944 Hidalgo
| Discovery | |
|---|---|
| Discovered by | Walter Baade |
| Discovery date | October 31, 1920 |
| Designations | |
| 1920 HZ | |
| Main belt, Jupiter-crosser asteroid, Saturn-crosser asteroid | |
| Orbital characteristics | |
| Epoch July 14, 2004 (JD 2453200.5) | |
| Aphelion | 1427.003 Gm (9.539 AU) |
| Perihelion | 291.846 Gm (1.951 AU) |
| 859.425 Gm (5.745 AU) | |
| Eccentricity | 0.660 |
| 5029.467 d (13.77 a) | |
Average orbital speed | 12.43 km/s |
| 346.285° | |
| Inclination | 42.567° |
| 21.549° | |
| 56.569° | |
| Physical characteristics | |
| Dimensions | 20 km |
| Mass | 8.4×1015 kg ??? |
Mean density | 2 g/cm³ ??? |
| 0.0056 m/s² ??? | |
| 0.011 km/s ??? | |
| 0.419 29 d[1] | |
| Albedo | 0.1 ? |
| Temperature | ~116 K |
Spectral type | D-type asteroid |
| 10.77 | |
944 Hidalgo is an unusual asteroid, and has the longest orbital period (13.77 years) of any asteroid in the traditional asteroid belt.
With a high eccentricity of 0.66, its perihelion of 1.95 AU takes it to the inner edge of the asteroid belt, while its aphelion of 9.54 AU takes it right out to Saturn's orbit, a characteristic normally associated with Saturn's family of comets. Some astronomers therefore suspect that it was once a comet. Strictly speaking, Hidalgo is a Saturn-grazer rather than a Saturn-crosser as its aphelion does not clear Saturn's. Hidalgo's severe orbital inclination of 43° is suspected to be the result of a close encounter with Jupiter. Its diameter is estimated to be 20 km.
944 Hidalgo was discovered by Walter Baade on October 31, 1920 at Bergedorf Observatory near Hamburg, Germany. German astronomers observed a total eclipse in Mexico on September 10, 1923 and had an audience with the president of Mexico, and in honour of this they named the asteroid after the Mexican hero Miguel Hidalgo y Costilla.
It was one of five minor planets included in the 1993 study, Transition Comets -- UV Search for OH Emissions in Asteroids, which was research involving amateur astronomers who were permitted to make use of the Hubble Space Telescope.