HD 168009

HD 168009 is a star in the northern constellation of Lyra. It has an apparent visual magnitude of 6.3,^[3] placing it just above to below the normal limit of stars visible to the naked eye under good viewing conditions of 6-6.5. An annual parallax shift of 42.93 mas provides a distance estimate of 76 light years. It is moving closer to the Sun with a heliocentric radial velocity of −65 km/s.^[5] In about 328,000 years from now, the star will make its closest approach at a distance of around 17 ly (5.1 pc).^[11]

This is a solar analog,^[3] which means its measured properties are similar to those of the Sun. However, it is much older than the Sun with an estimated age of around 8.1 billion years.^[5] The spectrum matches a stellar classification of G1 V,^[4] indicating this is an ordinary G-type main-sequence star that is generating energy through hydrogen fusion at its core. The level of chromospheric activity is low, making it a candidate for a Maunder minimum event.^[5]

HD 168009 has about the same mass as the Sun, but is 14% larger in radius.^[7] It has a similar metallicity to the Sun – what astronomers term the abundance of elements other than hydrogen and helium – and is spinning with a rotation period of six days.^[9] The star is radiating 1.43^[8] times the Sun's luminosity from its photosphere at an effective temperature of 5,792 K.^[5] It has been examined for an infrared excess that may indicate the presence of a circumstellar disk of dust, but no statistically significant excess was detected.^[12][13]