_Balam.png) Shape model of Balam from itslightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | E. Bowell |
| Discovery site | Anderson Mesa Stn. |
| Discovery date | 24 January 1982 |
| Designations | |
| (3749) Balam | |
| Pronunciation | /ˈbeɪləm/ |
Named after | David Balam (Canadian astronomer)[2] |
| 1982 BG1 · 1954 XM 1962 ED · 1974 YO | |
| main-belt · Flora[3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 61.66 yr (22,521 days) |
| Aphelion | 2.4818AU |
| Perihelion | 1.9920 AU |
| 2.2369 AU | |
| Eccentricity | 0.1095 |
| 3.35yr (1,222 days) | |
| 254.23° | |
| 0° 17m 40.56s / day | |
| Inclination | 5.3801° |
| 295.71° | |
| 173.74° | |
| Knownsatellites | 2(⌀: 1.66 km; 1.84 km)[4] |
| Physical characteristics | |
| 4.1±0.5 km(primary)[5] 4.663±0.21 km(effective)[6][7] 4.7±0.5 km(effective)[8] | |
| Mass | (5.09±0.2)×1014 kg[9][10] |
Meandensity | 2.61±0.45 g/cm3[9][10] |
| 2.805 h[11][12][13][a] | |
| 0.16[14] 0.277±0.096[8] 0.355±0.067[6][7] | |
| Sq[13][14] | |
| 13.3[1] 13.4[6] 13.66[3][8][12][a] | |
3749 Balam/ˈbeɪləm/ is a stonyFlora asteroid and raretrinary system orbiting in the inner regions ofasteroid belt. It also forms a securedasteroid pair with sub-kilometer sized asteroid(312497) 2009 BR60.[5] Balam was discovered on 24 January 1982, by American astronomerEdward Bowell at Lowell'sAnderson Mesa Station near Flagstaff, Arizona, and received theprov. designation1982 BG1. It was named after Canadian astronomerDavid Balam.[15] Balam measures approximately 4.1 kilometers (2.5 miles) in diameter.[5] Its twominor-planet moons have an estimated diameter of 1.66 and 1.84 kilometers, respectively.
Balam is a member of theFlora family, a very large group of stony asteroids in the inner main-belt. It orbits the Sun in theinner main-belt at a distance of 2.0–2.5 AU once every 3 years and 4 months (1,222 days). Its orbit has aneccentricity of 0.11 and aninclination of 5° with respect to theecliptic.[1]
It is named after the Canadian astronomerDavid Balam, principal observer atVictoria's Climenhaga Observatory in British Columbia.[2] The approved naming citation was published by theMinor Planet Center on 31 May 1988 (M.P.C. 13178).[16]
TheS-type asteroid has analbedo of 0.16.[14] The body'srotation around its axis has been measured several times by different lightcurve observations with a concurring period of 2.8 hours.[11][12][13][a]
On 13 February 2002, the discovery of aminor-planet moon, provisionally designatedS/2002 (3749) 1, was announced by a team of researchers fromSwRI,UA,JPL andOSUG, using theGemini North Telescope onMauna Kea in Hawaii.[17] It has an estimated diameter of 1.84 kilometers. It orbits289±13 km away in61±10 days, with a highorbital eccentricity of ~ 0.9. The distant and highly eccentric orbit of S/2002 (3749) 1 suggests that it was likely captured by Balam.[10]
Being such a small primary body in the innermain belt with a separation of over 100 primary radii, S/2002 (3749) 1 is the most loosely bound binary known.[18] Balam has aHill sphere with a radius of about 1,500 kilometers.[10]
In March 2008,Franck Marchis discovered another satellite from eclipses seen in Balam'slight curve, making Balam atrinary asteroid.[19][20] The inner satellite, which does not have a provisional designation,[1] has a derived diameter of 1.66 kilometers, based on diameter-ratio of0.42±0.03 with its primary.[4]
Other known trinary asteroids include45 Eugenia,87 Sylvia,93 Minerva,107 Camilla,130 Elektra and216 Kleopatra.
Balam forms anasteroid pair with(312497) 2009 BR60.[5] Asteroid pairs are on highly similarheliocentric orbits. At some point in the past, the pair of asteroids became gravitationally unbound due to rotational fission induced by theYORP-effect or from a collisional breakup of the parent body. After the discovery of Balam's two satellites byBill Merline (inner moon) andFranck Marchis (outer moon) in 2002 and 2008, respectively, Czech physicistDavid Vokrouhlický identified the unbound secondary in 2009. Based on backward orbit integrations, it is thought that Balam and2009 BR60 form a secured asteroid pair that became separated approximately 400,000 years ago.[5]
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