Jupiter analog

Jupiter analog ( English for Jupiter equivalent ; not to be confused with Jupiter-like planets in our solar system) is called an exoplanet whose mass and orbit are similar tothose of Jupiter .

Star systems with Jupiter analogously are considered to be potential homesteads of Earth-like planets on Earth-like orbits near the ice line .

definition

Jupiter is also defined as a gas planet with an orbital period of over 8 years. They should have masses between 0.1 and 12 times that of Jupiter (heavier celestial bodies are brown dwarfs ) and have a low orbital eccentricity of e <0.2, which means that the orbits of inner planets are not disturbed.

Instead of the term Jupiter analog , Jupiter-Saturn is also used analog .

Observation technique

In the search for Jupiter by analogy , the transit method , which is otherwise successfully used in the search for exoplanets, does not promise success due to the order of magnitude of the orbits of decades . For this, several transits of the planets in front of the central star would have to be observed, but the probability of this decreases sharply with the length of the orbit axis .

Therefore, Jupiter is searched for in the same way :

• by direct imaging in the infrared . Such observations are particularly promising for young stars, since a few million years after their formation the planets only emitted small parts of the thermal energy generated during their contraction .
• using the radial velocity method . Due to the diameter of the orbit axis, the amplitudes of the radial velocity changes only reach values ​​of around 10 m / s and can easily be confused with magnetic cycles on the central star .

Using microlensing , gas planets can be detected, but their path cannot be followed.

meaning

Planets with a mass similar to that of Jupiter, but on very narrow orbits around their central star, have already been found in large numbers as Hot Jupiters . These exoplanets may not have formed at their current orbit, but migrated from their place of origin in the outer planetary system to the inner planetary system. During this migration they removed all Earth-like inner planets from their orbit.

In contrast, planetary systems with Jupiter apply analogously , i.e. H. with Jupiter-like planets that have not migrated into the interior of the planetary system, as places with potentially habitable Earth-like planets that have so far been difficult to detect. The search for Jupiter analogs should also show how typical our solar system with its solar planetary system is for the Milky Way .

Candidates for Jupiter analogs

• HD150706b
• HD222155b
• HD24040b
• HD39807b

Individual evidence

1. ↑ Robert A. Wittenmyer et al .: The Anglo-Australian Planet Search. XXII. Two New Multi-Planet Systems . In: Astrophysics. Solar and Stellar Astrophysics . 2012, arxiv : 1205.2765v1 .
2. ↑ Robert A. Wittenmyer, CG Tinney, Simon J. O'Toole, HRA Jones, RP Butler, BD Carter, J. Bailey: On the Frequency of Jupiter analog . In: Astrophysics. Solar and Stellar Astrophysics . 2010, arxiv : 1011.4720v1 .
3. ↑ Sascha P. Quanz et al .: Searching for young Jupiter analogs around AP Col: L-band high-contrast imaging of the closest pre-main sequence star . In: Astrophysics. Solar and Stellar Astrophysics . 2012, arxiv : 1205.6890v1 .
4. ↑ Robert A. Wittenmyer et al .: Observing Strategies for the Detection of Jupiter analog . In: Astrophysics. Solar and Stellar Astrophysics . 2013, arxiv : 1303.3336v1 .
5. ^ I. Boisse et al .: The SOPHIE search for northern extrasolar planets V. Follow-up of ELODIE candidates: Jupiter-analogs around Sun-like stars . In: Astrophysics. Solar and Stellar Astrophysics . 2012, arxiv : 1205.5835v1 .