion rates, and white-dwarf temperatures of short-period CVs are somewhat too large to arise purely from the effects of gravitational radiation (because the unexpectedly long interval of enhanced postnova brightness boosts the mean mass-transfer rate). These are substantial rewards in return for one investment of hypothesis: that the second parameter in CV evolution, besides P_orb, is time since the last classical-nova eruption.
Note:
  • [1]
    (2) this paper
    • [1]
      (3) 2009
      • Zellem
      • [1]
        (4) 2003
        • Nogami
        • [1]
          (5) 2012
          • Ohshima
          • [1]
            (6) de 2013
            • Miguel
            • [1]
              (7) 1997
              • Thorstensen
              • [1]
                (8) 1995
                • Patterson
                • [1]
                  (9) 1995
                  • Robertson
                  • [1]
                    (10) 2008
                    • Olech
                    • [1]
                      (11) 1999
                      • Fried
                      • [1]
                        (12) 2009
                        • Rutkowski
                        • [1]
                          (13) 1995
                          • Harvey
                          • [1]
                            (14) 2002
                            • Kato
                            • [1]
                              (15) 2010
                              • Pavlenko
                              • [1]
                                (16) 2004
                                • Olech
                                • [1]
                                  (17) 2001
                                  • Ishioka
                                  • [1]
                                    (18) 2003
                                    • Kato
                                    • [1]
                                      (19) 2007
                                      • Olech
                                      • [1]
                                        (20) Urban & Sion 2006
                                        • [1]
                                          (21) 1989
                                          • O'Donoghue
                                          • [1]
                                            (22) 2012
                                            • Bianchini
                                            • [1]
                                              (23) Retter & Lipkin 2001
                                              • [1]
                                                (24) 2007
                                                • Tamburini
                                                • [1]
                                                  (25) 2008
                                                  • Hachisu
                                                  • [1]
                                                    (26) 1995
                                                    • Diaz