American Journal of Astronomy and Astrophysics
Volume 5, Issue 1, January 2017, Pages: 1-5
Received: Jan. 7, 2017;
Accepted: Jan. 21, 2017;
Published: Feb. 22, 2017
Views 1839 Downloads 70
Martin Beech, Campion College, The University of Regina, SK, Canada; Department of Physics, The University of Regina, SK, Canada
Corey McCowan, Campion College, The University of Regina, SK, Canada
Lowell Peltier, Department of Physics, The University of Regina, SK, Canada
A suite of stellar evolution models has been used to estimate the mass and metallicity of Proxima Centauri (GJ 551, HIP 70890, V645 Cen). It is found that the observations are best described by an M ≈ 0.12 M⊙ star with a heavy element mass fraction in the range 0.004 < Z < 0.01 (or equivalently, a metallicity of -0.5 < [Fe/H] < -0.3). The derived metallicity of Proxima is distinctly at odds with that established for α Cen A and αCen B. It is argued that both the observational data as well as the evolutionary models for Proxima Centauri are consistent with an age of some 7 to 8 Gyr and that its (presently derived) physical characteristics are inconsistent with an in situ or coevally origin with the α Cen AB binary.
The Composition and Evolutionary Status of Proxima Centauri, American Journal of Astronomy and Astrophysics.
Vol. 5, No. 1,
2017, pp. 1-5.
Beech, M. 2012. A journey through time and space: Alpha Centauri. Astron. Geophys. 53, 6.10.
Walke, D. 1979. Alpha and Proxima Centauri: radial velocities and the bound state. Ap. J. 234, L205.
Mathews, R and Gilmore, G. 1993. Is Proxima really in orbit about α Cen A/B? MNRAS. 261, L5.
Wertheimer, J., and Laughlin, G. 1995. Are Proxima and Alpha Centauri gravitationally bound? AJ. 132, 1995.
Beech, M. 2009. Proxima Centauri: a transitional modified Newtonian dynamics controlled orbital candidate? MNRAS. 399, L21.
Beech, M. 2011. The orbit of Proxima Centauri: a MOND versus standard Newtonian distinction. Astrophys. Space Sci. 333, 419.
Kervella, P., Thevenin, F., & Lovis. C. 2016. Proxima’s orbit around Alpha Centauri. arXiv:1611.03495v3.
Eggenberger, P. et al. 2004. Analysis of α Centauri AB including seismic constraints. A&A. 417, 235.
Bazot, M., et al. 2012. A Baysian approach to the modelling of α Cen A. MNRAS, 427, 1847.
Beech, M. 2011. Exploring alpha Centauri: from planets, to a cometary cloud, and impact flares from Proxima. The Observatory, 131, 212.
Demory, B. et al. 2009. Mass-radius relation of low and very low-mass stars revisited with the VLTI. A&A. 505, 205.
Mann, A. W. et al. 2015. How to constrain your M Dwarf: measuring effective temperature, bolometric luminosity, mass and radius. Ap. J. 804, 64.
Tayler, R. 1978. In, The Stars: their structure and evolution. Wykeham Publications, London.
Hansen, C., and Kawaler, S. 1994. In, Stellar Interiors: physical principles, structure and evolution. Springer-Verlag, New York.
Segransan, D. et al. 2003. First radius measurements of very low mass stars with the VLTI. A&A. 397, L57.
Doyle, J., and Butler, C. 1990. Optical and infrared photometry of dwarf M and K stars. A&A. 235, 335.
Townsend, R. 2015: http://www.astro.wisc.edu/~townsend/static.php?ref=ez-web.
Paxton, B. et al. 2015. Modules for experiments in stellar astrophysics (MESA): binaries, pulsations and explosions. Ap. J. Suppl. Ser. 220, article id. 15.
Eggleton, P. P. 1971. The evolution of low mass stars. MNRAS. 151, 351.
Schlaufman, K., Laughlin, G. 2010. A physically-motivated photometric calibration of M dwarf metallicity. A&A, 519, id. A105.
Brocato, E., Cassisi, S., & and Castellani, V. 1998. Stellar models for very low-mass main-sequence stars – the role of model atmospheres. MNRAS. 295, 711.
Cassisi, S. 2011. Very low-mass stars: structural and evolutionary properties. arXiv:1111.6464.
Baraffe, I. et al. 2015. New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit. A&A. 577, id. A42.
Baraffe, I. et al. 1997. Evolutionary models for metal-poor low-mass stars: lower main sequence of globular clusters and halo field stars. A&A. 327, 1054.
Haywood, M. 2001. A revision of the solar neighbourhood metallicity distribution. MNRAS. 325, 1375.
Shapley, H. 1951. Proxima Centauri as a flare star. PNAS. 37, 15.
Davenport, J. et al. 2016. MOST observations of our nearest neighbour: flares on Proxima Centauri. Ap. J. 829. article id. L31.
Yadav, R. et al. 2016. Magnetic cycles in a dynamo simulation of the fully convective M-star Proxima Centauri. Ap. J. 833, article id. L28.
West, A. et al. 2008. Constraining the age-activity relation for cool stars: The Sloan Digital Sky Survey Data Release 5 – low-mass star spectroscopic sample. AJ. 135, 785.
Benedict, G. et al. 1998. Photometry of Proxima Centauri and Barnard’s stars using Hubble Space Telescope Fine Guidance Sensor: A search for periodic variations. AJ. 116, 429.
Anglada-Escude, G. et al. 2016. A terrestrial planet candidate in a temperate orbit around Proxima Centauri. Nature, 536, 437.
Luger, R., and Barnes, R. 2014. Extreme water loss and abiotic O2 build-up on planets throughout the habitability zone of M Dwarfs. Astrobiology, 15, 119.
Brugger, B. et al. 2016. Possible internal structures and compositions of Proxima Centauri b. Ap. J. Lett. 831, article id. L16.