the existence of target asteroids #3
Description
1.3AU
A near-Earth object (NEO) is any small Solar System body whose orbit can bring it into proximity with Earth. By convention, a Solar System body is a NEO if its closest approach to the Sun (perihelion) is less than 1.3 astronomical units (AU).[2] If a NEO's orbit crosses the Earth's and the object is larger than 140 meters (460 ft) across, it is considered a potentially hazardous object (PHO).[3] Most known PHOs and NEOs are asteroids, but a small fraction are comets.[1]
Absolute Magnitude
An asteroid’s absolute magnitude is the visual magnitude an observer would record if the asteroid were placed 1 Astronomical Unit (au) away, and 1 au from the Sun and at a zero phase angle.
The magnitude of an asteroid at zero phase angle and at unit heliocentric and geocentric distances.
H is the absolute magnitude of the asteroid (represents the intrinsic brightness for example in the V band)
is the distance between the asteroid and Earth (or the observer)
r is the distance from the asteroid and the Sun
is the angle between the lines of sight to Earth and the Sun as seen from the asteroid.
is a phase function that depends on the movements of the NEO
Target asteroids
An asteroid family is a population of asteroids that share similar proper orbital elements, such as semimajor axis, eccentricity, and orbital inclination. The members of the families are thought to be fragments of past asteroid collisions. An asteroid family is a more specific term than asteroid group whose members, while sharing some broad orbital characteristics, may be otherwise unrelated to each other.
https://en.wikipedia.org/wiki/Asteroid_family
- JPL NEO Earth Close Approaches Data
- JPL Small-Body Mission-Design Tool
- Planetary Radar Science Group of Arecibo Observatory
- 1986 DB, Amor | 1986 EB (3554 Amun)
- The composition of M-type asteroids II- Synthesis of spectroscopic and radar observations, J.R. Neeley e al., Icarus, 2014
Impact crater
Detect
小龙哈勃:
6.5米镜，用他们所用的宽带测光，1%精度的话，到21等左右应该是可以的。就目前观测到NEO的星等分布来看，估计绝对星等在23等左右吧。
2米估计到19等。
- https://en.wikipedia.org/wiki/Las_Cumbres_Observatory
- http://www.chilescope.com/services-and-pricing/service-description/
- The Mission Accessible Near-Earth Objects Survey (MANOS)
asime-2018/pdfs/elvis.pdf, Harvard-Smithsonian Center for Astrophysics
Spectrum
- [Evaporating planetesimals, Nature, Sept28 2017](http://sims.ess.ucla.edu/eyoung/reprints/Young_2017_NV.pdf
- https://en.wikipedia.org/wiki/Planetesimal