B2IV

MK43 standard:           gam Ori - B2IV
                         pi Sco  - B2IV
			 tet Oph - B2IV
			 lam Sco - B2IV 
JM53 standards:          gam Peg (=HR 39) - B2IV 
                         del Cet (=HR 779) - B2IV
Garrison67 standard:     gam Peg - B2IV
		         del Cet - B2IV
Cowley69 standard:       gam Peg - B2IV 
MK73 standards:          gam Peg (=HR 39) - B2IV
                         zet Cas (=HR 153) - B2IV
MK78 standard:           gam Peg - B2IV 
Houk88 standard:         gam Peg - B2IV [MK73] 
Walborn90 standard:      gam Peg - B2IV
WiegertGarrison98 stan.: mu^2 Sco - B2IV
		         ups Sco - B2IV
GrayNstars standard:     gam Peg - B2IV

(U-B)(B2IV) =   -0.860 ; exemplar mu2 Sco 
(U-B)(B2IV) =  -0.863 ; sec. stan. del Cet
(U-B)(B2IV) = -0.872 ; pri. stan. gam Peg
(U-B)(B2IV) =  -0.884 ; sec. stan. zet Cas
=> adopt (U-B)(B2IV) = -0.872 [updated 10/3/2021]

(B-V)(B2IV) =   -0.236 ; exemplar mu2 Sco
(B-V)(B2IV) =  -0.237 ; sec. stan. del Cet
(B-V)(B2IV) = -0.240 ; pri. stan. gam Peg
(B-V)(B2IV) =  -0.243 ; sec. stan. zet Cas
=> adopt (U-B)(B2IV) = -0.240 [updated 10/3/2021]

Mv(B2IV) = -3.0 ; GrayCorbally09

Teff(B2IV) =  21170 K ; sec. stan. zet Cas 
Teff(B2IV) = 21400 K ; pri. stan. gam Peg 
Teff(B2IV) =  21600 K ; sec. stan. del Cet
Teff(B2IV) =   21900 K ; exemplar mu2 Sco 
=> adopt Teff(B2IV) = 21400 (logTeff=4.330) [updated 10/3/2011]

for the three B2IV, nice trend of: Teff(B2IV) = 39204 + 2.04054e4*(U-B)o

# Primary standard

gam Peg
   *B2IV: JM53,Garrison67(stan),Lesh68,Cowley69(stan),MK73,MK78,Houk88,Walborn90,GrayNstars
    B2.5IV: MK43

    V = 2.834+-0.015 (Mermilliod91), B-V=-0.226+-0.012 (Mermilliod91),
    U-B=-0.862+-0.012 (Mermilliod91). logN_HI = 20.04+-0.09
    (Bohlin78), 20.26+-0.05 (Shull85). Let's adopt logN_HI = 20.208.
    Using Savage & Mathis 1979 N_HI/E(B-V) relation, this suggests
    E(B-V) = 0.034. Hence (B-V)o = -0.260, (U-B)o =
    -0.886. PecautMamajek13 Q-method dereddening: (B-V)o=-0.240,
    (U-B)o=-0.872, E(B-V)=0.014, Av=0.045.  Teffs since 2000:
    19184K(Prugniel07#3), 19422K(Prugniel07#2),
    20454+-819K(Prugniel11), 20700+-822K(Koleva12), 21150K(Hohle10),
    21380K(Simon-Diaz17,logT=4.33), 21397+-382K(Wu11),
    21414+-393K(Cardiel21), 21581K(Sanchez-Blazquez06,Cnarro07),
    21870+-1390K(Zorec09), 21944K(Prugniel07#1), 22000+-400K(Nieva12),
    22398K(Katz11), 22670K(Valdes04) => <Teff> ~ 21400K.

# Secondary standards

zet Cas = Fulu = HR 153 = HD 3360 = 17 Cas = HIP 2920 
  *B2IV: MK43,Underhill57,MK73,Lesh68,Jaschek78(Lesh68),Garcia89,Hoffleit91
   B2V: Ahmad52,JM53
   B3: Cannon

   Jaschek64 shows mostly B2V with a few B2IV and B2.5IV. The
   consensus and MK73 suggest B2IV - little doubt about temperature
   type (B2). Johnson66: V=3.66, B-V=-0.19, U-B=-0.89. Mermilliod91:
   V=3.661+-0.017, B-V=-0.196+-0.006, U-B=-0.849+-0.024 => Q-method
   PecuatMamajek13 deredden => (B-V)o=-0.243, (U-B)o=-0.884,
   E(B-V)=0.047, Av=0.153.  Gordon19 estimates E(B-V)=0.061 and lists
   literature estimate E(B-V)=0.05.  Teffs: 19059+-1362K(Cardiel21),
   19486K(Prugniel07#2), 19498K(Simon-Diaz17),
   20375+-730K(Prugniel11), 20703+-984K(Koleva12),
   20750+-200K(Nieva12,Ahmed17,Stassun19), 21050K(Glagolevskij19),
   21170K(Sanchez-Blazquez06,Cenarro07), 21500+-500K(Gordon19#1)
   21500+-800K(Gordon19#3), 21603K(Prugniel07#1), 21652+-505K(Wu11),
   21850+-1390K(Zorec09), 21996K(Katz11), 24500+-800K(Gordon19#2) =>
   <Teff> = 21170K.

del Cet = HR 779 = HD 16582 
  *B2IV: JM53,Garrison67(stan),Lesh68,Zorec09(BCD)
   B2V: 1955MmMtS..12....1W,Cuchiaro76
   B2/3V: Levenhagen06

   V=4.067+-0.007(Mermilliod91), B-V=-0.219+-0.008(Mermilliod91),
   U-B=-0.850+-0.014(Mermilliod91). Q-method(PecautMamajek13) =>
   (B-V)o=-0.237, (U-B)o=-0.863, E(B-V)=0.018, Av=0.059.  Teffs:
   21150K(Hohle10), 21250+-400K(Nieva12), 21500+-500K(Levenhagen06),
   21699+-490K(Cardiel21), 21878K(Simon-Diaz17,logT=4.34),
   23160+-1500K(Zorec09) => <Teff> ~ 21600K.
   
# Tertiary Standard

mu02 Sco = HD 151985 = HR 6252
   *B2IV: 1955MmMtS..12....1W,deVaucouleurs57,Bertiau58,Slettebak68,Hiltner69,Houk82(Garrison82),WiegertGarrison98(stan)
    B2V: 1976A&AS...26..241C(S2/68)
    B2III:: Cannon21
    B2: 1927MNRAS..86..364E
    B3IV/V:: 1930MmMtS...2....1R

    Remarkable consistency with B2 type over time, but
    WiegertGarrison98 appears to be only one that list it as a
    standard. Colors and light reddening seem to be nearly a twin of
    standard del Cet.  V = 3.565+-0.005(Mermilliod91),
    B-V=-0.214+-0.005(Mermilliod91), U-B=-0.844+-0.014(Mermilliod91).
    Using Q-method and calibration from PecautMamajek13, dereddens to
    (B-V)o = -0.236, (U-B)o=-0.860, E(B-V)=0.022, Av=0.072. Age 17 Myr
    Pecaut16.  Teffs: 19998+-1283K(Cardiel21), 20913K(EEM:Castelli91
    dered Hauck97 phot), 21083K(EEM:BalonaShobbrook84 Teff/beta
    relation, Hauck97 phot), 21878K(Sartori03,logT=4.34),
    21989K(EEM:Castelli91 dered Hauck97 phot,Napiwotski93 Teff calib),
    22063K(Nieva13), 22699+-1726K(Pecaut16) => <Teff> ~ 21900K.

# Standard

tet Oph
   B2IV: MK43

lam Sco
   B2IV: MK43 

# Other Stars

NGC 2362 46
    B2IV: JM53(non-standard)

HR 3659 = HD 79351 = V357 Car = a Car
    B2IV-V: Hiltner69
    B2IV: DeVaucouleurs57,Levato75
    B2.5V: Slettebak82

    Appears to be a grazing eclipsing binary, with maximum brightness
    V=3.41, and minimum brightness V=3.44. P = 6.7447 day, e=0.18, K1
    = 21.50 km/s, Vo = 23.30 km/s (systemic).  V = 3.431+-0.010
    (Mermilliod91), B-V=-0.196+-0.005 (Mermilliod91), U-B =
    -0.697+-0.009 (Mermilliod91).  logN_HI = 20.78+-0.05 (Shull85),
    20.78+-0.17 (Bohlin83).  Adopting logN_HI = 20.78, then using
    Savage & Mathis (1979) relation N_HI/E(B-V)=4.8e21, then E(B-V) =
    0.126. (B-V)o = -0.322, (U-B)o = -0.787. This seems off the
    normal star sequence.

del Cru = HR 4656 = HD 106490 
    B2IV: DeVaucouleur57,Hiltner69
    B2Vn: Thackeray66
    B2III: Morris61
    B2:V:: Bertiau58

    Good agreement on B2 type, but not so much on luminosity class.
    V=2.787+-0.009 (Mermilliod91), B-V=-0.236+-0.004 (Mermilliod91),
    U-B=-0.909+-0.014 (Mermilliod91). logN_HI = 20.15+-0.07
    (Diplas94), 20.04+-0.11 (Bohlin83).  Adopt logN_HI = 20.12. Using
    Mathis & Savage 1979 N_HI/E(B-V) relation, then this suggests
    E(B-V) = 0.027, (B-V)o = -0.263, (U-B)o = -0.929.

gam Lup = HR 5776 = HD 138690
   *B2IV: Hiltner69
    B2V: Slettebak68,Bertieu58(B2Vn)
    B3V: DeVaucouleur57,Evans59(B3Vn)

    V = 2.780+-0.013 (Mermilliod91), B-V=-0.213+-0.009 (Mermilliod91),
    U-B = -0.823+-0.010 (Mermilliod91). logN_HI = 20.23+-0.13
    (Bohlin83). Adopting Savage & Mathis (1979) N_HI/E(B-V) relation,
    this suggests E(B-V) = 0.035, (B-V)o = -0.248, (U-B)o = -0.848, Q
    = -0.670.