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Cohen Primary and Secondary MIR Standards

To help with the planning of observations, the basic properties of Cohen's 2 primary and 10 secondary standards are listed in the following table. Also listed are a few other stars which are often used as mid-IR standards. Most of the K and N magnitudes are taken from papers I (1992, AJ, 104, 1650) and IV (1995, AJ, 110, 275). In Cohen's system, the 0 magnitude flux density is 655 Jy at K and 35.21 Jy at N.

Name RA
(2000)
Dec
(2000)
Sp. Type K N Notes
Cohen Primary Standards
Alpha CMa 06 45 09 -16 42 58 A1 V -1.37 -1.35 ()
Alpha Lyr 18 36 56 +38 47 01 A0 V 0.00 0.00 ()
Cohen Secondary Standards
Beta And 01 09 43 +35 37 14 M0 III -1.89 -2.05 ()
Alpha Cet 03 02 17 +04 05 23 M1.5 IIIa -1.7 -1.7 ()
Alpha Tau 04 35 55 +16 30 33 K5 III -2.90 -3.02 ()
Beta Gem 07 45 19 +28 01 34 K0 IIIb -1.12 -1.22 ()
Alpha Hya 09 27 35 -08 39 31 K3 II-III -1.22 -1.31 ()
Mu UMa 10 22 20 +41 29 58 M0 III -0.85 -1.03 ()
Gamma Cru 12 31 10 -57 06 47 M3.5 III -3.16 -3.36 (c)
Alpha Boo 14 15 40 +19 10 57 K1.5 III -3.04 -3.14 ()
Gamma Dra 17 56 36 +51 29 20 K5 III -1.38 -1.48 ()
Beta Peg 23 03 46 +28 04 58 M2.5 II-III -2.29 -2.44 (a)
Other Standards
Alpha Aur 05 16 41 +45 59 53 G5 IIIe -1.8 -1.94 ()
Gamma Aql 19 46 16 +10 36 48 K3 II -0.58 -0.78 (b)

Notes to table:
(a) Beta Peg is variable at about the 10% level but is useful for spectral calibration.
(b) Gamma Aql appears in Cohen et al. Paper X as one of the 422 stars with templates.
(c) Gamma Crux may be used as a flux calibration star, but it definitely is not useful as a PSF calibration star since the N-band PSF is found to be 50% larger than those of other standards taken at nearly the same time.