One penalty, i.eScorpio 18[2], is a lonely star 45.3 light-years (13.9 seconds) away from the Earth. Its location isscorpioAt the northern border.itsApparent magnitudeIt is 5.5. It has enough brightness to be seen directly with the naked eye outside the city.
Penalty one has many physical properties similar to the sun.Cayrel de Strobel (1996) listed it as a sun like star when she examined the star, and Porto de Mello and da Silva (1997) determined that it wasTwin sun。Therefore, some scientists believe that there is a promising prospect of life in its vicinity.However, it has not been found that the star has planets around it.[1]
One penalty is oneMain sequence starThe spectral and photometric classification is G2 Va, and the photometric classification is V, indicating that it generates energy in the core area through hydrogen nuclear fusion.Sousaet al.(2008) found that its metal content is about 1.1 times that of the sun, which means that the abundance of elements other than hydrogen or helium is 10% more than that of the sun.Its radius is determined by Bazotet al.(2011) Measured with an interferometer, it is 101% of the solar radius.Combined with the results of astroseismic measurements, it is estimated that the mass of this star is 102% of the mass of the sun.The effective temperature measured on the surface of this star is 5433K, so its radiation is 106% of that of the sun.Its heat causes this star to emit white hot G-type stars with yellow color.
According to Lockwood (2002), its instantaneous luminosity behavior is very similar to the sun.In its entire activity cycle, its brightness changes only 0.09%, which is about the same as that of the current solar cycle.Using Zeeman-Color Doppler Image Technology, Petit et al. (2008) has measured the magnetic field on its surface, showing that its strength and geometry are very similar to the magnetic field of the sun.It is estimated that its activity cycle is about 7 years, which is much shorter than the sun, but its overall chromosphere activity level is significantly higher than the sun.The sun is similar. It has a high temperature crown, with a temperature range of 1.5-200 million K;The luminosity of X-ray is 8 ± 1.5 ergs s–1。
Although the total amount of metal is only slightly higher than that of the sun, its lithium abundance is about 3 times;For this reason, Mel é ndez and Ram í rez (2007) suggested that a penalty of one could be calledQuasi solar twins, to be separated from sun like stars (such asHIP 56948）All its parameters, within the error range, are completely consistent with the sun.
Planetary exploration
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In September 2003, Marguerite Teblin, a space biologist from Arizona University in Tucson, Arizona, was selected as the most promising star to cultivate life based on her analysis of the list of habitable stars.This is a lonely star. As of 2005, no sign of planets orbiting it has been found through radial velocity measurement.This star does not have excessive infrared radiation, which is not enough to suggest that it has loose peristellar matter, such asDebris panThe exists of.[1]
