List of least voluminous stars

This is a list of stars which are the least voluminous known (the smallest stars by volume).

List

This list is incomplete; you can help by expanding it.
Star name Radius
Solar radii
(Sun = 1)		 Radius
Jupiter radii
(Jupiter = 1)		 Notes
Sirius B 0.00874 [1]
Procyon B 0.01235 [2]

Smallest by type

List of the smallest stars by star type
Type Star name Radius
Solar radii
(Sun = 1)		 Radius
Jupiter radii
(Jupiter = 1)		 Radius
Earth radii
(Earth = 1)		 Radius
(km / mi)		 Date Notes
Red dwarf 2MASS J0523-1403 0.086 89.6 28477.568 2013 This red dwarf considered the smallest star known, and representative of the smallest star possible, which is not a brown dwarf or a dead star. [3]
Brown dwarf
White dwarf A.C.+70°8247 0.00000150734 0.00157316804 0.5 1934 [4]
Neutron star
Stellar-mass black hole XTE J1650-500 B 24 km (15 mi) 2008 This binary X-ray transient system, XTE J1650-500, component black hole, at 3.8 solar masses, is smaller than the previous recordholder GRO J1655-40 B of 6.3 MSun in the microquasar system GRO J1655-40. [5]

Smallest active stars

This is a listing of the smallest stars that are incontrovertibly stars that are still alive and fusing. Hence they are the smallest red dwarfs known, and those brown dwarfs that are known to be still in their short actively fusing phase.

List of the smallest live stars
Star name Radius
Solar radii
(Sun = 1)		 Radius
Jupiter radii
(Jupiter = 1)		 Type Notes
2MASS J0523-1403 0.086 89.6 Red dwarf This red dwarf is considered the smallest star known, since being found in 2013, and representative of the smallest star possible, which is not a brown dwarf. [3][6]
SSSPM J0829-1309 0.088 91.7 Red dwarf [6]
OGLE-TR-122B 0.120 1.16 Red dwarf This was once the smallest known actively fusing star, when found in 2005, through 2013. It is the smallest eclipsing red dwarf, and smallest observationally measured diameter. [7][8][9]
Proxima Centauri 0.145 151.0 Red dwarf This is the nearest neighbouring star to the Sun. [9][10]
Barnard's Star 0.196 204.2 Red dwarf [9][10]
CM Draconis B 0.2396 249.6 Red dwarf Part of the binary red dwarf system CM Draconis [9][11]
CM Draconis A 0.2534 264.0 Red dwarf Part of the binary red dwarf system CM Draconis [9][11]
Kapteyn's Star 0.291 303.1 Red dwarf This is the closest halo star to the Sun. [9][10]
Timeline of smallest live star recordholders
Star name Date Radius
Solar radii
(Sun = 1)		 Radius
Jupiter radii
(Jupiter = 1)		 Type Notes
2MASS J0523-1403 2013— 0.086 89.6 Red dwarf This red dwarf is considered the smallest star known, and representative of the smallest star possible that is not a brown dwarf. [3][6]
OGLE-TR-122B 2005-2013 0.120 1.16 Red dwarf This is the smallest eclipsing red dwarf, and smallest observationally measured diameter. [7][8][9]

References

  1. ↑ Zhang, B.; Reid, M. J.; Menten, K. M.; Zheng, X. W.; Brunthaler, A. (2012). "The distance and size of the red hypergiant NML Cygni from VLBA and VLA astrometry". Astronomy & Astrophysics 544: A42. arXiv:1207.1850. Bibcode:2012A&A...544A..42Z. doi:10.1051/0004-6361/201219587.
  2. ↑ name="Levesque2009"
  3. ↑ 3.0 3.1 3.2 John Bochanski (23 December 2013). "New Cutoff for Star Sizes". Sky and Telescope.
  4. ↑ Kuiper, G. P. (February 1936). "The White Dwarf A.C.+70°8247, the Smallest Star Known". Journal of the Royal Astronomical Society of Canada 30: 48. Bibcode:1936JRASC..30...48K.
  5. ↑ Andrea Thompson (1 April 2008). "Smallest Black Hole Found". Space.com.
  6. ↑ 6.0 6.1 6.2 Sergio B. Dieterich, Todd J. Henry, Wei-Chun Jao, Jennifer G. Winters, Altonio D. Hosey, Adric R. Riedel, John P. Subasavage (May 2014). "The Solar Neighborhood XXXII. The Hydrogen Burning Limit". The Astronomical Journal 147 (5): 25. arXiv:1312.1736. Bibcode:2014AJ....147...94D. doi:10.1088/0004-6256/147/5/94. 94.
  7. ↑ 7.0 7.1 Robert Roy Britt (3 March 2005). "Newfound Star Smaller than Some Planets". Space.com.
  8. ↑ 8.0 8.1 Jonathan O'Callaghan; Josh Barker (National Space Centre) (22 March 2013). "What is the smallest star?". SpaceAnswers.com.
  9. ↑ 9.0 9.1 9.2 9.3 9.4 9.5 9.6 Pont, F.; Melo, C. H. F.; Bouchy, F.; Udry, S.; Queloz, D.; Mayor, M.; Santos, N. C.; (27 January 2005). "A planet-sized transiting star around OGLE-TR-122. Accurate mass and radius near the hydrogen-burning limit". Astronomy and Astrophysics (April 2005) 433 (2): L21-L24. arXiv:astro-ph/0501611. Bibcode:2005A&A...433L..21P. doi:10.1051/0004-6361:200500025.
  10. ↑ 10.0 10.1 10.2 B.-O. Demory, D. Segransan, T. Forveille, D. Queloz, J.-L. Beuzit, X. Delfosse, E. Di Folco, P. Kervella, J.-B. Le Bouquin, C. Perrier (2 June 2009). "Mass-radius relation of low and very low-mass stars revisited with the VLTI". Astronomy and Astrophysics (October 2009) 505 (1): 205–215. arXiv:0906.0602. Bibcode:2009A&A...505..205D. doi:10.1051/0004-6361/200911976.
  11. ↑ 11.0 11.1 J.C. Morales, I. Ribas, C. Jordi, G. Torres, J. Gallardo, E.F. Guinan, D. Charbonneau, M. Wolf, D.W. Latham, G. Anglada-Escudé, D.H. Bradstreet, M.E. Everett, F.T. O'Donovan, G. Mandushev, R.D. Mathieu (8 October 2008). "Absolute properties of the low-mass eclipsing binary CM Draconis". The Astrophysical Journal (February 2009) 691 (2): 1400–1411. arXiv:0810.1541. Bibcode:2009ApJ...691.1400M. doi:10.1088/0004-637X/691/2/1400. Check date values in: |year= / |date= mismatch (help)