KK9V

JM53, Houk75, KeenanMcNeil76, Keenan85, Keenan85, Kirkpatrick91,
Henry02 do not list any K9V standards.  Skiff08 does not flag any
stars as K9V MK standards.

Pecaut13 standard:     HIP 3261 [K9V following Gray06]

Keenan84 does not list K9 as a full subtype like K5 and M0, and "other
possible subdivisions are utilized only for interpolation whenever we
think that we can classify accurately enough to justify their
use. Thus when we call a star G3 we mean only that it is closer to G2
than to G5."

Gray01/03/06 classify 13 stars are K9V, and 11 have useful BVI colors
in HIP. The brightest are HIP 8768 (V=8.89) and HIP 63833
(V=9.05). Median HIP colors:

<B-V>(K9V) = 1.418 (+-0.016 sem, +-0.040 stdev; N=11)
<V-I>(K9V) = 1.735 (+-0.039 sem, +-0.103 stdev; N=11)
<B-I>(K9V) = 3.156 (+-0.057 sem, +-0.144 stdev; N=11)
The K9V star with median B-I color is HIP 3261 (V=10.58)

<B-V>(K9V) =  1.37  ; Fitzgerald70
(B-V)(K9V) =  1.38  ; 1 ARICNS K8V star
(B-V)(K9V) =  1.40  ; interpolated between K7V (1.34) and M0V (1.43)
<B-V>(K9V) = 1.418 ; 11 Gray03/06 K9V stars (+-0.016 sem, +-0.040 stdev)
(B-V)(K9V) =  1.44  ; B-V for Gray03/06 star with median B-I: GJ 1016 
=> adopt (B-V)(K9V)  = 1.42  [updated 9/20/2019] (rest of values are interp from V-Ks)
=> adopt (U-B)(K9V)  = 1.213
=> adopt (V-I)(K9V)  = 1.645
=> adopt (V-R)(K9V)  = 0.850
=> adopt (R-I)(K9V)  = 0.795
=> adopt (V-J)(K9V)  = 2.733
=> adopt (V-H)(K9V)  = 3.363
=> adopt (V-Ks)(K9V) = 3.543 *** <= adopt (V-Ks)=3.54 interp K7V-M0V [9/20/2019]
=> adopt (H-Ks)(K9V) = 0.180
=> adopt (J-H)(K9V)  = 0.631
=> adopt (K-W1)(K9V) = 0.113

(G-V)(K9V) = -0.688 ; from color locus fit for B-V = 1.42
(G-V)(K9V) = -0.69  ; GJ_1016
=> adopt (G-V)(K9V) = -0.69 [updated 12/10/2018]
=> adopt (G-Ks)(K9V) = 3.54 + -0.69 = 2.85 [updated 11/1/2019]

(Bp-Rp)(K7V)= 1.71 ; K7V mean
(Bp-Rp)(K8V)= 1.7162 ; HD_88230  K8V
(Bp-Rp)(K8V)= 1.73 ; K8V  
(Bp-Rp)(M0V)= 1.84 ; M0V mean
=> adopt (Bp-Rp)(K9V) = 1.79 [updated 3/1/2019]

(G-Rp)(K7V)= 0.87 ; K7V mean
(G-Rp)(K8V)= 0.8738  HD_88230  K8V
(G-Rp)(K8V)= 0.88 ; K8V 
(G-Rp)(M0V)= 0.92 ; M0V mean
=> adopt (G-Rp)(K9V) = 0.90 [updated 3/1/2019]
=> adopt (Bp-G)(K9V) = 0.89 [updated 3/1/2019; Bp-Rp=1.79, G-Rp=0.90]

Teff(K9V) =  3856 K ; mean photometric Teff
Teff(K9V) = 3875 K ; Casagrande08 Teff calibration for V-Ks=3.54
Teff(K9V) =  3883 K ; smooth Teff(SpT) trend
Teff(K9V) = 3887 K ; Alonso96 Teff for V-Ks=3.54
Teff(K9V) = 3903 K ; vanBelle09 Teff calibration for V-Ks=3.54
Teff(K9V) = 3909 K ; Mozurkewich03 for V-Ks=3.54
Teff(K9V) = 3910 K ; Morrell19 Teff for stars w/i +-0.1 mag of M_Ks=5.06
Teff(K9V) = 3912 K ; GJ 1016 (Morales08)
Teff(K9V) = 3931 K ; Boyajian12 for V-Ks=3.54
Teff(K9V) = 3943 K ; Ramirez05 Teff calibration for B-V=1.42
Teff(K9V) = 3970 K ; interp K7V (4100K) and M0V (3900K)
Teff(K9V) = 4045 K ; Gray92 for B-V=1.42
Teff(K9V) = 4246 K ; Biazzo07 Teff calibration for B-V=1.42
=> adopt Teff(K9V) = 3970 K (logT = 3.599) [updated 9/20/2019]
 
Mv(K9V)  = 8.53 mag ; V-K=3.54 => EEM fit to Reid CNS3 data
Mv(K9V)  = 8.59 mag ; V-K=3.54 => EEM fit to Jao16 data
Mv(K9V)  = 8.61 mag ; V-K=3.54 => Mv(JohnsonApps09)
Mv(K9V)  = 8.67 mag ; V-K=3.54 => EEM fit to MS data
Mv(K9V)  =  8.78 mag ; Wegner07
Mv(K9V)  = 9.00 mag ; B-V=1.42 => Mv(Wright05)
=> adopt Mv(K9V)   = 8.60 mag [updated 10/23/2019]
=> adopt M_Ks(K9V) = 5.06 mag [updated 10/23/2019, V-Ks=3.54]

BCv(K9V) = -1.171 mag ; Flower96(Teff=3970K, set so BCv(5772K)=-0.085)
BCv(K9V) = -1.094 mag ; Casagrande18(Teff=3970K,logg=4.5, set so BCv(5772K)=-0.085)
BCv(K9V) = -1.084 mag ; Mann15(V-J=2.907)
BCv(K9V) = -1.05  mag ; BC_K=2.49, V-Ks=3.54
BCv(K9V) = -1.047 mag ; Bessell98(ATLAS9,logg=4.5,Teff=3970K, set so BCv(5772K)=-0.085)
BCv(K9V) = -1.014 mag ; EEM fit to Casagrande06/08/10 (Teff=3970K, set so BCv(5772K)=-0.085)
=> adopt BCv(K9V) = -1.05 mag [updated 11/3/2019, set so BCv(5772K)=-0.085]

BC_Ks(K9V) = 2.490 mag ; Mann15(V-J=2.907)
BC_Ks(K9V) = 2.517 mag ; BCv=-1.14, V-Ks=3.737
=> adopt BC_Ks(K9V) = 2.49 mag [updated 11/3/2019]

logL(K9V) = -1.108 dex ; Mv=8.6, BCv=-1.09 => Mbol = 7.51
=> adopt logL(K9V) = -1.108 dex [updated 10/23/2019]
=> adopt Mbol(K9V) =  7.510 mag [updated 10/23/2019]

Mass(K9V) = 0.589 Msun ; Mann18 calib. for M_Ks=5.06
Mass(K9V) = 0.598 Msun ; Eker15 calibration for logL=-1.108
Mass(K9V) = 0.603 Msun ; Eker18 calib. for logL=-1.108
Mass(K9V) =  0.607 Msun ; HenryMcCarthy93 calibration for Mv=8.6
Mass(K9V) =  0.622 Msun ; EEM logL vs. Mass fit for binaries (logL=-1.108)
Mass(K9V) = 0.631 Msun ; Benedict16 for M_Ks=5.06
Mass(K9V) =  0.645 Msun ; Delfosse00 calibration for  M_Ks=5.06
Mass(K9V) = 0.669 Msun ; Benedict16 for Mv=8.6
Mass(K9V) =  0.681 Msun ; EEM fit to Torres10 binaries for Mv=8.6
=> adopt Mass(K9V) = 0.59 Msun [updated 10/23/2019]

Rad(K9V) = 0.590 Rsun ; logL=-1.108,Teff=3970K
=> adopt Rad(K9V) = 0.590 Rsun [updated 10/23/2019]

# Exemplar

GJ 1016 = HIP 3261 = CD-34_239 = LTT_377 = G269-17
  K9V: Gray06,Pecaut13(stan)
  K7V: Hawley97 (a rare K7?), Reid04

  There appear to be no K9V standard stars in the literature before
  2013.  PecautMamajek13 adopted HIP 3261 as their K9V standard based
  on Gray06's classification and an intermediate appearance of the red
  spectrum between that of GJ 673 (K7V) and GJ 701 (M0V) [HIP 111288
  was adopted as K8V standard; Gray06].  Gliese91 lists only "k"
  type. U-B=1.170 (M91), B-V = 1.440 (M91), plx = 51.2+-2.2 (HIP2),
  B-V=1.432 (HIP), V-I=1.75+-0.03 (HIP), Ks=6.884+-0.007 (2M)
  V=10.597+-0.05 (M91), (V-Ks) = 3.713 +- 0.05: Hamuy94
  spectrophotometric standard?  Teffs: 3835K(Gaidos14),
  3885K(Hinkel17), 3906K(Cloutier19), 3918K(Muirhead18,Stassun18),
  3970K(Morales08), 4073K(GaiaDR2) => <Teff> = 3912K.

# Others Stars

HD 11507
  K9V: Gray06,1944ApJ....99..271M

HD 113538
  K9V(k): Gray06,Evans61(K9V)