The phrase Solar System's largest Planet should modify Jupiter.
In B the phrase is modifying Jupiter's mass, hence incorrect

An international team of astronomers working at telescopes in the Canary Islands and Spain has detected at least 18 huge gas spheres estimated to have 5 to 15 times the mass of Jupiter, the solar system’s largest planet.

A. astronomers working at telescopes in the Canary Islands and Spain has detected at least 18 huge gas spheres estimated to have 5 to 15 times the mass of Jupiter
B. astronomers work at telescopes in the Canary Islands and Spain has detected at least 18 huge gas spheres estimated to be 5 to 15 times Jupiter’s mass
C. astronomers working at telescopes in the Canary Islands and Spain, having detected at least 18 huge gas spheres that are estimated at 5 to 15 times the mass of Jupiter
D. astronomers, working at telescopes in the Canary Islands and Spain, and has detected at least 18 huge gas spheres estimated at 5 to 15 times the mass of Jupiter
E. astronomers, working at telescopes in the Canary Islands and Spain, has detected at least 18 huge gas spheres they have estimated to be 5 to 15 times Jupiter’s mass


I have googled and found Ron's (Manhattan Gmat Staff ) answer thanks to him.

First estimate can be used with any infinitive so my thoughts about estimate to be is wrong.

ESTIMATE + TO BUILD
+ TO HAVE
+ TO MAKE
All correct.

Second point in this question look at the answer choices B and E

....estimated to be 5 to 15 times Jupiter’s mass, the solar system’s largest planet.
Jupiter's mass is not the solar system's largest planet it is just Jupiter what is known to be largest planet.

IMO A due to the above reasons..

refer: https://www.manhattangmat.com/forums/an- ... t2002.html

IMO A, because that is the most clear an concise choice.