2015 TB 145

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Asteroid
2015 TB 145
In this animation, 2015 TB145 is the object moving left in the center of the image.
In this animation, 2015 TB 145 is the object moving to the left in the center of the image.
Properties of the orbit ( animation )
Epoch:  4th September 2017 ( JD 2,458,000.5)
Orbit type Near-Earth asteroid, Apollo-type
Major semi-axis 2.101  AU
eccentricity 0.86
Perihelion - aphelion 0.294 AU - 3.908 AU
Inclination of the orbit plane 39.7 °
Length of the ascending node 37.7 °
Argument of the periapsis 121.8 °
Sidereal period 3.05 a
Physical Properties
Medium diameter ~ 600 m
Albedo 0.06
Rotation period 2.938 h
Absolute brightness 20.0 mag
history
Explorer Pan-STARRS
Date of discovery October 10, 2015
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . The affiliation to an asteroid family is automatically determined from the AstDyS-2 database . Please also note the note on asteroid items.

2015 TB 145 (unofficially also Halloween asteroid ) is an asteroid that was discovered on October 10, 2015 by the large telescope system Pan-STARRS . Since it crosses the earth's orbit at a short distance, it is classified as a near-earth object .

The approximately 600-meter-large, semi-spherical asteroid passed Earth on October 31, 2015 at 17:01 UTC (18:01 Central European Time ) at a distance of about 486,000 kilometers, which corresponds to about 1.3 lunar distances, at a speed of 35 km / s relative to the earth. 2015 TB 145 was not visible to the naked eye when it passed Earth. At least a simple telescope was needed. Due to the date, 2015 TB 145 is also known as the " Halloween asteroid". The name also got a special "coat of paint" with one of the first better radar images from October 31, 2015, on which TB 145 showed a certain resemblance to a skull.

Orbit

With an eccentricity of 0.86, the extremely elliptical orbit on which TB 145 moves around the sun in 2015 is inclined at 39.7 ° to the plane of the ecliptic in which the earth and the planets move. 2015 TB 145 moves towards the sun as it approaches the earth, and its orbit then leads it closer to the sun than the planet Mercury in its orbit. After orbiting the sun, in 2015 TB 145 is about four times as far from the sun as the earth. It takes the asteroid around 3 years, 17 days and 6 hours to orbit the sun.

Orbit display when flying past the earth. Times in UTC (= CET minus 1 hour)
Illustration of the orbit in the area of ​​the inner planets (light blue ≙ above, dark blue ≙ below the plane of the ecliptic )

Earth orbit cruiser

Delay Doppler radar image from the Arecibo Observatory in Puerto Rico , October 30, 2015

2015 TB 145 belongs to the Apollo type of near-earth asteroids. These have large semiaxes of more than 1 AU - so they are further away from the sun than the earth. At the same time, their perihelion (point closest to the sun) is closer to the sun than the aphelion (point furthest from the sun ) of the earth, which means they cross the earth's orbit . Since its perihelion with 0.29 AU brings it closer to the sun than Mercury, TB 145 is also one of the Mercury cruisers and Venus cruisers in 2015 .

2015 TB 145 passed very close to the earth at 1.3 times the earth-moon distance by astronomical standards. This was predicted with certainty after its orbit was calculated. In future orbits, it will no longer come nearly as close to the earth as in 2015.

Compared to other objects, TB 145 was discovered late in 2015 . Small bodies of comparable size are typically detected in automatic processes at distances of more than 2.5 AU - that is, 2.5 times the distance between the sun and the earth.

Physical Properties

2015 TB 145 has an approximate diameter of 600 meters. It rotates on its own axis in around three hours.

According to observations on October 31, 2015, the object reflects only about 6 percent of the sunlight that falls on it ( albedo ). This is a very low value - even fresh asphalt reflects 7 percent. Comet nuclei are comparatively dark and reflect an average of only 4 percent of the light. Their coma and tail, on the other hand, ensure their luminous phenomena . Given its unusual orbit inclination, this led to the assumption that TB 145 was originally a comet in 2015 . As a “dead comet” it would have lost its volatile components in the course of previous orbits around the sun, which means that it cannot form a coma or a tail today. C-type asteroids such as (47) Aglaja and (54) Alexandra with high carbon surfaces have similarly low albedo values.

Web links

Commons : 2015 TB145  - Collection of Images, Videos, and Audio Files

Individual evidence

  1. ↑ a b c d e f Halloween Skies to Include Dead Comet Flyby. In: jpl.nasa.gov. Jet Propulsion Laboratory of the California Institute of Technology , October 30, 2015. Retrieved on October 31, 2015 (English).
  2. ↑ NASA Spots the "Great Pumpkin": Halloween Asteroid a Treat for Radar Astronomers. In: jpl.nasa.gov. Jet Propulsion Laboratory of the California Institute of Technology , October 29, 2015. Retrieved on October 31, 2015 (English).
  3. ↑ a b c JPL Small-Body Database Browser - 2015 TB145. In: jpl.nasa.gov. Jet Propulsion Laboratory of the California Institute of Technology , accessed on 31 October 2015 (English).
  4. ↑ Christina Horsten: Halloween Asteroid: At 6:05 p.m. "2015 TB145" passed the earth. In: Welt.de . October 31, 2015, accessed November 3, 2017 .
  5. ↑ image "Skull 2015 TB 145 ". In: jpl.nasa.gov. Jet Propulsion Laboratory of the California Institute of Technology , October 30, 2015 accessed November 1, 2017 .
  6. ↑ Asteroid Discovered by UH Telescope to Make Close Halloween Flyby. In: ifa.hawaii.edu. University of Hawaii Institute for Astronomy , October 22, 2015, accessed October 31, 2015 .
  7. ↑ a b Halloween asteroid flies past Earth. ESA , October 29, 2015, accessed October 31, 2015 .
  8. ↑ At a distance of 486,000 kilometers: The Halloween asteroid has passed Earth. In: RP Online . October 31, 2015, accessed November 3, 2017 .
  9. ↑ Asteroids. In: nssdc.gsfc.nasa.gov. NASA , accessed November 3, 2017 .