36 Serpentis

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36 Serpentis
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Serpens
Right ascension 15h 51m 15.59418s [1]
Declination −03° 05′ 25.7938″ [1]
Apparent magnitude  (V)5.09 [2] (5.2 + 7.8) [3]
Characteristics
Spectral type A3Vn [4] or A2IV-Vn [5] (A7 + G0) [6]
U−B color index +0.07 [7]
B−V color index +0.12 [7]
Astrometry
Radial velocity (Rv)−8 [8] km/s
Proper motion (μ)RA: −91.09 [1] mas/yr
Dec.: −28.21 [1] mas/yr
Parallax (π)20.10±0.33  mas [1]
Distance 162 ± 3  ly
(49.8 ± 0.8  pc)
Absolute magnitude  (MV)1.61 [2]
Orbit [9]
Primary36 Ser A
Companion36 Ser B
Period (P)1,073 days
Eccentricity (e)0.7
Semi-amplitude (K1)
(primary)		6 km/s
Orbit [6]
Primary36 Ser AB
Companion36 Ser C
Period (P)50.6±1.5 yr
Semi-major axis (a)0.400±0.006″
Eccentricity (e)0.8323±0.0047
Inclination (i)98.08±0.31°
Longitude of the node (Ω)74.00±0.31°
Periastron epoch (T)2002.78±0.17
Argument of periastron (ω)
(secondary)		72.84±0.91°
Details
36 Ser A
Mass 1.97 [9]   M☉
Radius 2.25 [9]   R☉
Luminosity 19.13 [2]   L☉
Surface gravity (log g)3.89 [10]   cgs
Temperature 8,213 [9]   K
Metallicity [Fe/H]−2.00 [10]   dex
Rotational velocity (v sin i)229 [11]  km/s
Age 710 [9]   Myr
36 Ser B
Mass ≥0.37 and ≤0.50 [9]   M☉
36 Ser C
Mass 1.27 [9]   M☉
Radius 1.26 [9]   R☉
Temperature 6,255 [9]   K
Age 710 [9]   Myr
Other designations
b Ser, 36 Ser, BD−02°4058, FK5 2249, GC 4210, HD 141851, HIP 77660, HR 5895, SAO 140801, WDS J15513-0305 [12]
Database references
SIMBAD data

36 Serpentis is a triple star [9] system in the equatorial constellation of Serpens. It has the Bayer designation b Serpentis, while 36 Serpentis is the Flamsteed designation. [12] The system is visible to the naked eye as a dim, white-hued point of light with a combined apparent visual magnitude of 5.09. [2] It is located 162  light years away from the Sun based on parallax, [1] and is moving closer with a radial velocity of −8 km/s. [8]

Characteristics

The system consists of two spectroscopic binaries. The inner pair contains components A and B, while the outer pair contains components AB and C. The age of the whole system is estimated at 710 million years. [9]

The components AB and C orbit each other over a long orbital period of 52.8 years and a high eccentricity of 0.83. [6] Gray et al. (2017) found a merged stellar classification of A2IV-Vn for this system, [5] while Cowley et al. matched it with a class of A3Vn, [4] where the 'n' indicates "nebulous" lines caused by rapid rotation.

The primary component, 36 Serpentis A, is an A7-class [6] main sequence star of visual magnitude 5.2. [3] It is spinning rapidly, showing a projected rotational velocity of 229 km/s. [11] It was once thought to be a Lambda Boötis star [13] but this is now disputed. [9] The star is 710 million years old with 1.97 times the mass of the Sun and 2.25 times the Sun's radius. [9] It is radiating 19 times the Sun's luminosity from its photosphere [2] at an effective temperature of 8,213 K. [9]

The secondary, 36 Serpentis B, has been detected only by spectroscopy. It has an orbital period of 1,073 days (2.94 years) and a high eccentricity of 0.7. Interferometric observations have failed to detect this star, implying a luminosity-derived mass less than 0.50 M☉. The radial velocity data suggest a mass of at least 0.37 solar masses. It may be a faint red dwarf or a white dwarf. 36 Ser B is likely the source for the X-ray emission that has been detected coming from this system. [9]

The tertiary, 36 Serpentis C, is a G0 star [6] with a visual magnitude of 7.8. [3] It has 1.27 times the Sun's mass, 1.26 times the Sun's radius, and an effective temperature of 6,555 K. [9]

References

  1. 1 2 3 4 5 6 van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv: 0708.1752 . Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID   18759600.
  2. 1 2 3 4 5 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv: 1108.4971 . Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID   119257644.
  3. 1 2 3 Docobo, José A.; et al. (2010). "EMCCD Speckle Interferometry with the 6 m Telescope: Astrometric Measurements, Differential Photometry, and Orbits". The Astronomical Journal. 140 (4): 1078–1083. Bibcode:2010AJ....140.1078D. doi: 10.1088/0004-6256/140/4/1078 .
  4. 1 2 Cowley, A.; et al. (April 1969). "A study of the bright A stars. I. A catalogue of spectral classifications". Astronomical Journal. 74: 375–406. Bibcode:1969AJ.....74..375C. doi:10.1086/110819.
  5. 1 2 Gray, R. O.; et al. (July 2017). "The Discovery of λ Bootis Stars: The Southern Survey I". The Astronomical Journal. 154 (1): 11. Bibcode:2017AJ....154...31G. doi: 10.3847/1538-3881/aa6d5e . 31.
  6. 1 2 3 4 5 Mason, Brian D.; et al. (September 2010). "Binary Star Orbits. IV. Orbits of 18 Southern Interferometric Pairs". The Astronomical Journal. 140 (3): 735–743. Bibcode:2010AJ....140..735M. doi: 10.1088/0004-6256/140/3/735 .
  7. 1 2 Johnson, H. L. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99. Bibcode:1966CoLPL...4...99J.
  8. 1 2 Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Carnegie Institute Washington D.C. Publication. Bibcode:1953GCRV..C......0W.
  9. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Waisberg, Idel; Klein, Ygal; Katz, Boaz (2023-06-01). "Binarity and beyond in A stars – I. Survey description and first results of VLTI/GRAVITY observations of VAST targets with high Gaia–Hipparcos accelerations". Monthly Notices of the Royal Astronomical Society. 521 (4): 5232–5254. arXiv: 2206.05251 . Bibcode:2023MNRAS.521.5232W. doi: 10.1093/mnras/stad872 . ISSN   0035-8711.
  10. 1 2 Prugniel, Ph.; et al. (1986). "The atmospheric parameters and spectral interpolator for the MILES stars". Astronomy & Astrophysics. 531: A165. arXiv: 1104.4952 . Bibcode:2011A&A...531A.165P. doi:10.1051/0004-6361/201116769. S2CID   54940439.
  11. 1 2 Royer, F.; et al. (2007). "Rotational velocities of A-type stars. III. Velocity distributions". Astronomy & Astrophysics. 463 (2): 671–682. arXiv: astro-ph/0610785 . Bibcode:2007A&A...463..671R. doi:10.1051/0004-6361:20065224. S2CID   18475298.
  12. 1 2 "36 Ser". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2019-07-14.
  13. ↑ Nikolov, G.; et al. (April 2008). "Spectroscopic orbit determination of two metal-weak dwarf stars: HD64491 and HD141851". Contributions of the Astronomical Observatory Skalnaté Pleso. 38 (2): 433–434. Bibcode:2008CoSka..38..433N.
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