HD 12098 -A new northern hemisphere roAp star

¹ ISRO Satellite Centre, Airport road, Bangalore-560 017, India
² South African Astronomical Observatory, PO Box 9, Observatory 7935, South Africa
³ State Observatory, Manora Peak, Naini Tal-263 129, India
⁴ Dept. of Astronomy, University of Cape Town, Rondebosch 7700, South Africa
⁵ Centre for Astrophysics, University of Central Lancashire, Preston PR1 2HE, UK

Corresponding author: S. Seetha seetha@isac.ernet.in

Received: 10 July 2001
Accepted: 10 August 2001

Abstract

We present the analysis of 65 hours of high speed photometric observations of HD 12098 taken from State Observatory, Naini Tal and Gurushikhar Observatory, Mt. Abu on sixteen nights spanning from November 1999 to November 2000. HD 12098 is the first rapidly oscillating Ap star discovered from the "Naini Tal-Cape survey for northern hemisphere roAp stars". It is the 32nd in the complete list. HD 12098 exhibits one predominant mode of oscillation at mHz. The second-most significant frequency in our data is at mHz with a 1 cycle/day alias ambiguity. We argue that is a rotational sidelobe of , rather than an independent pulsation mode. Evidence for the presence of two other frequencies at 2.1807 and 2.3056 mHz is also presented.