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Magellanic Clouds. Xi. Survey of the Novae by Karl G

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Magellanic Clouds. Xi. Survey of the Novae by Karl G Proceedings of the NATIONAL ACADEMY OF SCIENCES Volume 40 * Number 6 * June 15, 1954 MAGELLANIC CLOUDS. XI. SURVEY OF THE NOVAE BY KARL G. HENIZE, DORRIT HOFFLEIT, AND VIRGINIA MCKIBBEN NAIL OBSERVATORY OF THE UNIVERSITY OF MICHIGAN AND HARVARD COLLEGE OBSERVATORY Communicated by Harlow Shapley, March 25, 1954 The New Novae.-The recent discovery of four additional novae in the Magellanic Clouds (N Doradus 1948, N Mensae 1951, N Tucanae 1951, and N Tucanae 1952) brings to nine the number observed in these systems. Five have occurred in the Large Cloud and four in the Small. Of the four new novae, two, N Mensae 1951 and N Tucanae 1951,1 were discovered on Ha objective-prism spectrograms taken with the Mount Wilson 10-inch camera, while it was temporarily located at the Lamont-Hussey Observatory of the University of Michigan. N Doradus 1948 and N Tucanae 19522 were discovered on Harvard plates: N Doradus 1948 ap- peared during the course of a program for measuring variable stars, and N Tucanae 1952 was detected on a blue-sensitive objective-prism plate taken with the ADH telescope. N Tucanae 1952 is discussed by Henry J. Smith in the following paper in this series. Data on the light-curves of the other three new novae (Table 1) were ob- tained from Harvard plates by Mrs. Nail. The magnitudes of N Tucanae 1951 in the Small Cloud are based on an unpublished photoelectric sequence of Ivan King, while those of N Doradus 1948 and N Mensae 1951 in the Large Cloud depend on a photoelectric sequence by Uco van Wijk3 supplemented by Harvard photo- graphic sequences. An additional possible nova in the Magellanic Clouds, N Hydri 1935,4 is located only 1 minute of arc from the center of the spiral galaxy NGC 1511; it may be a supernova in that galaxy, or it may be a member of the Large Cloud and hence an ordinary nova. It is situated within the boundaries of the Cloud as indicated by the radio observations of Kerr and Hindman.5 The Light-Curves.-Light-curves of the nine Magellanic Cloud novae and N Hydri 1935 are plotted in Figure 1. In spite of their faint apparent magnitudes, the novae reveal a wide variety of types. All fit reasonably well into the patterns fol- lowed by galactic novae. Possible exceptions are N Tucanae 1927 and N Doradus 1948. At first glance the light-curve of N Doradus 1926 also appears unusual, but this fragment corresponds well with the flat, prolonged maxima of T Aurigae 1891 and DQ Herculis 1934.6 Accepting the similarity, we may infer that N Doradus 1926 reached a maximum magnitude of about 12.0 in mid-August of 1926 (about JD 2424750). 365 Downloaded by guest on September 27, 2021 366 ASTRONOMY: HENIZE ET AL. PROC. N. A. S. The light-curves of N Tucanae 1927 and N Doradus 1948 are more difficult to ex- plain. If we reconstruct the curve of N Doradus 1948 by inferring that a maxi- TABLE 1 PHOTOGRAPHIC LIGHT-CURVES OF MAGELLANIC CLOUD NOVAE Date Julian Day Magnitude* Date Julian Day Magnitude N DORADUS 1948 1948 NOV. 28 2432884 [17.0 (4) 1949 Jan. 24 2432941.38I 14.4 Dec. 2 888 [17.0 (4) Jan. 24 941.43 14.4 Dec. 3 889 [14.0 Feb. 15 963 13.3 Dec. 5 891 16.8:(4) Feb. 18 966 [12.0 Dec. 20 906 [14.0 Feb. 24 975 15.0 Dec. 21 907 [15.0 Mar. 28 3004 13.5 Dec. 22 908 [15.9:(2) Apr. 3 010 13.8 Dec. 29 915.29 15.6 Apr. 5 012 14.0: Dec. 29 915.34 15.6 Apr. 19 026 [13.5 Dec. 29 915.38 15.5 June 30 098 [13.5 Dec. 29 915.44 15.4 July 5 103 [13.0 Dec. 30 916.28 15.7 Aug. 21 150 16.7 Aug. 24 153 16.5: 1949 Jan. 2 919.29 15.5 Aug. 31 160 [12.5 Jan. 2 919.34 15.2 Sept. 20 180 16.5: Jan. 2 919 ;38 15.2 Oct. 17 207 17.0: Jan. 2 919.43 15.2 Oct. 26 216 17.2: Jan. 23 940.31 13.7 Nov. 21 242 [16.5 Jan. 23 940.36 13.8 Jan. 23 940.41 13.8 1950 Mar. 6 347 17.0: Jan. 23 940.46 13.8 Dec. 10 626 [18.0 Jan. 24 941.29 14.3 Jan. 24 941.34 14.4 1951 Jan. 12 659 [18.5 N MENSAE 1951 1950 Sept. 12 2433537 [16.8 1951 Jan. 4 2433651 16.0:t Sept. 17 542 [15.0 Jan. 5 652 11.95 Nov. 9 595 [17.0 Jan. 9 656 13.15 Nov. 12 598 [14.5 Jan. 12 659 15.05 Nov. 13 599 [16.5 Jan. 14 661 15.5 Dec. 10 - 626 [19.0: Jan. 30 677 16.6 Dec. 17 633 [18.0: Jan. 30 678 17.35 Feb. 7 685 18.25: 1951 Jan. 2 649 [12.5(2) Mar. 29 735 [17.0 Jan. 4 651 [14.0 (2) N TUCANAE 1951 1951 June 12 2433810 [15.5 1951 Aug. 31 2433890 14.00 July 30 858 13.5: Sept. 4 894 14.20 Aug. 2 861 11.8:+ Sept. 6 896 14.20 Aug. 4 863 11.8:t Sept. 7 897 14.40 Aug. 12 871 12.1t Oct. 5 925 15.15 Aug. 12 871 13.3 Nov. 6 957 15.8: Aug. 23 882 13.95 Nov. 18 969 16.5 Aug. 28 887 14.05 Dec. 2 983 16.87 Aug. 28 887 14.10 ADDITIONAL OBSERVATIONS: N DORADUS 1926 Date Julian Day Magnitude Date Julian Day Magnitude 1926 Sept. 15 2424774 13.0: 1927 Oct. 9 2424798 13.9 Sept. 17 776 12.8 * Numbers in parentheses indicate the number of observations included in the mean value given. t Red magnitude. $ Red magnitude estimated from the continuous spectrum of an Hea spectrogram. mum magnitude of about 13.0 occurred near JD 2432935, we find that subsequent to the first observation both it and N Tucanae 1927 rose slowly to maximum through Downloaded by guest on September 27, 2021 VOL. 40, 1954 ASTRONOMY: HENIZE ET AL. 367 a range of more than 3.5 magnitudes in an interval of 40-60 days. As no galactic novae (excepting, perhaps, RT Serpentis type stars7) have shown as slow a final I I I I I I I I I 2425150 250 350 450 J. D. 12.0 J Nova Tucanae *1 1927 vea V .00% I l I I 2432900 0W 100 200 J0.D 14.0 V 4*~~0 V Nova Doradus %# ~0 0 16.0j _ 1948 * 0 Ivy IIII I~~~~~~~0 *2482250 350 J. D 2424775 JD. 12.0 Nova Doradus 1936 - * _ V Nova Doradus ** 1926 2433850 950 JD. 2414225 J.D. 2428050 * 1 - A~O 8_._ Nova Tucanae Nova Tucanae Nova Hydri V 1951 1897 1935 VV \K S V V 1 193I V 1951 vv 1937 8 _-o V V V 16.0 V _ Nova Tucnon_ 0 1952 * v 180 _- I I I__I vI I * I I - FIG. 1.-Light-curves of novae in the Magellanic Clouds. Open circles indicate red magnitudes; inverted carets, "fainter than"; crosses indicate for N Tucanae 1951 magnitudes based on Ha objective prism plates. rise to maximum, we are tempted to class N Tucanae 1927 and N Doradus 1948 as possible objects of the Z Andromedae type, although no recurrences of maxima have been observed. Downloaded by guest on September 27, 2021 368 ASTRONOMY: HENIZE ET AL. PROC. N. A. S. The light-curves in Figure 1 may be classified according to rate of decline, as one very fast, five fast, and three slow. A comparison with galactic novae shows that five of the nine Magellanic Cloud novae have rates of decline within a range which contains only one-sixth of the Milky Way novae.8 The agreement of the distribu- tion of rates of decline of novae in Messier 31 with that for the Magellanic Clouds would indicate that the data for the Milky Way novae are distorted by selection effects. The very rapid decline of N Mensae 1951 places it among the fastest novae known. Its steady decline through 6 magnitudes in 30 days is exceeded only by T Coronae Borealis 1866 and 1946 and N Puppis 1942. The Absolute Magnitudes.-The observed apparent magnitudes at maximum are given in the fifth column of Table 2. For five of the novae the light-curves indicate that the true maximum was somewhat brighter. In these cases conserva- tive upward revisions have been made, and the resulting probable magnitudes at maximum are recorded in the sixth column. The seventh column gives the corre- sponding absolute magnitudes based on the revised distance modulus of 19.0.9 TABLE 2 NOVAE IN THE MAGELLANIC CLOUDS Dis- TANCE FROM _ _1900 - -in (MAX) CORE NOVA REFERENCE R.A. Dec. Obs. Prob. M TYPE ° NTucanael897 HB 920 Oh 56N4 _70° 47' 11.4 -11.0 -8.0 Fast 1.8 N Tucanae 1927 HB 898 0 30.1 -73 49 11.4 -11.4 -7.6 Slow 0.7 NTucanae 1951 HAC 1143 0 31.3 -73 31 11.8: 11.5 -7.5 Fast 0.7 N Tucanae 1952 0 44.9 -74 03 11.0 11.0 -8.0 Fast 0 Dis- TANCE FROM 190 - _-m- (MAX.)- BAR NOVA REFERENCE R.A.
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