44 Nysa

44 Nysa
A blurry black-and-white photograph of Nysa taken by the Large Binocular Telescope on 15 February 2026. The asteroid resembles a jagged triangular shard bent at an angle, resembling the upside-down letter V.
Nysa photographed by the Large Binocular Telescope on 15 February 2026
Discovery
Discovered byHermann Goldschmidt
Discovery siteParis, France
Discovery date27 May 1857
Designations
Pronunciation/ˈnaɪsə/
Named after
Nysa (nymph)
A857 KA · 1977 CE
Main belt (inner) · Nysa–Polana complex (interloper)
AdjectivesNysian /ˈnɪsiən/
Orbital characteristics
Epoch 9 June 2026 (JD 2461200.5)
Uncertainty parameter 0
Aphelion2.785 AU
Perihelion2.060 AU
2.422 AU
Eccentricity0.1497
3.77 yr (1,377 d)
41.457°
0° 15m 41.046s / day
Inclination3.713°
131.476°
343.893°
Known satellites1
Proper orbital elements
2.423 AU
0.174
3.06°
95.4524 deg / yr
3.77151 yr
(1377.545 d)
Precession of perihelion long.
41.2913 arcsec / yr
Precession of asc. node
−46.3579 arcsec / yr
Physical characteristics
Dimensions
  • 113 km × 67 km × 65 km
  • (±15% uncertainty)
75+3
−1 km (volume equivalent)
Mass(5.76±1.43)×1017 kg
Mean density
> 3 g/cm3
6.4214175±0.0000005 h
34.7°±0.5° (to ecliptic)
102.7°±0.5°
+55.3°±0.5°
0.48 (average)
9 to 12
6.75

44 Nysa is an asteroid located in the inner region of the main asteroid belt. It is the largest, brightest, and first confirmed E-type asteroid, a rare type of asteroid with a highly reflective surface rich in enstatite. It was discovered by Hermann Goldschmidt in Paris, France on 27 May 1857 and was named after the nymph who raised the god Dionysus in Greek mythology. Nysa has one small moon which was discovered in 2026 and has not yet been named.

High-resolution imaging in 2026 revealed that Nysa has a highly concave and irregular shape, with three apparent lobes carved by several massive valleys and craters. Astronomers believe that it most likely resulted from the slow agglomeration of three asteroids—making Nysa a contact trinary. The asteroid has a uniform surface color and rotates with a period of 6.42 hours.

The origin of Nysa is uncertain. It probably did not experience any destructive collision events, as it is not known to host a family of asteroids sharing similar orbits and compositions. However, some small near-Earth asteroids including 2015 TC25 and 1998 KY26 have been suspected of being escaped fragments of Nysa. The asteroid orbits the Sun in the same region as the Nysa–Polana complex, a group of overlapping asteroid families. Despite the Nysa–Polana complex's name, researchers generally do not consider it related to Nysa due to their different compositions.

History

Discovery and naming

Nysa was discovered by German–French astronomer Hermann Goldschmidt in Paris, France on the night of 27 May 1857. He made the discovery using a 4-inch (10 cm) telescope, which was usually stationed at the upper floor of either his apartment or studio. Goldschmidt spotted the asteroid as a star-like object in the constellation Libra, at an apparent magnitude of 10.1. Although the weather became poor afterwards, Goldschmidt was able to reobserve Nysa on 1 June. He reported his discovery to the Astronomische Nachrichten via telegram and announced it as the 44th planet on the next day. It was his sixth asteroid discovery.

Over the next few weeks, Goldschmidt and other astronomers took additional observations of Nysa, allowing for the calculation of the asteroid's orbit and ephemerides. In the meantime, Goldschmidt continued discovering new asteroids, beginning with 45 Eugenia on 27 June 1857. Earlier that month, he had asked German polymath Alexander von Humboldt to suggest a name for the 44th asteroid. Humboldt chose the name Nysa, after the nymph and daughter of Aristaeus who raised the god Dionysus (also known as Bacchus) in Greek mythology. In a letter responding to Goldschmidt, Humboldt expressed his honor of naming Nysa and praised Goldschmidt's discovery on behalf of astronomers Johann Franz Encke, Karl Christian Bruhns, Heinrich Louis d'Arrest, and Franz Brünnow. Humboldt's choice of name was announced to Goldschmidt in a separate letter by Encke.

Nysa never received a planetary symbol, as their use had fallen out of favor due to the increasing rate of asteroid discoveries in the 1850s. Nysa was instead represented by its minor planet number 44 (enclosed in parentheses), which historically meant it was the 44th asteroid discovered. This became the modern minor-planet designation scheme where the asteroid's number is prefixed to its name, as in (44) Nysa or 44 Nysa.

Observational characterization

In terms of apparent magnitude from Earth, Nysa ranks among the top 40 brightest main-belt asteroids. Its apparent magnitude ranges from 9 to 12 depending on its phase angle and distance from Earth. Although Nysa is too faint to be seen with the naked eye, it could be observed with a pair of binoculars or through a telescope with a moderate aperture size (at least 3 to 6 inches or 8 to 15 cm). Because of its brightness, Nysa has attracted numerous observational studies.

In 1913, astronomers began suspecting that Nysa exhibits brightness variations over short periods.: 40  This was confirmed by Emilio Bianchi [it] and E. Padova in 1920, who plotted Nysa's light curve for the first time and measured a period of 3.2 hours. By the 1950s, astronomers recognized that the 3.2-hour period is actually half of Nysa's rotation period. The direction of Nysa's rotation axis was determined by 1962.

During the 1970s, astronomers began measuring the diameters of asteroids for the first time via infrared radiometry. This led to the first measurement of Nysa's diameter and albedo, revealing it to be a small and highly reflective object. In 1975, polarimetry and color measurements revealed that Nysa had an enstatite-rich surface unlike any previously observed asteroid.: 675  Two more asteroids—64 Angelina and 434 Hungaria—were later found to share similar compositions as Nysa, which led astronomers to introduce the E-type asteroid classification for these objects in 1977.: 675 

In 1979, astronomers pointed out that Nysa's light curve resembles that of the contact binary star W Ursae Majoris, which raised suspicions that the asteroid might be a binary or contact binary. This prompted an international campaign for observing Nysa later that year. Although the 1979 campaign was unable to confirm Nysa's binarity, it provided more accurate measurements of the asteroid's rotation period and axis direction. Subsequent studies using light curves, radar observations, interferometric imaging, and stellar occultations all hinted that Nysa's shape must be elongated, lopsided, and concave, but could not conclude whether it is a contact binary.

Nysa was first imaged in detail in 2026, through the use of large ground-based telescopes (Large Binocular Telescope and Very Large Telescope) equipped with adaptive optics. The images revealed that Nysa has a three-lobed shape and a tiny moon; the shape was reported by a team of astronomers led by Kate Minker in February 2026, while the moon's discovery was reported later by a team led by Anthony Berdeu in May 2026. The finalized results were later announced in an August 2026 press release by the Lowell Observatory.

Orbit

Diagram showing the orbits of Nysa and the inner Solar System planets

Nysa is located in the main asteroid belt between the orbits of Mars and Jupiter. Specifically, it is in the inner region of the main belt, where the outer edge is cut off by the 3:1 mean-motion orbital resonance with Jupiter. Nysa follows an elliptical orbit around the Sun with a semi-major axis of 2.42 astronomical units (AU) and an orbital period of 3.77 Earth years. Its current orbit brings it within 2.1 AU of Sun at perihelion to 2.8 AU at aphelion, with an eccentricity of 0.15 and a low inclination of 3.7° with respect to the ecliptic. Over millions of years, Nysa's orbital elements vary and average out with a proper eccentricity of 0.17 and a proper inclination of 3.1°.

Nysa orbits within a densely populated region of the inner main belt, where several asteroid families including the Nysa–Polana complex and Massalia family can be found. Nysa occasionally passes close enough to other asteroids to show noticeable gravitational perturbations. For example, in April 1988, astronomers observed Nysa pass within 0.037 AU (5.5 million km; 3.4 million mi) of 20 Massalia.

Physical characteristics

Size and shape

Surface features of Nysa
Label Type Width
(km)		 Depth
(km)
A Crater/secondary basin 38 6
B Crater 20
C Crater 35
D Crater 21
E Southern cavity 53 17
F Northern cavity 44 5
G Crater 17
H Crater 8
I Collum/Valley
J Collum/Valley
Top row: Animated time lapse of Nysa rotating, as seen in Large Binocular Telescope photographs (left) versus a rendered 3D shape model (right).
Bottom row: Light curve of Nysa, showing two brightness peaks per 6.42-hour rotation.

Nysa is an elongated object with dimensions of 113 km × 67 km × 65 km (70 mi × 42 mi × 40 mi) (15% uncertainty for each axis). When treated as a sphere, Nysa's has a volume equivalent diameter of 75+3
−1 km (47+2
−1 mi). Long-term measurements of perturbations in the trajectories of other asteroids indicate that Nysa has a mass of (5.76±1.43)×1017 kg. The asteroid is expected to have a bulk density of at least 3 g/cm3, similar to other asteroids and meteorites that share Nysa's composition. This density is higher than that of a typical main-belt asteroid, which may indicate an internal structure consisting of compact (low porosity) rock or a metal-rich core.

Nysa's shape is extremely irregular and more concave than any previously observed asteroid. High-resolution imaging by telescopes has shown that Nysa is carved by ten major indentations, which researchers have alphabetically labeled A to J. These include two deep valleys (labeled I and J), which divide the asteroid into three distinct lobes. These valleys wrap around the asteroid's circumference and make the lobes appear connected by narrow necks, called "colli". At least five craters have been identified on Nysa, with diameters ranging from 8 to 35 km (5.0 to 21.7 mi). Nysa additionally has two major cavities at its south and north poles (labeled E and F, respectively), with E being 53 km (33 mi) wide and 17 km (11 mi) deep and F being 44 km (27 mi) wide and 5 km (3.1 mi) deep. A possible crater or secondary basin, labeled A, lies next to F between Nysa's smallest lobes with a width of 38 km (24 mi) and a depth of 6 km (3.7 mi).

The origin of Nysa's shape is uncertain; it could either be the result of multiple large asteroid impacts or the slow agglomeration of three asteroids 20 to 60 km (12 to 37 mi) in size. The latter scenario would suggest that Nysa is a contact trinary—making it the first such object discovered. Astronomers believe that this is the most likely case, since impacts alone could not explain the asteroid's valleys. Nevertheless, impacts still play a role in reshaping Nysa, particularly in the creation of impact craters which appear as small concavities.

Rotation

Nysa spins around a fixed axis with a rotation period of approximately 6.42 hours. Its rotation axis crosses through its shortest dimension, with its north pole pointing toward the ecliptic coordinates (λ, β) = (102.7°±0.5°, +55.3°±0.5°). The asteroid's rotation is prograde with an axial tilt of 34.7°±0.5° with respect to the ecliptic. Because of its elongated shape, Nysa's brightness periodically varies as it rotates. Astronomers have exploited this phenomenon to measure Nysa's rotation period since the 1920s. When plotted as a light curve, Nysa's brightness exhibits two rounded peaks and two sharp minima per rotation.: L20 

Surface and composition

Visible and near-infrared reflectance spectra of Nysa (light blue), the E(III)-type near-Earth asteroid 2015 TC25 (black), and different-sized samples of an aubrite from Rantila (navy and orchid). All objects share the 0.9 μm absorption feature due to pyroxene.

Nysa has a bright, colorless surface rich in enstatite, a reflective silicate mineral that is generally poor in iron. This makes Nysa an E-type asteroid, a relatively rare type of asteroid typically found in the inner main asteroid belt.: 3  It is the prototype of the E-type asteroids,: 675 : 88  being the largest, brightest, and first confirmed member of this group. Nysa and the E-type asteroids are believed to be the parent bodies of enstatite-rich meteorites, which include aubrites and enstatite chondrites.

Estimates of Nysa's visible geometric albedo range from 0.41 to 0.55, with the average being 0.48. Resolved imaging of Nysa has shown that its surface is uniform, with no albedo and color variations greater than 5%. Nysa is thought to have a dense surface regolith like other E-type asteroids due to its high radar albedo and polarization ratio—meaning it reflects and polarizes radar waves in large amounts. As Nysa comes to opposition (phase angle less than 5°), the asteroid's brightness in visible light sharply peaks by about 0.3 magnitudes. Nysa's sharp opposition surge is thought to be caused by coherent backscattering due to fine, submicron-sized particles composing much of its surface.

In visible light, Nysa exhibits a mostly flat reflectance spectrum that slightly increases reflectance at longer (redder) wavelengths. In near-infrared, Nysa absorbs light at wavelengths of 0.9 and 1.8 μm, indicating that its surface contains iron-bearing pyroxene such as orthopyroxene or forsterite.: 120  This makes Nysa a member of the E(III) subclass of E-type asteroids, which are thought to be fragments of an igneous parent body that underwent extensive reduction.: 120 : 5  Nysa and other E-type asteroids are also classified as X-type asteroids, because their visible reflectance spectra are indistinguishable from those of metallic M-type and organic-rich P-type asteroids.: 220 : 2  In the Bus–DeMeo classification system, Nysa is further classified an Xn-type asteroid because its spectrum exhibits a sharp absorption feature at 0.9 μm.: 4 : 2 

Satellite

Nysa and its moon (arrow) photographed by the Large Binocular Telescope on 15 February 2026. A low-exposure photo of Nysa is superimposed on top of a grainy long-exposure photo of the moon.

Nysa is classified as a binary asteroid because it has one known moon. The moon of Nysa is unnamed with the informal designation S/2026 (44) 1. It was discovered in 2026 by a team of astronomers led by Anthony Berdeu, during analyses of Large Binocular Telescope images of Nysa taken on 15 February and 21 March 2026. The discovery was announced by the Central Bureau of Astronomical Telegrams on 26 May 2026.

S/2026 (44) 1 is significantly fainter than Nysa, having an apparent magnitude difference of about 9. Because of this, the moon is hidden within Nysa's glare, which necessitates the use of advanced image processing techniques to detect it. Assuming the moon has the same albedo as Nysa, its diameter is estimated to be 1.0 ± 0.5 km (0.6 ± 0.3 mi). S/2026 (44) 1 has not been observed long enough to have its orbit determined, though the moon's observed projected separation from Nysa suggests that it orbits at least 180 km (110 mi) away.

Origin and family

Many details about Nysa's origin and collisional history are uncertain, and studies of its shape, composition, and surroundings in the asteroid belt have produced different interpretations.

A 2026 study by Kate Minker and colleagues proposed that Nysa could either be a contact trinary of slowly-merged asteroids or a coherent single body deformed by several large impacts. Of these scenarios, Minker et al. considered the former more likely. In the contact trinary scenario, the three constituent asteroids most likely had a common composition and origin, since Nysa has a uniform present-day surface. However, the origin of these asteroids is unclear: if they are reaccumulated fragments from a destructive collision event, then there should also be many smaller fragments on similar orbits around the Sun, forming an asteroid family. However, no such family sharing Nysa's orbit and composition has been found.: 6 

Proper orbital elements (inclination vs. eccentricity) of the Nysa–Polana complex, with each asteroid represented as a circle scaled by diameter and color-coded by albedo. Low-albedo (C-type) asteroids are clustered near 142 Polana, while moderate-albedo (S-type) asteroids are clustered near 135 Hertha. Nysa does not have a cluster of high-albedo asteroids.

Some E-type near-Earth asteroids have been suggested to be escaped fragments of Nysa, due to their similar orbital inclinations and E(III) classification. These include 2015 TC25 and 1998 KY26, both of which are only a few meters in diameter. These asteroids are thought to have migrated from the inner main belt to the near-Earth region via the Yarkovsky effect and ν6 secular resonance, which are caused by sunlight and Saturn's apsidal precession, respectively.

Nysa orbits within a region of the asteroid belt populated by multiple overlapping asteroid families, collectively known as the Nysa–Polana complex. The Nysa–Polana complex includes the Hertha family of S-type asteroids, which was historically named the "Nysa family". Despite their names, the Nysa–Polana complex and its "Nysa family" are likely not physically related to Nysa because they have completely different compositions. For this reason, researchers generally consider Nysa an interloper of the Nysa–Polana complex. Nevertheless, some studies have attempted to link Nysa to the complex by proposing that the two originated from compositionally different layers of a collisionally destroyed parent body.

See also

Notes

  1. 1 2 3 According to sources from the 1800s, the asteroid was named after the nymph and daughter of Aristaeus who raised the god Dionysus (Bacchus). On the other hand, in the Dictionary of Minor Planet Names from the 2000s, astronomer Lutz D. Schmadel claimed that the asteroid was named after the mythical land of Nysa, where Dionysus (Bacchus) was raised by nymphs. Schmadel's claim was cited in a 2026 paper by Minker et al. and was propagated in press releases and news reports on the aforementioned paper.
  2. 1 2 Fuentes-Muñoz et al. (2025) give Nysa's mass in terms of the standard gravitational parameter GM = 0.038444658±0.009560725 km3 s−2 (or after converting to SI units, (3.8444658±0.9560725)×107 m3 s−2). This can be converted into mass (M) by dividing GM (in SI units) by the gravitational constant G = 6.6743×10−11 m3⋅kg−1⋅s−2. The resulting mass of Nysa is approximately M = (5.76±1.43)×1017 kg.
  3. 1 2 Minker et al. (2026) says that Nysa's density is at least 3 g/cm3. Given Nysa's volume-equivalent sphere diameter of D = 75+3
    −1     km     from Minker et al. (2026) and mass of M = (5.76±1.43)×1017 kg from Fuentes-Muñoz et al. (2025), the density formula gives .
  4. 1 2 The ecliptic latitude β is the angle offset from the ecliptic plane (β = 0°), while the axial tilt (obliquity i) with respect to the ecliptic is the angle offset from the ecliptic north pole (β = +90°). Nysa's ecliptic obliquity of i = 34.7° is calculated by subtracting its rotation pole's ecliptic latitude of β = +55.3° from the ecliptic north pole's latitude of β = +90°: i = +90°−(55.3°) = 34.7°.
  5. 1 2 Nysa was previously classified as an Xc-type asteroid in the Bus–DeMeo classification system, but was later reclassified as an Xn-type asteroid. The Xn class was introduced to the Bus–DeMeo system in 2019.
  6. 1 2 Tatsumi et al. (2026) provide a list of confirmed and candidate E-type asteroids (high-albedo X-type asteroids) in Appendix A (Table A.1). In that table, Nysa has the smallest absolute magnitude (H) value of all confirmed E-type asteroids, meaning it is the brightest and largest known member.: 9  Although the high-albedo X-type asteroid 92 Undina is brighter and larger than Nysa, it has not been confirmed as an E-type asteroid.: 9 
  7. ↑ The JPL Horizons On-Line Ephemeris System says Nysa was in the constellation Libra at the time of discovery, which corroborates this claim.
  8. ↑ Asteroids were considered a type of small planet in the 19th century.
  9. ↑ In chronological order, Goldschmidt's first five asteroid discoveries were: 21 Lutetia, 32 Pomona, 36 Atalante, 40 Harmonia, and 41 Daphne.
  10. ↑ The name is also spelled "Nyssa" in some of the earliest references, as in an article in the French journal Cosmos from July 1857.
  11. ↑ Described as "cone-shaped" in light curve studies.
  12. ↑ All information in this table is sourced from Table R.1 of Minker et al. (2026).
  13. ↑ Nysa's color has been described as "blue", "colorless", or "neutral" with respect to the Sun. This essentially means Nysa reflects similar amounts of light across the visible spectrum, making its color white.
  14. ↑ The discoverers of S/2026 (44) 1 include: Anthony Berdeu, Kate Minker, Gianluca Li Causi, Al Conrad, Fernando Pedichini, Simone Antoniucci, Michaël Marsset, Benoit Carry, and Frédéric Vachier. Full names are mentioned in Lowell Observatory's press release.

References

  1. 1 2 3 Goldschmidt, Hermann (2 June 1857). "Schreiben des Hrn. Goldschmidt an den Herausgeber". Astronomische Nachrichten (in German). 46 (9): 143. Bibcode:1857AN.....46..143G. doi:10.1002/asna.18570460910.
  2. 1 2 Goldschmidt, Hermann (12 June 1857). "Discovery of a New Planet". Monthly Notices of the Royal Astronomical Society. 17: 223. Bibcode:1857MNRAS..17..223G. doi:10.1093/mnras/17.8.223.
  3. 1 2 3 4 Gould, B. A. (3 June 1857). "Letter from Mr. Goldschmidt to the Editor". The Astronomical Journal. 5 (104): 57. Bibcode:1857AJ......5...57G. doi:10.1086/100589.
  4. ↑ Noah Webster (1884) A Practical Dictionary of the English Language
  5. 1 2 3 4 5 "(44) Nysa = 1857 KA = 1977 CE". Minor Planet Center. Retrieved 28 July 2026.
  6. 1 2 3 4 5 6 Dykhuis, Melissa J.; Greenberg, Richard (May 2015). "Collisional family structure within the Nysa–Polana complex". Icarus. 252: 199–211. arXiv:1501.04649. Bibcode:2015Icar..252..199D. doi:10.1016/j.icarus.2015.01.012.
  7. ↑ Katz (2004) The complete elegies of Sextus Propertius
  8. ↑ Stein (2004) Persephone Unveiled
  9. 1 2 3 4 5 6 7 "44 Nysa (A857 KA)". JPL Small-Body Database (2026-03-22 last obs.). Jet Propulsion Laboratory. Retrieved 28 July 2026.
  10. 1 2 "(44) Nysa – Proper Elements". Asteroids Dynamic Site. Retrieved 28 July 2026. For more information about proper orbital elements, go to the "Proper Elements" tab and then click "[Help]" at the upper right corner. The synthetic proper orbital elements shown come from simulations over a 2-million-year integration time span (ITS). To convert sin(i) into degrees, use the arcsine function (arcsin(0.0533592) ≈ 3.0587°).
  11. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 Minker, Kate; Berdeu, Anthony; Causi, Gianluca Li; Hanuš, Josef; Marsset, Michaël; Conrad, Al; et al. (August 2026). "Unmasking (44) Nysa: Evidence for a trilobate structure". Astronomy & Astrophysics. 712: L26. arXiv:2607.25786. Bibcode:2026A&A...712A..26M. doi:10.1051/0004-6361/202661603.
  12. 1 2 3 4 5 Shepard, Michael K.; Kressler, Karelyn M.; Clark, Beth Ellen; Ockert-Bell, Maureen E.; Nolan, Michael C.; Howell, Ellen S.; et al. (May 2008). "Radar observations of E-class Asteroids 44 Nysa and 434 Hungaria" (PDF). Icarus. 195 (1): 220–225. Bibcode:2008Icar..195..220S. doi:10.1016/j.icarus.2007.12.018.
  13. 1 2 3 4 5 6 7 8 9 10 11 12 13 Tatsumi, Eri; de León, Julia; Popescu, Marcel M. (May 2026). "Hayabusa2# enstatite-like target 1998 KY26 originating from the Nysa family". Astronomy & Astrophysics. 709: A105. Bibcode:2026A&A...709A.105T. doi:10.1051/0004-6361/202659046.
  14. 1 2 3 Whitt, Kelly Kizer (2 August 2026). "Does asteroid Nysa have 3 lobes and a moon?". EarthSky. Archived from the original on 3 August 2026. Retrieved 2 August 2026.
  15. ↑ Cave, Edward (1867). "Hermann Goldschmidt, Artist and Astronomer". The Gentleman's Magazine. Vol. 223. p. 339.
  16. 1 2 Schirach, W. F. H. (1 June 1953). "Huntsmen of the Night Sky". Monthly Notes of the Astronomical Society of South Africa. 12 (6): 50–51. Bibcode:1953MNSSA..12...50S. hdl:10520/AJA00248266_1315.
  17. 1 2 "Miscellen". Natur und Offenbarung (in German). Vol. 3. Münster: Aschendorff. June 1857. p. 336. [The 44th minor planet was discovered one month later, on 27 May at 11 p.m., by Mr Hermann Goldschmidt in Paris, in the constellation Libra. Writing to us on the 15th of the current month, Mr Goldschmidt informs us concerning the name to be given to the planet: "My wish has finally been fulfilled, to leave the naming of one of the planets I have discovered to Mr von Humboldt.]
  18. ↑ "JPL Horizons On-Line Ephemeris for 44 Nysa (A857 KA) on 1857 May 27–1857 May 28 (UT)". JPL Horizons On-Line Ephemeris System. Jet Propulsion Laboratory. Retrieved 8 August 2026. Ephemeris Type: Observer and Center: 500@399 (geocentric). In the URL, quantity "1" gives RA/Dec coordinates and quantity "29" gives the abbreviation for the constellation.
  19. 1 2 3 4 Hilton, J. L. (16 November 2007). "When did asteroids become minor planets?". U.S. Naval Observatory. Archived from the original on 21 September 2007. Retrieved 27 March 2025.
  20. ↑ Metzger, Philip; Sykes, Mark; Stern, Alan; Runyon, Kirby (February 2019). "The reclassification of asteroids from planets to non-planets". Icarus. 319: 21–32. arXiv:1805.04115. Bibcode:2019Icar..319...21M. doi:10.1016/j.icarus.2018.08.026.
  21. 1 2 Peebles, Curtis (2000). Asteroids: a history. Smithsonian Institution Press. p. 13. ISBN 1-56098-389-2.
  22. 1 2 Goldschmidt, Hermann (11 June 1857). "Fernere Beobachtungen des Planeten (44). Auszug aus einem Schreiben des Hrn. Goldschmidt". Astronomische Nachrichten (in German). 46 (11): 171. Bibcode:1857AN.....46..171G. doi:10.1002/asna.18570461106.
  23. 1 2 Pape, M. (12 June 1857). "Elements of Planet (44)". Monthly Notices of the Royal Astronomical Society. 17 (8): 253. Bibcode:1857MNRAS..17..253P. doi:10.1093/mnras/17.8.253.
  24. ↑ Pape, C. F. (24 June 1857). "Elemente und Ephemeride für Planet (44), berechnet von Herrn Pape". Astronomische Nachrichten (in German). 46 (12): 191. Bibcode:1857AN.....46..191P. doi:10.1002/asna.18570461204.
  25. 1 2 "Revue encyclopédique hebdomadaire des progrès des sciences et de leur applications aux arts e a l'industrie". Cosmos (in French). Vol. 6. Paris, France. 24 July 1857. p. 85. [Mr. Élie de Beaumont learned yesterday at the Academy of Sciences that the forty-fourth minor planet, discovered by Mr. Goldschmidt on May 27, had, at the suggestion of Mr. von Humboldt, been given the name Nyssa or Nysa, the nurse of Bacchus, one of the nymphs who raised the god of wine]{{cite book}}: CS1 maint: location missing publisher (link)
  26. 1 2 Meunier, Victor, ed. (2 August 1857). "Bulletin des sciences pures et appliquées – Astronomie". L'Ami des sciences: journal du dimanche (in French). Vol. 3. Paris, France. p. 493. [Mr. Goldschmidt had asked Mr. von Humboldt to give a name to the 44th minor planet. The illustrious scholar chose the name Nysa, the nymph to whom the upbringing of the young Bacchus had been entrusted. Mr. von Humboldt's letter to Mr. Goldschmidt deserves to be reproduced [...] expressing my gratitude for your kind communication, and above all in conveying to you the feelings of the very highest esteem [...] My good friends, Messrs. Encke, Bruhns, d’Arrest, and Brunnow, who have come to see me, join me in expressing their high esteem for you and your noble ardor.]{{cite book}}: CS1 maint: location missing publisher (link)
  27. ↑ "Miscellen". Natur und Offenbarung (in German). Vol. 3. Münster: Aschendorff. 1857. p. 384. [Alexander von Humboldt has given the name Nysa to the 44th planet discovered by Goldschmidt. According to mythology, Nysa was a daughter of Aristaeus, to whom Jupiter entrusted the upbringing of the young Bacchus.]
  28. ↑ Littré, Émile (1877). Dictionnaire de la langue française (in French). Vol. 1–4. Demillecamps. p. 244. La 44e planète télescopique, découverte en 1857 par M. Goldschmidt. ETYM. Νῦσα, fille d'Aristée, laquelle éleva Bacchus. [The 44th telescopic planet, discovered in 1857 by Mr. Goldschmidt. ETYM. Nysa, daughter of Aristaeus, who raised Bacchus.]
  29. ↑ Schmadel, Lutz D. (January 2012). "(44) Nysa". Dictionary of Minor Planet Names (6th ed.). Springer Berlin Heidelberg. p. 17. doi:10.1007/978-3-642-29718-2_2. ISBN 978-3-642-29718-2.
  30. 1 2 3 Stolte, Daniel (29 July 2026). "Three-lobed asteroid is a world unlike any other". University of Arizona. Archived from the original on 31 July 2026. Retrieved 4 August 2026.
  31. ↑ "Unmasking an unusual asteroid". No. potw2631a. European Southern Observatory. 3 August 2026. Archived from the original on 5 August 2026.
  32. 1 2 3 4 Cooper, Keith (30 July 2026). "1st three-headed asteroid found in our solar system — and it has a little moon". Space.com. Archived from the original on 2 August 2026. Retrieved 2 August 2026.
  33. ↑ "ASTRONOMIE. – Observation faite à Vienne de la 45e petite planète. – Nom donné à la 44e petite planète. Extrait d'une Lettre de M. H. Goldschmidt à M. Élie de Beaumont. (Extract from a letter from Mr. H. Goldschmidt to Mr. Élie de Beaumont)". Comptes rendus hebdomadaires des séances de l'Académie des Sciences. Vol. 45. Paris, France: Académie des Sciences. 1857. [Mr. Goldschmidt reproduces an excerpt from a letter he received from Mr. von Humboldt. He had asked the venerable Academician to give a name to the planet he had discovered before this one, and which is the 44th of the minor planets. A letter from Mr. Encke, received that very day, announced to him that the name chosen was Nysa, the nymph to whom the upbringing of the young Bacchus had been entrusted.]
  34. 1 2 van Buitenen, Gideon. "Bright asteroids". astro.vanbuitenen.nl. Archived from the original on 25 May 2026. Retrieved 4 August 2026.
  35. ↑ "The Brightest Bodies of the Solar System". promenade.imcce.fr. European Satellite Partnership for Computing Ephemerides. Archived from the original on 15 July 2026. Retrieved 6 August 2026.
  36. ↑ Ratcliffe, Martin; Ling, Alister (23 February 2015). "A brief glimpse of totality". Astronomy. Archived from the original on 10 April 2026. Retrieved 7 August 2026.
  37. ↑ Ford, Dominic (23 January 2026). "Asteroid 44 Nysa at opposition". In-The-Sky.org. Archived from the original on 6 August 2026. Retrieved 6 August 2026.
  38. 1 2 3 4 5 6 7 Schindler, Kevin (29 July 2026). "Press Release: Asteroid (44) Nysa May Be the First-Known Three-Lobed World". Lowell Observatory. Archived from the original on 30 July 2026. Retrieved 29 July 2026.
  39. 1 2 Bianchi, E.; Padova, E. (1920). "Le variazioni di luce del pianeta (44) Nysa". Memorie della Società Astronomia Italiana (in Italian). 1: 39. Bibcode:1920MmSAI...1...39B.
  40. 1 2 3 4 5 6 Rosenbush, Vera K.; Shevchenko, Vasilij G.; Kiselev, Nikolai N.; Sergeev, Alexander V.; Shakhovskoy, Nikolai M.; Velichko, Feodor P.; et al. (June 2009). "Polarization and brightness opposition effects for the E-type Asteroid 44 Nysa". Icarus. 201 (2): 655–665. Bibcode:2009Icar..201..655R. doi:10.1016/j.icarus.2009.01.007.
  41. ↑ Piironen, J. O. (August 1982). "Photoelectric observations of 44 NYSA during 1981 opposition". Astronomy & Astrophysics. 112 (1): 172–173. Bibcode:1982A&A...112..172P.
  42. ↑ Morrison, David (January 1978). Physical observations and taxonomy of asteroids (PDF). Asteroids: An Exploration Assessment. Vol. Section II. University of Chicago: NASA. pp. 81–97. Bibcode:1978NASCP2053...81M. (A full PDF for the conference can be found here)
  43. 1 2 Zellner, B. (May 1975). "44 Nysa: an iron-depleted asteroid". The Astrophysical Journal. 198: L45–L47. Bibcode:1975ApJ...198L..45Z. doi:10.1086/181807.
  44. 1 2 Zellner, B.; Leake, M.; Morrison, D.; Williams, J. G. (December 1977). "The E asteroids and the origin of the enstatite achondrites". Geochimica et Cosmochimica Acta. 41 (12): 1759–1767. Bibcode:1977GeCoA..41.1759Z. doi:10.1016/0016-7037(77)90208-3. S2CID 129410474.
  45. 1 2 3 4 Morrison, D. (June 1977). "Radiometric diameters of 84 asteroids from observations in 1974 - 1976". The Astrophysical Journal. 214: 667–677. Bibcode:1977ApJ...214..667M. doi:10.1086/155293.
  46. ↑ Schober, H. J. (February 1984). "A comparison between binary star light curves and those of possible binary asteroids" (PDF). Astrophysics and Space Science. 99 (1–2): 387–392. Bibcode:1984Ap&SS..99..387S. doi:10.1007/BF00650261.
  47. 1 2 3 Birch, P. V.; Tedesco, E. F.; Taylor, R. C.; Binzel, R. P.; Blanco, C.; Catalano, S.; et al. (April 1983). "Lightcurves and phase function of asteroid 44 Nysa during its 1979 apparition". Icarus. 54 (1): 1–12. Bibcode:1983Icar...54....1B. doi:10.1016/0019-1035(83)90066-0.
  48. 1 2 Kaasalainen, M.; Torppa, J.; Piironen, J. (March 2002). "Binary structures among large asteroids". Astronomy & Astrophysics. 383 (3): L19–L22. Bibcode:2002A&A...383L..19K. doi:10.1051/0004-6361:20020015.
  49. ↑ Minker, K.; Conrad, A.; Pedichini, F.; Li Causi, G.; Antoniucci, S.; Berdeu, A.; et al. (23 February 2026). Green, Daniel W. E. (ed.). "CBET 5664: (44) NYSA". Central Bureau Electronic Telegrams (5664). Central Bureau of Astronomical Telegrams: 1. Bibcode:2026CBET.5664....1M. Retrieved 29 July 2026.
  50. 1 2 3 4 Berdeu, A.; Minker, K.; Li Causi, G.; Conrad, A.; Pedichini, F.; Antoniucci, S.; et al. (26 May 2026). Green, Daniel W. E. (ed.). "CBET 5693: (44) NYSA". Central Bureau Electronic Telegrams (5693). Central Bureau of Astronomical Telegrams: 1. Bibcode:2026CBET.5664....1M. Retrieved 29 July 2026.
  51. 1 2 Walsh, Kevin J.; Delbó, Marco; Bottke, William F.; Vokrouhlický, David; Lauretta, Dante S. (July 2013). "Introducing the Eulalia and new Polana asteroid families: Re-assessing primitive asteroid families in the inner Main Belt" (PDF). Icarus. 225 (1): 283–297. arXiv:1305.2821. Bibcode:2013Icar..225..283W. doi:10.1016/j.icarus.2013.03.005.
  52. ↑ Michtchenko, T. A.; Lazzaro, D.; Carvano, J. M.; Ferraz-Mello, S. (February 2010). "Dynamic picture of the inner asteroid belt: implications for the density, size and taxonomic distributions of real objects". Monthly Notices of the Royal Astronomical Society. 401 (4): 2499–2516. Bibcode:2010MNRAS.401.2499M. doi:10.1111/j.1365-2966.2009.15825.x.
  53. 1 2 Bange, Jeff (December 1998). "An estimation of the mass of asteroid 20-Massalia derived from the HIPPARCOS minor planets data". Astronomy & Astrophysics. 340: L1–L4. Bibcode:1998A&A...340L...1B. In Table 2, Nysa's closest encounter was with 20 Massalia on the date JD 2447262.5, which translates to 11 April 1988 UT (use the Julian date converter).
  54. 1 2 Fuentes-Muñoz, Oscar; Farnocchia, Davide; Giorgini, Jon D.; Park, Ryan S. (December 2025). "Asteroid Mass Estimation by Mutual Perturbations During Close Encounters After Gaia Focused Product Release". The Astronomical Journal. 170 (6): 353. Bibcode:2025AJ....170..353F. doi:10.3847/1538-3881/ae0cc9. GM of Nysa is shown in Table 5 of the Appendix (A.1. List of Perturber Asteroids).
  55. ↑ "2022 CODATA Value: Newtonian constant of gravitation". The NIST Reference on Constants, Units, and Uncertainty. NIST. May 2024. Retrieved 18 May 2024.
  56. ↑ Taylor, R. C.; Tedesco, Edward F. (April 1983). "Pole orientation of asteroid 44 Nysa via photometric astrometry, including a discussion of the method's application and its limitations". Icarus. 54 (1): 13–22. Bibcode:1983Icar...54...13T. doi:10.1016/0019-1035(83)90067-2. OSTI 6399525. S2CID 120591859.
  57. 1 2 3 4 Cantillo, David C.; Pearson, Neil C.; Ridenhour, Kaycee I.; McBride, Vrinda; Miranda, Miren; Battle, Adam (June 2026). "Grain Size Effects on UV-MIR Spectra of Aubrites: Clues for Interpreting E-type Near-Earth Asteroids". The Planetary Science Journal. 7 (6): 151. Bibcode:2026PSJ.....7..151C. doi:10.3847/PSJ/ae6db2.
  58. 1 2 3 4 5 6 Reddy, Vishnu; Sanchez, Juan A.; Bottke, William F.; Thirouin, Audrey; Rivera-Valentin, Edgard G.; Kelley, Michael S.; et al. (December 2016). "Physical Characterization of ∼2 M Diameter Near-Earth Asteroid 2015 TC25: A Possible Boulder from E-type Asteroid (44) Nysa". The Astronomical Journal. 152 (6): 162. arXiv:1612.00113. Bibcode:2016AJ....152..162R. doi:10.3847/0004-6256/152/6/162.
  59. ↑ Harris, A. W.; Young, J. W.; Contreiras, L.; Dockweiler, T.; Belkora, L.; Salo, H.; et al. (October 1989). "Phase relations of high albedo asteroids: The unusual opposition brightening of 44 Nysa and 64 Angelina". Icarus. 81 (2): 365–374. Bibcode:1989Icar...81..365H. doi:10.1016/0019-1035(89)90057-2.
  60. 1 2 3 Fornasier, S.; Migliorini, A.; Dotto, E.; Barucci, M. (July 2008). "Visible and near infrared spectroscopic investigation of E-type asteroids, including 2867 Steins, a target of the Rosetta mission" (PDF). Icarus. 196 (1): 119–134. Bibcode:2008Icar..196..119F. doi:10.1016/j.icarus.2008.02.015.
  61. 1 2 Gaffey, M. J.; Kelley, M. S. (March 2004). Mineralogical Variations Among High Albedo E-Type Asteroids: Implications for Asteroid Igneous Processes (PDF). 35th Lunar and Planetary Science Conference. League City, Texas: Lunar and Planetary Institute. Bibcode:2004LPI....35.1812G. Archived from the original (PDF) on 5 June 2011.
  62. 1 2 3 Burbine, Thomas H.; Khanani, Iman; Kumawat, Deepika; Hussain, Ahlay; Wallace, Sydney M.; Dyar, M. Darby (September 2024). "Testing the Bus–DeMeo Asteroid Taxonomy Using Meteorite Spectra". The Planetary Science Journal. 5 (9): 194. Bibcode:2024PSJ.....5..194B. doi:10.3847/PSJ/ad57b6.
  63. ↑ Binzel, R. P.; DeMeo, F. E.; Turtelboom, E. V.; Bus, S. J.; Tokunaga, A.; Burbine, T. H.; et al. (May 2019). "Compositional distributions and evolutionary processes for the near-Earth object population: Results from the MIT-Hawaii Near-Earth Object Spectroscopic Survey (MITHNEOS)". Icarus. 324: 41–76. arXiv:2004.05090. Bibcode:2019Icar..324...41B. doi:10.1016/j.icarus.2018.12.035.
  64. 1 2 3 Bottke, William F.; Vokrouhlický, David; Dykhuis, Melissa; Zellner, Nicolle (July 2026). "An 800 Myr-old Impact Shower on the Terrestrial Planets from the Breakup of the Eulalia Parent Body". The Planetary Science Journal. 7 (7): 171. arXiv:2606.05036. Bibcode:2026PSJ.....7..171B. doi:10.3847/PSJ/ae74cc.
  65. ↑ Masiero, Joseph; DeMeo, Francesca; Kasuga, Toshihiro; Parker, Alex H. (2015). "Asteroid Family Physical Properties". In Michel, P.; DeMeo, F. E.; Bottke, W. F. (eds.). Asteroids IV. University of Arizona Press. pp. 323–340. arXiv:1502.00961. doi:10.2458/azu_uapress_9780816532131-ch017. ISBN 978-0-8165-3213-1. JSTOR j.ctt18gzdvc.23.
  66. 1 2 Marsset, M.; Vernazza, P.; Brož, M.; Avdellidou, C.; Thomas, C. A.; McGraw, L.; et al. (June 2026). "The Nysa family as the main source of unequilibrated LL ordinary chondrites". Astronomy & Astrophysics. 710: A389. arXiv:2602.08732. Bibcode:2026A&A...710A.389M. doi:10.1051/0004-6361/202659352.