The Observation of AM CVn type star SDSS J080449.49+161624.8
Chatief Kunjaya (a,b,c*), Keisuke Isogai (d,e), Daisaku Nogami (d), Rafa N. Akilah (a), Tian A. Bayuadri (a), Sahabista A. Armantara (a), Kiki Vierdayanti (a,c), Fumihide Iwamuro (d), Anton T. Jaelani (a,c), Putra Mahasena (a,c), Yusuke Tampo (f,g)

a) FMIPA, Intitut Teknologi Bandung, Jl. Ganesa 10, Bandung 40132, Indonesia
*kunjaya[at]itb.ac.id
b) University Center of Excellence for Space Science Technology and Innovation, Jl. Ganesa 10, Bandung 40132, Indonesia
c) Bosscha Observatory, Jl. Peneropongan Bintang 1, Lembang 40391, Indonesia
d) Department of Astronomy, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto-shi, Kyoto 606-8502, Japan
e) Okayama Observatory, Kyoto University, 3037-5 Honjo, Kamogata-cho, Asakuchi-shi, Okayama 719-0232, Japan
f) South African Astronomical Observatory, PO Box 9, Observatory, 7935, Cape Town, South Africa
g) Department of Astronomy, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa

Abstract

AM CVn type stars are ultra short period binary below the minimum period of Cataclysmic Variables. The components are very close to each other so that their hydrogen was stripped off during second common envelope phase, resulting in little or no hydrogen lines in their spectra. It is expected that it evolves from Cataclysmic Variables with angular momentum losses by magnetic braking and/or gravitational wave radiation. SDSS J080449.49+161624.8 is an AM CVn type cataclysmic variable which has 44.5 minutes orbital period. We observed the star in February 2024 using Seimei 3.8m Telescope at Okayama Astrophysical Observatory. The spectra showed several elements dominated by neutral and ionized Helium, other elements detected are NII and SiII. This indicates a high temperature system with Helium as dominant material without Hydrogen.

Keywords: Stars: individual : SDSS J080449.49+161624.8, Stars: variables: AM CVn, Cataclysmic Variables

Topic: Stellar Physics