HD 170657
Encyclopedia
HD 170657 is a star in the constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

 Sagittarius
Sagittarius (constellation)
Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow...

. It is located at a distance of about 43 light years. It has 0.79 solar mass
Solar mass
The solar mass , , is a standard unit of mass in astronomy, used to indicate the masses of other stars and galaxies...

es and is a suspected variable star that varies in apparent magnitude from 6.82−6.88.

When observed with the Spitzer Space Telescope
Spitzer Space Telescope
The Spitzer Space Telescope , formerly the Space Infrared Telescope Facility is an infrared space observatory launched in 2003...

, this star did not display an excess emission of infrared radiation, which may otherwise indicate the presence of an orbiting debris disk
Debris disk
A debris disk is a circumstellar disk of dust and debris in orbit around a star. Sometimes these disks contain prominent rings, as seen in the image of Fomalhaut on the right. Debris disks have been found around both evolved and young stars, as well as at least one debris disk in orbit around a...

. The space velocity components of this star are = .

Sources give contradictory measurements for the abundance of elements in this star. Lawler et al (2009) lists an iron abundance of [Fe/H] = 0.27 dex, while Valenti et al (2005) has an iron abundance of [Fe/H] = –0.15.
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