_Grubba.png) Modelled shape ofGrubba from itslightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | G. Shajn |
| Discovery site | Simeiz Obs. |
| Discovery date | 22 June 1925 |
| Designations | |
| (1058) Grubba | |
Named after | Howard Grubb[2][3] (Irish telescope maker) |
| 1925 MA · 1932 WO 1955 YH · A906 VG | |
| main-belt[1][3] · (inner) Flora[4][5] · Augusta[6] | |
| Orbital characteristics[3] | |
| Epoch 23 March 2018 (JD 2458200.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 111.28yr (40,646 d) |
| Aphelion | 2.6082AU |
| Perihelion | 1.7842 AU |
| 2.1962 AU | |
| Eccentricity | 0.1876 |
| 3.25 yr (1,189 d) | |
| 149.50° | |
| 0° 18m 10.08s / day | |
| Inclination | 3.6932° |
| 221.75° | |
| 94.490° | |
| Physical characteristics | |
| 10.920±0.057 km[7] 11.910±0.270 km[8] 13.03±0.28 km[9] 14.64 km(derived)[4] | |
| >12 h[10] >18 h[11] >20 h[10] 46.30±0.01 h[12] | |
| 0.133[13] 0.171±0.008[9] 0.201±0.020[8] 0.2416±0.0245[7] | |
| Tholen =S[3] SMASS =S[3][4] B–V = 0.880[3] U–B = 0.500[3] | |
| 11.82±0.20[14] 11.98[3][4][7][8][9] | |
1058 Grubba, provisional designation1925 MA, is a stonyFlora asteroid from the inner regions of theasteroid belt. It was discovered on 22 June 1925, by Soviet–Russian astronomerGrigory Shajn at theSimeiz Observatory on the Crimean peninsula.[1] TheS-type asteroid was named for Irish telescope makerHoward Grubb.[2] It has a longer-than averagerotation period of 46.30 hours and measures approximately 12 kilometers (7.5 miles) in diameter.[4]
Grubba is a member of theFlora family (402),[4][5] a giantasteroid family and the largest family of stony asteroids in the main-belt.[15] It has also been grouped into theAugusta family byVincenzo Zappalà in a previous study in the 1990s, also using thehierarchical clustering method.[6] The Augusta family, named after254 Augusta, can be considered a sub-family of the Flora-complex.
It orbits the Sun in theinner asteroid belt at a distance of 1.8–2.6 AU once every 3 years and 3 months (1,189 days;semi-major axis of 2.2 AU). Its orbit has aneccentricity of 0.19 and aninclination of 4° with respect to theecliptic.[3]
The asteroid was first observed asA906 VG atHeidelberg Observatory in November 1916. The body'sobservation arc begins with aprecovery taken at theYerkes Observatory in November 1932, or more than 7 years after its official discovery observation at Simeiz.[1]
Thisminor planet was named after Irish telescope maker SirHoward Grubb (1844–1931), whose company Grubb Parson and Co., Newcastle upon Tyne, England, manufactured the 40-inch reflector of the discoveringSimeiz Observatory. The official naming citation was mentioned inThe Names of the Minor Planets byPaul Herget in 1955 (H 100).[2]
Grubba is a common, stonyS-type asteroid in both theTholen andSMASS classification,[3][4] which also agrees with the overallspectral type for the Florian asteroids.[15]: 23
In August 2013, a rotationallightcurve ofGrubba was obtained from photometric observations by Andrea Ferrero at the Bigmuskie Observatory (B88) in Italy. Lightcurve analysis gave a longer than averagerotation period of 46.30 hours with a brightness variation of 0.24magnitude (U=3).[4][12] The result supersedes observations by French amateur astronomersLaurent Bernasconi (>12 hours) andRené Roy (>20 hours), as well as by astronomers at theUniversity of Arizona (18 hours) in Tucson, United States (U=n.a./2/n.a.).[10][11] While not being aslow rotator, its period is significantly longer than that for most asteroids, which rotate every 2 to 20 hours once around their axis.
According to the surveys carried out by the JapaneseAkari satellite and theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Grubba measures between 10.920 and 13.03 kilometers in diameter and its surface has analbedo between 0.171 and 0.2416.[7][8][9] TheCollaborative Asteroid Lightcurve Link adopts an albedo of 0.133,[13] and derives a diameter of 14.64 kilometers based on anabsolute magnitude of 11.98.[4]
