Gliese 710


Gliese 710, or HIP 89825, is an orangish star in the constellation Serpens Cauda. It is projected to pass near the Sun in about 1.29 million years at a predicted minimum distance of 0.051 parsecs – – about of the current distance to Proxima Centauri. Such a distance would make for a similar brightness to the brightest planets, optimally reaching an apparent visual magnitude of about −2.7 . The star's proper motion will peak around one arcminute per year, a rate of apparent motion that would be noticeable over a human lifespan. This is a timeframe, based on data from Data Release 3 from the Gaia spacecraft, well within the parameters of current models which cover the next 15 million years.

Description

Gliese 710 is currently from Earth in the constellation Serpens and has a below naked-eye visual magnitude of 9.69 . A stellar classification of K7 Vk means it is a small main-sequence star mostly generating energy through the thermonuclear fusion of hydrogen in its core. Stellar mass is about 57% of the Sun's mass with an estimated 58% of the Sun's radius. It is suspected to be a variable star that may vary in magnitude from 9.65 to 9.69 . As of 2020, no planets have been detected orbiting it.

Computing and details of the closest approach

Image:Kuiper oort-en.svg|thumb|right|An artist's rendering of the Oort cloud and the Kuiper belt
In their 2010 work, Bobylev et al. suggested that Gliese 710 has an 86% chance of passing through the Oort cloud, assuming the Oort cloud to be a spheroid around the Sun with semiminor and semimajor axes of 80,000 and, respectively. The distance of closest approach of Gliese 710 is generally difficult to compute precisely as it depends sensitively on its current position and velocity; Bobylev et al. estimated that Gliese 710 would pass within of the Sun. At the time, there was even a 1-in-10,000 chance of the star penetrating into the region where the influence of the passing star on Kuiper belt objects would be significant.
Results from new calculations that include input data from Gaia DR3 indicate that the flyby of Gliese 710 to the Solar System will on average be closer at in time, considerably more precise than previous estimates. The effects of such an encounter on the orbit of the Pluto–Charon system are negligible, but Gliese 710 will traverse the outer Oort cloud and reach the outskirts of the inner Oort cloud.
Gliese 710 has the potential to perturb the Oort cloud in the outer Solar System, exerting enough force to send showers of comets into the inner Solar System for millions of years, triggering visibility of about ten naked-eye comets per year, and possibly causing an impact event. According to Filip Berski and Piotr Dybczyński, this event will be "the strongest disrupting encounter in the future and history of the Solar System." Earlier dynamic models indicated that the net increase in cratering rate due to the passage of Gliese 710 would be no more than 5%. They had originally estimated that the closest approach would happen in 1.36 million years when the star will approach within of the Sun. Gaia DR2 later found the minimum perihelion distance to be or, about 1.281 million years from now.

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