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This star system is located about 36.3 light-years (ly) away from our Sun, Sol. It lies in the northwestern part (15:56:27.2+15:39:41.8, ICRS 2000.0) of Constellation Serpens, the Serpent, in its head portion (Serpens Caput) on the west side of Constellation Ophiuchus -- east of Beta Serpentis; northeast of Delta, Alpha (Unukalhai, and Epsilon Serpentis; northwest of Lambda (Marfik) and Kappa Ophiuchi; southeast of Delta, Gamma, Alpha (Alphecca), and Beta (Nusakan) Coronae Borealis; and southwest of Gamma Herculis and Kornephoros (Beta Herculis). Although no confirmed stellar or substellar companions have been found, the star appears to have detectable dust towards the outer ring or shell of its "planet-forming region" (more below).
Gamma Serpentis is a main sequence dwarf star of spectral and luminosity type F6 V, but it is still listed as a subgiant in some catalogues. The star may have around 1.15 to 1.27 times Sol's mass (Bi et al, 2008; Takeda et al, 2004; Caliskan et al, 2002; NASA Stars and Exoplanet Database; and David F. Gray, 1992), around 1.37 +/- 0.06 times Sol's diameter based on a power-law estimate (NASA Stars and Exoplanet database; and Kenneth R. Lang, 1980); and around 3 times its visual luminosity and perhaps around 2.74 +/- 0.04 times its theoretical bolometric luminosity (NASA Stars and Exoplanet database; and Kenneth R. Lang, 1980). It may be around 1.6 to 3.4 billion years old (Trilling et al, 2007; Chen et al, 2006; Bryden et al, 2006; Nordstrom et al, 2004; and Edvardsson et al, 1993, page 124 for HR 5933). The star may only be around 40 to 85 percent as enriched as Sol with elements heavier than hydrogen ("metallicity") based on its abundance of iron (Takeda et al, 2004; Chen et al, 2001; Carretta et al, 2000; and Cayrel de Strobel et al, 1991, page 299). With an active chromosphere and a fast rotational period of around three days (Cumming et al, 1999, page 902, Table 7 as HR 5933), it has been designated NSV 7350 as a New Suspected Variable star. Useful star catalogue numbers for the star include: Gam Ser, 41 Ser, HR 5933, Gl 603, HIP 78072, HD 142860, BD+16 2849, SAO 101826, FK 591, LHS 408, LTT 14730, and LFT 1234.
The orbital distance from Gamma Serpentis where an Earth-type planet currently would be "comfortable" with liquid water is centered near 1.7 AU -- in the Main Asteroid Belt between the orbital distances of Mars and Jupiter in the Solar System. At that distance from the star, such a planet would have an orbital period close to 1.9 years (690 days). It would be very difficult for astronomers to detect with today's astronomical instruments and methods.
Dust and Hunt for Companion Objects
In observations with the 1983 Infrared Astronomical Satellite (IRAS) mission, a shell of cool dust around 9.5 micronmeters was detected at an "equilibrium distance" of 25.9 AUs from Gamma Serpentis (within its "planet-forming region"), which may be related to a ring of large dust particles at an orbital distance that was previously calculated somewhat "subjectively" to be around 19 AUs (Rautela et al, 1990, pp. 14-15; and Hartmut Hans-Georg Aumann, 1985, page 890). More recent detections of infrared excess from particles of 60 micrometers in size have been detected with the Spitzer Space Telescope (Chen et al, 2006; and Bryden et al, 2006). The cold dust is found at the outer orbital distances that would appear to be related to collisions between Edgeworth-Kuiper Belt type bodies studied in the Solar System.
The Washington Double Star (WDS) catalog lists two companions (WDS 15565+1540STT 584AB and 584BC, or WDS J15565_1540 B and C) over three arc-minutes away from Gamma Serpentis. These appear to be optical companions only. The star was also suspected of having a spectroscopic companion which was not confirmed by radial-velocity variations (Cumming et al, 1999; and Duquennoy and Mayor, 1991, page 492 for Gl 603).
The following star systems are located within 10 light-years, plus more bright stars within 10 to 20 ly, of Gamma Serpentis.
|Star System||Spectra &|
|L 1346-53||M3 V||4.7|
|Ross 508||M4 V||5.9|
|Lambda Serpentis||G0 V||6.0|
|BD+21 2763||M0-9 Ve||6.3|
|G 169-29||M V||9.3|
|CD Bootis AB||M0-2 Ve |
|* plus bright stars *||. . .|
|Zeta Herculis AB||F9-G0 IV |
|Psi Serpentis 3?||G2.5-5 V |
|L 989-20 AB||G-M3.5 V |
|Xi Bootis 3?||G8 Ve |
|Mu Herculis 4||G5 IV |
|Muphrid AB||G0 V |
|18 Scorpii||G1-5 V-Va||20|
|BD+39 2947 AB||G8 V |
Up-to-date technical summaries on this stasr can be found at: the Astronomiches Rechen-Institut at Heidelberg's ARICNS; the NASA Stars and Exoplanet Database; and SIMBAD. Additional information may be available at Roger Wilcox's Internet Stellar Database, and more recent research papers may become available at the SAO/NASA ADS.
Constellation Serpens is composed of two parts: Serpens Caput (the Head of the Serpent) and Serpens Cauda (the Tail). Separating them is Constellation Ophiuchus, the Serpent Holder. For more information on stars and other objects in this Constellation, go to Christine Kronberg's Serpens. For an illustration, see David Haworth's Serpens.
For more information about stars including spectral and luminosity class codes, go to ChView's webpage on The Stars of the Milky Way.
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