| Discovery[1] | |
|---|---|
| Discovered by | C. J. van Houten I. van Houten-G. T. Gehrels |
| Discovery site | Palomar Obs. |
| Discovery date | 24 September 1960 |
| Designations | |
| (1777) Gehrels | |
Named after | Tom Gehrels(astronomer)[2] |
| 4007 P-L · 1937 GN 1941 BU · 1951 QB 1958 DA · A905 UE A923 AA | |
| main-belt · (middle)[3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 111.43 yr (40,699 days) |
| Aphelion | 2.6705AU |
| Perihelion | 2.5810 AU |
| 2.6258 AU | |
| Eccentricity | 0.0171 |
| 4.25yr (1,554 days) | |
| 37.596° | |
| 0° 13m 53.76s / day | |
| Inclination | 3.1476° |
| 334.69° | |
| 131.12° | |
| Physical characteristics | |
| Dimensions | 11.860±0.184[4] 12.486±0.228 km[5] 12.667 km[6] 12.67 km(taken)[3] 13.14±1.25 km[7] |
| 2.83±0.05 h[8] 2.83552±0.00001 h[8] 2.8356±0.0002 h[a][b] 2.8356±0.0001 h[a] 2.8358±0.0001 h[9] 2.836±0.001 h[10] 2.837±0.002 h[8] 2.840±0.004 h[11][c] | |
| 0.2151[6] 0.2212±0.0170[5] 0.244±0.013[4] 0.277±0.274[7] | |
| SMASS = Sq[1] · S[3] | |
| 11.42[7] · 11.6[1] · 11.77±0.03[a] · 11.773±0.03[3][6] · 11.78[5] · 11.78±0.05[11] | |
1777 Gehrels, also designated4007 P-L, is a stonyasteroid from the middle region of theasteroid belt, approximately 13 kilometers in diameter. It was discovered during thePalomar–Leiden survey in 1960, and named for astronomerTom Gehrels, one of the survey's principal investigators and credited discoverer.
Gehrels was discovered during thePalomar–Leiden survey by the Dutch astronomer coupleIngrid andCornelis van Houten, in collaboration with Dutch–American astronomerTom Gehrels atPalomar Observatory, California, on 24 September 1960.[12]
Thesurvey designation "P-L" stands forPalomar–Leiden, named after Palomar andLeiden Observatory, which collaborated on the fruitful Palomar–Leiden survey in the 1960s. Gehrels used Palomar'sSamuel Oschin telescope (also known as the 48-inch Schmidt Telescope), and shipped thephotographic plates to Ingrid and Cornelis van Houten at Leiden Observatory, whereastrometry was carried out. The trio are credited with the discovery of several thousand minor planets.[13]
It orbits the Sun in thecentral main-belt at a distance of 2.6–2.7 AU once every 4 years and 3 months (1,554 days). Its orbit has aneccentricity of 0.02 and aninclination of 3° with respect to theecliptic.[1]
First observed asA905 UE atHeidelberg Observatory in 1905,Gehrels' first used observation was made atGoethe Link Observatory in 1958, extending the body'sobservation arc by 2 years prior to its official discovery at Palomar.[12]
ThisS-type asteroid is characterized as a transitional Sq-type in theSMASS classification.[1]
According to the survey carried out by NASA'sWide-field Infrared Survey Explorer (WISE) with its subsequentNEOWISE mission,Gehrels measures between 11.860 and 13.14 kilometers in diameter and its surface has analbedo between 0.2212 and 0.277.[4][5][7]
TheCollaborative Asteroid Lightcurve Link adoptsPetr Pravec's revised WISE-data and takes an albedo of 0.2151 with a diameter of 12.67 kilometers based on anabsolute magnitude of 11.773.[3][6]
Several rotationallightcurve ofGehrels were obtained from photometric observations by astronomersWiesław Wiśniewski, Petr Pravec,Pierre Antonini,Raoul Behrend, Donn Starkey,Laurent Bernasconi, Jacques Montier, Serge Heterier, Daniel Klinglesmith andRobert Stephens. Lightcurve analysis gave arotation period between 2.83 and 2.840 hours with a brightness variation of 0.21 and 0.27magnitude (U=2/3/3/2+/2/3).[8][9][10][11][a][b][c]
Thisminor planet was named in honor of Dutch-born American astronomer Tom Gehrels (1925–2011), professor at theUniversity of Arizona, staff member of theLPL research center at Tucson, a principal investigator in thePioneer program, receiver of theMasursky Award, initiator of theSpacewatch project, and co-discoverer of thousands of minor planets in the Palomar–Leiden survey(see above). He was a pioneer in the field ofphotometric andpolarimetric observations of Solar System bodies in the 1950s.[2][14] The officialnaming citation was published by theMinor Planet Center on 25 September 1971 (M.P.C. 3185).[15]
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