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NEAR-CONTACT BINARY NEAR-CONTACT BINARY V836 Cygni V836 Cygni Çanakkale, 2004
NEAR-CONTACT BINARYNEAR-CONTACT BINARY
V836 CygniV836 CygniÇanakkale, 2004
ObservationsObservations
Ege University Obs. (30 cm.) Turkish National Obs. (40 cm.) Date range:2000-2002 U B V filters
No brightness deficiency at 0.5(Zhukov & Markova1994)but at ~1.1
Before the analysisBefore the analysis
Mode definition for WD code
Evidence for (semi-detached?) configuration
Breinhorst et al.(1989): “detached, but...”
f2=0.98 ±0.02
Ωcr=2.5911 > f2= 1.0008
f1= 0.9143
*f(m) : Durbeck & Schumann (1982)
NCB test: the criteriaNCB test: the criteria
P < 1 day Facing surfaces < 0.1 orb. radius apart X Not in contact 1 component at or near its Roche lobe Hotter: A v F ; cooler: 1 v 2 later -------------------------------------------------------------- Agreement in M-R-L relations of [Hilditch etal.(1988)] Two comp. lines parallel to the ZAMS [Oh et al. (2000)]
? Harmony in M-R-L relations of collected data
Shaw (1994)
1 2
NCB A
W X x
NCB A
W X
Classification for 836 Classification for 836
NCBs
V1010 Oph FO VirUndermassive
1st:.at or near its R.L. .normal sized
2nd:.inside R.L. .”oversized”
(1-1.5 times) .Max I > Max II
1st:.inside R.L. .normal sized
2nd:. at or near its R.L .”oversized”
(2-3 times) . No Max I > Max II
1st:. at or near its R.L. .”undermassive”2nd:. inside R.L.
.”undermassive” (1-1.5 times)
Marginal contacteg.Hillditch et al. (1988)
Detached ?eg.Hillditch et al. (1988)
Shaw (1994)
about Evolutionabout Evolution
Disadvantage: Single-lined, only f(m) FO Vir type
A. if
come close enough to transfer required energy from hot to cool, photospere of the cool comp. is getting hot
thenA-type W UMa system. Shaw (1994)
!!(AML by magnetic breaking is needed)
B. Longer-period detached systemvia Case-A mass transfer
semi-detached (836 is here)
marginal contact (not in thermal eq.)
the deeper contact A-type W UMa system[Hilditch etal.(1988), Budding(1984)]
1 2
NCB A
W X x
Problems and FutureProblems and Future
Single-lined spectrae. Prevent the morphology from varying study to study, by
reducing the errors. Eg. q range:
q=0.348 Ω cr=2.5699 near R.L.
q=0.358 (10) Ω cr=2.5911 at R.L.
q=0.368 Ω cr=2.6120 at R.L.
AML: “ The secondaries of FO Vir types must be undermassive”.
