COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS Number 2542 Konkoly Observatory Budapest 25 June 1984 HU ISSN 0374-0676 HD 91948: A NEW PROBABLE Be STAR Gorga (1971) investigated the binary nature of the star HD 91948 (=BD+60d 1274 = SAO 15243; F8V). He found it to be a spectroscopic binary with an orbital period of 2.7700266d. The first photoelectric (UBV) observations were carried out by Padalia (1980) from May 1973 to May 1978 on 17 nights to see its variable (eclipsing binary) nature. However, Padalia (1980) found the variability of this star only on two nights (falling at phases 0.09d and 0.25d), though the star had been observed almost in the entire phase region. It was concluded that the star was a suspected variable and not an eclipsing binary. From his photoelectric observations he determined its spectral type to be A0V. The UBV observations of this star taken by Padalia on one of the two nights, 21 March 1977 (JD 2443224) at phase near 0.25d showed a variation of 0.26m in U, 0.15m in B and 0.10m in V filter (Figure 1). However, the variation was not repeated at the same phase on other nights which indicated that the light variation of HD 91948 was not of eclipsing nature. It is clear from Figure 1 that the variation in U is larger than that in B and V. Similar type of photoelectric variation has been observed in Be stars, for example 88 Her and Pleione (Magalashvili and Kumsishvili, 1982), The variation found in different colours for HD 91948 and 88 Her are as follows: Star Filters U B V HD 91948 0m26 0m15 0m10 (Padalia,1980) 88 Her 0.14 0.10 0.07 (Magalashvili and Kumsishvili,1982) 88 Her 0.30 0.15 0.15 (Harmanec et al.,1978) In order to investigate the Be nature of this star we have carried out spectrophotometric observations. The star was observed by us on the night of 29 April 1984 on the 104-cm reflector of the Uttar Pradesh State Observatory. A Hilger and Watts [FIGURE 1] Figure 1 Individual observations on the night JD 2443224 (Padalia, 1980). The differential magnitudes are in the sense variable minus comparison. The solid line indicates free hand curve. Points with (Delta) are instrumental magnitudes for comparison star used. monochromator was used for taking spectral scans. The standard star a Leo and the comparison star BD +60d 1289 = HD 93286 (which was also used for our earlier UBV observations) was observed along with the variable star. We noticed that the H alpha line of variable star was found to be filled-in by emission (Figure 2). An inspection of Figure 2 reveals that the standard and the comparison stars have H alpha lines in absorption whereas the variable star has no absorption lines. We have also observed H beta, H gamma, H delta, H epsilon etc. lines and found that these lines are in absorption for the standard and the comparison stars used by us, but these absorption lines fade away for HD 91948. [FIGURE 2] Figure 2 Spectrophotometry of HD 91948 along with the standard and comparison stars. The Balmer lines are shown by vertical arrows. The amplifier sensitivities used for various stars are indicated by numbers inside brackets. The sharp discontinuity in the spectrum at a wavelength of lambda 6000 A is due to change in sensitivities. From this we infer that HD 91948 is an emission line (Ae) star. Further UBV and scanner observations are in progress. P.S. GORAYA and T.D. PADALIA Uttar Pradesh State Observatory, Manora Peak, Naini Tal-263129, India References: Gorga, W.: 1971, J.Roy.Astron.Soc. Canada, 65, 277 [BIBCODE 1971JRASC..65..277G ] Harmanec, P., Horn, J., Koubsky, P., Kriz, S., Zdarsky, P., Papousek, J., Doazan, V., Bourdonneau, B., Baldinelli, L., Ghedini, S., Pavlovski, K.: 1978, Bull.Astron.Inst.Czech. 29, 278 [BIBCODE 1978BAICz..29..278H ] Magalashvili, N. and Kumsishvili, Ya.I.: 1982, Abastumanskaya Astrofiz.Obs. Byull. No. 55, p. 81 [BIBCODE 1982AbaOB..55...81M ] Padalia, T.D.: 1980, Inf.Bull. Variable Stars, No. 1733