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=7.416, the bolometric magnitude of the Sun |group="note"|name=luminosity_bolometric}} | luminosity_visual = 0.044〔 | temperature = 4,250〔 | metal = | rotational_velocity = 〔 | age= }} Gliese 710 is a star in the constellation Serpens Cauda with an apparent visual magnitude of 9.69. It has a stellar classification of K7 Vk,〔 which means it is a main sequence star that is generating energy through the thermonuclear fusion of hydrogen at its core. (The suffix 'k' indicates that the spectrum shows absorption lines from interstellar matter.) The mass of this star is about 60%〔 of the Sun's mass and it has an estimated 67% of the Sun's radius.〔 It is a suspected variable star that may vary in magnitude from 9.65–9.69. This star is currently about from Earth, but its proper motion, distance, and radial velocity〔See also: Stellar kinematics.〕 indicate that it will approach within a very small distance—perhaps under one light year—from the Sun within 1.4 million years, based on past and current ''Hipparcos'' data.〔 At closest approach it will be a first-magnitude star about as bright as Antares. The proper motion of Gliese 710 is very small for its distance, meaning it is traveling nearly directly in our line of sight. In a time interval of ±10 million years from the present, Gliese 710 is the star whose combination of mass and close approach distance will cause the greatest gravitational perturbation of the Solar System. == Computing and details of the closest approach == Gliese 710 has the potential to perturb the hypothetical Oort cloud enough to send a shower of comets into the inner Solar System, possibly causing an impact event. However, dynamic models by García-Sánchez, et al. in 1999 indicate that the net increase in cratering rate due to the passage of Gliese 710 will be no more than 5%.〔 They estimate that the closest approach will happen in 1,360,000 years when the star will approach within 0.337 ± 0.177 parsecs (1.100 ± 0.577 light years) of the Sun. More recent calculations by Bobylev in 2010 suggest Gliese 710 has an 86% chance of passing through the Oort cloud, considering the Oort cloud to be a spheroid around the Sun with semiminor and semimajor axes of 80,000 and 100,000 astronomical units. The distance of closest approach of Gliese 710 is difficult to compute precisely as it depends sensitively on its current position and velocity; Bobylev estimates that it will pass within 0.311 ± 0.167 pc (1.014 ± 0.545 light years) of the Sun. There is even a 1/10,000 chance of the star penetrating into the region (d < 1,000 AU) where the influence of the passing star on Kuiper belt objects is significant.〔 Gliese 710 would have an apparent magnitude at the time of its closest approach of about 0.5 The star with the second greatest perturbational effect in the past or future 10 million years was Algol, a triple star system that passed no closer than 9.8 light years, 7.3 million years ago, but with a considerably larger total mass of 5.8 solar masses. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Gliese 710」の詳細全文を読む スポンサード リンク
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