Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Is Mira B a low mass white dwarf?

R. K. Zamanov, V. Irincheva, B. Spassov, A. Kurtenkov, D. Marchev, M. Minev, M. F. Bode, L. Dankova, B. Borisov, M. Dechev, G. Yordanova

Abstract

We report photometric observations in Johnson B and V bands of the short term variability (flickering) of Mira (omicron Ceti). The observations were performed during 7 nights in the period August - October 2025, in the course of the last minimum of the Mira pulsations. The observed peak-to-peak amplitude of the flickering is 0.11-0.28 mag in B band. For the flickering source we find luminosity in the range 0.10-0.46 L_sun. Using the amplitude-flux relation, we estimate an average luminosity of the accretion disc L_d = 0.91 +/- 0.28 L_sun. Assuming that the white dwarf accretes material through Wind Roche Lobe Overflow (WRLOF), we find that Mira B is a low mass white dwarf with M_wd = 0.24 +/- 0.04 M_sun accreting at a rate 6.8x10^{-9} M_sun/yr. This value of the mass is in the range of the extremely low mass white dwarfs. The data are available on Zenodo: zenodo.org/records/18756532

Is Mira B a low mass white dwarf?

Abstract

We report photometric observations in Johnson B and V bands of the short term variability (flickering) of Mira (omicron Ceti). The observations were performed during 7 nights in the period August - October 2025, in the course of the last minimum of the Mira pulsations. The observed peak-to-peak amplitude of the flickering is 0.11-0.28 mag in B band. For the flickering source we find luminosity in the range 0.10-0.46 L_sun. Using the amplitude-flux relation, we estimate an average luminosity of the accretion disc L_d = 0.91 +/- 0.28 L_sun. Assuming that the white dwarf accretes material through Wind Roche Lobe Overflow (WRLOF), we find that Mira B is a low mass white dwarf with M_wd = 0.24 +/- 0.04 M_sun accreting at a rate 6.8x10^{-9} M_sun/yr. This value of the mass is in the range of the extremely low mass white dwarfs. The data are available on Zenodo: zenodo.org/records/18756532
Paper Structure (11 sections, 8 equations, 2 figures, 3 tables)

This paper contains 11 sections, 8 equations, 2 figures, 3 tables.

Table of Contents

  1. Introduction
  2. Observations
  3. Results
  4. Flickering
  5. Optical luminosity of Mira B
  6. Accretion luminosity of Mira B
  7. Bondi-Hoyle-Lyttleton accretion
  8. Wind Roche-Lobe Overflow (WRLOF)
  9. Discussion
  10. Conclusions
  11. Acknowledgments

Figures (2)

  • Figure 1: Short term variability of Mira in $B$ and $V$ bands. An intra-night variability with an amplitude $\Delta B \sim 0.15$ mag is visible. The date of observations is marked on each panel.
  • Figure 2: a) B-band versus V-band magnitude. b) Colour magnitude diagram. The colours are as follows: data from 2024-11 (black), 2025-08-28 and 2025-08-29 (red), 2025-09-22 (green), 2025-10-19 and 2025-10-23 (blue), 2025-10-29 and 2025-10-31 (yellow).