Denebola

Source: Wikipedia, the free encyclopedia.
This article is about the star. For other uses, see Denebola (disambiguation).
Not to be confused with Deneb, a star in the constellation Cygnus.
Denebola
Location of β Leonis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Leo
Pronunciation
 /dəˈnɛbələ/,[1]
Right ascension 11h 49m 03.57834s[2]
Declination +14° 34′ 19.4090″[2]
Apparent magnitude (V) 2.14[3]
Characteristics
Spectral type A3Va[4]
U−B color index +0.07[5]
B−V color index +0.09[5]
Variable type δ Sct[3]
Distance
35.9 ± 0.2 ly
(11.00 ± 0.06 pc)
Absolute magnitude (MV)+1.93[7]
Details
Myr
LTT 13249[11][12]
Database references
SIMBADdata

Denebola is the

apparent visual magnitude is 2.14, making it readily visible to the naked eye. Denebola is a Delta Scuti type variable star
, meaning its luminosity varies very slightly over a period of a few hours.

Nomenclature

Denebola is the most eastward (left) bright star in this stick-figure diagram overlaid on a constellation photograph of Leo

β Leonis (

Beta Leonis) is the star's Bayer designation. In Johann Bayer's Uranometria (1603), it was designated β (Beta) as the second-brightest star in the constellation. It also bears the Flamsteed designation of 94 Leonis (assigned on the basis of increasing right ascension rather than luminosity) and additional designations followed as the star was recorded in subsequent star catalogues
.

The traditional name Denebola is shortened from Deneb Alased, from the

R. A. Proctor's 1871 star chart of the Northern Hemisphere it was designated Deneb Aleet. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[16] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[17] included a table of the first two batches of names approved by the WGSN, which included Denebola for this star. It is now so entered in the IAU Catalog of Star Names.[18]

15th century astronomer Ulugh Beg, gives the name Al Ṣarfah, the Changer (i.e. of the weather), as the star's individual title.[19] Al-Biruni, a Muslim scholar and polymath of the 11th century, wrote of it: "The heat turns away when it rises, and the cold turns away when it disappears."[19]

Ancient Chinese astronomers designated it the first star of the five-star asterism "Seat of the Five Emperors", hence its

Chinese name
五帝座一 (Wǔdìzuò-yī).

In

Hindu astronomy, Denebola corresponds to the Nakshatra (a sector along the ecliptic
) named Uttara Phalgunī (second reddish one).

Denebola, along with Spica and Arcturus, is part of the Spring Triangle asterism, and by extension, also of the Great Diamond together with the star Cor Caroli.[20]

Properties

Denebola is a relatively young star with an age estimated at less than 400 million years. Interferometric observations give a radius that is about 173% that of the Sun. Its high rate of rotation results in an oblate shape with an equatorial bulge. It has 75% more mass than the Sun, which results in a much higher overall luminosity and a shorter life span on the main sequence.[8]

Illustration of an A-type dwarf star

Based upon the star's

luminosity class 'Va' indicating this is a particularly luminous dwarf, a main sequence star that is generating energy through the nuclear fusion of hydrogen at its core. The effective temperature of Denebola's outer envelope is about 8,500 K, which results in the white hue typical of A-type stars. Denebola has a high projected rotational velocity of 128 km/s, which is of the same order of magnitude as for the very rapidly rotating star Achernar. The Sun, in comparison, has an equatorial rotation velocity of 2 km/s.[9] This star is believed to be a Delta Scuti variable star that exhibits fluctuations in luminosity of 0.025 magnitudes roughly ten times per day.[21]

Denebola shows a strong

extrasolar planets
.

Kinematic studies have shown that Denebola is part of a stellar association dubbed the IC 2391 supercluster. All the stars of this group share a roughly common motion through space, although they are not gravitationally bound. This suggests that they were born in the same location, and perhaps initially formed an open cluster. Other stars in this association include Alpha Pictoris, Beta Canis Minoris and the open cluster IC 2391. In total more than sixty probable members of the group have been identified.[24]

In culture

In astrology, Denebola was believed to portend misfortune and disgrace.[25]

See also

References

  1. ^ "Denebola". Merriam-Webster.com Dictionary.
  2. ^
    S2CID 18759600
    .
  3. ^
    S2CID 125853869
    .
  4. ^
    S2CID 119417105
    .
  5. ^
    Bibcode:1991bsc..book.....H
    .
  6. Bibcode:1967IAUS...30...57E
    .
  7. S2CID 119257644
    .
  8. ^
    doi:10.1051/0004-6361:20047189
    .
  9. ^
    S2CID 16615394
    .
  10. S2CID 18475298
    .
  11. ^ "* bet Leo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2007-06-18.
  12. ^ "Denebola". Alcyone. Retrieved 2006-08-10.
  13. γ Leonis
    double star, which are unresolved to the naked eye, have a combined magnitude brighter than it.
  14. ISBN 0-486-21079-0
    . Retrieved 2010-12-12.
  15. S2CID 118597258
    .
  16. ^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
  17. ^ "Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). Retrieved 28 July 2016.
  18. ^ "IAU Catalog of Star Names". Retrieved 28 July 2016.
  19. ^ a b LacusCurtius • Allen's Star Names — Leo
  20. ^ Rao, Joe (June 11, 2012). "How to See Mars and Saturn in Night Sky's Spring Triangle". Space.com. Archived from the original on 2023-05-29. Retrieved 2024-01-29.
  21. ISBN 80-85882-08-6
    .
  22. Bibcode:1987A&A...181...77C
    .
  23. S2CID 54013449
    .
  24. doi:10.1086/116025
    .
  25. ^ Allen, Richard Hinckley (1899). Star Names and their Meanings. New York, Leipzig: G. E. Stechert.

Further reading

External links
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