B7V

Garrison94 does not list a B7V anchor standard, and MK73 does not
list a B7V dagger standard.

HD 21071 appears to be the best standard available, however its colors
are slightly bluer, and it appears to be a bit hotter, than most B7V
stars in the Hipparcos catalog. This may be traced to the fact that
MK43 did not list a B7V standard, the only B7V standard in Johnson &
Morgan (1953) [alf Leo] was later considered B8V in most work, MK73
then did not list a B7V dagger standard, and the current MK78/Gray
standard (HD 21071) has only been in use since the late 1970s. Houk
did not list a B7V standard in the Michigan Spectral Survey, and that
survey provided many of the types for the Hipparcos catalog.  So the
definition of B7V - initially undefined, then poorly defined (arguably
twice) - has migrated a bit over the years. The mean values I list are
leaned towards the majority of B7Vs in the Hipparcos catalog (and the
secondary standard 49 Eri), and not so much the hotter/bluer primary
standard HD 21071.

JM53 standard:        alf Leo - B7V
Lesh68 standard:      49 Eri  - B7V
Cowley72 standard:    alf Leo - B7V
MK78 standard:        HD 21071 (= HR 1029 = HL 675) - B7V
Keenan85 standard:    HD 21071 (= "BS 1029" = HR 1029) - B7V
WiegertGarrison98 st: alf Leo - B7V
GrayNstars standards: HD 21071 (= HR 1029) - B7V
	   	      alf Leo - B7V

All dereddenings done via Q-method in this file have been updated with
the revised calibration (10/17/2011).

B-V(B7V)  = -0.144 ; prim. stan. HD 21071 (EEM dereddened via Q-method)
B-V(B7V)  =  -0.14  ; Bessell79
B-V(B7V)  =  -0.13  ; JohnsonMorgan53, Fitzgerald70, SchmidtKaler82
B-V(B7V)  = -0.128 ; sec. stan. 49 Eri (EEM dereddened via Q-method)
B-V(B7V)  = -0.127 ; EEM dereddened N=36 HIP B7V stars (Q-method,E(B-V)<0.1)
B-V(B7V)  =  -0.12  ; Morgan53, Johnson63, Johnson66
B-V(B7V)  = -0.112 ; deprecated standard alf Leo
B-V(B7V)  =  -0.11  ; KenyonHartmann95 
=> adopt (B-V)(B7V)  = -0.128 [updated 4/8/2022]

U-B(B8V)  =  -0.364 ; adopted for B8V 
U-B(B7V)  =  -0.365 ; deprecated standard alf Leo
U-B(B7V)  =  -0.41  ; Bessell98
U-B(B7V)  =  -0.42  ; Johnson63, Johnson66
U-B(B7V)  =  -0.43  ; Fitzgerald70, Schmidt-Kaler82 
U-B(B7V)  = -0.455 ; sec. stan. 49 Eri (EEM dereddened via Q-method)
U-B(B7V)  = -0.459 ; EEM dereddened N=36 HIP B7V stars (Q-method,E(B-V)<0.1)
U-B(B6V)  =  -0.504 ; adopted for B6V 
U-B(B7V)  = -0.530 ; pri. stan. HD 21071 (EEM dereddened via Q-method)
=> adopt (U-B)(B7V)  = -0.459 ***
=> adopt     Q(B7V)  = -0.367 (=(U-B)-0.72*(B-V) = -0.459 - 0.72*-0.128)
=> adopt (V-I)(B7V)  = -0.132
=> adopt (V-R)(B7V)  = -0.058
=> adopt (R-I)(B7V)  = -0.075

(V-Ks)(B7V) =  -0.123 ; HIP_24327_ B7V d= 142.653pc, (B-V)=0.004 (dereddened from Kervella19)
(V-Ks)(B7V) =  -0.190 ; HIP_71353_ B7V d= 107.945pc, (B-V)=0.010 (dereddened from Kervella19)
(V-Ks)(B7V) =  -0.239 ; HIP_17734_ B7V d= 157.878pc, (B-V)=0.002 (dereddened from Kervella19)
(V-Ks)(B7V) =  -0.269 ; HIP_109789_ B7V d= 162.127pc, (B-V)=0.005 (dereddened from Kervella19)
(V-Ks)(B7V) =  -0.274 ; HIP_46333_ B7V d= 175.162pc, (B-V)=0.018 (dereddened from Kervella19)
(V-Ks)(B7V) =  -0.277 ; HIP_73341_ B7V d= 157.555pc, (B-V)=0.020 (dereddened from Kervella19)
(V-Ks)(B7V) = -0.284 ; sec. stan. 49 Eri = HD 29335 = HIP 21515 
(V-Ks)(B7V) =  -0.284 ; HIP_36917_ B7V d= 73.3245pc, (B-V)=0.001 (dereddened from Kervella19)
(V-Ks)(B7V) =  -0.308 ; HIP_60379_ B7Vn d= 103.864pc, (B-V)=0.012 (dereddened from Kervella19)
(V-Ks)(B7V) = -0.325 ; intrinsic color sequence for (U-B)o=-0.459
(V-Ks)(B7V) =  -0.327 ; HIP_13327_ B7V d= 140.964pc, (B-V)=0.021 (dereddened from Kervella19)
(V-Ks)(B7V) =  -0.375 ; HIP_76669_ B7V d= 154.847pc, (B-V)=0.019 (dereddened from Kervella19)
(V-Ks)(B7V) =  -0.423 ; HIP_19968_ B7V d= 149.656pc, (B-V)=0.016 (dereddened from Kervella19)
(V-Ks)(B7V) = -0.424 ; pri. stan. HD 21071 = HR 1029 (see below, a bit hotter than most B7Vs)
(V-Ks)(B7V) =  -0.647 ; HIP_74950_ B7V d= 149.276pc, (B-V)=0.012 (dereddened from Kervella19)
=> adopt (V-Ks)(B7V) = -0.325 [updated 4/8/2022]
=> adopt (V-J)(B7V)  = -0.244 [updated 4/8/2022]
=> adopt (V-H)(B7V)  = -0.321 [updated 4/8/2022]
=> adopt (H-Ks)(B7V) = -0.004 [updated 4/8/2022]
=> adopt (J-H)(B7V)  = -0.077 [updated 4/8/2022]

(Ks-W1)(B7V) = 0.031 ; EEM trend for d<30pc for B-V=-0.128
=> adopt (Ks-W1)(B7V) = 0.031 [updated 12/29/2019]

(Bp-Rp)(B7V) = -0.187 ; Evans18 trend for V-I=-0.132

V-I(B7V)  = -0.120 ; Bessell78

R-I(B7V)  = -0.070 ; Bessell79

(g-r)(B7V) = -0.36 ; Covey07 interp B5/7V -0.39, B8V -0.33

(G-V)(B7V) =  0.012 ; fit for B dwarfs from Kervella19 corrected for E(B-V), eval for (V-Ks)=-0.325
=> adopt (G-V)(B7V) = 0.012 [updated 4/8/2022]

Teff(B7V) =   11940 K ; Bertone04[ATLAS]
Teff(B7V) =  12357 K ; deprecated standard alf Leo
Teff(B7V) =   12600 K ; GrayCorbally94
Teff(B7V) =   12735 K ; Bessell98
Teff(B7V) =   12764 K ; Flower96 Teff for B-V=-0.13
Teff(B7V) =   12912 K ; Zorec12 median
Teff(B7V) =   12915 K ; Theodossiou90
Teff(B7V) =   13000 K ; Crowther97/Fig.3 
Teff(B7V) =   13000 K ; Bessell79
Teff(B7V) =   13000 K ; GrayCorbally09
Teff(B7V) =   13000 K ; Bohm-Vitense81
Teff(B7V) =   13000 K ; Schmidt-Kaler82
Teff(B7V) =   13132 K ; B-V=-0.128 => Teff(Napiwotski93)
Teff(B7V) = 13224 K ; U-B=-0.459 => Teff(Bessell98,logg=4.2)
Teff(B7V) = 13490 K ; Simon-Diaz17 for B7V (N=2)
Teff(B7V) = 13831 K ; B-V=-0.128 => Teff(Bessell98,logg=4.2)
Teff(B7V) =  13850 K ; Chavez95 (+-150K)
Teff(B7V) = 13931 K ; sec. stan. 49 Eri (median Teff)
Teff(B7V) = 14024 K ; EEM median of 82 published Teffs for B7V stars
Teff(B7V) = 14911 K ; prim. stan. HD 21071 (median Teff)
=> adopt Teff(B7V) = 14000K (logT = 4.146) [last updated 9/16/2019]

[EEM 12/1/2012: there seems little reason to quote a median Teff to
better precision as there is disagreement at the +-1000K level among
the only three B7V standards that I've found in the literature. 14000K
is close to the median Teff for 82 stars with literature Teffs and B7V
classifications, so I will go with that value.]

Mv(B7V) =  0.19 mag ; Upper Sco MS Mv for B-V=-0.128
Mv(B7V) = -0.11 mag ; ONC MS Mv for B-V=-0.128
Mv(B7V) = -0.30 mag ; median Mv for B7V calc using Kervella19 HIP & Gaia DR2
Mv(B7V) = -0.39 mag ; pri. stan. HD 21071 (see below) 
Mv(B7V) =  -0.4 mag ; GrayCorbally09
Mv(B7V) = -0.4  mag ; HD 87901 (Jaschek98)
Mv(B7V) = -0.57 mag ; weak stan. alf Leo (see below)
Mv(B7V) =  -0.6 mag ; Schmidt-Kaler82
Mv(B7V) =  -0.67 mag ; Wegner07
Mv(B7V) = -1.78 mag ; sec. stan. 49 Eri (see below)
=> adopt Mv(B7V)   = -0.40  mag [updated 9/26/2019]
=> adopt M_Ks(B7V) = -0.075 mag = Mv - (V-Ks) = -0.40 - -0.325 [updated 12/30/2020]

BCv(B7V) = -1.158 mag ; Flower96(Teff=14000K, set so BCv(5772K)=-0.085)
BCv(B7V) = -1.150 mag ; Code76(Teff=14000K, set so BCv(5772K)=-0.085)
BCv(B7V) = -1.048 mag ; Bessell98(ATLAS9,logg=4.0,Teff=14000K, set so BCv(5772K)=-0.085
BCv(B7V) = -1.019 mag ; Balona94(Teff=14000K, set so BCv(5772K)=-0.085)
BCv(B7V) = -0.999 mag ; Bertone04(ATLAS,T=14000K, set so BCv(5772K)=-0.085)
BCv(B7V) =  -0.89  mag ; Schmidt-Kaler82(BCv=-1.02 + 0.13) 
BCv(B7V) =  -0.64  mag ; Bertone04[ATLAS,T=11940K,from their study]
=> adopt BCv(B7V) = -1.05 [updated 9/16/2019, set so BCv(5772K)=-0.085]

logL(B7V) = 2.432 dex ; logL/Teff trend for OB dwarf EBs (Torres10; Teff=14000K)
logL(B7V) = 2.476 dex ; Mv=-0.4, BCv=-1.05 => Mbol = -1.450
logL(B7V) = 2.53  dex ; Zorec12 median 
=> adopt logL(B7V) =  2.476 dex [updated 9/26/2019]
=> adopt Mbol(B7V) = -1.450 mag [updated 9/26/2019]

Mass(B7V) = 4.106+-0.044 Msun ; Eclipsing binary GG Lup A (Torres10)
Mass(B7V) = 3.99 Msun ; Ekers18 ML calibration for logL=2.476
Mass(B7V) = 3.93 Msun ; EEM Teff vs. Mass fit for binaries (Teff=14000K)
Mass(B7V) = 3.92 Msun ; Zorec12 median
Mass(B7V) = 3.92 Msun ; EEM logL vs. Mass fit for binaries (logL=2.476)
Mass(B7V) = 3.84 Msun ; EEM Mv vs. Mass fit for binaries (Mv=-0.4)
Mass(B7V) =  3.38 Msun ; Harmanec88
=> adopt Mass(B7V) = 3.92 Msun [updated 1/2/2020]

Rad(B7V) = 2.940 Rsun ; Teff=14000K, logL=2.476
=> adopt Rad(B7V) = 2.940 Rsun [updated 9/26/2019]

# No Standard

MK43, Garrison67, Cowley69, Hiltner69, MK73, Houk75, Garrison77,
Garrison79, and GrayAtlas do not list a B7V standard. GarrisonGray94 only
cover B8-B9, so no B7 standard is listed. 

# Primary Standards

HD 21071 = HR 1029 = Cl Melotte 20 675 = HIP 15988 (alpha Per cluster)
  B7V: Heckman58(B7),Morgan71,MK78,Jaschek78,Abt78(B7Vsn),Keenan85,Garcia89,GarrisonGray94
  B5: Petrie69,Cannon
  B5IV: Lesh68
  B6V: Roman50,Jaschek64

  Appears to be a decent standard; consistently B7V after Morgan71.
  V=6.060(Hauck97), V=6.09(HIP), V=6.08(Tycho), M91: V=6.070+-0.014,
  B-V=-0.076+-0.005, U-B=-0.483+-0.012 => updated Q-method
  (10/17/2011) => (B-V)o=-0.144, (U-B)o=-0.530, E(B-V)= 0.068,
  Av=0.221.  Dereddening the Hauck97 ubvy data using Castelli91
  dereddening, I find: E(b-y) = 0.083. alpha Per cluster d=177 pc =>
  plx = 5.65 assumed => Mv = -0.39.  2MASS: J=6.198+-0.021(2MASS),
  H=6.274+-0.016(2MASS), Ks=6.309+-0.016(2MASS). (V-Ks)o = (6.07 -
  3.1*0.068) - (6.309 - 0.382*0.068) = -0.424.  Teffs:
  14211K(U-Bo=>Bessell98), 14759K(Hauck97=>Napiwotski93 cal.),
  15062K(Hauck97=>BalonaShobbrook84 cal.), 15118K(Hauck97=>Balona94
  cal.) => median Teff = 14911K.  It appears that HD 21071 is slightly
  hotter than most B7V stars.  It could be due to the fact that Houk
  started the MSS survey before this star was considered a MK
  standard.

# Secondary Standard

49 Eri = HD 29335 = HR 1469 = HIP 21515
  B7V: Slettebak55,Jaschek64,Kennedy83(Lesh68(stan))
  B5: Cannon
  B8IV: Houk99 

  Houk99 says vsini=120 km/s.  Slettebak and Lesh both agree B7V. M91:
  V=5.307, B-V=-0.128, U-B=-0.455 => updated Q-method (10/17/2011) =>
  negligible reddening E(B-V) = -0.003, i.e. can considered UBV colors
  unreddened.  Lesh68 B7V standard. Dereddening Hauck97 ubvy
  photometry using Castelli91, I find: E(b-y) = 0.055.  2MASS:
  J=5.518+-0.023(2MASS), H=5.573+-0.027(2MASS),
  Ks=5.591+-0.017(2MASS).  V-Ks = 5.307 - 5.591 = -0.284. vanLeeuwen07
  plx = 3.83+-0.35 mas => D = 261+-24 pc => Mv = -1.78 +- 0.20
  mag. Pretty far distance to be negligibly reddened, but this appears
  to be directed in the general direction of the bet CMa "tunnel" of
  low extinction.  Teffs: 13711+-150K(Huang10), 13816K(Hauck97
  phot.=>Napiwotzki93 calib.), 14046K(Hauck97 phot.=>Balona94 calib.),
  14065K(Hauck97 phot.=>BalonaShobbrook84 beta calib.)  => median Teff
  = 13931K.  logg=4.268+-0.020(Huang10). vsini=62+-13km/s.

# Deprecated standard

HD 87901 = Alf Leo = Regulus = 32 Leo = HR 3982 = GJ 9316A
  B7V: JM53,Osawa59,Jaschek64(major. are B7V),Cowley72(stan),Jaschek78(Murphy69),Garcia89,Garrison96(B7Vn)
  B8IVn: Gray03 
  B8III: Williams36
  B8V: MK43,GarrisonGray94(B8Vnn),Palmer68(B8Vn),Cannon(B8)

  Oscillates between B7V and B8V in the literature (both Garrison &
  Gray have called it both B7V and B8V.  Cannon then MK43 called it
  B8V, then JM53 called it B7V and it was B7V in most literature until
  Garrison and Gray considered it a B8V again.  Probably not a great
  choice of standard given the changes in published type for this
  star. Definitely cooler than the other B7V standards, so B8V might
  be more appropriate anyway. vanLeeuwen07 plx = 41.13+-0.35 mas, Mv =
  -0.57 mag (so probably negligibly reddened!). The only B7V star in
  the Hipparcos catalog within 100 pc. B-V = -0.087+-0.015 mag =>
  somewhat redder than the other B7V standards. Mermilliod91:
  V=1.357+-0.013, B-V=-0.112+-0.005, U-B=-0.365+-0.011 (revised
  Q-method suggests E(B-V)=0.00). Hauck97 photometry dereddened
  following Castelli91 => (b-y)0=-0.111, c0=0.698, E(b-y)=0.074,
  Av=0.326. Teffs: 11535K(Zorec09), 11949K(Hauck97
  phot.=>BalonaShobbrook84 beta calib.), 11962K(Gray03),
  12254K(Hauck97 phot.=>Balona94 calibration), 12357K(Hauck97
  phot.=>Napiwotzki93 calibration), 12360K(Gerbaldi01),
  12540K(LeBorgne03), 12862+-200K(Wu11), 14231+-314K(vanBelle09) =>
  median Teff = 12357K.  logg=3.56(Gray03),
  4.05+-0.09(Wu11). [M/H]=0.00(Gray03), [Fe/H]=0.21+-0.09(Wu11).

# Other Stars

alf Gru
  B7Vn: Garrison96
  Ranges from B5-B7 in the other literature

pi Cet = HD 17081
  B7V: Slettebak55, Lesh68, Cucchiaro77, 
  B7IV: GarrisonGray94
  B6IV: Zorec09
  B6III: deVacoulears57

  3 B7V classifications in Skiff compendium (2012), but some other B6
  and B7 classifications of differing luminosity class as well.

HD 18537 = HR 890
  B7V: Roman50, Slettebak63, Abt83
  B7: Petrie69
  B7III: Lesh68
  B7IV: Slettebak55
  B6IV/V: Berger62, 
  B5V: Berger58
  B8V: Wilson50
  B5/7III: Maury1897

  3 B7V classifications and 3 other B7s, but a mixed bag, and no
  recent classifications. Member of alpha Persei cluster. Proper
  motion is roughtly consistent with alpha Per membership.

Stars in Skiff compendium (2012) with at least 3 classifications as B7V or variant:

HD 23363 
1972AJ.....77..750C 
1977A&AS...30...71C 
1994AJ....107.1556G 

HD 32273
1969AJ.....74.1082M
1994AJ....107.1556G
1995ApJS...99..135A

HD 36760
1971ApJ...169..529S 
1976AJ.....81..537G 
1977PASP...89..797A 

HD 36898
1976AJ.....81..537G 
1977PASP...89..797A 
2004ApJS..155..175A 

72 Ori = HD 43153
 5 references all listing B7V, but I'm having a problem with SIMBAD's
 bibcodes as referenced by Skiff's catalog. I will come back to this
 and list the actual references later. Teffs:
 13263K(Heacox79,LeBorgne03).  logg=4.30(Heacox79,LeBorgne03),
 [Fe/H]=-0.50(Heacox79,LeBorgne03).

HD 56306
1969AJ.....74.1082M  
1974AJ.....79.1022C  
1999A&AS..137..451G  

HD 62893
1966PASP...78..301F 
1969ApJ...157..313H 
1975PASP...87..823L 

HD 73837
1965MNRAS.129..411B 
1975MSS...C01....0H 
1984ApL....24...37L 

HD 139891
1963ApJ...138..118S  
1959ApJ...130..159O  
1972AJ.....77..750C  

HD 142250
1958ApJ...128..533B  
1961MNRAS.122..325M  
1968ApJ...151.1043S  

HD 147932
1979PASP...91..176A  
1983ApJ...272..182A  
1986ApJ...304..688A  

9 Vul
1954ApJ...119..146S 
1959ApJ...130..159O 
1972ApJ...175..453M 

HD 202862
1970MmRAS..72..233H  
1972AJ.....77..750C  
1999A&AS..137..451G  

HD 204770
1950ApJ...111..221W 
1968ApJS...17..371L 
1977A&AS...30...71C 

HD 208095
1963ApJ...138..118S  
1969AJ.....74.1082M  
1983ApJ...272..182A  

HD 210129
1955ApJS....2..195R 
1972AJ.....77..750C 
1980A&AS...40..207C