On the δ Scuti variability in the pre-main sequence Herbig Ae star HR 5999

A reanalysis of photometric data for the bright, southern Herbig Ae star HR 5999 obtained by Praderie et al. (1991) at ESO in 1985 shows delta Scuti pulsation with the same period, 4.812 d(-1), and semi-amplitude, 6 mmag, found by Kurtz & Marang (1995) in data obtained from SAAO in 1994. HR 5999 is. therefore, a potential candidate to test Breger & Pamyatnykh's (1998) predictions of evolutionary period changes 10 to 100 times faster in premain sequence delta Scuti stars than in post-main sequence stars. We argue that the low frequency, low amplitude alpha (2) CVn variability of HR 6000 with a period near 2 d, and its long-term variability are no hindrance to using it as a comparison star for study of the delta Scuti variability of HR 5999. With a separation of 44 arcsec between ISR 5999 and NE 6000, and similar brightnesses for the two stars, R e urge the use of small telescopes with CCD photometers to obtain the long-term data necessary for the study of period change. We point out that this can be done under less-than-ideal photometric conditions and urban lighting with CCD photometers on small telescopes which are widely available at small observatories, at universities and at the home observatories of serious amateur astronomers.