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Leo Minor

Coordinates: Sky map 10h 00m 00s, +35° 00′ 00″
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Leo Minor
Constellation
Leo Minor
List of stars in Leo Minor
AbbreviationLMi
GenitiveLeonis Minoris
Pronunciation/ˌliːoʊ ˈmaɪnər/,
genitive /liːˈoʊn[invalid input: 'ɨ']s m[invalid input: 'ɨ']ˈnɒr[invalid input: 'ɨ']s/
Symbolismthe lesser Lion
Right ascension10
Declination+35
QuadrantNQ2
Area232 sq. deg. (64th)
Main stars2
Bayer/Flamsteed
stars		34
Stars with planets2
Stars brighter than 3.00m0
Stars within 10.00 pc (32.62 ly)0
Brightest star46 LMi (Praecipua) (3.83m)
Messier objects0
Meteor showersLeonis Minorids
Bordering
constellations		Ursa Major
Lynx
Cancer (corner)
Leo
Visible at latitudes between +90° and −45°.
Best visible at 21:00 (9 p.m.) during the month of April.

Leo Minor is a small and faint constellation in the northern celestial hemisphere. Its name is Latin for "the smaller lion", in contrast to Leo, the larger lion. It lies between the larger and more recognizable Ursa Major and Leo. Leo Minor was not regarded as a separate constellation by the ancients; it was designated by Johannes Hevelius in 1687.[1]

There are three stars brighter than magnitude 4.5, these forming a rough triangle. 46 Leonis Minoris, an orange giant of magnitude 3.8 which is located some 98 light years from earth. At magnitude 4.4, Beta Leonis Minoris is the second brightest star and the only one in the constellation with a Bayer designation. It is binary star, the brighter component of which is an orange giant and the fainter a yellow-white main sequence star. The third star of the triangle is 21 Leonis Minoris, a white main sequence star of average magnitude 4.5. Rapidly rotating, it is likely flattened in shape. Two stars with orbiting planets have been discovered. Leo Minor contains two pairs of interacting galaxies.

History

The Classical astronomers Aratus and Ptolemy had noted the region of what is now Leo Minor to be undefined and not forming any pattern in the sky, the latter classifying the stars there as άμὸρφωτοι (not belonging to a constellation outline) of the constellation of Leo.[2] Johannes Hevelius set about filling parts of the northern celestial hemisphere as he mapped the heavens, designating ten new constellations, seven of which are still recognised. Leo Minor was first depicted in his 1687 work Firmamentum Sobiescianum,[3] with 18 stars catalogued in the accompanying star catalogue Catalogus Stellarum Fixarum.[4] Hevelius decided upon Leo Minor or Leo Junior as a depiction that would align with its beastly neighbours the Lion and the Great Bear.[5] In 1845, English astronomer Francis Baily embarked on cataloging the stars of Hevelius' new constellations, and gave those brighter than apparent magnitude 4.5 a Greek letter known as a Bayer designation.[6] Richard A. Proctor gave the constellation the name Leaena "the Lioness" in 1870,[2] explaining that he sought to shorten the constellation names to make them more manageable on celestial charts.[7]

German astronomer Christian Ludwig Ideler posited that the stars of Leo Minor had been termed Al Thibā' wa-Aulāduhā, "Gazelle with her Young" on the Borgian globe, however Lach held that they had been Al Haud "the Pond", which the Gazelle jumps into.[2] In Chinese astronomy, the stars Beta, 30, 37 and 46 Leonis Minoris made up Neiping, a "Court of Judge or Mediator", or Shi "Court Eunuch"[8] or were combined with stars of the neighbouring Leo to make up a large celestial dragon or State Chariot.[2] A line of four stars representing four Imperial advisors known as Shaowei, may have consisted of stars from Leo Minor, Leo or somewhere else.[8]

Characteristics

Leo Minor is a small constellation bordered by Ursa Major to the north, Lynx to the west, and Leo to the south. It touches the corner of Cancer to the southwest. The three-letter abbreviation for the constellation, as adopted by the International Astronomical Union in 1922, is 'LMi'.[9] The official constellation boundaries, as set by Eugène Delporte in 1930, are defined by a polygon of 16 segments. In the equatorial coordinate system, the right ascension coordinates of these borders lie between 9h 22.4m and 11h 06.5m , while the declination coordinates are between 22.84° and 41.43°.[10] Ranked 64th out of 88 constellations in size, Leo Minor covers an area of 232.0 square degrees, or 0.562 per cent of the sky.[11] It culminates each year at 9 p.m. on 24 May.[12]

Notable features

The constellation Leo Minor as it can be seen by the naked eye.

Leo Minor is a dark area of the sky with a triangle of brighter stars just visible to the naked eye in good conditions.[13] Patrick Moore has described it as having "dubious claims to a separate identity".[14]

Stars

Main article: List of stars in Leo Minor

There are only three stars in the constellation brighter than magnitude 4.5,[5] and 37 stars with a magnitude brighter than 6.5.[11] Leo Minor does not have a star designated Alpha because Baily erred and allocated a Greek letter to only one star, Beta.[15] It is unclear whether he intended to give 46 Leonis Minoris a Bayer designation, as he recognised Beta and 46 Leonis Minoris as of the appropriate brightness in his catalogue. He died before revising his proofs, which might explain this star's omission.[5]

The brightest star in Leo Minor is an orange giant of magnitude 3.8 named 46 Leonis Minoris or Praecipua, which is situated 98 light-years from Earth.[15] With a spectral class K0III,[16] it has around 32 times the luminosity and is 8.5 times the size of our sun,[17] its orange colour evident when seen through binoculars.[14] It was also catalogued and named as o Leonis Minoris by Johann Elert Bode, which has been misinterpreted as Omicron Leonis Minoris.[5] There has also been confusion of its proper name, which appears to have been originally applied to 37 Leonis Minoris in the 1814 Palermo Catalogue of Giuseppe Piazzi, who mistakenly assessed the latter star as the brighter, and later applied (wrongly) by Allen to 46 Leonis Minoris—an error followed by subsequent astronomers.[8] The original Praecipua, 37 Leonis Minoris has an apparent magnitude of 4.69,[18] but is a distant yellow supergiant of spectral type G2.5IIa and absolute magnitude of −1.84.[19]


Beta Leonis Minoris is a binary star system. The primary is a giant star of spectral class G8 and apparent magnitude of 4.4. It has around double the mass, 7.8 times the radius and is 36 times as luminous as the Earth's sun. The secondary is a yellow-white main sequence star of spectral type F8 and separated by 11 seconds of arc. The two orbit around a common centre of gravity every 38.62 years.[20]

Around 98 light years away and around 10 times as luminous as our sun, 21 Leonis Minoris is a rapidly rotating white main sequence star, spinning on its axis in less than 12 hours and very likely flattened in shape.[21] Of average apparent magnitude 4.5 and spectral type A7V, it is a Delta Scuti variable.[22] These are short period (six hours at most) pulsating stars which have been used as standard candles and as subjects to study astroseismology.[23]

Also known as SU and SV Leonis Minoris, 10 and 11 Leonis Minoris are yellow giants of spectral type G8III, with average magnitudes 4.54 and 5.34 respectively. Both are RS Canum Venaticorum variables,[24][25] with 10 Leonis Minoris varying by 0.012 magnitude over 40.4 days, and 11 Leonis Minoris by 0.033 magnitude over 18 days.[26] 11 Leonis Minoris has a red dwarf companion of spectral type M5V and apparent magnitude 13.0.[27] 20 Leonis Minoris is a multiple star system only 49 light years away from the Sun. The main star is another yellow star, this time a dwarf of spectral type G3Va and apparent magnitude 5.4.[28] The companion is an old, active red dwarf that has a relatively high metallicity and is of spectral type M6.5. The fact that the secondary star is brighter than expected indicates it is likely two stars very close together that are unable to be made out separately with current viewing technology.[29]

R and S Leonis Minoris are long period Mira variables, while U Leonis Minoris is a semiregular variable;[30] all three are red giants of spectral types M6.5e-M9.0e,[31] M5e [32] and M6 D respectively.[33] R varies between magnitudes 6.3 and 13.2 during a period of 372 days, S varies between magnitudes 8.6 and 13.9 during a period of 234 days, and U varies between magnitudes 10.0 and 13.3 during a period of 272 days. The lack of bright stars makes finding these objects challenging for amateur astronomers.[30] G117-B15A, also known as RY Leonis Minoris, is a pulsating white dwarf of apparent magnitude 15.5.[34] With a period of approximately 215 seconds, and losing a second every 8.9 million years, the 400 million year old star has been touted as the most stable celestial clock.[35]

SX Leonis Minoris is a dwarf nova of the SU Ursae Majoris type that was identified in 1994.[36] It consists of a white dwarf and a donor star which orbit each other every 97 minutes. The white dwarf sucks matter from the other star onto an accretion disc which is heated to between 6000 and 10000 K and periodically erupts every 34 to 64 days, reaching magnitude 13.4 in these outbursts and remaining at magnitude 16.8 when quiet.[37] Leo Minor contains another dwarf nova, the little-studied RZ Leonis Minoris, which brightens to magnitude 14.2 from a baseline magnitude of around 17 but does so at shorter intervals than other dwarf novae.[38]

Two stars with planetary systems have been found. HD 87883 is an orange dwarf of magnitude 7.57 and spectral type K0V which lies 18 parsecs distant. With a diameter three quarters that of our sun, it is only 31 percent as luminous. It is orbited by a planet around 1.78 times the mass of Jupiter every 7.9 years, and there are possibly other smaller planets.[39] HD 82886 is a yellow dwarf of spectral type G0 and visual magnitude 7.63.[40] A planet 1.3 times the mass of Jupiter and orbiting every 705 days was discovered in 2011.[41]

Deep-sky objects

Leo Minor above the head of Leo, as depicted in Urania's Mirror, a set of constellation cards published in London c. 1825.[42]

Located 3 degrees southeast of 38 Leonis Minoris, NGC 3432 is seen nearly edge on. Known as the knitting needle galaxy, it is of apparent magnitude 11.2 and lies 42 million light years away. In 2000, a star within the galaxy brightened to magnitude 17.4, and has since been determined to be a luminous blue variable and supernova imposter.[43] NGC 3003, a SBbc barred spiral galaxy with an apparent magnitude of 12.3 and an angular size of 5.8 arcminutes, is seen almost edge-on.[44] NGC 3344, 25 million light years distant, is face-on towards earth.[45] Measuring 7.1 by 6.5 arcminutes in size, it has an apparent magnitude of 10.45.[46] NGC 3504 is a starburst barred spiral galaxy of apparent magnitude 11.67 and measuring 2.1 by 2.7 arcminutes.[47] It has hosted supernovae in 1998[48] and 2001.[49] It and the spiral galaxy NGC 3486 are also almost face-on towards Earth. This latter is magnitude 11.05 and measures 7.1 by 5.2 arcminutes.[50] NGC 2859 is an SB0 type lenticular galaxy.[51]

Arp 107 is a pair of galaxies in the process of merging, located some 450 million light years away.[52] NGC 3395 and NGC 3396 are a spiral and irregular barred spiral galaxy respectively that are interacting, located 1.33 degrees southwest of Praecipua.[53]

The mysterious deep sky object known as Hanny's Voorwerp was discovered in Leo Minor in 2007 by Dutch school teacher Hanny van Arkel while participating as a volunteer in the Galaxy Zoo project. Lying near the 730-light-year distant galaxy IC 2497, it is thought to be the visual light echo of a quasar now gone inactive.[54]

Meteor showers

Discovered by Dick McCloskey and Annette Posen of the Harvard Meteor Program in 1959,[55] the Leonis Minorids peak between October 18 and October 29. The shower's parent body is the long period comet C/1739 K1 (Zanotti).[56] A minor shower, it can only be seen from the Northern Hemisphere.[57]

References

Citations
  1. ^ Ridpath & Tirion 2001, pp. 168–69.
  2. ^ a b c d Allen 1963, p. 263.
  3. ^ Ridpath, Star Tales Filling the remaining gaps.
  4. ^ Hevelius 1687, pp. 214–15.
  5. ^ a b c d Wagman 2003, pp. 189–90.
  6. ^ Wagman 2003, p. 8.
  7. ^ Proctor 1870, pp. 16–17.
  8. ^ a b c Ridpath, Star Tales Leo Minor.
  9. ^ Russell 1922, p. 469.
  10. ^ IAU, The Constellations, Leo Minor.
  11. ^ a b Ridpath, Star Tales Constellations – part two.
  12. ^ The Constellations : Part 2 Culmination Times.
  13. ^ Thompson & Thompson 2007, p. 290.
  14. ^ a b Moore 2000, p. 103.
  15. ^ a b Ridpath & Tirion 2001, pp. 168–169.
  16. ^ SIMBAD 46 Leonis Minoris.
  17. ^ Kaler, Praecipua.
  18. ^ SIMBAD 37 Leonis Minoris.
  19. ^ Kovtyukh et al. 2010.
  20. ^ Kaler, Beta Leonis Minoris.
  21. ^ Kaler, 21 Leonis Minoris.
  22. ^ SIMBAD 21 Leonis Minoris.
  23. ^ Delta Scuti and the Delta Scuti variables.
  24. ^ SIMBAD 10 Leonis Minoris.
  25. ^ SIMBAD 11 Leonis Minoris.
  26. ^ Skiff & Lockwood 1986.
  27. ^ SIMBAD GJ 356 B.
  28. ^ SIMBAD 20 Leonis Minoris.
  29. ^ Gizis et al. 2000.
  30. ^ a b Levy 2005, pp. 186–87.
  31. ^ SIMBAD R Leonis Minoris.
  32. ^ SIMBAD S Leonis Minoris.
  33. ^ SIMBAD U Leonis Minoris.
  34. ^ SIMBAD RY Leonis Minoris.
  35. ^ McDonald Observatory.
  36. ^ Nogami & Masuda 1997.
  37. ^ Wagner et al. 1998.
  38. ^ Robertson et al. 1995.
  39. ^ Fischer et al. 2009.
  40. ^ SIMBAD HD 82886.
  41. ^ Planet HD 82886 b.
  42. ^ Ridpath, Urania’s Mirror.
  43. ^ O'Meara 2011, p. 196.
  44. ^ NED NGC 3003.
  45. ^ galaxy in a spin.
  46. ^ NED NGC 3344.
  47. ^ NED NGC 3504.
  48. ^ Garnavich 1998.
  49. ^ Matheson et al. 2001.
  50. ^ NED NGC 3486.
  51. ^ NED NGC 2859.
  52. ^ Spitzer Arp 107.
  53. ^ Motz & Nathanson 1991, p. 180.
  54. ^ Rincon 2008.
  55. ^ Jenniskens 2006.
  56. ^ Jenniskens 2012.
  57. ^ IMO Meteor Shower Calendar 2012.

Sources

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  • Fischer, Debra; Driscoll, Peter; Isaacson, Howard; Giguere, Matt; Marcy, Geoffrey W.; Valenti, Jeff; Wright, Jason T.; Henry, Gregory W.; Johnson, John Asher (2009). "Five Planets and an Independent Confirmation of HD 196885 Ab from Lick Observatory". The Astrophysical Journal. 703 (2): 1545–56. arXiv:0908.1596. Bibcode:2009ApJ...703.1545F. doi:10.1088/0004-637X/703/2/1545.
  • Garnavich, P. (1998). "Supernova 1998cf in NGC 3504". IAU Circular (6914): 1. Bibcode:1998IAUC.6914....1G. {{cite journal}}: Invalid |ref=harv (help)
  • Gizis, J. E.; Monet, D. G.; Reid, I. N.; Kirkpatrick, J. D.; Burgasser, A. J. (2000). "Two Nearby M Dwarf Binaries from 2MASS" (abstract page). Monthly Notices of the Royal Astronomical Society. 311 (2): 385–88. Bibcode:2000MNRAS.311..385G. doi:10.1046/j.1365-8711.2000.03060.x.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  • Hevelius, Johannes (1687). Catalogus Stellarum Fixarum (in Latin). Gdaņsk: Gedani, typis J.-Z. Stollii. {{cite book}}: Invalid |ref=harv (help)
  • Jenniskens, Peter (2006). Meteor Showers and their Parent Comets. Cambridge, United Kingdom: Cambridge University Press. pp. 83–84. ISBN 9780521853491. {{cite book}}: Invalid |ref=harv (help)
  • Jenniskens, Peter (September 2012). "Mapping Meteoroid Orbits: New Meteor Showers Discovered". Sky & Telescope: 22. {{cite journal}}: Invalid |ref=harv (help)
  • Kovtyukh, V. V.; Chekhonadskikh, F. A.; Luck, R. E.; Soubiran, C.; Yasinskaya, M. P.; Belik, S. I. (2010). "Accurate luminosities for F-G supergiants from FeII/FeI line depth ratios". Monthly Notices of the Royal Astronomical Society. 408 (3): 1568–75. doi:10.1111/j.1365-2966.2010.17217.x.{{cite journal}}: CS1 maint: multiple names: authors list (link) CS1 maint: unflagged free DOI (link)
  • Levy, David H. (2005). David Levy's Guide to Variable Stars. Cambridge University Press. ISBN 9780521608602. {{cite book}}: Invalid |ref=harv (help)
  • Matheson, P.; Jha, S.; Challis, P.; Kirshner, R.; Calkins, M. (2001). "Supernova 2001ac in NGC 3504". IAU Circular (7597): 3. Bibcode:2001IAUC.7597....3M.
  • Moore, Patrick (2000). Exploring the Night Sky with Binoculars. Cambridge, United Kingdom: Cambridge University Press. ISBN 9780521793902. {{cite book}}: Invalid |ref=harv (help)
  • Motz, Lloyd; Nathanson, Carol (1991). The Constellations: An Enthusiast's Guide to the Night Sky. London, United Kingdom: Aurum Press. ISBN 978-1-85410-088-7. {{cite book}}: Invalid |ref=harv (help)
  • Nogami, Daisaku; Masuda, Seiji; Kato, Taichi (1997). "The 1994 Superoutburst of the New SU UMa-type Dwarf Nova, SX Leonis Minoris". Publications of the Astronomical Society of the Pacific. 109: 1114–21. Bibcode:1997PASP..109.1114N. {{cite journal}}: Invalid |ref=harv (help)
  • O'Meara, Stephen James (2011). Deep-Sky Companions: The Secret Deep. Cambridge, United Kingdom: Cambridge University Press. ISBN 978-0-521-19876-9. {{cite book}}: Invalid |ref=harv (help)
  • Proctor, Richard Anthony (1870). A Star Atlas for the Library, the School and the Observatory. London, United Kingdom: Longmans, Green. {{cite book}}: Invalid |ref=harv (help)
  • Ridpath, Ian; Tirion, Wil (2001), Stars and Planets Guide, Princeton University Press, ISBN 0-691-08913-2
  • Robertson, J. W.; Honeycutt, R. K.; Turner, G. W. (1995). "The New International Symbols for the Constellations". Publications of the Astronomical Society of the Pacific. 107: 443-49. Bibcode:1995PASP..107..443R.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  • Russell, Henry Norris (1922). "The New International Symbols for the Constellations". Popular Astronomy. 30: 469. Bibcode:1922PA.....30..469R. {{cite journal}}: Invalid |ref=harv (help); Unknown parameter |month= ignored (help)
  • Skiff, Brian A.; Lockwood, G.W. (1986). "The Photometric Variability of Solar-type Stars. V. The Standard Stars 10 and 11 Leonis Minoris". Publications of the Astronomical Society of the Pacific. 98: 338-41. JSTOR 40678678. {{cite journal}}: Invalid |ref=harv (help)
  • Thompson, Robert Bruce; Thompson, Barbara Fritchman (2007). Illustrated Guide to Astronomical Wonders: From Novice to Master Observer. North Sebastopol, California: O'Reilly Media. ISBN 9780596526856. {{cite book}}: Invalid |ref=harv (help)
  • Wagman, Morton (2003). Lost Stars: Lost, Missing and Troublesome Stars from the Catalogues of Johannes Bayer, Nicholas Louis de Lacaille, John Flamsteed, and Sundry Others. Blacksburg, Virginia: The McDonald & Woodward Publishing Company. ISBN 978-0-939923-78-6. {{cite book}}: Invalid |ref=harv (help)
  • Wagner, R. Mark; Thorstensen, John R.; Honeycutt, R. K.; Howell, S. B.; Kaitchuck, R. H.; Kreidl, T. J.; Robertson, J. W.; Sion, E. M.; Starrfield, S. G. (1998). "A Photometric and Spectroscopic Study of the Cataclysmic Variable SX Leonis Minoris in Quiescence and Superoutburst". The Astronomical Journal. 109: 787. doi:10.1086/300201.{{cite journal}}: CS1 maint: multiple names: authors list (link)

Online sources

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