COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 1753

                                        Konkoly Observatory
                                        Budapest
                                        1980 March 3


              RHO Vir: A HOT DELTA SCUTI STAR?


The star Rho Vir was observed photoelectrically during 12 nights since February
27, 1971 to March 1, 1976 with the UBV photometer described by Piccioni (1972)
mounted on the 60 cm telescope of the Bologna observatory.

31 Vir and 33 Vir were used as comparison stars; the reductions were performed
taking into account also the colour effects of the atmosphere. Light curves
obtained during the nights March 20, 1973, April 19, 1974 and February 23, 1975
are reproduced in the Figures.

                         [FIGURE 1]

In order to confirm the variability of Rho Vir we have made search for periods
in the observations secured in 7 nights with the Barning (1963) method using a
program written by F. Grilli. From the results reported in Table I and II,
for the comparison stars 31 Vir and 33 Vir respectively, we note that periods
close to 0.022d, 0.029d and 0.08d occur very often.

                         [FIGURE 2]

The actual variability of this star is supported also by the fact that Frost et
al. (1929) detected radial velocity variations up to 20 km/sec in about one
hour. However the spectral type A0V (Eggen, 1963) or A1V (Osawa, 1959) puts
this star outside the normal Delta Scuti instability strip, not far from the
left corner of the H-R diagram (Breger, 1979, page 7), being M_v=2.05 (Eggen,
1963). We suggest therefore that Rho Vir could be a "Maia variable" linking
the Delta Scuti stars with the Beta CMa stars (Breger, 1979, page 23).

Table I

J.D.             Period          Amplitude    R.F.
2442467.   P1  0.074+-0.007   0.010+-0.002   26.6%
           P2  0.023+-0.001   0.007+-0.002   16.0%
           P3  0.100+-0.008   0.006+-0.002   12.0%
2442468.   P1  0.023+-0.001   0.010+-0.002   19.2%
           P2  0.08+-0.01     0.008+-0.002   16.0%
           P3  0.029+-0.001   0.006+-0.002   10.0%
2442833.   P1  0.042+-0.003   0.006+-0.001   18.0%
           P2  0.028+-0.001   0.006+-0.001   28.6%
2442836.   P1  0.08+-0.01     0.008+-0.001   22.8%
           P2  0.022+-0.001   0.006+-0.001   11.0%
2442837.   P1  0.09+-0.01     0.006+-0.002   14.7%
2442838.   P1  0.07+-0.01     0.016+-0.004   24.3%
           P2  0.024+-0.001   0.010+-0.004   13.0%
           P3  0.032+-0.002   0.009+-0.004    8.0%

Table II

J.D.             Period         Amplitude      R.F.
2442451.   P1  0.048+-0.002   0.010+-0.001    21.5%
           P2  0.036+-0.004   0.005+-0.001     7.5%
           P3  0.076+-0.006   0.005+-0.001     8.0%
2442467.   P1  0.029+-0.001   0.010+-0.002    23.0%
           P2  0.10+-0.01     0.008+-0.002    16.4%
           P3  0.022+-0.001   0.006+-0.002    20.0%
2442468.   P1  0.029+-0.001   0.014+-0.002    27.0%
           P2  0.040+-0.002   0.010+-0.002    21.0%
           P3  0.08+-0.01     0.010+-0.002    19.0%


C. BARTOLINI
A. DAPERGOLAS
G. PARMEGGIANI
A. PICCIONI
M. VOLI
Osservatorio Astronomico dell' Universita di Bologna,
via Zamboni 33, 40126 Bologna
Italy

References:

Barning, F.J.M., 1963, Bull. Astr. Netherland 17, 22 [BIBCODE 1963BAN....17...22B ]
Breger, M., 1979, P.A.S.P., 91, 5 [BIBCODE 1979PASP...91....5B ]
Eggen, O.J., 1963, A.J. 68, 697 [BIBCODE 1963AJ.....68..697E ]
Frost, E.B., Barrett, S.B., Struve, O., 1929, Publ. Yerkes Obs. 7, 1 [BIBCODE 1929PYerO...7....1F ]
Osawa, K. 1959, Ap.J. 130, 159 [BIBCODE 1959ApJ...130..159O ]
Piccioni, A., 1972, Mem. Soc. Astr. It. 43, 159 [BIBCODE 1972MmSAI..43..159P ]