O7V

Garrison94 lists 15 S Mon (= HD 47839) as the O7 or O7(V) anchor
standard, and MK73 lists 15 Mon as the O7 dagger standard.

Garrison, Gray, Walborn, and others have subsequently adopted it as
the primary O7V standard (although Walborn lists it as "O7V((f))").

MK43 standard:        HD 47839 = 15 (S) Mon - O7 (adopted from Plaskett 1922)
Lesh68 standard:      HD 47839 = 15 Mon - O7
Hiltner69 standard:   HD 47839 = 15 Mon - O7V
Walborn71 standard:   HD 47839 = 15 (S) Mon - O7V((f))
MK73 dagger standard: HD 47839 = 15 Mon - O7
Garrison77 standard:  HD 47839 = 15 Mon - O7V 
MK78 standard:        HD 47839 = 15 Mon - O7V
Keenan85 standard:    HD 47839 = 15 Mon - O7V
Walborn90 standard:   HD 47839 = 15 Mon - O7V 
GrayAtlas standard:   HD 47839 = 15 Mon - O7V
GrayNstars standard:  HD 47839 = 15 Mon - O7V

Garcia89 and Skiff08 list only one O7V standard: HD 47839 = 15 Mon
(MK78).

GrayCorbally09 do not advocate 15 Mon as an O7V anchor standard since
Walborn has found the star to be variable with a mean type near O7.5V. 

B-V(O7V)  = -0.32   ; SchmidtKaler82
B-V(O7V)  = -0.32   ; Morgan53,Johnson58,Johnson63,Johnson66,Fitzgerald70,Morgan71
B-V(O7V)  = -0.318  ; sec. stan. HD 91824 Q-method
B-V(O7V)  = -0.318  ; U-B=-1.13 from Q-method
B-V(O7V)  = -0.301  ; pri. stan. 15 S Mon Q-method
B-V(O7V)  = -0.27   ; Martins06
=> adopt (B-V)(O7V) = -0.318 [updated 2/7/2020]

U-B(O7V)  = -1.072  ; pri. stan. 15 S Mon
U-B(O7V)  = -1.12   ; Martins06
U-B(O7V)  = -1.131  ; sec. stan. HD 91824 
U-B(O7V)  = -1.14   ; Johnson58,Johnson63,Johnson66
U-B(O7V)  = -1.15   ; Schmidt-Kaler82
U-B(O7V)  = -1.16   ; Bessell98 (linearly interp. by EEM between O6V and O9V)
U-B(O7V)  = -1.17   ; Fitzgerald70
=> adopt (U-B)(O7V) = -1.13 [updated 2/7/2020]

(g-r)(O7V) = -0.62 ; Covey07 interp O5V -0.62 to O9V -0.62


Teff(O7V) =  33620 K ; Flower96 Teff for B-V = -0.30 
Teff(O7V) =  34256 K ; U-B=-1.12 => Teff(Bessell98)
Teff(O7V) = 35531 K ; Martins05(theo. scale)
Teff(O7V) =  36000 K ; HD 46485 (Martins11)
Teff(O7V) =  36000 K ; non-stan. HD 217086 (Repolust04)
Teff(O7V) = 36302 K ; EEM N=10 Teffs
Teff(O7V) = 36872 K ; Martins05(obs. scale),GrayCorbally09
Teff(O7V) = 37000 K ; Massey05(Milky Way)
Teff(O7V) = 37100 K ; EEM trend for O dwarfs 1/2020 **
Teff(O7V) = 37154 K ; Simon-Diaz17 median for O7V (N=5)
Teff(O7V) =  37500 K ; Bohm-Vitense81
Teff(O7V) = 37703 K ; Simon-Diaz14 linear fit for O7V
Teff(O7V) =  38000 K ; Schmidt-Kaler82
Teff(O7V) = 38000 K  ; prim. stan. 15 Mon (median Teff)
Teff(O7V) = 38040 K ; Holgado18 
Teff(O7V) =  38600 K ; Bessell98 (linearly interp. O6V and O9V)
Teff(O7V) = 39500 K  ; sec. stan. HD 91824 
Teff(O7V) =  40000 K ; Crowther97/Fig.3 
=> adopt Teff(O7V) = 37100 K (logT = 4.569) [updated 1/20/2020]

Mv(O7V) = -5.2  mag ; Schmidt-Kaler82
Mv(O7V) = -4.99 mag ; Garmany92 (O7V,IV)
Mv(O7V) = -4.94 mag ; HD 46573 (Mon OB2 member; Martins11)
Mv(O7V) = -4.94 mag ; Russeil03
Mv(O7V) = -4.90 mag ; Bowen08
Mv(O7V) = -4.87 mag ; Wegner07
Mv(O7V) = -4.82 mag ; EEM trend for O7V
Mv(O7V) = -4.8  mag ; GrayCorbally09
Mv(O7V) = -4.8  mag ; Conti71(V)
Mv(O7V) = -4.71 mag ; Martins06/theor.scale
Mv(O7V) = -4.70 mag ; Martins06/obs.scale
Mv(O7V) = -4.688 mag ; logL/Teff trend for O dwarfs (logL=5.140,BCv=-3.42)
Mv(O7V) = -4.63 mag ; Martins05
Mv(O7V) = -4.57 mag ; HD 46485 (NGC 2244 member; Martins11)
Mv(O7V) = -4.50 mag ; non-stan. HD 217086 (Repolust04)
Mv(O7V) = -4.2  mag ; Conti71(ZAMS)
=> adopt Mv(O7V) = -4.8 mag [updated 2/8/2020]

BCv(O7V) =  -3.661 mag ; Flower96(Teff=37100K,BCv(5772K)=-0.085)
BCv(O7V) = -3.557  mag ; Chen19 PARSEC Teff=37100K,solar,logg=3.83
BCv(O7V) =  -3.55  mag ; Schmidt-Kaler82(BCv=-3.68 + 0.13 offset)
BCv(O7V) = -3.47   mag ; Martins05(obs.scale)
BCv(O7V) = -3.426  mag ; Bessell98(ATLAS,logg=4.0,Teff=37100K, set so BCv(5772K)=-0.085)
BCv(O7V) = -3.417  mag ; LanzHubeny03(Teff=37100K,Z/Zsun=1)
BCv(O7V) = -3.40   mag ; Martins06(obs.scale)
BCv(O7V) = -3.36   mag ; Martins05(theo.scale)
BCv(O7V) =  -3.327 mag ; Balona94(Teff=37100K,BCv(5772K)=-0.085)
BCv(O7V) = -3.29   mag ; Martins06(theor.scale)
=> adopt BCv(O7V) = -3.41 [last updated 1/31/2020]

logL(O7V) = 5.180 dex ; Mv = -4.8, BCv=-3.41 => Mbol = -8.210
logL(O7V) = 5.175 dex ; LogL/Teff trend for O dwarfs for Teff=37000K
logL(O7V) = 5.14  dex ; Martins05(obs. scale)
logL(O7V) = 5.140 dex ; EEM trend for O7V
logL(O7V) = 5.10  dex ; Martins05(theo. scale)
logL(O7V) = 5.05  dex ; HD 46485 (Martins11)
logL(O7V) = 5.05  dex ; non-stan. HD 217086 (Repolust04)
=> adopt logL(O7V) =  5.180 dex [updated 2/8/2020]
=> adopt Mbol(O7V) = -8.210 mag [updated 2/8/2020]

Mass(O7V) =  32.0+-4.0 Msun ; V1036 Sco B (Weidner10)
Mass(O7V) = 28.9 Msun  ; MIST/Choi16 solar tracks for logT=4.569,logL=5.180
Mass(O7V) =  27.95 Msun ; Ekers15 ML calibration for logL=5.18 (extrapolation)
Mass(O7V) = 27.27+-0.55 Msun; Eclipsing binary V3903 Sgr A (Torres10)
Mass(O7V) =  27+6-5 Msun ; Weidner10
Mass(O7V) =  26.44 Msun ; Ekers18 ML calibration for logL=5.18 (extrapolation)
Mass(O7V) =  26.52 Msun ; Martins05/theo. Teff scale
Mass(O7V) =  25.29 Msun ; Martins05/obs. Teff scale 
Mass(O7V) =  22.7+-4.0 Msun ; CPD-59_2603A (Weidner10)
Mass(O7V) =  17.52+-9.33 Msun ; Hohle10
Mass(O7V) =  14.2 Msun  ; non-stan. HD 217086 (Repolust04; in error? is it really 24.2 Msun?)
=> adopt Mass(O7V) = 28 Msun [updated 4/16/2022]

logg(O7V) = 3.50 dex ; non-stan. HD 217086 (Repolust04)
logg(O7V) = 3.83 dex ; Holgado18
logg(O7V) = 3.917+-0.15 (stdev) ; Martins05
=> adopt logg(O7V) = 3.83 dex [updated 1/31/2020]

Rad(O7V) = 9.4168 Rsun ; Teff=37100K, logL=5.180
Rad(O7V) = 9.077  Rsun ; Martins05 (Teff=36873K,logL=5.137)
Rad(O7V) = 8.6    Rsun ; HD217086/Repolust04
=> adopt Rad(O7V)  = 9.417 Rsun [updated 2/8/2020]

# No Standard

JM53 does not list a O7V standard. 

# Primary Standard

HD 47839 = 15 S Mon = HR 2456 = NGC 2264 131
  O7: MK43,Lesh68,MK73(dagger)
  O7V: Buscombe69,Hiltner69(stan),Bisiacchi76,Garrison77(stan),MK78(stan),Keenan85,Garcia89,Garrison94,GrayAtlas
  O7V((f)): Walborn71(stan),Walborn72,Walborn73,Walborn90
  O8III((f)): Conti74
  O8IIIf: Conti71
  B1Ve: Levenhagen06^

  ^Perhaps the Levenhagen06 type is for the companion B?
 
  15 Mon is clearly the best O7V standard available. 2.9" binary with
  Hp=4.61 and Hp=7.94 components (CCDM). Mermilliod91 lists B-V =
  -0.254+-0.008 and U-B=-1.038+-0.005. Revised Q-method (1/2020),
  this dereddens to: (B-V)o = -0.301, (U-B)o = -1.072, E(B-V)=0.047,
  Av=0.153.  Teffs:
  25200K(Levenhagen06,Zorec16; companion?),
  30467K(U-Bo=>Bessell98),
  32130+-1409K(Koleva12),
  37000+-2000K(NebotGomez-Moran18),
  38000K(Hohle10),
  38019K(Simon-Diaz17),
  39500K(LeBorgne03),
  40175+-914K(Wu11) =>
  <Teff> = 38000K.  Not sure what to conclude for median Teff,
  probably in 32000-39500K range.  logg=3.47+-0.20(Koleva12),
  3.71(LeBorgne03), 3.93+-0.05(Wu11). logL=3.74(Simon-Diaz17).

# Secondary Standard

HD 91824 = Cl* NGC 3293 Feas 1
  O7V((f)): Walborn71,Walborn73(standard),Markova11(low-res)
 *O7V((f))z: Sota14
  O7V: Garrison77
  O7: Hoffleit56,Feast57,Feast58
  O6/7: Houk75
  O8V((f)): Markova11(higher-res)

  Long history with "O7" subtype, and Walborn has used it as a
  "O7V((f))" standard, however not in his 1990 catalog (Walborn90),
  which adopted 15 Mon as the primary O7V((f)) standard. Probably can
  be still considered a good secondary "O7V((f))" standard.  Teffs:
  37000K(Fitzpatrick07), 39500K(Hohle10), 40100K(Snow94) => median
  Teff=39500K. Missing in Mermilliod91, but here I list unweighted
  medians from 4 published values in Mermilliod87 compilation:
  V=8.1655, B-V=-0.0525, U-B=-0.942 => Q-method(1/2020) =>
  (B-V)o=-0.318, (U-B)o=-1.131, E(B-V)=0.266, Av=0.856.

# Other Stars

Morgan65 classified the NGC 2264 131 as "O7" (not standard)

Walborn72 classifies 3 stars as O7V or variant: HD 152623
(O7V(n)((f))), HD 47839 (O7V((f))), and HD 48099 (O7V).

Martins11 calls HD 48485 (in NGC 2244) a O7Vn with 36000K.
Martins11 calls theta^1 Ori C a O7V with Teff=38000+-2000K. 
Martins11 calls HD 46573 a O7V((f))z with Teff=36500K.