HIP 85605

Hip 85605
Observation data
Epoch J2000      Equinox J2000
Constellation Hercules
Right ascension 17h 29m 36.25s[1]
Declination +24° 39′ 14.12″
Apparent magnitude (V) 11.03[1]
Characteristics
Spectral type K4V
M dwarf?[2]
B−V color index 1.1[1][2]
Astrometry
Radial velocity (Rv)−21[1] km/s
Distance22.2? 200?[3] ly
Absolute magnitude (MV)11.8?[2][lower-alpha 1]
Details
Luminosity0.001?[lower-alpha 1] L☉
Temperature4700?[3] K
Metallicitypoor?
Other designations
2MASS J17293627+2439111, TYC 2079-1800-1[1]

HIP 85605 is a star in the constellation Hercules with a visual apparent magnitude of 11.03.[1] It may be a M dwarf or K-type main-sequence star potentially 18–28 light-years (5.6–8.5 parsecs) from the Sun.[2][3] It was previously thought to be a companion of the brighter star HIP 85607,[lower-alpha 2] but they are now believed to be an optical double.

The original Hipparcos parallax measurement in 1997 was 202 mas, which would place it 16.1 light-years from the Solar System.[1] In 2007, van Leeuwen revised the number to 147 mas, or 22.2 light-years.[1] With a parallax of 147 mas (0.147 arcseconds), HIP 85605 is unlikely to be one of the 100 closest star systems to the Sun.[4] In 2014, it was estimated that HIP 85605 could approach to about 0.13 to 0.65 light-years (0.04 to 0.2 pc) from the Sun within 240,000 to 470,000 years, though this assumes parallax and distance measurements to the object are correct.[2] More accurate astrometry is required to determine the distance to the star, and thus if it will pass close to the Sun. If correct, its gravitational influence will disrupt the orbits of comets in the Oort cloud and cause some of them to enter the inner Solar System. But the distance to this object is not well determined,[5] and it may turn out to be a much more distant luminous star, which would be a better fit to the Hertzsprung–Russell diagram.[3]

If the parallax data for HIP 85605 is substantially in error, and it is currently ~200 light-years from the Sun, it may simply pass ~30 light-years from the Sun in 2.8 million years.[6]

See also

Notes

  1. 1 2 Assuming a distance of ~22.2 light-years based on van Leeuwen's parallax of 147mas: (3.26ly/0.147arcsecond=22.2)
  2. ↑ Optical companion HIP 85607 could be a K0III orange giant ~1200 light-years from the Sun based on a small parallax of 2.72mas.

References

  1. 1 2 3 4 5 6 7 8 "HIP 85605". Strasbourg astronomical Data Center. Retrieved Jan 3, 2015.
  2. 1 2 3 4 5 Coryn A.L. Bailer-Jones (Dec 11, 2014). "Close encounters of the stellar kind". Astronomy & Astrophysics. arXiv:1412.3648Freely accessible. Bibcode:2014yCat..35759035B. doi:10.1051/0004-6361/201425221.
  3. 1 2 3 4 Mamajek, Eric (2015-01-03). "Reason to Doubt the Hipparcos Distance and the Close Flyby Scenario for the "Rogue Star" HIP 85605". doi:10.6084/m9.figshare.1284334. Retrieved 2015-01-04.
  4. ↑ "THE ONE HUNDRED NEAREST STAR SYSTEMS". RECONS (Research Consortium On Nearby Stars). Retrieved 2015-01-12.
  5. ↑ Coryn Bailer-Jones (2015-01-01). "The closest encounter is Hip 85605. How reliable is this?". Retrieved 2015-01-05.
  6. ↑ Mamajek, Eric E.; Barenfeld, Scott A.; Ivanov, Valentin D. (2015). "The Closest Known Flyby of a Star to the Solar System". The Astrophysical Journal. 800 (1). arXiv:1502.04655Freely accessible. Bibcode:2015ApJ...800L..17M. doi:10.1088/2041-8205/800/1/L17.

External links


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