COMMISSION 27 OF THE I. A. U.
            INFORMATION BULLETIN ON VARIABLE STARS
                         Number 3632  

                                                   Konkoly Observatory
                                                   Budapest
                                                   8 July 1991

                                                   HU ISSN 0374 - 0676


                HR 2146 A NEW VARIABLE IN AURIGA


Photometric photometry of HR 2146 = SAO 077958 = HD 41429 obtained January 14
to April 13, 1991 in VBRI wavelengths indicates a period of 32.5 days between
maxima (Figure 1). 27 Data points in VB taken over 102 days were used in a
Data-Compensated-Discrete Fourier Transform program (Belserene, 1986) to
determine a period of 32.896 days. Two discernible cycles of maximum light
show the period to remain constant while the amplitude fluctuates from 0.112 -
0.064 in V and from 0.088 - 0.069 in B.

The General Catalogue of Variable Stars (Kholopov et al. 1985), the New
Catalogue of Suspected Variable Stars (Kholopov et al. 1982) and the 67th,
68th, 69th and 70th Name-List of Variable Stars (Kholopov et al., 1985, 1987,
1989, 1990) do not list HR 2146 as a variable. HR 2146 along with HR 8062
(Snyder, 1990) was selected as a potential variable because the spectrum is
similar to those of known variables of mainly small amplitude (Hoffleit, 1979).

HR2146 is listed as 6.08 V, B-V = 1.68, spectral type M3II (Buscombe, 1962)
with a dwarf companion F7V, 10.72V at a separation of 10.0" (Hoffleit and
Jaschek, 1982). With the luminosity classification of a bright giant HR 2146
is a Small Amplitude Red Variable (SARV) having an amplitude < 0.2 m and p = 20
- 40 days (Eggen, 1972a,b, 1973). HR 2146 color variations are 0.12 +-.01 in
V-R and 0.07 +- .01 in V-I which is typical of small amplitude red variables.
R-I of 1.6 is redder than the boundary of the classical red variables (R-I ~
1.0) where light variations tend to be more erratic. Total radiant luminosity,
bolometric magnitude = 4.37 and a color temperature of 3200K. Maximum rise is
more rapid than minimum decline and amplitudes at longer wavelength are
progressively more depressed due to the TiO absorption enhancing the V
amplitude more than BR and I (Figure 1).

Observations were made with an Optec SSP-3 photometer using the 0.56m telescope
at MacLean Observatory and the 0.25m reflector at Tahoe Observatory.
Comparison star = HD 41430, K3III, 7.51 V, B-V = 1.24, and Check star = HD
41398, B2Ib. 7.46 V, B-V = 0.32 (Figure 2). Magnitudes were corrected for
extinction and transformed to the standard Johnson BV system.

I acknowledge my gratitude to Gordon MacLean and Sierra Nevada College for the
use of the MacLean Observatory and equipment.


                               [FIGURE 1]

              Figure 1. VBRI Color Curves of HR 2146

                                [FIGURE 2]

        Figure 2. V - HR 2146   C - Comparison   K - Check



                           LeROY F. SNYDER
                           MacLean Observatory
                           Tahoe Observatory
                           P.O. Box 1092
                           Crystal Bay, NV 89402 USA

References:

Belserene, E.P.: 1986, in the Study of Variable Stars Using Small Telescopes, 
   ed. J.R. Percy (Cambridge University)
Buscombe: 1962, Mt. Stromlo Mim. No. 4.
Eggen, O.J.: 1972a, Astrophys.J., 174, 45. [BIBCODE 1972ApJ...174...45E ]
Eggen, O.J.: 1972b, Astrophys.J., 177, 489. [BIBCODE 1972ApJ...177..489E ]
Eggen, O.J.: 1973, Astrophys.J., 184, 793. [BIBCODE 1973ApJ...184..793E ]
Hoffleit, D.: 1979, Journ.Amer.Assoc.Var. Star Obs., 8, No. 1,17. [BIBCODE 1979JAVSO...8...17H ]
Hoffleit, D., Jaschek, C.: 1982, The Bright Star Catalogue 4th edition,
   Yale Univ. Observatory, New Haven, CT. [BIBCODE 1982bscf.book.....H ]
Kholopov, P.N. et al.: 1982, New Catalogue of Suspected Variable Stars,
   Moscow (Publ. Office Nauka). [BIBCODE 1982ncss.book.....K ]
Kholopov, P.N. et al.: 1985, General Catalogue of Variable Stars, 4th
   edition, Moscow.
Kholopov, P.N. et al.: 1985, IBVS, No. 2681.
Kholopov, P.N, et al.: 1987, IBVS, No. 3058.
Kholopov, P.N. et al.: 1989, IBVS, No. 3323.
Kholopov, P.N. et al.: 1990, IBVS, No. 3530.
Snyder, L.F.: 1990, IBVS, No. 3445.