Published on November 15, 2007
Binarity & Symbiotics: Binarity & Symbiotics Hugo E. Schwarz. Cerro Tololo Inter-American Observatory, NAOA/AURA. Asymmetries in PNe.: Asymmetries in PNe. Most field stars are unpolarized. 3/4 of AGB stars is polarized. (Johnson, Jones 1991, AJ 101, 1735) Most PNe are not circular, many are extreme. Some ~50% have binaries. Extreme global asymmetries due to binaries. Point symmetry due to precession. Links to symbiotics & symbiotic nebulae. Different properties of bipolar PNe. Bipolar properties: Bipolar properties Scale height 130pc v. 260pc Nearer pure circular Galactic rotation Hotter central stars 145kK v. 75kK He, N, & Ne are overabundant Vexp higher 150km/s v.15km/s Large size 0.76pc v. 0.1pc More massive progenitors >1.5M Bipolars-Symbiotics-PNe: Bipolars-Symbiotics-PNe 40% of D&D’ symbiotics have nebulae. Post-PN nebulae: BI Crucis (3 nebulae). AS201 fossil PN, ionized nebula, G star. 5/14 symbiotic nebulae are bipolar. Binaries explain both phenomena. M2-9 needs faint, hot star binary. Blue-red shifts in the same lobe (IC4234). Point symmetry explained by precession. Symbiotics with optical nebulae: Corradi et al. 1999 A&A 343, 841 Symbiotics with optical nebulae Symbiotic nebulae: Symbiotic nebulae Symbiotic nebulae (SyNe): Symbiotic nebulae (SyNe) Nearly 4 times more are bipolar cf. PNe. Average Vexp is 140km/s as for BPNe. Average z = 133pc as for BPNe. For BSyNe z = 98pc (only 5 objects) Most have [NII] as strongest lines. SO SYMBIOTIC NEBULAE SHARE MANY PROPERTIES WITH BPNe & are binaries… BI Cru: Post-PN-Nebula Schwarz & Corradi 1992, AA 265, 37 Model of Morris 1987, PASP, 95, 1115 BI Cru Vexp = 280 km/s VH = 3000 km/s Central reversal 2 nebulae: H/L exc. D = 1.8kpc S = 1.3pc, Age = 3ka L = 4300L High excitation nebula (unresolved) M2-9: PN & symbiotic: M2-9: PN & symbiotic Size = 115“, outer lobes point symmetric, Inner nebula has plane symmetry. Outer lobes reflecting dust L=553L; d=640pc; age=1200yrs; s=0.37pc HST image Both plane and point symmetries due to binary orbit phenomena: rotating central dustclouds and precession? “Symbiotic“ emission lines, prob. disk. [OIII] line, so hot, subluminous *: WD+MS or RG are present = binary. Schwarz et al. 1997 AA 319, 267 Doyle et al. 2000 AJ 119, 1339 Sa2-237: Sa2-237 Vexp=308km/s S = 0.37 pc 34” L = 340 L D = 2.1kpc Age = 624 a As M2-9: [OIII] present, low L, so WD, so binary. Study CS…. AS201: P-PN-N in the making?: AS201: P-PN-N in the making? Low excitation nebula, old, faint, extended. High excitation inner nebula. Symbiotic & PN. When CS forms disk… get an object like BI Cru? A79, He2-428, M1-91Rodriguez, Corradi, Mampaso 2001 AA 377, 1042: A79, He2-428, M1-91 Rodriguez, Corradi, Mampaso 2001 AA 377, 1042 Strong mass loss/exchange in unresolved cores. CaII triplet in emission, high , excretion disk. Cont. and absorption lines indicate hot star with cool companion. Equatorial rings and polar lobes. Slide13: Precession, point symmetry Red and blue shifts on the same side of the object. Only if LoS or Sky cut precession cone. Observed in IC4634 IC4634 Long slit spectrum. SPATIAL VELOCITY Strong links: PNe-Symbiotics-Binaries: Strong links: PNe-Symbiotics-Binaries All (extreme) bipolars are binaries All symbiotics are binaries Evolutionary stage is important (P-PN-N) Some equatorial density enhancement Orientation effects should occur Model these, cf. observations. Inclination effects.: Inclination effects. High inclination objects hide the central object behind their equatorial mass concentration, and therefore show more FIR radiation; low inclination objects show the central object and this increases the fraction of visible & NIR light we see. So… Computing the UBV (VIS), JHK (NIR), & IRAS (FIR) relative fraction of the total flux, we should see an effect. Crude model of inclined nebulae: Crude model of inclined nebulae Donut (BB) around point source (BB) Stellar flux captured is converted to IR Random i orientation in space Plot fractions of BVR, JHK, & IRAS (i) Cf. observations for various BBs: Donut 600K; Star 10, 20, 40, 80kK Observed sample: Observed sample ~30 objects, partial SEDs, some distances Estimate inclinations from images (3x) Use BVR, JHK, IRAS “bands” relative to sum of these bands. Do same for simulation data, compare. Observed sample: FIR VIS & NIR Observed sample Random sample: Random sample Generate random binaries. i random with sin(i) histogram Donut dust distribution, 15% stellar Plot same parameters as observed data. Random sample: Random sample = FIR = NIR = VIS 1000WD 200RG 200K dust 1000WD 200RG 400K dust Slide22: LUMINOSITIES Another predicted effect is that high inclination objects should have lower apparent luminosities due to the fact that only the equatorial “donut” is seen, while for low inclination the central object plus donut is observed giving an apparent over-luminosity. Over all angles, averaging makes sure that no energy conservation laws are broken; Ltot = n.Lave Distances being uncertain for all but a few objects, we have: High inclination (>45) Sa2-237 I=70 2.1kpc 340 Lo M2-9 I=75 0.64kpc 553 Lo He2-104 I=50 1kpc 205 Lo He2-111 I=70 2.8kpc 440 Lo M1-16 I=70 1.8kpc 194 Lo 346 Lo Low inclination (<45) R Aqr I=20 0.2kpc 2800 Lo BI Cru I=40 1.8kpc 4300 Lo 3550 Lo There is some indication of lower luminosities being associated with high inclinations. Luminosity v. inclinationfrom the same simulation.: Luminosity v. inclination from the same simulation. Statistics: Note that the number of objects increases with inclination as sin(i); this is expected just from the statistics of randomly orientated objects, and is strengthened by observational selection of bipolars by their morphology. Objects that are (near) pole-on are not recognized as bipolars and are therefore selected against. We have: 0 - 30 3 objects 31- 60 11 objects 61- 90 14 objects This is the expected behavior and is of the right order but there are too few objects to make this harder. Statistics Conclusions: Conclusions PNe, SyNe are linked. PNe, SyNe are often indistinguishable Asymmetrical nebulae ( nearly always) have binaries. Orientation effects are important in interpreting & constraining observations.