Discovery | |
---|---|
Discovered by | Joel Hastings Metcalf |
Discovery site | Taunton, Massachusetts |
Discovery date | 30 September 1908 |
Designations | |
(757) Portlandia | |
1908 EJ | |
Orbital characteristics [1] | |
Epoch 31 July 2016 ( JD 2457600.5) | |
Uncertainty parameter 0 | |
Observation arc | 99.16 yr (36218 d) |
Aphelion | 2.6327 AU (393.85 Gm) |
Perihelion | 2.1142 AU (316.28 Gm) |
2.3734 AU (355.06 Gm) | |
Eccentricity | 0.10922 |
3.66 yr (1335.6 d) | |
133.453 ° | |
0° 16m 10.38s / day | |
Inclination | 8.1694° |
22.515° | |
44.204° | |
Physical characteristics | |
16.045±0.7 km | |
6.5837 h (0.27432 d) [1] | |
0.1427±0.014 [1] | |
M | |
12.3 to 15.7 | |
10.20 [1] | |
757 Portlandia is a main-belt asteroid 32 km in diameter. [1] It was discovered on 30 September 1908 from Taunton, Massachusetts by the amateur American astronomer Joel E. Metcalf. The asteroid was named for the city of Portland, Maine, where Hastings was a church minister at the time. [2] In November 2015, amateur astronomers captured it with images of comet 67P/Churyumov–Gerasimenko. [3] Portlandia came to opposition in March 2016 at apparent magnitude 13.2.[ citation needed]
This body is orbiting at a distance of 2.37 AU with a period of 3.66 years and an eccentricity of 0.109. The orbital plane is inclined at an angle of 8.2° to the plane of the ecliptic. [1] 757 Portlandia is classified as an X-type asteroid and is a core member of the proposed Athor asteroid family, named after 161 Athor. This asteroid spans a girth of 32.89±0.24 km and is rotating with a period of 6.58 hours. [4] During 2003, the asteroid was observed occulting a star. The resulting chords were used to determine a diameter estimate of 36.7 km. [5]