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FIELD BLUE STRAGGLERS AND RELATED MASS TRANSFER ISSUES

FIELD BLUE STRAGGLERS AND RELATED MASS TRANSFER ISSUES. George Preston, ESO, Santiago, 2012. TO BEGIN: A LITTLE HOMAGE. We stand on the shoulders of giants who pioneered stellar structure and evolution in interacting binaries. mass transfer giants of the 20 th century. O. Struve.

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FIELD BLUE STRAGGLERS AND RELATED MASS TRANSFER ISSUES

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  1. FIELD BLUE STRAGGLERS AND RELATED MASS TRANSFER ISSUES George Preston, ESO, Santiago, 2012

  2. TO BEGIN: A LITTLE HOMAGE

  3. We stand on the shoulders of giants who pioneered stellar structure and evolution in interacting binaries

  4. mass transfer giants of the 20th century O. Struve Z. Kopal H. Bondi G. P. Kuiper A. Sandage W. H. McCrea F. Hoyle R. Kippenhahn L. Lucy B. Paczynski

  5. mass transfer giants of the 20th century mentor O. Struve Z. Kopal H. Bondi G. P. Kuiper mentor friend A. Sandage W. H. McCrea F. Hoyle R. Kippenhahn friend friend L. Lucy B. Paczynski

  6. mass transfer giants of the 20th century Detached Semi-detached Contact gas streams Beta Lyrae O. Struve Z. Kopal Roche lobe overflow Mass transfer Bondi-Hoyle accretion H. Bondi G. P. Kuiper The BS mass-transfer model He discovered Blue stragglers A. Sandage W. H. McCrea Hoyle-Bondi accretion Cases A B & C F. Hoyle R. Kippenhahn The most camera-shy giant known The Algol paradox & more L. Lucy B. Paczynski

  7. While reading papers on the subject of my talk, I was surprised to discover …

  8. how often first-class astronomers ignore each other’s work! Thus, Sandage (AJ 1953) first identified blue stragglers unambiguosly in M3 McCrea invented an explanation for Sandage’s blue stragglers 11 years later (MNRAS 1964) with no reference to Sandage. Böhm-Vitense (ApJ 1980) confirmed operation of McCrea’s process 16 years later in the ζ Capricorni system with no reference to either Sandage or McCrea. McClure (ApJ 1984) brilliantly generalized Böhm-Vitense’s result 4 years later with no reference to Sandage or McCrea or Böhm-Vitense.

  9. how often first-class astronomers ignore each other’s work! Thus, Sandage (AJ 1953) first identified blue stragglers unambiguosly in M3 McCrea invented an explanation for Sandage’s blue stragglers 11 years later (MNRAS 1964) with no reference to Sandage. Böhm-Vitense (ApJ 1980) confirmed operation of McCrea’s process 16 years later in the ζ Capricorni system with no reference to Sandage or McCrea. McClure (ApJ 1984) brilliantly generalized Böhm-Vitense’s result 4 years later with no reference to Sandage or McCrea or Böhm-Vitense. Three decades of ignoring! WTF!

  10. Finally, in 1989 Peter Leonard set the stage for this conference AJ 98, 217 CHRONOLOGICAL LIST OF HYPOTHESES

  11. HOW TO IDENTIFY FBS

  12. Of necessity, in the field we first identified metal-poor FBS by colorimetry.

  13. Of necessity, in the field we first identified metal-poor FBS by colorimetry. Any photometric system with a uv filter will work. Metal poor stars near GC turnoff BMPstars MS [Fe/H = 1 BHB RHB MS [Fe/H] = 0 W. W. Morgan would have called the BMP stars a “natural group”. Preston et al. 1994 HK Survey: Beers et al. 1985, 1992

  14. Of necessity, in the field we first identified metal-poor FBS by colorimetry. Any photometric system with a uv filter will work. FBSare a subset of BMP Metal poor stars near GC turnoff BMPstars MS [Fe/H = 1 BHB RHB MS [Fe/H] = 0 W. W. Morgan would have called the BMP stars a “natural group”. Preston et al. 1994

  15. In BMP domain isochrones with a wide range of ages and metallicities overlap in a tangled mess. Turnoffs for: [Fe/H] = 2.2 ages 3 7,10 Gy main sequence isochrones Isochrones of various [Fe/H] values and ages overlap in a 2-color diagram of the BS domain. subgiant isochrones Hence, “straggle” RYI Isochrones Green et al. (1987) Preston & Sneden 2000

  16. In BMP domain isochrones with a wide range of ages and metallicities overlap in a tangled mess. Location in this trapezoid doesn’t tell us much about age and composition main sequence isochrones Turnoffs for: [Fe/H] = 2.2 ages 3 7,10 Gy Isochrones of various [Fe/H] values and ages overlap in a 2-color diagram of the BS domain.  subgiant isochrones Hence, “straggle” RYI Isochrones Green et al. (1987) Preston & Sneden 2000

  17. MEMBERSHIP CRITERION Thecool (red) edgeof the BS domain in any stellar system is defined by stars that are not members of the domain STRANGE DEFINITION Mandushev, Fahlman, Richer 1997, AJ

  18. MEMBERSHIP CRITERION Thecool (red) edgeof the BS domain in any stellar system is defined by stars that are not members of the domain STRANGE DEFINITION what they did mass transfer sequence what I see Mandushev, Fahlman, Richer 1997, AJ

  19. MOST FBS COMPRISE A SUBSET OF A LARGER FAMILY OF MAIN SEQUENCE MASS-TRANSFER BINARIES STRANGE DEFINITION Use of MSTO color as a boundary obscures this reality Mandushev, Fahlman, Richer 1997, AJ

  20. MOST FBS COMPRISE A SUBSET OF A LARGER FAMILY OF MAIN SEQUENCE MASS-TRANSFER BINARIES Use of MSTO color as a boundary obscures this reality What happened here? Mandushev, Fahlman, Richer 1997, AJ

  21. MOST FBS COMPRISE A SUBSET OF A LARGER FAMILY OF MAIN SEQUENCE MASS-TRANSFER BINARIES We all do it! Struve - dodging

  22. CASE IN POINT Metal-poor CEMP binaries below MSTO in hierarchical triples Masseron et al. 2012, ApJ, 751:14 surely FBS 12 Gy isochrone CS 22964-161 CS 22949-008 pri. & sec. ~ 3 mag. mass transfer sequence = CEMP, literature

  23. MOST FBS COMPRISE A SUBSET OF A LARGER FAMILY OF MAIN SEQUENCE MASS-TRANSFER BINARIES CS 22949-008 secondary mass transfer sequence 3 mag Mandushev, Fahlman, Richer 1997, AJ

  24. Various tools have been devised to isolate field blue stragglers. Pier (1983) pioneered the identification of FBSs. Abundance calibration of Ca II K line Ca II K line versus color Manduca & Bell 1978 FBS FBS 0.2 D(0.2) BHB BHB any Balmer line what it accomplishes

  25. Clewley et al. borrowed this one from extragalactic astronomy. The Sersic function Y = Galaxies are merely Balmer lines turned upside down

  26. Clewley et al. borrowed this one from extragalactic astronomy. Sersic (b,c) Balmer parameters isolate FBS particularly well. Their use does not require knowledge of photometric colors. FBS BHB Clewley et al. 2002

  27. Clewley et al. borrowed this one from extragalactic astronomy. Sersic (b,c) Balmer parameters isolate FBS particularly well. Their use does not require knowledge of photometric colors. FBS BHB Clewley et al. 2002

  28. An application of Sersic parameters to Sloan data in the distant halo A nuisance for Xue et al.  (n = many) (n = 4985) “One man's trash is another man's treasure.” - old English aphorism Xue et al. 2011

  29. Globular clusters provide luminosity calibration for Galactic structure applications, e.g. halo (R) Z = 0.0001 Z = 0.004 Sarajedini 1993, ASP Conf. Ser.

  30. Globular clusters provide luminosity calibration for Galactic structure applications, e.g. halo (R) (MV)  0.5 mag/star (distance)  3 %/100 stars Z = 0.0001 Z = 0.004 68% within  1  Sarajedini 1993, ASP Conf. Ser.

  31. GROUP PROPERTIES OF FBS

  32. It is easy to find binaries among FBS candidates 10 years JD - 2400000 RV-constant stars Binary stars A child can do it

  33. Ahigh %of FBS are members of spectroscopic binaries 4 km/s vertical scales are not uniform 20 km/s Preston & Sneden 2000

  34. Ahigh %of FBS are members of spectroscopic binaries Very high (70% vs 15%) Preston & Sneden 2000, AJ

  35. But alow %of FBS are indouble-linedspectroscopic binaries Very low (essentially zero) ≤ The one DLSB, CS 22873-139, included here is contested by Spite et al. 2000, A&A, 360, 1077 Preston & Sneden 2000, AJ

  36. FBS & CEMP binaries have distinctive orbital characteristics Normal MS binaries disk = x halo = o BMP blue metal-poor C, s-process rich Preston & Sneden 2000, AJ

  37. FBS & CEMP binaries have a high % of small orbital eccentricities, deficits of short periods, and no P > 4000 d COROTATION circularization Vrot 50R/Porb Porb Vrot 25 2 10 5 5 10 1 50 Normal MS binaries disk = x halo = o BMP blue metal-poor no BMP, CEMP binaries with P > 4000 d deficit of short periods excess of low eccentricities C, s-process rich Preston & Sneden 2000, AJ

  38. and their small mass functions suggest companions with white dwarf masses (~ 0.6M). f1 = K13 P / (2 π G) = M23 (sin3 i) / (M1 + M2)2 FBS BaII FBS Ba, CH cousins Preston & Sneden 2000, AJ McClure & Woodsworth 1990, ApJ

  39. All of the preceding: High binary fraction Deficit of short (and very long) periods Low orbital eccentricities Small mass functions No visible secondaries * And Thank You, Erika, for  Capricorni tell us that FBS are a species sui generis *Hierarchical triples excepted

  40. white dwarf flux red wing of L in white dwarf

  41. All of the preceding: High binary fraction Deficit of short periods Low orbital eccentricities Small mass functions Few (no) visible secondaries And Thank You, Erika, for  Capricorni tell us that FBS are a species sui generis My perspective: Wide binary disruption is main reason for the specific frequency deficit in GCs relative to the Galactic field

  42. Specific frequency of FBS appears to be the upper bound of a sequence defined by OCs (DeMarchi et al 2006) and GCs (Piotto et al 2004) FBS This is a logarithm FBS 4.0 Something like “concentration” must be what matters This isn’t Preston & Sneden 2000, AJ

  43. These more frequent wide binaries are largely disrupted in GCs.Hence, the relatively low specific frequency of blue stragglers in globular clusters. This interpretation follows from the presumption that the Duquennoy-Mayor (1991, A&A) period distribution is universal. Ockham’s Razor, etc radial velocity binaries P<4000 d visual binaries c.p.m. binaries { William of Ockham 1248-1307 This 13% of radial velocity binaries with P  5 d merge in less than a Hubble time (Vilhu, 1982, A&A, 109, 17). Hence, the deficit of short period binaries in the field.

  44. DUSTING

  45. DUSTING Wind accretion

  46. DUST: The thin layer that you notice on tables just before your guests arrive How do you hide it?

  47. DUST: The thin layer that you notice on tables just before your guests arrive In the house use this

  48. DUST: The thin layer that you notice on tables just before your guests arrive In stars redistribute by thermohaline mixing.

  49. Reconciliation of theory and observation Observational facts & procedures: Census of orbital parameters for MS and post-MS C and Ba stars Detection criteria Detection threshholds  bias  incompleteness Observer persistence (w/r RV) Theory: Mass transfer by winds Including details like solving the Davies-Pringle (1980) puzzle. AGB theory and practice of Busso & Gallinoand Convective envelopes Gravitational settling and stabilizing molecular gradients Dilution with and without thermohaline mixing those all those other Italians

  50. How many MS CEMP survive the RGB ascent? INNOCENT QUESTION: Is the observed density ratio (RGB)/(MS) OK? IF (crude example) LRGB /LMS ~ 40 i. e., Volume ratio = VR ~ 250 and with n(RGB)/n(MS) ~ 102 OBTAIN (RGB)/(MS) ~ VR*n~ 2.5 Is this OK? CEMP(RGB) MS MV ~ 4 mag RGB those CEMP(MS) all (kpc-3) = space density n= nuclear time scale relative volumes searched (in apparent magnitude limited surveys)

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