25 Serpentis

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25 Serpentis
Serpens constellation map.svg
Red circle.svg
Location of 25 Serpentis (circled)
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Serpens
Right ascension 15h 46m 05.63636s [1]
Declination −01° 48 15.0830 [1]
Apparent magnitude  (V)5.37 - 5.40 [2]
Characteristics
Spectral type B8IV/V [3]
U−B color index −0.40 [4]
B−V color index −0.05 [4]
Variable type SPB [5]
Astrometry
Radial velocity (Rv)9.50±0.3 [6]  km/s
Proper motion (μ)RA: −23.15 [1]   mas/yr
Dec.: −30.50 [1]   mas/yr
Parallax (π)7.25 ± 0.31 [1]   mas
Distance 450 ± 20  ly
(138 ± 6  pc)
Orbit [7]
Period (P)38.927±0.004
Eccentricity (e)0.731±0.006
Periastron epoch (T)2450132.80±0.06
Argument of periastron (ω)
(secondary)
201.8±0.8°
Semi-amplitude (K1)
(primary)
43.1±0.7 km/s
Semi-amplitude(K2)
(secondary)
86±1 km/s
Details [8]
Mass 4.1  M
Luminosity 383  L
Temperature 13,932  K
Rotational velocity (v sin i)80 km/s
Other designations
A2 Ser, [9] 25 Ser, PT Ser, HD 140873, HIP 77227, HR  5863, SAO 140740, BD−01°3092
Database references
SIMBAD data

25 Serpentis is a star system in the constellation of Serpens Caput. With an apparent magnitude of 5.37, it is just barely visible to the naked eye. The system is estimated to be some 450 light-years (138 parsecs) based on its parallax. [1]

A light curve for PT Serpentis, plotted from Hipparcos data PTSerLightCurve.png
A light curve for PT Serpentis, plotted from Hipparcos data

25 Serpentis is a spectroscopic binary, [11] meaning that the individual components are too close to be resolved, but periodic Doppler shifts in their spectra indicate orbital motion. The system consists of a hot B-type giant and an A-type main-sequence star. The two stars orbit each other every 38.9 days, and have a very eccentric orbit, with an orbital eccentricity of 0.731. [7] The primary is a slowly pulsating B-type star, which causes the system to vary by 0.03 magnitudes; [2] for that reason it has been given the variable star designation PT Serpentis.

Related Research Articles

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Omicron Serpentis is a solitary star in the Serpens Cauda (tail) section of the equatorial constellation Serpens. Based upon an annual parallax shift of 18.83 mas as seen from Earth, it is located around 173 light years from the Sun. The star is visible to the naked eye with a base apparent visual magnitude of +4.26.

Chi Aquarii Star in the constellation Aquarius

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15 Arietis Single, variable star in the constellation Aries

15 Arietis is a single variable star in the northern constellation of Aries. 15 Arietis is the Flamsteed designation; it also bears the variable star designation AV Arietis. It has an apparent visual magnitude of 5.74, which is just bright enough to be visible to the naked eye from dark suburban skies. An annual parallax shift of 5.84 mas corresponds to a physical distance of approximately 560 light-years from Earth. At that distance, the star's brightness is reduced by 0.33 in magnitude because of extinction from interstellar gas and dust.

9 Aurigae Star system in the constellation Auriga

9 Aurigae is a star system in Auriga (constellation). It has an apparent magnitude of about 5, making it visible to the naked eye in many suburban skies. Parallax estimates made by the Hipparcos spacecraft put it at about 85.7 light-years from the solar system.

14 Aurigae Quadruple star system in the constellation Auriga

14 Aurigae is a quadruple star system located 269 light years away from the Sun in the zodiac constellation of Auriga. It has the variable star designation KW Aurigae, whereas 14 Aurigae is the Flamsteed designation. It is visible to the naked eye as a faint, white-hued star with a combined apparent visual magnitude of 5.01. The system is moving closer to the Sun with a heliocentric radial velocity of −9 km/s.

26 Aurigae is a binary star system in the northern constellation of Auriga. It is visible to the naked eye as a faint star with an apparent visual magnitude of 5.41.

Iota Canis Majoris Variable star in the constellation Canis Major

Iota Canis Majoris, Latinized from ι Canis Majoris, is a solitary variable supergiant star in the southern constellation of Canis Major. It is visible to the naked eye with an apparent visual magnitude that varies between +4.36 and +4.40. The distance to this star is approximately 3,100 light years based on parallax measurements. It is drifting further away with a radial velocity of +41.2 km/s.

2 Centauri Star in the constellation Centaurus

2 Centauri is a single star in the southern constellation of Centaurus, located approximately 183 light-years from Earth. It has the Bayer designation g Centauri; 2 Centauri is the Flamsteed designation. This object is visible to the naked eye as faint, red-hued star with an apparent visual magnitude of 4.19. It is moving away from the Earth with a heliocentric radial velocity of +41 km/s. The star is a member of the HD 1614 supercluster.

Y Carinae Variable star in the constellation Carina

Y Carinae is a Classical Cepheid variable, a type of variable star, in the constellation Carina. Its apparent magnitude varies from 7.53 to 8.48.

Iota Herculis Variable star in the constellation Hercules

Iota Herculis is a fourth-magnitude variable star system in the constellation Hercules, consisting of at least four stars all about 139 parsecs away. The brightest is a β Cephei variable, a pulsating star.

Phi Draconis Star in the constellation Draco

Phi Draconis is a fourth-magnitude variable star in the constellation Draco. It has the Flamsteed designation 43 Draconis. It is also a triple star system where the brightest component is a chemically peculiar Ap star.

1 Geminorum Star in the constellation Gemini

1 Geminorum is a star in the constellation Gemini. Its apparent magnitude is 4.15.

Delta Sagittae Star in the constellation Sagitta

Delta Sagittae is a binary star in the constellation of Sagitta, with an apparent magnitude of +3.68. The primary component is a red M-type bright giant, and the secondary is a B-type main-sequence star. It is approximately 430 light years from Earth, based on its Gaia Data Release 2 parallax.

Omicron<sup>1</sup> Orionis Star in the constellation Orion

Omicron1 Orionis is a binary star in the northeastern corner of the constellation Orion. It is visible to the naked eye with an apparent visual magnitude of 4.7. Based upon an annual parallax shift of 5.01±0.71 mas, it is located approximately 650 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an interstellar absorption factor of 0.27 due to intervening dust.

Lambda Pavonis Single, variable star in the constellation Pavo

λ Pavonis, Latinized as Lambda Pavonis, is a single, variable star in the southern constellation of Pavo. It is a blue-white hued star that is faintly visible to the naked eye with an apparent visual magnitude that fluctuates around 4.22. This object is located approximately 1,400 light years from the Sun, based upon parallax. It is a member of the Scorpius-Centaurus Association.

Gamma Phoenicis

Gamma Phoenicis is a star system in the constellation Phoenix, located around 71.63 parsecs (233.6 ly) distant.

HY Velorum is a binary star system in the southern constellation of Vela. It is a dim star but visible to the naked eye with an apparent visual magnitude of 4.83. The distance to this system, as estimated from its annual parallax shift of 7.1 mas, is 460 light years. HY Vel most likely forms a gravitationally bound pair with the magnitude 5.45 binary system KT Vel ; both are members of the IC 2391 open cluster. As of 1998, HY Vel and KT Vel had an angular separation of 76.1″ along a position angle of 311°.

W Cygni Semi-regular variable star in the constellation Cygnus

W Cygni is a semi-regular variable star in the constellation Cygnus, located 570 light-years from Earth. It lies less than half a degree southeast of ρ Cygni. W Cygni is, at times, a naked-eye star but it was not given a Bayer or Flamsteed designation. It has been proposed as a binary star system with a hotter main sequence companion, but this has not been confirmed.

References

  1. 1 2 3 4 5 6 van Leeuwen, F.; et al. (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 VSX; Otero, S. A (10 February 2012). "PT Serpentis". AAVSO Website. American Association of Variable Star Observers . Retrieved 28 May 2014.
  3. Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars, Vol. 5". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
  4. 1 2 Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
  5. Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
  6. Pourbaix, D.; et al. (2004). "SB9: The ninth catalogue of spectroscopic binary orbits". Astronomy and Astrophysics. 424 (2): 727–732. arXiv: astro-ph/0406573 . Bibcode:2004A&A...424..727P. doi:10.1051/0004-6361:20041213. S2CID   119387088.
  7. 1 2 De Cat, P.; et al. (2000). "A study of bright southern slowly pulsating B stars. I. Determination of the orbital parameters and of the main frequency of the spectroscopic binaries". Astronomy and Astrophysics. 355: 1015–1030. Bibcode:2000A&A...355.1015D.
  8. Szewczuk, W.; Daszyńska-Daszkiewicz, J. (2015). "Identification of pulsational modes in rotating slowly pulsating B-type stars". Monthly Notices of the Royal Astronomical Society. 450 (2): 1585. arXiv: 1504.04490 . Bibcode:2015MNRAS.450.1585S. doi:10.1093/mnras/stv715.
  9. Hoffleit, D. (July 1979), "Discordances in Star Designations", Bulletin d'Information du Centre de Données Stellaires, 17 (17): 38, Bibcode:1979BICDS..17...38H
  10. "Light Curve". Hipparcos ESA. ESA. Retrieved 17 February 2022.
  11. Petrie, R. M.; Phibbs, E. (1950). "Redetermination of the spectrographic orbits of iot Peg and 25 Ser". Publications of the Dominion Astrophysical Observatory Victoria. 8: 225. Bibcode:1950PDAO....8..225P.