Regulus

Brightest star in the constellation Leo

This article is about the star. For other uses, see Regulus (disambiguation).

Regulus

Location of Regulus (circled)

Observation data
Epoch J2000 Equinox J2000
Constellation | Leo
Pronunciation | UK: /ˈrɛɡˌjulʊs/ US: /ˈrɛɡˌjʊlʊsˌ/[1]
Regulus A
Right ascension | 10h 08m 22.311s[2]
Declination | +11° 58′ 01.95″[2]
Apparent magnitude (V) | 1.40[3]
Regulus B
Right ascension | 10h 08m 12.788s[4]
Declination | +11° 59′ 49.06″[4]
Apparent magnitude (V) | 8.13[5]
Regulus C
Right ascension | 10h 08m 12.897s[6]
Declination | +11° 59′ 48.88″[6]
Apparent magnitude (V) | 13.50[5]
Characteristics
Regulus A
Evolutionary stage | Blue straggler[7]
Spectral type | B8 IVn[3]
U−B color index | –0.36[8]
B−V color index | –0.11[8]
Variable type | Suspected[9]
Regulus BC
Evolutionary stage | Main sequence
Spectral type | K2 V[10] \+ M4 V[10]
U−B color index | +0.51[8]
B−V color index | +0.86[8]
Astrometry

Radial velocity (Rv)| 4.39±0.09[11] km/s
Proper motion (μ)|  RA: −248.73±0.35 mas/yr[2]
Dec.: 5.59±0.21 mas/yr[2]
Parallax (π)| 41.13±0.35 mas[2]
Distance| 79.3 ± 0.7 ly
(24.3 ± 0.2 pc)
Absolute magnitude (MV)| –0.57[12]
Astrometry

Radial velocity (Rv)| +6.72[4] km/s
Proper motion (μ)|  RA: −254.399 mas/yr[4]
Dec.: 8.127 mas/yr[4]
Parallax (π)| 41.2745±0.0270 mas[4]
Distance| 79.02 ± 0.05 ly
(24.23 ± 0.02 pc)
Absolute magnitude (MV)| 6.20[13]

Proper motion (μ)|  RA: −224.824 mas/yr[6]
Dec.: +9.091 mas/yr[6]
Parallax (π)| 41.2424±0.0589 mas[6]
Distance| 79.1 ± 0.1 ly
(24.25 ± 0.03 pc)
Absolute magnitude (MV)| 11.56[13]
Orbit[11]
Primary| α Leo Aa (HD 87901 A)
Companion| α Leo Ab (HD 87901 B)
Period (P)| 40.102±0.002 d
Semi-major axis (a)| 6.00±0.17 R☉ projected
Eccentricity (e)| 0 (assumed)
Semi-amplitude (K1)
(primary)| 7.58±0.12 km/s
Details

Mass| 4.15±0.06[14] M☉
Radius| 4.21+0.07
−0.06 (equatorial), 3.22+0.05
−0.06 (polar)[14] R☉
Luminosity| 341+27
−28[14] L☉
Surface gravity (log g)| 3.54±0.09[15] cgs
Temperature| 11,010 (equatorial), 14,520 (polar)[14] K
Metallicity [Fe/H]| +0.21[16] dex
Rotation| 15.9 hours[17]
Rotational velocity (v sin i)| 318±8[18] km/s
Age| ≳1[19] Gyr

Mass| 0.31±0.10[11] M☉
Radius| 0.061±0.011[11] R☉
Temperature| 20,000±4,000[11] K

Mass| 0.794±0.040[4] M☉
Radius| 0.778±0.017[4] R☉
Luminosity| 0.322±0.005[4] L☉
Surface gravity (log g)| 4.527[4] cgs
Temperature| 4,968+1
−3[4] K
Metallicity [Fe/H]| −0.21[20] dex

Mass| 0.315±0.025[21] M☉
Radius| 0.332±0.023[21] R☉
Luminosity| 0.0206±0.0006[21] L☉
Temperature| 3,783±126[21] K
Other designations
α Leonis, 32 Leonis, GJ 9316, HR 3982, ADS 7654, WDS J10084+1158
α Leo A: BD+12°2149, FK5 380, HD 87901, HIP 49669, SAO 98967, LTT 12716
α Leo B/C: BD+12°2147, HD 87884, SAO 98966, LTT 12714
Database references
SIMBAD| Regulus
| B
| C

Regulus is the brightest object in the constellation Leo and one of the brightest stars in the night sky. It has the Bayer designation designated α Leonis, which is Latinized to Alpha Leonis, and abbreviated Alpha Leo or α Leo. Regulus appears single, but is actually a quadruple star system composed of four stars that are organized into two pairs. The system lies approximately 79 light years from the Solar System.

The spectroscopic binary Regulus A consists of a blue-white main-sequence star and its companion, a pre-white dwarf. Regulus BC, also known as HD 87884, is separated from Regulus A by 176″ and is itself a close pair.

Regulus and five slightly dimmer stars (Zeta Leonis, Mu Leonis, Gamma Leonis, Epsilon Leonis, and Eta Leonis) have collectively been called 'the Sickle', which is an asterism that marks the head of Leo.

## Nomenclature

[edit]

α Leonis (Latinized to Alpha Leonis) is the star system's Bayer designation. The traditional name Rēgulus is Latin for 'prince' or 'little king'. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[22] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[23] included a table of the first two batches of names approved by the WGSN; which included Regulus for this star. It is now so entered in the IAU Catalog of Star Names.[24]

## Observation

[edit]

Regulus through Celestron CGEM DX 1100 @ F6.3, Canon T3i, Televue 4X Powermate, ISO 800, 30 sec exposure

The Regulus system as a whole is the twenty-first brightest star in the night sky with an apparent magnitude of +1.35. The light output is dominated by Regulus A. Regulus B, if seen in isolation, would be a binocular object of magnitude +8.1, and its companion, Regulus C, the faintest of the three stars that has been directly observed, would require a substantial telescope to be seen, at magnitude +13.5. Regulus A is itself a spectroscopic binary; the secondary star has not yet been directly observed as it is much fainter than the primary. The BC pair lies at an angular distance of 177 arc-seconds from Regulus A, making them visible in amateur telescopes.[25]

Regulus as viewed through a 110mm refractor in full daylight.

Regulus is 0.465 degrees from the ecliptic,[26] the closest of the bright stars, and is often occulted by the Moon. This occurs in spates every 9.3 years, due to lunar precession. The last spate was around 2017, with occultations every month from December 2016 till July 2017, each one limited to certain areas on Earth.[27] Occultations by Mercury and Venus are possible but rare, as are occultations by asteroids. Seven other stars which have a Bayer designation are less than 0.9° from the ecliptic (perfected, mean plane of Earth's orbit and mean apparent path of the Sun) the next brightest of which is δ (Delta) Geminorum, of magnitude +3.53.

The last occultation of Regulus by a planet was on July 7, 1959, by Venus.[28] The next will occur on October 1, 2044, also by Venus. Other planets will not occult Regulus over the next few millennia because of their node positions. An occultation of Regulus by the asteroid 166 Rhodope was filmed in Italy on October 19, 2005. Differential bending of light was measured to be consistent with general relativity.[29] Regulus was occulted by the asteroid 163 Erigone in the early morning of March 20, 2014.[30] The center of the shadow path passed through New York and eastern Ontario, but no one is known to have seen it, due to cloud cover. The International Occultation Timing Association recorded no observations at all.[31]

Although best seen in the evening in the northern hemisphere's late winter and spring, Regulus appears at some time of night throughout the year except for about a month (depending on ability to compensate for the Sun's glare, ideally done so in twilight) on either side of August 22–24, when the Sun is too close.[32] The star can be viewed the whole night, crossing the sky, in late February. Regulus passes through SOHO's LASCO C3 every August.[33]

For Earth observers, the heliacal rising (pre-sunrise appearance) of Regulus occurs late in the first week of September, or in the second week. Every 8 years, Venus passes very near the star system around or a few days before the heliacal rising, as on 5 September 2022 (the superior conjunction of Venus happens about two days earlier with each turn of its 8-year cycle, so as this cycle continues Venus will more definitely pass Regulus before the star's heliacal rising).[citation needed]

## Stellar system

[edit]

Regulus is the brightest star in the constellation of Leo (right tip, below is bright Jupiter in 2004).

Regulus is a multiple star system consisting of at least four stars and a substellar object. Regulus A is the dominant star, with a binary companion 177" distant that is thought to be physically related. Regulus D is a 12th magnitude companion at 212",[34] but is an unrelated background object.[35]

Regulus A is a binary star consisting of a blue-white subgiant star of spectral type B8, which is orbited by a star of at least 0.3 solar masses, which is probably a white dwarf. The two stars take approximately 40 days to complete an orbit around their common centre of mass. Given the extremely distorted shape of the primary, the relative orbital motion may be notably altered with respect to the two-body purely Keplerian scenario because of non-negligible long-term orbital perturbations affecting, for example, its orbital period. In other words, Kepler's third law, which holds exactly only for two point-like masses, would no longer be valid for the Regulus system. Regulus A was long thought to be fairly young, only 50–100 million years old, calculated by comparing its temperature, luminosity, and mass. The existence of a white dwarf companion would mean that the system is at least 1 billion years old, just to account for the formation of the white dwarf. The discrepancy can be accounted for by a history of mass transfer onto a once-smaller Regulus A.[19]

The primary of Regulus A has about 4.15 times the Sun's mass.[14] It is spinning extremely rapidly, with a rotation period of only 15.9 hours (for comparison, the rotation period of the Sun is 25 days[36]), which causes it to have a highly oblate shape.[17] This results in so-called gravity darkening: the photosphere at Regulus's poles is considerably hotter, and five times brighter per unit surface area, than its equatorial region.[19] The star's surface at the equator rotates at about 320 kilometres per second (199 miles per second), or 96.5% of its critical angular velocity for break-up. It is emitting polarized light because of this.[18]

Regulus BC is 5,000 AU[37] from Regulus A. A and BC share a common proper motion and are thought to orbit each other[5] taking several million years. Designated Regulus B and Regulus C, the pair has Henry Draper Catalogue number HD 87884. The first is a K2V star, while the second is about M4V.[17] The companion pair has an orbital period of about 600 years[5] with a separation of 2.5" in 1942.[17]

A far more distant brown dwarf named SDSS J1007+1930 (full name: SDSS J100711.74+193056.2) may be bound to the Regulus system, since it shares a similar proper motion and radial velocity and has a similar metal abundance to Regulus B, which hints for a physical connection between both systems. The estimated distance from Regulus is 3.9+0.6
−0.5 parsecs (12.6+2.0
−1.5 ly), and the orbital period assuming a circular orbit would be around 200 million years, comparable to the Sun's orbital period around the Milky Way (galactic year). It is estimated to have a mass of roughly 60 MJ (0.06 M☉),[note 1] an effective temperature of 1,600 K and a spectral type L9 or T0, making it a L dwarf or T dwarf. In the future it will either be stripped away by stellar encounters because it is so weakly bound to the system, or it was once closer and got ejected by dynamical interactions. The extreme distance makes it uncertain to conclude whether it is gravitationally bound to Regulus.[38]

Approximate true-color reconstruction of Regulus based on interferometric imaging.[14] Regulus system  | Separation
(arcsec)  | Projected
separation
(AU)  | Orbital
period  | Spectral
type | Mass
(M☉)  | App. mag.
(V)

|
|
|
|
|
|

Regulus ABC | Regulus A[orbit note 1] | Regulus Aa | 0.015 | 0.356 | 40.1 days | B8 IVn | 3.44 | 1.4
(combined)
Regulus Ab | pre-WD | 0.31
Regulus BC[orbit note 1] | Regulus B | 2.1 | 60 | 600 years | K2V | 0.78 | 8.1
Regulus C | M4V | 0.32 | 13.5
SDSS J1007+1930 | 27,200 | 800,000 | 200 million
years | L9 | 0.06 | 26

1. ^ a b Regulus A and B are separated by 180 arcseconds, resulting in a projected separation of 4400 AU/0.07 light years. The combined binary system may have an approximate orbital period of 130,000 years.

## Etymology and cultural associations

[edit]

Rēgulus is Latin for 'prince' or 'little king';[39] its Greek equivalent is Basiliskos or, in Latinised form, Basiliscus.[40][41][42] The name Regulus first appeared in the early 16th century.[42] It is also known as Qalb al-Asad, from the Arabic قلب الأسد, meaning 'the heart of the lion', a name already attested in the Greek Kardia Leontos[40][43] whose Latin equivalent is Cor Leōnis. The Arabic phrase is sometimes approximated as Kabelaced.[44] In Chinese it is known as 軒轅十四, the Fourteenth Star of Xuanyuan, the Yellow Emperor. In Indian astronomy, Regulus corresponds to the Nakshatra Magha ("the bountiful").

Babylonians called it Sharru ("the King"), and it marked the 15th ecliptic constellation. In India it was known as Maghā ("the Mighty"), in Sogdiana Magh ("the Great"), in Persia Miyan ("the Centre") and also as one of the four 'royal stars' of the Persian monarchy.[45] It was one of the fifteen Behenian stars known to medieval astrologers, associated with granite, mugwort, and the kabbalistic symbol .

In the Babylonian MUL.APIN, Regulus is listed as Lugal, meaning king, with co-descriptor, "star of the Lion's breast".[46]

## See also

[edit]

* Table of stars with Bayer designations
* List of nearest B-type stars

## Notes

[edit]

1. ^ Assuming an age of one billion years. This mass is below the hydrogen burning limit and make SDSS J100711.74+193056.2 substellar, unable to fuse hydrogen and become a dim star.

## References

[edit]

1. ^ "regulus". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
2. ^ a b c d van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664\. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600. Vizier catalog entry
3. ^ a b van Belle, Gerard T.; von Braun, Kaspar (2009). "Directly Determined Linear Radii and Effective Temperatures of Exoplanet Host Stars". The Astrophysical Journal. 694 (2): 1085–1098\. arXiv:0901.1206. Bibcode:2009ApJ...694.1085V. doi:10.1088/0004-637X/694/2/1085. S2CID 18370219.
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5. ^ a b c d Tokovinin, A. A. (1997). "MSC – a catalogue of physical multiple stars". Astronomy and Astrophysics Supplement Series. 124: 75–84\. Bibcode:1997A&AS..124...75T. doi:10.1051/aas:1997181.
6. ^ a b c d Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
7. ^ Fuhrmann, Klaus; Chini, Rolf (October 2017). "On the ancient field blue straggler HR 5455". Monthly Notices of the Royal Astronomical Society. 471 (2): 1888–1891\. doi:10.1093/mnras/stx1784. ISSN 0035-8711.
8. ^ a b c d Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237: 0. Bibcode:2002yCat.2237....0D.
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10. ^ a b Gies, D.R.; Dieterich, S.; Richardson, N. D.; Riedel, A. R.; Team, B. L.; McAlister, H. A.; Bagnuolo, Jr., W. G.; Grundstrom, E. D.; Štefl, S.; Rivinius, Th.; Baade, D.; et al. (2008). "A Spectroscopic Orbit for Regulus". The Astrophysical Journal. 682 (2): L117 – L120. arXiv:0806.3473. Bibcode:2008ApJ...682L.117G. doi:10.1086/591148. S2CID 118491233.
11. ^ a b c d e Gies, Douglas R.; et al. (2020). "Spectroscopic Detection of the Pre-White Dwarf Companion of Regulus". The Astrophysical Journal. 902 (1). Table 3. arXiv:2009.02409. Bibcode:2020ApJ...902...25G. doi:10.3847/1538-4357/abb372.
12. ^ Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
13. ^ a b Johnson, H. M.; Wright, C. D. (1983). "Predicted infrared brightness of stars within 25 parsecs of the Sun". Astrophysical Journal Supplement Series. 53: 643–711\. Bibcode:1983ApJS...53..643J. doi:10.1086/190905.
14. ^ a b c d e f Che, X.; Monnier, J. D.; Zhao, M.; Pedretti, E.; Thureau, N.; Mérand, A.; ten Brummelaar, T.; McAlister, H.; Ridgway, S. T.; Turner, N.; Sturmann, J.; Sturmann, L. (2011-04-18). "Colder and Hotter: Interferometric imaging of β Cassiopeiae and α Leonis". The Astrophysical Journal. 732 (2): 68. arXiv:1105.0740. Bibcode:2011ApJ...732...68C. doi:10.1088/0004-637x/732/2/68. ISSN 0004-637X.
15. ^ Fitzpatrick, E. L.; Massa, D. (March 2005). "Determining the Physical Properties of the B Stars. II. Calibration of Synthetic Photometry". The Astronomical Journal. 129 (3): 1642–1662\. arXiv:astro-ph/0412542. Bibcode:2005AJ....129.1642F. doi:10.1086/427855. S2CID 119512018.
16. ^ Baines, Ellyn K.; Armstrong, J. Thomas; Schmitt, Henrique R.; Zavala, R. T.; Benson, James A.; Hutter, Donald J.; Tycner, Christopher; van Belle, Gerard T. (2017). "Fundamental parameters of 87 stars from the Navy Precision Optical Interferometer". The Astronomical Journal. 155 (1): 16. arXiv:1712.08109. Bibcode:2018AJ....155...30B. doi:10.3847/1538-3881/aa9d8b. S2CID 119427037.
17. ^ a b c d McAlister, H. A.; ten Brummelaar, T. A.; Gies; Huang; Bagnuolo, Jr.; Shure; Sturmann; Sturmann; Turner; Taylor; Berger; Baines; Grundstrom; Ogden; Ridgway; Van Belle; et al. (2005). "First Results from the CHARA Array. I. An Interferometric and Spectroscopic Study of the Fast Rotator Alpha Leonis (Regulus)". The Astrophysical Journal. 628 (1): 439–452\. arXiv:astro-ph/0501261. Bibcode:2005ApJ...628..439M. doi:10.1086/430730. S2CID 6776360.
18. ^ a b Cotton, Daniel V; Bailey, Jeremy; Howarth, Ian D; Bott, Kimberly; Kedziora-Chudczer, Lucyna; Lucas, P. W; Hough, J. H (2017). "Polarization due to rotational distortion in the bright star Regulus". Nature Astronomy. 1 (10): 690–696\. arXiv:1804.06576. Bibcode:2017NatAs...1..690C. doi:10.1038/s41550-017-0238-6. S2CID 53560815.
19. ^ a b c Rappaport, S.; Podsiadlowski, Ph.; Horev, I. (2009). "The Past and Future History of Regulus". The Astrophysical Journal. 698 (1): 666–675\. arXiv:0904.0395. Bibcode:2009ApJ...698..666R. doi:10.1088/0004-637X/698/1/666. S2CID 15519189.
20. ^ Casagrande, L.; et al. (2011). "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey". Astronomy & Astrophysics. 530 (A138): 21. arXiv:1103.4651. Bibcode:2011A&A...530A.138C. doi:10.1051/0004-6361/201016276. S2CID 56118016.
21. ^ a b c d Hardegree-Ullman, Kevin K.; Apai, Dániel; Bergsten, Galen J.; Pascucci, Ilaria; López-Morales, Mercedes (2023-06-01). "Bioverse: A Comprehensive Assessment of the Capabilities of Extremely Large Telescopes to Probe Earth-like O2 Levels in Nearby Transiting Habitable-zone Exoplanets". The Astronomical Journal. 165 (6): 267. arXiv:2304.12490. Bibcode:2023AJ....165..267H. doi:10.3847/1538-3881/acd1ec. ISSN 0004-6256.
22. ^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
23. ^ "Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). Retrieved 28 July 2016.
24. ^ "IAU Catalog of Star Names". Retrieved 28 July 2016.
25. ^ Pugh, Philip (2009). "Simple Deep Sky Viewing". The Science and Art of Using Telescopes. Patrick Moore's Practical Astronomy Series. pp. 157–185\. doi:10.1007/978-0-387-76470-2_6. ISBN 978-0-387-76469-6.
26. ^ "Zodiac Stars". John Pratt's stars. Retrieved 2019-06-23.
27. ^ See 2016 Bright Star Occultations and 2017 Bright Star Occultations.
28. ^ "Occultations of bright stars by planets between 0 and 4000". Retrieved 2007-10-16.
29. ^ Sigismondi, Costantino; Troise, Davide (2008). "Asteroidal Occultation of Regulus:. Differential Effect of Light Bending". THE ELEVENTH MARCEL GROSSMANN MEETING on Recent Developments in Theoretical and Experimental General Relativity: 2594–2596\. Bibcode:2008mgm..conf.2594S. doi:10.1142/9789812834300_0469. ISBN 9789812834263.
30. ^ Sigismondi, C.; Flatres, T.; George, T.; Braga-Ribas, F. (2014). "Stellar limb darkening scan during 163 Erigone asteroidal occultation of Regulus on March 20, 2014 at 6:06 UT". The Astronomer's Telegram. 5987: 1. Bibcode:2014ATel.5987....1S.
31. ^ "Regulus 2014". International Occultation Timing Association. Archived from the original on 2020-11-21. Retrieved 2019-06-23.
32. ^ "In the Sky". Retrieved 2019-06-23.
33. ^ Battams, Karl. "Notable objects in LASCO C3". Sungrazing Comets. Navy.mil. Archived from the original on 2017-01-09. Retrieved 2012-09-05.
34. ^ Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466–3471\. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.
35. ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
36. ^ "Sun Fact Sheet". nssdc.gsfc.nasa.gov. Retrieved 2023-12-15.
37. ^ Lindroos, K. P. (1985). "A study of visual double stars with early type primaries. IV Astrophysical data". Astronomy and Astrophysics Supplement Series. 60: 183. Bibcode:1985A&AS...60..183L.
38. ^ Mamajek, Eric E.; Burgasser, Adam J. (December 2024). "SDSS J100711.74+193056.2: A Candidate Common Motion Substellar Companion to the Nearest B-type Star Regulus". The Astronomical Journal. 169 (2): 77. arXiv:2412.04599. doi:10.3847/1538-3881/ad991b. ISSN 1538-3881.
39. ^ regulus. Charlton T. Lewis and Charles Short. A Latin Dictionary on Perseus Project.
40. ^ a b Geminus; James Evans; J. L. Berggren (29 October 2006). Geminos's Introduction to the Phenomena: A Translation and Study of a Hellenistic Survey of Astronomy. Princeton University Press. ISBN 978-0-691-12339-4.
41. ^ βασιλίσκος. Liddell, Henry George; Scott, Robert; A Greek–English Lexicon at the Perseus Project.
42. ^ a b "Ian Ridpath's Star Tales – Regulus, the little king". Retrieved 20 Feb 2024.
43. ^ καρδία in Liddell and Scott.
44. ^ Pultar, Mustafa. "YILDIZ ADLARI SÖZLÜĞÜ - K" [Glossary of Star Names - K] (in Turkish). Retrieved 2025-05-04.
45. ^ Allen, Richard Hinckley (1963) [1899]. Star Names: Their Lore and Meaning. Dover Publications. pp. 255–6.
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## External links

[edit]

Wikimedia Commons has media related to Regulus (star).

* Portrait of a Star on the Edge
* Egg-Shaped Regulus is Spinning Fast
* APOD Pictures:

* Regulus Occulted
* Regulus & Leo 1 Dwarf Galaxy
* Bright Star Regulus near the Leo I Dwarf Galaxy
* Regulus, Mars & Coma Star Cluster

* "Regulus 3". SolStation. Retrieved December 1, 2005.

* v
* t
* e

Constellation of Leo

* List of stars in Leo
* Leo in Chinese astronomy

Stars|

| Bayer|

* α (Regulus)
* β (Denebola)
* γ (Algieba)
* δ (Zosma)
* ε (Algenubi)
* ζ (Adhafera)
* η
* θ (Chertan)
* ι
* κ (Al Minliar al Asad)
* λ (Alterf)
* μ (Rasalas)
* ν
* ξ
* ο (Subra)
* π
* ρ (Shaomin)
* σ
* τ
* υ
* φ
* χ
* ψ
* ω

|

Flamsteed|

* 3
* 6 (h)
* 7
* 8
* 9
* 10
* 11
* 12
* 13
* 15 (f)
* 18
* 19
* 20
* 21
* 22 (g)
* 23
* 26
* 31 (Yunü)
* 33
* 34
* 35
* 37
* 39
* 40
* 42
* 43
* 44
* 45
* 46
* 48
* 49
* 50
* 51 (m)
* 52 (k)
* 53 (l)
* 54
* 55
* 56
* 57
* 58 (d)
* 59 (c)
* 60 (b)
* 61 (p2)
* 62 (p3)
* 64
* 65 (p4)
* 66
* 67
* 69 (p5)
* 71
* 72
* 73 (n)
* 75
* 76
* 79
* 80
* 81
* 82
* 83
* 85
* 86
* 87 (e)
* 88
* 89
* 90
* 92
* 93
* 95 (o)
* 6 LMi
* 18 LMi
* 49 LMi
* 52 LMi

Variable|

* R
* AD
* CN
* CW
* DP
* EE
* GQ

HR|

* 4253 (p1)
* 4459 (Formosa)

HD|

* 81040
* 88133
* 89307
* 96063 (Dingolay)
* 97658
* 99109 (Shama)
* 100777 (Sagarmatha)
* 102272

Other|

* BD+20 2457
* Gliese 408
* Gliese 436 (Noquisi)
* GJ 3685
* HVS 7
* K2-3
* K2-18
* 2MASSI J0937347+293142
* 2MASS J10475385+2124234
* MACS J1149 Lensed Star 1
* PSR B0943+10
* PSR B0950+08
* SDSS J102915+172927
* TOI-6894

| Exoplanets|

* γ1 Leonis b
* Gliese 436 b (Awohali)
* HD 81040 b
* HD 88133 b
* HD 89307 b
* HD 89345 b
* HD 99109 b (Perwana)
* HD 100777 b (Laligurans)
* K2-18b

|

Galaxies|

| Messier|

* 65
* 66
* 95
* 96
* 105

|

NGC|

* 2903
* 2906
* 2911
* 2964
* 3041
* 3048
* 3049
* 3177
* 3185
* 3187
* 3190
* 3193
* 3226
* 3227
* 3239
* 3274
* 3301
* 3338
* 3357
* 3362
* 3367
* 3370
* 3377
* 3384
* 3412
* 3426
* 3447
* 3455
* 3489
* 3501
* 3506
* 3507
* 3521
* 3524
* 3535
* 3593
* 3596
* 3598
* 3599
* 3602
* 3605
* 3607
* 3608
* 3628
* 3632
* 3640
* 3646
* 3647
* 3664
* 3666
* 3678
* 3681
* 3684
* 3686
* 3697
* 3705
* 3710
* 3758
* 3799
* 3800
* 3801
* 3805
* 3806
* 3810
* 3816
* 3821
* 3837
* 3840
* 3841
* 3842
* 3844
* 3845
* 3851
* 3857
* 3859
* 3860
* 3861
* 3862
* 3864
* 3867
* 3868
* 3873
* 3875
* 3883
* 3884
* 3886
* 3900
* 3902
* 3908
* 3925
* 3937
* 3947
* 3951
* 3954
* 4002
* 4003
* 4005

Numbered|

* I
* II
* III
* IV
* V

Other|

* CLASS B1152+199
* Cosmic Horseshoe
* FBQ 0951+2635
* IC 2498
* IC 2628
* IRAS 10565+2448
* J1000+1242
* Leo P
* Leo T
* PSO J172.3556+18.7734
* SDSS J1029+2623
* UGC 6614
* UGC 6697

| Galaxy clusters|

* MACS J1149.5+2223

|

| Astronomical events|

* SN 1988Z

|

Category

* v
* t
* e

Notable stars and star systems coplanar with the ecliptic (and sun and approximately its planets, but specifically earth)

Stars or star systems
and time when
in opposition to sun
(culmination at midnight)|

| Bayer
designation|

* δ (Delta) Geminorum (mid January)
* δ (Delta) Cancri (start of February)
* α (Alpha) Leonis (or "Regulus") (late February)
* α (Alpha) Librae (early May)
* ο (Omicron) Sagittarii (early July)
* θ (Theta) Capricorni (early August)
* λ (Lambda) Aquarii (early September)
* ζ (Zeta) Piscium (early October)

|

Portals:

* Astronomy
* Stars
* Outer space

*[RA:]: Right Ascension
*[Dec.:]: Declination
*[v]: View this template
*[t]: Discuss this template
*[e]: Edit this template