Search for global oscillations on Jupiter with a double-cell sodium magneto-optical filter

¹ Università degli Studi di Roma "La Sapienza", P.le A. Moro 5, 00185 Rome, Italy
² Osservatorio Astronomico "V. Cerulli" di Teramo, Via M. Maggini, 64100 Teramo, Italy
³ Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy
⁴ Osservatorio Astronomico di Roma, Via Frascati 33, 00040, Monte Porzio Catone, Italy

Corresponding author: M. Dolci, dolci@astrte.te.astro.it

Received: 30 January 2001
Accepted: 22 March 2001

Abstract

Doppler observations on Jupiter are presented and discussed. A two-cells Magneto-Optical Filter (MOF), able to obtain two separate signals, Red and Blue, on the opposite wings of the Sodium D-lines, along with a continuum reference signal, has been used. This set of data permits to discriminate between real oscillations and albedo "modes" by means of the two algorithms and /conti nuum. No unambiguous oscillation modes were detected with amplitudes above the 1-σ level of ~1.2 m s^-1 in the range between 0.5 and 0.7 mHz. However, using refined analysis for signal recovery in a noisy background we notice an increase of power also in the region of the solar 5 min oscillations. The albedo variations on the Jupiter's surface and instrumental effects are addressed to be responsible for the spurious signals.