NGC 581

Number of stars per data source

	Reference  113 :    2 stars
	Reference  202 :    1 star
	Reference  206 :    1 star
	Reference  207 :    4 stars
	Reference  221 :    3 stars
	Reference  268 :    1 star
	Reference  284 :    1 star
	Reference  320 :    3 stars
	Reference  427 :    1 star
	Reference  582 :    1 star
	Reference  731 :    1 star

References

113: Abt H.A.; (1988) Astrophys. J. 331, 922; Maximum separations among cataloged binaries; 1988ApJ...331..922A
202: Morgan W.W., Code A.D., Whitford A.E.; (1955) Astrophys. J. Suppl. 2, 41; Studies in galactic structure. II. Luminosity classification for 1270 blue giant stars; 1955ApJS....2...41M
206: Hiltner W.A.; (1956) Astrophys. J. Suppl. 2, 389; Photometric, polarization and spectrographic observations of O and B stars; 1956ApJS....2..389H
207: Hoag A.A., Applequist L.; (1965) Astrophys. J. Suppl. 12, 215; Distance moduli of open clusters; 1965ApJS...12..215H
221: Sowell J.R; (1987) Astrophys. J. Suppl. 64, 241; Yellow evolved stars in open clusters; 1987ApJS...64..241S
268: Humphreys R.M.; (1970) Astron. J. 75, 602; The space distribution and kinematics of supergiants; 1970AJ.....75..602H
284: McCuskey S.W., Pesch P., Snyder G.A.; (1974) Astron. J. 79, 597; The space distribution and radial velocities of some early-type stars in the Perseus spiral arm; 1974AJ.....79..597M
320: Sears R.L., Sowell J.R.; (1997) Astron. J. 113, 1039; Spectral classification of "photometric subgiants" in open clusters; 1997AJ....113.1039S
427: Jensen K.S.; (1981) Astron. Astrophys. Suppl. 45, 455; Spectral classification in the MK system of 167 northern HD stars; 1981A&AS...45..455J
582: Keenan P.C., Pitts R.E.; (1985) Publ. Astr. Soc. Pacific 97, 297; Spectral types and luminosities of supergiants in open clusters; 1985PASP...97..297K
731: Hardorp J., Rohlfs K., Slettebak A., Stock J.; (1959) Astr. Abh. Hamb. Sternw. Bergedorf; Luminous stars in the northern Milky Way I - VI