HD 164595

Coordinates: Sky map 18h 00m 38.894s, +29° 34′ 18.92″
Source: Wikipedia, the free encyclopedia.

HD 164595

Position of star HD 164595 in the constellation Hercules
Observation data
Epoch J2000      Equinox J2000
Constellation Hercules[1]
Right ascension 18h 00m 38.894s[2]
Declination +29° 34′ 18.92″[2]
Apparent magnitude (V) 7.07[1] + 12.538[3]
Characteristics
Spectral type G2 V[4] + M2.5 V[5]
B−V color index 0.635±0.005[1]
Distance
92.13 ± 0.04 ly
(28.25 ± 0.01 pc)
Absolute magnitude (MV)+4.81[1]
Details
HD 164595 A (primary)
Gyr
HD 164595 B (secondary)
Mass0.455±0.046[3] M☉
Radius0.464±0.018[3] R☉
Temperature3,648±21[3] K
Rotation43.486848 d[10]
TYC 2103-1620-1, 2MASS J18003890+2934188[11]
Database references
SIMBADdata

HD 164595 is a wide

angular rate of 0.222″ yr−1.[14]

The

magnetic activity in the chromosphere is comparable to solar levels.[15]

The secondary member, component B, is a magnitude 12.5

projected separation of 2,509±27 AU from the primary.[12] It is a small red dwarf of spectral class M2.5 V.[5] Periodic variations in the light curve of this star suggest a rotation period of 43.5 days.[10]

Planetary system

HD 164595 has one known exoplanet, HD 164595 b, which orbits HD 164595 A every 40 days.[19][20] It was detected with the radial velocity technique with the SOPHIE echelle spectrograph. Since the inclination of the orbital plane is unknown, only a lower bound on the mass of the object can be determined. The exoplanet has a minimal mass equivalent of 16 Earths.[19]

The HD 164595 A planetary system[21]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b >0.0516±0.00856 MJ 0.23 40.00±0.24 0.088+0.12
−0.066 		— —

Signal observation and SETI

In 2016, HD 164595 briefly attracted media attention after it was reported that a possible

SETI
signal had been detected from the direction of the star in the previous year. The signal was only heard once and never confirmed by other telescopes, and is thought to have been due to terrestrial interference.

On 15 May 2015, a brief, single radio signal at 11 GHz (2.7 cm wavelength)[22] was observed in the direction of HD 164595 by a team led by N. N. Bursov[23] involving Claudio Maccone at the RATAN-600 radio observatory. The signal may have been caused by terrestrial radio-frequency interference or gravitational lensing from a more distant source.[24][25] It was observed only once (for two seconds), by a single team, at a single telescope, giving it a Rio Scale[26] score of 1 (insignificant) or 2 (low). Discussions in the media from 29 August 2016 onwards featured speculation that the signal could be caused by an isotropic beacon from a Type II civilization.[27]

The senior astronomer of the

Nicholas Suntzeff of Texas A&M University stated that the signal is in a military frequency band, and that it could have been a satellite downlink, implying that some such systems may be kept secret and therefore would be unknown to SETI scientists.[22]

SETI and

METI studies followed with the Allen Telescope Array and the Boquete Optical SETI Observatory.[29][28] Also, scientists at Berkeley SETI Research Center at the University of California, Berkeley observed HD 164595 using the Green Bank Telescope as part of the Breakthrough Listen program. No signal was detected at the position and frequency of the transient reported by the RATAN group.[30][31]

The

Special Astrophysical Observatory of the Russian Academy of Sciences has since released an official statement that the signal is of a "most probable terrestrial origin".[32]

See also

Footnotes

  1. ^ An exact solar twin would be a G2V star with a 5778 K temperature, be 4.6 billion years old, with the correct metallicity and a 0.1% solar luminosity variation.[18][17]

References

  1. ^
    S2CID 119257644
    .
  2. ^
    S2CID 244398875
    . Gaia DR3 record for this source at VizieR.
  3. ^
    S2CID 19269312
    . 64.
  4. ^
    doi:10.1086/110986
    .
  5. ^
    S2CID 53135130
    . A128.
  6. ^
    S2CID 52952408
    .
  7. ^
    S2CID 119491061
    , A72.
  8. ^
    S2CID 118507965
    .
  9. ^
    S2CID 119111150
    .
  10. ^
    doi:10.1088/0004-6256/141/5/166
    . 166.
  11. ^ "HD 164595". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 28 December 2023.
  12. ^
    S2CID 119260219
    .
  13. ISBN 0-933346-84-0
    .
  14. S2CID 2603568
    .
  15. ^
    S2CID 119111150
    .
  16. S2CID 119205608
    .
  17. ^ a b Williams, D. R. (2004). "Sun Fact Sheet". NASA. Retrieved 23 June 2009.
  18. ^ "Solar Variability and Terrestrial Climate - NASA Science". NASA. Retrieved 8 January 2013.
  19. ^ a b "HD 164595 b Confirmed Planet Overview Page". NASA. Retrieved 31 August 2016.
  20. S2CID 119181352
    .
  21. ^ HD 164595 b on exoplanet.eu
  22. ^ a b Berger, Eric (29 August 2016). "Ars Technica". Ars Technica. Ars Technica. Retrieved 29 August 2016.
  23. ^ Gilster, Paul (27 August 2016). "An Interesting SETI Candidate in Hercules". Centauri Dreams. Retrieved 29 August 2016.
  24. ^ Bursov, N.; et al. (2016). "SETI observations on the RATAN-600 telescope in 2015 and detection of a strong signal in the direction of HD 164595". IAA SETI Permanent Committee. Guadalajara, Mexico.
  25. KurzweilAI
    . 29 August 2016. Retrieved 31 August 2016.
  26. ^ "Rio scale calculator". AV Sport. Archived from the original on 2 September 2016. Retrieved 29 August 2016.
  27. ^ Seemangal, Robin (29 August 2016). "Not a Drill: SETI Is Investigating a Possible Extraterrestrial Signal From Deep Space". Observer. Retrieved 29 August 2016.
  28. ^ a b "They're not saying it's aliens, but signal traced to sunlike star sparks SETI interest". GeekWire. 29 August 2016. Retrieved 29 December 2023.
  29. ^ "'Leaked' space signal report has SETI groups scrambling". SFGate. 29 August 2016. Retrieved 29 December 2023.
  30. University of Berkeley
    . Retrieved 29 December 2023.
  31. ^ Croft, Steve; et al. "Breakthrough Listen Follow-up of a Transient Signal from the RATAN-600 Telescope in the Direction of HD 164595" (PDF). University of Berkeley. Retrieved 29 December 2023.
  32. ^ "Monitoring of the continuum of SETI candidates with RATAN-600 (SAO RAS official comment)". Sternberg Astronomical Institute. Retrieved 29 December 2023.


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