![]() A three-dimensional model of 127 Johanna based on its light curve | |
Discovery | |
---|---|
Discovered by | Paul Henry and Prosper Henry |
Discovery date | 5 November 1872 |
Designations | |
(127) Johanna | |
Pronunciation | /dʒoʊˈhænə/ [1] |
Named after | Joan of Arc |
A872 VB | |
Main belt | |
Orbital characteristics [2] | |
Epoch 31 July 2016 ( JD 2457600.5) | |
Uncertainty parameter 0 | |
Observation arc | 98.53 yr (35989 d) |
Aphelion | 2.94 AU (439.95 Gm) |
Perihelion | 2.57 AU (384.67 Gm) |
2.76 AU (412.31 Gm) | |
Eccentricity | 0.067041 |
4.58 yr (1,671.3 d) | |
Average
orbital speed | 17.92 km/s |
67.782 ° | |
0° 12m 55.44s / day | |
Inclination | 8.2449° |
31.154° | |
94.611° | |
Earth MOID | 1.60 AU (239.57 Gm) |
Jupiter MOID | 2.11 AU (315.95 Gm) |
TJupiter | 3.325 |
Physical characteristics | |
Dimensions | 122
[2] 116.14±3.93 km [3] |
Mass | (3.08 ± 1.35) × 1018 kg [3] |
Mean
density | 3.75±1.68 g/cm3 [3] |
12.7988 h (0.53328 d) [2] [4] | |
0.0557±0.0039 [5] | |
Temperature | ~168 K |
CX
[6] (
Tholen) Ch [6] ( Bus) | |
8.6, [2] 8.30 [5] | |
Johanna ( minor planet designation: 127 Johanna) is a large, dark main-belt asteroid that was discovered by French astronomers Paul Henry and Prosper Henry on 5 November 1872, and is believed to be named after Joan of Arc. [7] It is classified as a CX-type asteroid, indicating the spectrum shows properties of both a carbonaceous C-type asteroid and a metallic X-type asteroid. [6]
A photoelectric study was performed of this minor planet in 1991 at the Konkoly Observatory in Hungary. The resulting light curve showed a synodic rotation period of 6.94 ± 0.29 hours with a brightness variation of 0.2 in magnitude. It was estimated to have an absolute magnitude of 8.459 ± 0.013 with a diameter of 96–118 km (60–73 mi) and an albedo of 0.06–0.04. [8]
Infrared observations made in 1982 at Konkoly showed a rapid variation that seemed to suggest a shorter rotation period of 1.5 hours; one of the fastest known at the time. However, an irregular shape was suggested as an alternative cause of the rapid variation. [9] The present day established rotation period of this object is 12.7988 hours. [4]
During 2001, 127 Johanna was observed by radar from the Arecibo Observatory. The return signal matched an effective diameter of 117 ± 21 km. [6] A larger diameter value of 123.41 ± 4.07 km was obtained from the Midcourse Space Experiment observations, with an albedo of 0.0557 ± 0.0039. [5] A 2012 study gave a refined diameter estimate of 116.14 ± 3.93 km. [3]
![]() A three-dimensional model of 127 Johanna based on its light curve | |
Discovery | |
---|---|
Discovered by | Paul Henry and Prosper Henry |
Discovery date | 5 November 1872 |
Designations | |
(127) Johanna | |
Pronunciation | /dʒoʊˈhænə/ [1] |
Named after | Joan of Arc |
A872 VB | |
Main belt | |
Orbital characteristics [2] | |
Epoch 31 July 2016 ( JD 2457600.5) | |
Uncertainty parameter 0 | |
Observation arc | 98.53 yr (35989 d) |
Aphelion | 2.94 AU (439.95 Gm) |
Perihelion | 2.57 AU (384.67 Gm) |
2.76 AU (412.31 Gm) | |
Eccentricity | 0.067041 |
4.58 yr (1,671.3 d) | |
Average
orbital speed | 17.92 km/s |
67.782 ° | |
0° 12m 55.44s / day | |
Inclination | 8.2449° |
31.154° | |
94.611° | |
Earth MOID | 1.60 AU (239.57 Gm) |
Jupiter MOID | 2.11 AU (315.95 Gm) |
TJupiter | 3.325 |
Physical characteristics | |
Dimensions | 122
[2] 116.14±3.93 km [3] |
Mass | (3.08 ± 1.35) × 1018 kg [3] |
Mean
density | 3.75±1.68 g/cm3 [3] |
12.7988 h (0.53328 d) [2] [4] | |
0.0557±0.0039 [5] | |
Temperature | ~168 K |
CX
[6] (
Tholen) Ch [6] ( Bus) | |
8.6, [2] 8.30 [5] | |
Johanna ( minor planet designation: 127 Johanna) is a large, dark main-belt asteroid that was discovered by French astronomers Paul Henry and Prosper Henry on 5 November 1872, and is believed to be named after Joan of Arc. [7] It is classified as a CX-type asteroid, indicating the spectrum shows properties of both a carbonaceous C-type asteroid and a metallic X-type asteroid. [6]
A photoelectric study was performed of this minor planet in 1991 at the Konkoly Observatory in Hungary. The resulting light curve showed a synodic rotation period of 6.94 ± 0.29 hours with a brightness variation of 0.2 in magnitude. It was estimated to have an absolute magnitude of 8.459 ± 0.013 with a diameter of 96–118 km (60–73 mi) and an albedo of 0.06–0.04. [8]
Infrared observations made in 1982 at Konkoly showed a rapid variation that seemed to suggest a shorter rotation period of 1.5 hours; one of the fastest known at the time. However, an irregular shape was suggested as an alternative cause of the rapid variation. [9] The present day established rotation period of this object is 12.7988 hours. [4]
During 2001, 127 Johanna was observed by radar from the Arecibo Observatory. The return signal matched an effective diameter of 117 ± 21 km. [6] A larger diameter value of 123.41 ± 4.07 km was obtained from the Midcourse Space Experiment observations, with an albedo of 0.0557 ± 0.0039. [5] A 2012 study gave a refined diameter estimate of 116.14 ± 3.93 km. [3]