VZ Cancri is a variable star in the constellationCancer, abbreviated VZ Cnc. It varies in brightness with a period of 0.178364 days, from an apparent visual magnitude of 7.18 down to 7.91,[3] which lies below the typical threshold of visibility for the naked eye. The distance to this star is approximately 724 light years based on parallax measurements,[2] and it is receding from the Sun with a radial velocity of 25 km/s.[6]
This star was discovered to vary in brightness by B. S. Whitney in 1950, and was classified as a cluster-type Cepheid variable,[10] or RR Lyrae star.[11] In 1955, W. S. Fitch found the light curve to be variable and discovered a beat period of 0.716292 d,[12] from which is inferred a second pulsation period of 0.1428041 days.[13]H. A. Abt found that the stellar class of this star varied from A7–A9 III during peak brightness to F1–F2 III at minimum.[14] After H. J. Smith pointed out the distinctiveness of short period RR Lyrae variables in 1956, VZ Cnc has been grouped under the category of Delta Scuti variables.[15]
The star is located near the center of the instability strip.[13] Both pulsation periods for this star are in the first and second overtone;[16] it appears to lack a fundamental mode, possibly as a result of helium depletion in the outer atmosphere.[13] In 1994, an examination of five decades of data on this star suggested a variation in the period of maximum light with a cycle length of 49.3 years.[17] This could be the result of previously undetected pulsation frequencies.[16]
^ abcKahraman Aliçavuş, F.; et al. (October 2017), "High-resolution spectroscopy and abundance analysis of δ Scuti stars near the γ Doradus instability strip", Monthly Notices of the Royal Astronomical Society, 470 (4): 4408–4420, arXiv:1706.04782, Bibcode:2017MNRAS.470.4408K, doi:10.1093/mnras/stx1498.
^ abcCox, A. N.; et al. (September 1984), "Observations and a new interpretation for the Delta Scuti variable star VZ Cancri", Astrophysical Journal, 284: 250–256, Bibcode:1984ApJ...284..250C, doi:10.1086/162403.
^Abt, Helmut A. (November 1955), "Spectroscopic Observations of the Cluster-Type Variable VZ CANCRI.", Astrophysical Journal, 122: 390, Bibcode:1955ApJ...122..390A, doi:10.1086/146099.
^Arellano Ferro, A.; Núñez, N. S.; Avila, J. J.; Trejoluna, J. J. (July 1994), "Period variations and duplicity of the δ Scuti star VZ Cancri", Revista Mexicana de Astronomía y Astrofísica, 29: 218, Bibcode:1994RMxAA..29..218A.
Arellano Ferro, A.; et al. (July 1994), "On the Period Variation of the Delta Scuti Star VZ Cancri", Publications of the Astronomical Society of the Pacific, 106 (701): 696, Bibcode:1994PASP..106..696A, doi:10.1086/133432, S2CID250876310.
Arellano Ferro, A.; et al. (June 1994), "Times of Light Maximum of VZ Cancri: 1994 Season", Information Bulletin on Variable Stars, 4039: 1, Bibcode:1994IBVS.4039....1A.
Quester, W. (June 1990), "Photoelectric Observations of VZ Cancri 1988-1990", Information Bulletin on Variable Stars, 3484: 1, Bibcode:1990IBVS.3484....1Q.
Garbuzov, G. A.; Mitskevich, A. S. (April 1984), "On the existence of an extended atmosphere in the delta Sct-type star VZ Cnc", Pis'ma v Astronomicheskii Zhurnal, 10: 223–228, Bibcode:1984PAZh...10..223G.
Garbusov, G. A. (October 1982), "Spectroscopic Investigation of VZ Cnc", Information Bulletin on Variable Stars, 2205: 1, Bibcode:1982IBVS.2205....1G.
Cester, B.; et al. (September 1977), "VZ Cancri", Information Bulletin on Variable Stars, 1338: 1, Bibcode:1977IBVS.1338....1C.
Todoran, I. (June 1976), "Photoelectric Maxima of VZ Cancri", Information Bulletin on Variable Stars, 1141: 1, Bibcode:1976IBVS.1141....1T.
Hahn, G.; et al. (December 1975), "Photoelectric Observations of VZ Cnc (HD 73857)", Information Bulletin on Variable Stars, 1078: 1, Bibcode:1975IBVS.1078....1H.
Catalano, C. P.; Neff, J. S. (1967), "Variations in the Photometric Properties of RR Lyrae and VZ Cancri with Beat Phase", Astronomical Journal, 72: 788, Bibcode:1967AJ.....72S.788C, doi:10.1086/110531.
Ponsen, J.; Oosterhoff, P. T. (1965), "Photoelectric observations of VZ Cnc and RZ Cep", Bulletin of the Astronomical Institutes of the Netherlands, 18: 459, Bibcode:1965BAN....18..459P.