O9.5V

Garrison94 does not list a O9.5V anchor standard, but MK73 lists sig Ori 
as the O9.5V dagger standard. 

Unfortunately sig Ori is a tight (0".7) binary, so its not clear that it
should be considered the best available standard. 

I list HD 93027 and AE Aur as the best available "O9.5V" standards,
and zet Oph as the best "O9.5Vn" standard. 

MK43 standard:        sig Ori  - O9.5V
     		      zet Oph  - O9.5V
JM53 standard:        sig Ori  - O9.5V
     		      zet Oph  - O9.5V 
		      HD 34078 - O9.5V
Lesh68 standard:      sig Ori  - O9.5V 
Walborn71 standard:   AE Aur   - O9.5V 
MK73 dagger standard: sig Ori  - O9.5V
Houk75 standard:      sig Ori  - O9.5V (primary standard) 
Walborn90 standard:   HD 93027 - O9.5V 

Garcia89 lists 3 O9.5V MK standards: AE Aur, Sig Ori, Zet Oph
Skiff08 flags only one star as O9.5V standard: HD 37468 = Sig Ori (MK73)

All Q-method dereddenings in this file have been updated with the new
calibration (10/8/2011).

B-V(O9.5V)  = -0.308  ; EEM dereddened pri. stan. zet Oph (Q-method)
B-V(O9.5V)  = -0.307  ; U-B=-1.09 via trend/Q-method
B-V(O9.5V)  = -0.305  ; EEM dereddened sec. stan. HD 93207 (Q-method)
B-V(O9.5V)  = -0.305  ; EEM dereddened pri. stan. AE Aur (Q-method)
B-V(O9.5V)  = -0.30   ; Johnson63, Johnson66, Fitzgerald70, Morgan71
B-V(O9.5V)  = -0.295  ; EEM dereddened O9.5V mu Col (see below)
B-V(O9.5V)  = -0.26   ; Martins06
=> adopt (B-V)(O9.5V) = -0.307 [updated 2/7/2020]

U-B(O9.5V)  = -1.083  ; EEM dereddened sec. stan. HD 93027 (Q-method)*
U-B(O9.5V)  = -1.085  ; EEM dereddened pri. stan. AE Aur (Q-method)*
U-B(O9.5V)  =  -1.09   ; Martins06
U-B(O9.5V)  = -1.094  ; EEM dereddened pri. stan. zet Oph (Q-method)*
U-B(O9.5V)  =  -1.10   ; Johnson63, Johnson66, Fitzgerald70
U-B(O9.5V)  =  -1.11   ; Bessell98
=> adopt (U-B)(O9.5V) = -1.09 *** [updated 2/7/2020]

=> adopt   Q(O9.5V) = -0.862 (=(U-B)-0.72*(B-V) = -1.087 - 0.72*-0.312)
=> adopt (V-K)(O9.5V) = -0.977
=> adopt (V-J)(O9.5V) = -0.747
=> adopt (V-H)(O9.5V) = -0.908
=> adopt (H-K)(O9.5V) = -0.069
=> adopt (J-H)(O9.5V) = -0.161
=> adopt (V-I)(O9.5V) = -0.361

(g-r)(O9.5V) = -0.605 ; Covey07 interp O9V -0.62 to B0V -0.59

(Bp-Rp)(O9.5V) = -0.501 ; Evans18 trend for V-I=-0.361

Teff(O9.5V) =   30488 K ; Martins05(theo. scale)
Teff(O9.5V) = 30605 K ; weak standard Sig Ori (only Teff from Zorec09)*
Teff(O9.5V) =   30750 K ; Massey05(Milky Way)
Teff(O9.5V) =   30850 K ; Bessell98
Teff(O9.5V) =   31000 K ; Crowther97/Fig.3 
Teff(O9.5V) = 31206 K ; EEM N=22 Teffs*
Teff(O9.5V) = 31368 K ; sec. stan. HD 93027*
Teff(O9.5V) =   31382 K ; U-B=-1.085 => Teff(Bessell98)
Teff(O9.5V) =   31600 K ; Bohm-Vitense81
Teff(O9.5V) = 31700 K ; pri. stan. zet Oph median Teff
Teff(O9.5V) =   31884 K ; Martins05(obs. scale),GrayCorbally09
Teff(O9.5V) = 31900 K ; EEM trend for all O dwarfs 1/2020 **
Teff(O9.5V) =   32750 K ; halfway between O9V(34000K) and B0V(31500K). 
Teff(O9.5V) =   32830 K ; Theodossiou90 
Teff(O9.5V) = 32955 K ; Q=-0.862 => Nieva13 calibration
Teff(O9.5V) = 33922 K ; Simon-Diaz14 linear fit for O9.5V
Teff(O9.5V) = 33990 K ; Holgado18
Teff(O9.5V) = 34763 K ; pri. stan. AE Aur (median Teff)*
=> adopt Teff(O9.5V) = 31900 K (logT = 4.504) [updated 1/20/2020]

Mv(O9.5V) =  -4.28 mag ; Wegner07
Mv(O9.5V) =  -4.22 mag ; Garmany92 (O9.5V,IV)
Mv(O9.5V) = -4.2  mag ; Russeil03
Mv(O9.5V) = -4.2  mag ; Conti71(V)
Mv(O9.5V) = -4.19 mag ; HD 46202 (in NGC 2244; Martins11)
Mv(O9.5V) = -4.15 mag ; Bowen08
Mv(O9.5V) = -4.1  mag ; GrayCorbally09
Mv(O9.5V) = -4.04 mag ; EEM trend for O9.5V
Mv(O9.5V) = -3.98 mag ; Martins06/obs.scale
Mv(O9.5V) = -3.94 mag ; logL/Teff trend for OB dwarfs for Teff=32000K,BCv=-3.03
Mv(O9.5V) = -3.93 mag ; pri. stan. HD 93027 (see below)
Mv(O9.5V) = -3.9  mag ; halfway between O9V (-4.0) and B0V (-3.8)
Mv(O9.5V) = -3.90 mag ; Martins05
Mv(O9.5V) = -3.73 mag ; pri. stan. zet Oph (see below)
Mv(O9.5V) =  -3.6  mag ; Conti71(ZAMS)
=> adopt Mv(O9.5V)   = -4.05  mag [updated 2/8/2020]
=> adopt M_Ks(O9.5V) = -3.073 mag = -4.05 - -0.977 [updated 12/30/2020]

BCv(O9.5V) = -2.83  mag ; Martins06(theor.scale)
BCv(O9.5V) = -2.91  mag ; Martins05(theor.scale)
BCv(O9.5V) = -2.97  mag ; Martins06(obs.scale)
BCv(O9.5V) = -3.005 mag ; LanzHubeny03(Teff=31900K,Z/Zsun=1)
BCv(O9.5V) =  -3.022 mag ; Bessell98(ATLAS,logg=4.0,Teff=31900K, set so BCv(5772K)=-0.08)
BCv(O9.5V) =  -3.028 mag ; Balona94(Teff=31900K, set so BCv(5772K)=-0.08)
BCv(O9.5V) = -3.04  mag ; Martins05(obs. scale)
BCv(O9.5V) = -3.050 mag ; Nieva13(Teff=31900K)
BCv(O9.5V) =  -3.063 mag ; Code76(Teff=31900K, set so BCv(5772K)=-0.08)
BCv(O9.5V) = -3.162 mag ; Chen19 PARSEC Teff=31900K,solar,logg=3.88
BCv(O9.5V) =  -3.177 mag ; Flower96(Teff=31900K, set so BCv(5772K)=-0.08)
=> adopt BCv(O9.5V) = -3.01 [updated 1/31/2020, adjusted so that BCv(5772K)=-0.085]

logL(O9.5V) = 4.58  dex ; pri. stan. zet Oph (see below)
logL(O9.5V) = 4.62  dex ; Martins05(theo. scale)
logL(O9.5V) = 4.66  dex ; pri. stan. HD 93027 (see below)
logL(O9.5V) = 4.68  dex ; Martins05(obs. scale)
logL(O9.5V) = 4.685 dex ; logL/Teff trend for OB dwarfs (Teff=32000K)
logL(O9.5V) = 4.720 dex ; Mv=-4.05, BCv=-3.01 => Mbol = -7.060
logL(O9.5V) = 4.85  dex ; HD 46202 (Martins11)
logL(O9.5V) = 4.86  dex ; pri. stan. zet Oph (Marcolino09)
=> adopt logL(O9.5V) =  4.720 dex [updated 2/8/2020]
=> adopt Mbol(O9.5V) = -7.060 mag [updated 2/8/2020]

logg(O9.5V) = 3.915+-0.15 ; Martins05
logg(O9.5V) = 3.88 dex ; Holgado18
logg(O9.5V) = 3.6 +- 0.2 dex ; zet Oph (Marcolino09)
=> adopt logg(O9.5V) = 3.88 dex [updated 1/31/2020]

Mass(O9.5V) =  14.5+-4.0 Msun ; CPD-59_2603B (Weidner10)
Mass(O9.5V) =  15.55 Msun ; Martins05/obs. Teff scale 
Mass(O9.5V) =  16.0+-1.0 Msun ; FO15B (Weidner10)
Mass(O9.5V) =  16.27+-0.33 Msun ; Eclipsing binary V478 Cyg B (Torres10)
Mass(O9.5V) =  16.46 Msun  ; Martins05/theo. Teff scale 
Mass(O9.5V) =  16.62+-0.33 Msun ; Eclipsing binary V478 Cyg A (Torres10)
Mass(O9.5V) =  17.16 Msun  ; EEM Teff vs. Mass fit for binaries (Teff=32000K)
Mass(O9.5V) =  18+4-5 Msun ; Weidner10
Mass(O9.5V) =  18.53 Msun  ; EEM logL vs. Mass fit for binaries (logL=4.76)
Mass(O9.5V) = 18.7  Msun  ; MIST/Choi16 solar tracks for logT=4.504,logL=4.720
Mass(O9.5V) =  19.59 Msun  ; EEM Mv vs. Mass fit for binaries (Mv=-4.1)
Mass(O9.5V) =  19.61 Msun  ; Ekers15 ML calibration for logL=4.76
Mass(O9.5V) =  20.0  Msun  ; mean HRD position, Bertelli09 tracks
=> adopt Mass(O9.5V) = 18.7 Msun [updated 4/16/2022]

Rad(O9.5V) = 7.5002 Rsun ; Teff=31900K, logL=4.720
Rad(O9.5V) = 7.126  Rsun ; Martins05 (Teff=31886K,logL=4.675)
=> adopt Rad(O9.5V) = 7.500 Rsun [updated 2/8/2020]

# No standard

Hiltner69, Garrison77, MK78, & Keenan85 do not list a O9.5V standard

# Primary Standards

HD 149757 = zet Oph = HR 6175
 *O9.5V: MK43,JM53,Morgan55,Jaschek64(nearly all),Slettebak82,Garcia89,Garrison96(O9.5Vn),Houk99(Garrison96,O9.5Vn)
  O9.5Vnn: Lesh68
  O9V(e): Conti74
  O9.5IV: Negueruela04
  O9III: Herrero92
  O9V: Garmany82
  B0: Cannon
  B0.5Ve: Levenhagen06

  The only O9.5Vn class in Garrison96's table "The Brightest Stars" in
  the 1996 Observer's Handbook. Runaway O-star from Sco-Cen (indeed,
  the only O-type star associated with Sco-Cen), and as such the
  nearest O-type dwarf.  M91: V=2.567+-0.005, B-V=0.017+-0.007,
  U-B=-0.861+-0.006 => updated Q-method calibration (1/2020) =>
  (B-V)o=-0.308, (U-B)o=-1.094, E(B-V)=0.325, Av=1.048. Yet another
  Levenhagen06 spectral type at odds with nearly all others. Adopt
  "O9.5Vn" for Zet Oph. This is the nearest O-type dwarf and the one
  with the best individual trigonometric parallax (vanLeeuwen07: plx =
  8.91+-0.20 mas => D = 112+-3 pc). Mv = -3.73, logL = 4.58 dex.

  Teffs:
  26378K(Fremat05#1),
  27000+-650K(Levenhagen06),
  28797+-729K(Fremat#2),
  29242K(Chauville01),
  30400+-3640K(Zorec16),
  31000K(Kobulnicky17,19),
  31500K(Cazorla17),
  31900K(Bondar12),
  32000K(Repolust04),
  32000+-2000K(Marcolino09),
  32059K(U-Bo=>Bessell98),
  32750+-1000K(Fitzpatrick07),
  33262+-836K(Wu11),
  33500+-1300K(Gordon18)
  => <Teff> = 31700K (but with large scatter!).
  log(g) = 3.85(Reolust04),
  4.00+-0.10(Levenhagen06), 4.00(Chauville01),
  4.00+-0.31(Fitzpatrick07).

HD 34078 = AE Aur = HR 1712
 *O9.5V: JM53,Jaschek64(all),Lesh68,Conti71,Walborn71(stan),Walborn72,Walborn73,Jaschek78(Morgan55),Garcia89
  O9.5III:Abt85
  B0p: Cannon

  M91: V=5.956+-0.015, B-V=0.225+-0.005, U-B=-0.704+-0.015 => updated
  Q-method calibration (1/2020) => (B-V)o=-0.305, (U-B)o=-1.085,
  E(B-V)=0.530, Av=1.716. There is no hint from the literature that AE
  Aur is binary - indeed it is a famous runaway star, and has a very
  well-defined RV for an O-type star (+56.7+-0.7 km/s; Kharchenko07).
  I adopt "O9.5V" based on JM53 and Walborn papers.
  Teffs:
  31057+-1696K(Koleva12),
  31382K(U-Bo=>Bessell98),
  32750+-1000K(Fitzpatrick07),
  33884K(Simon-Diaz17),
  34745K(Prugniel#3),
  34781K(Prugniel07#2),
  34900K(Snow94),
  36000K(Prugniel07#1),
  36210K(Prugniel07#4),
  35994K(Prugniel07#5)
  => median Teff = 34763K.
  log(g) = 3.54(Koleva12), 4.02(Prugniel07).

# Secondary Standard

HD 93027 = TYC 8957-482-1 (J1043-6008)
 *O9.5V: Jaschek78(Walborn72),Walborn73,Walborn90(stan)
  O9.5IV: Levato81
  O9V: Massey01
  B3: Cannon,Houk75

  M91: V=8.720+-0.000, B-V=-0.015+-0.019, U-B=-0.875+-0.019 => revised
  Q-method calibration (1/2020) => (B-V)o=-0.305, (U-B)o=-1.083,
  E(B-V)=0.290, Av=0.935. Adopt "O9.5V" from Walborn90. Not in HIP,
  but in Tycho. In Carina region, in Collinder 228 (D = 2201 pc,
  Dias+2001 catalog). For this distance, Mv ~ -3.93, logL ~
  4.66. Teffs: 31236K(U-Bo=>Bessell98), 31500K(Povich11) => median
  Teff= 31368K. I've only considered this a secondary standard since
  it did not have use as a O9.5V standard before Walborn's papers.

# Deprecated Standard 

HD 37468 = sig Ori = HR 1931
  O9.5V: Houk,MK43,Sharpless52,JM53,Jaschek64(all),Lesh68,MK73,Bisiachhi82,Garcia89,Houk99(Garrison),Zorec09
  O9.5V SB: Morgan55
  O9V+B0.5V: Edwards76
  B0: Cannon

  M91: V=3.795+-0.021, B-V=-0.241+-0.008, U-B=-1.022+-0.013 => updated
  Q-method calibration (10/8/2011) => (B-V)o=-0.299, (U-B)o=-1.064,
  E(B-V)=0.058, Av=0.187. Spectroscopic binary. 0".7 away. Adopt
  "O9.5V" from MK43, JM53, and MK73. I can't find a Walborn
  classification. Unfortunately the companion is bright enough to make
  an effect (Edwards76 called it O9V+B0.5V!). logN_NI = 20.52+-0.09
  (Bohlin85), 20.56+-0.07 (Schull85), adopt logNH = 20.54. Then
  adopting Savage & Mathis (1979) logNH/E(B-V) = 4.8e21
  atoms/cm^2/mag, then E(B-V) = 0.072.  Then (B-V)o = (B-V) - E(B-V) =
  -0.241 - 0.072 = -0.313, and (U-B)o = (U-B) - 0.72*E(B-V) = -1.022 -
  0.72*0.060 = -1.074. Teffs: 29939K(U-Bo=>Bessell98), 31270+-2130K(Zorec09) =>
  median Teff = 30605K. 

# Other Stars

Lesh68 classified four stars as O9.5V or variant: HD 34078, 37041,
37468, 149757.

Walborn72 classified two stars as O9.5V: HD 34078 & HD 93027.

Mu Col = HD 38666 
  O9.5V: Bidelman48, Morgan55, Buscombe69, Walborn73
  O9.5IV: Hiltner69
  O9V: Conti71, Conti74, Bisiacchi82
  O8.5V: Bisiacchi76
  B1IV/V: Houk

  This star is of some significance as it has the bluest B-V in
  Johnson 1966's compilation of UBV photometry, so it may be
  instructive for estimating the intrinsic B-V colors of late O
  stars. B-V = -0.281+-0.006 (Mermilliod91), B-V=-0.28 (Johnson66),
  B-V = -0.274+-0.013 (HIP), U-B=-1.077+-0.064 (Mermilliod91), V =
  5.169+-0.004 (Mermilliod91), V=5.18 (HIP), V-I = -0.30+-0.03
  (HIP). Johnson66 does not list a U-B magnitude.  There are three
  spectroscopic estimates of the hydrogen column density towards mu
  Col from Lyman alpha absorption: logN_HI[cm^-2] = 19.90+-0.10
  (York76), 20.04+-0.07 (Shull85), 19.85+-0.09 (Bohlin75). If we take
  the median value (N_HI = 19.9 cm^-2), and the conversion from
  N_(HI+H2)/E(B-V) from Savage & Mathis 1979 (5.8e21 atoms/cm^2; and
  assuming negligble H2), I estimate E(B-V) = 0.0137 mag. This would
  suggest that mu Col's intrinsic color is (B-V)o = (B-V)obs - E(B-V)
  = -0.281 - 0.0137 = -0.295.  Combining Mermilliod91 averaged colors
  with the updated Q-method calibration (10/8/2011), I estimate (B-V)o
  = -0.310, (U-B)o = -1.102, E(B-V)=0.036, Av=0.116.