5391 Emmons

5391 EmmonsDiscovery [1]

Discovered by| E. F. Helin
Discovery site| Palomar Obs.
Discovery date| 13 September 1985
Designations

MPC designation

| (5391) Emmons

Named after

| Richard Emmons [1]
(American astronomer)

Alternative designations

| 1985 RE2 * 1934 RH
1951 RF1 * 1975 VE3

Minor planet category

| main-belt [1][2] * (inner)
background [3]
Orbital characteristics [2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc| 67.86 yr (24,787 d)
Aphelion| 2.8087 AU
Perihelion| 1.7108 AU

Semi-major axis

| 2.2598 AU
Eccentricity| 0.2429

Orbital period (sidereal)

| 3.40 yr (1,241 d)

Mean anomaly

| 220.53°

Mean motion

| 0° 17m 24.36s / day
Inclination| 2.5123°

Longitude of ascending node

| 336.40°

Argument of perihelion

| 344.75°
Physical characteristics

Mean diameter

| 5.578±0.083 km[4][5]
5.93 km (calculated)[6]

Synodic rotation period

| 3.028±0.004 h[7]

Geometric albedo

| 0.20 (assumed)[6]
0.298±0.035[4][5]

Spectral type

| C (assumed)[6]
S (SDSS-MOC)
S (Pan-STARRS)[8]

Absolute magnitude (H)

| 13.2[5]
13.4[2]
13.5[6]
13.57±0.29[8]

5391 Emmons, provisional designation 1985 RE2, is a background asteroid from the inner regions of the asteroid belt, approximately 6 kilometers (4 miles) in diameter. It was discovered on 13 September 1985, by American astronomer Eleanor Helin at the Palomar Observatory.[1] The likely S-type asteroid has a rotation period of 3.0 hours.[6] It was named for American astronomer Richard Emmons.[1]

## Contents

* 1 Orbit and classification
* 2 Physical characteristics
* 2.1 Rotation period
* 2.2 Diameter and albedo
* 3 Naming
* 4 References
* 5 External links

## Orbit and classification[edit]

Emmons is a non-family asteroid from the main belt's background population.[3] It orbits the Sun in the inner main-belt at a distance of 1.7–2.8 AU once every 3 years and 5 months (1,241 days; semi-major axis of 2.26 AU). Its orbit has an eccentricity of 0.24 and an inclination of 3° with respect to the ecliptic.[2]

The asteroid was first observed as 1934 RH at the Union Observatory in September 1934. The body's observation arc begins 35 years prior to its official discovery observation with a precovery at Palomar in April 1950.[1]

## Physical characteristics[edit]

Emmons has been characterized as a common, stony S-type asteroid by the Pan-STARRS' survey and by the SDSS-based taxonomic system (latter poorly secured; LSQ). The asteroid is also a generically assumed C-type.[6][8][9]

### Rotation period[edit]

In September 2002, a rotational lightcurve of Emmons was obtained from photometric observations by astronomers at the Goodsell Observatory (741). Lightcurve analysis gave a rotation period of 3.028 hours with a brightness amplitude of 0.16 magnitude (U=2).[7]

### Diameter and albedo[edit]

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Emmons measures 5.578 kilometers in diameter and its surface has an albedo of 0.298,[4][5] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for a stony asteroid of 0.20, and calculates a diameter of 5.93 kilometers based on an absolute magnitude of 13.5.[6]

## Naming[edit]

This minor planet was named after American astronomer Richard H. Emmons (1919–2005), who was a longtime professor of physics and astronomy at Kent State University and known as "Mr. Astronomy" to the thousands of children and residents who looked at the heavens through his homemade telescopes. From the 1950s to 1963, school children, Boy Scouts, church groups and community organizations visited his North Canton garage, known as "The Star Barn," which he had converted into the area's only planetarium. It seated 38. Emmons was also an early observer of artificial satellites.[1]

The official naming citation was published by the Minor Planet Center on 23 May 2000 (M.P.C. 40701).[10]

## References[edit]

1. ^ a b c d e f g "5391 Emmons (1985 RE2)". Minor Planet Center. Retrieved 28 May 2018.
2. ^ a b c d "JPL Small-Body Database Browser: 5391 Emmons (1985 RE2)" (2018-02-26 last obs.). Jet Propulsion Laboratory. Retrieved 28 May 2018.
3. ^ a b "Asteroid 5391 Emmons". Small Bodies Data Ferret. Retrieved 28 May 2018.
4. ^ a b c Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J.; et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal. 741 (2): 20. arXiv:1109.4096. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68.
5. ^ a b c d Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. (catalog)
6. ^ a b c d e f g "LCDB Data for (5391) Emmons". Asteroid Lightcurve Database (LCDB). Retrieved 28 May 2018.
7. ^ a b Clark, Maurice; Joyce, Brian (December 2002). "Asteroid lightcurve photometry from Goodsell Observatory (741)". The Minor Planet Bulletin. 30 (1): 4–7. Bibcode:2003MPBu...30....4C. ISSN 1052-8091.
8. ^ a b c Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007.
9. ^ Carvano, J. M.; Hasselmann, P. H.; Lazzaro, D.; Mothé-Diniz, T. (February 2010). "SDSS-based taxonomic classification and orbital distribution of main belt asteroids". Astronomy and Astrophysics. 510: 12. Bibcode:2010A&A...510A..43C. doi:10.1051/0004-6361/200913322. Retrieved 30 October 2019. (PDS data set)
10. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 28 May 2018.

## External links[edit]

* Asteroid (5391) Emmons, at twcac.org
* Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
* Dictionary of Minor Planet Names, Google books
* Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
* Discovery Circumstances: Numbered Minor Planets (5001)-(10000) – Minor Planet Center
* 5391 Emmons at AstDyS-2, Asteroids—Dynamic Site
* Ephemeris * Observation prediction * Orbital info * Proper elements * Observational info
* 5391 Emmons at the JPL Small-Body Database
* Close approach * Discovery * Ephemeris * Orbit diagram * Orbital elements * Physical parameters

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