757 Portlandia

757 Portlandia is a main-belt asteroid 32 km in diameter.[1] In November 2015, amateur astronomers captured it with images of comet 67P/Churyumov–Gerasimenko.[2] Portlandia came to opposition in March 2016 at apparent magnitude 13.2.

757 Portlandia

Discovery
Discovered by	Joel Hastings Metcalf
Discovery site	Taunton, Massachusetts
Discovery date	30 September 1908
Designations
MPC designation	(757) Portlandia
Alternative designations	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)
Semi-major axis	2.3734 AU (355.06 Gm)
Eccentricity	0.10922
Orbital period	3.66 yr (1335.6 d)
Mean anomaly	133.453°
Mean motion	0° 16^m 10.38^s / day
Inclination	8.1694°
Longitude of ascending node	22.515°
Argument of perihelion	44.204°
Physical characteristics
Mean radius	16.045±0.7 km
Rotation period	6.5837 h (0.27432 d)[1]
Geometric albedo	0.1427±0.014[1]
Spectral type	M
Apparent magnitude	12.3 to 15.7
Absolute magnitude (H)	10.20[1]

References

1. "JPL Small-Body Database Browser: 493 Griseldis (1902 JS)". Jet Propulsion Laboratory. Retrieved 5 May 2016.
2. https://www.facebook.com/photo.php?fbid=10206800415562318

External links

• 757 Portlandia at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 757 Portlandia at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters