Astronomy:Pi5 Orionis
  | |
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Orion |
| Right ascension | 04h 54m 15.09604s[1] |
| Declination | +02° 26′ 26.4231″[1] |
| Apparent magnitude (V) | 3.69[2] |
| Characteristics | |
| Spectral type | B2 III[3] |
| U−B color index | −0.81[2] |
| B−V color index | −0.18[2] |
| Variable type | Ellipsoidal[4] (SPB?)[5] |
| Astrometry | |
| Radial velocity (Rv) | +23.4[6] km/s |
| Proper motion (μ) | RA: +0.55[1] mas/yr Dec.: +0.61[1] mas/yr |
| Parallax (π) | 2.43 ± 0.39[1] mas |
| Distance | approx. 1,300 ly (approx. 410 pc) |
| Absolute magnitude (MV) | −4.3[7] |
| Orbit[5] | |
| Period (P) | 3.700373 d |
| Semi-major axis (a) | 25.9 astronomical unit|AU |
| Eccentricity (e) | 0.083±0.040 |
| Inclination (i) | 34° |
| Periastron epoch (T) | 2,433,341.088±0.010 JD |
| Semi-amplitude (K1) (primary) | 60.41±1.99 km/s |
| Details | |
| π5 Ori A | |
| Mass | 12[5] M☉ |
| Radius | 12[5] R☉ |
| Luminosity | 11,262[8] L☉ |
| Surface gravity (log g) | 3.51[9] cgs |
| Temperature | 14,496[8] K |
| Metallicity [Fe/H] | −0.28[9] dex |
| Rotational velocity (v sin i) | 90[10] km/s |
| Age | 15.8±0.2[11] Myr |
| π5 Ori B | |
| Mass | 5.0[5] M☉ |
| Radius | 2.8 - 3.8[5] R☉ |
| Luminosity | 525 - 741[5] L☉ |
| Surface gravity (log g) | 3.98 - 4.24[5] cgs |
| Temperature | 15,596 - 16,520[5] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
Pi5 Orionis (π5 Ori, π5 Orionis) is a binary star system in the constellation Orion. It has an apparent visual magnitude of 3.69,[2] which is bright enough to be visible to the naked eye on a clear night. Based upon an annual parallax shift of 2.43 mas,[1] it is around 1,300 light-years distant from the Sun.
This is a single-lined[3] spectroscopic binary star system in a circular orbit with an orbital period of 3.7005 days.[14] It is an ellipsoidal variable, which means the orbit is sufficiently close that the shapes of the components are being distorted by their mutual gravitation. This is causing the visual magnitude of the system to vary regularly by 0m.05 over the course of each orbit, as the orientation of the stars change with respect to the Earth.[4] Detailed analysis of the light curve suggests that the primary star is also pulsating and is probably a Slowly pulsating B-type star.[5]
The primary component is a B-type giant star with a stellar classification of B2 III.[3] It is only about 16 million years old[11] and spins with a projected rotational velocity of 90 km/s.[10] Despite the spectral class, the primary star is thought to be at or near the end of its main sequence evolution.[5] It has about 12.5 times the mass of the Sun and radiates 11,262[8] times the solar luminosity from its outer atmosphere at an effective temperature of 14,496 K.[8]
The secondary star is not detectable clearly, but modelling of the brightness variations and orbit suggest that it is a main sequence star with a spectral class of about B6. It is smaller, cooler, and much less luminous than the primary, and orbits at about 26 astronomical units.[5]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ 2.0 2.1 2.2 2.3 Crawford, D. L. et al. (1971), "Four-color, H-beta, and UBV photometry for bright B-type stars in the northern hemisphere", The Astronomical Journal 76: 1058, doi:10.1086/111220, Bibcode: 1971AJ.....76.1058C.
- ↑ 3.0 3.1 3.2 Chini, R. et al. (2012), "A spectroscopic survey on the multiplicity of high-mass stars", Monthly Notices of the Royal Astronomical Society 424 (3): 1925, doi:10.1111/j.1365-2966.2012.21317.x, Bibcode: 2012MNRAS.424.1925C.
- ↑ 4.0 4.1 Morris, S. L. (August 1985), "The ellipsoidal variable stars", Astrophysical Journal, Part 1 295: 143–152, doi:10.1086/163359, Bibcode: 1985ApJ...295..143M.
- ↑ 5.00 5.01 5.02 5.03 5.04 5.05 5.06 5.07 5.08 5.09 5.10 5.11 Jerzykiewicz, M.; Pigulski, A.; Handler, G.; Moffat, A. F. J.; Popowicz, A.; Wade, G. A.; Zwintz, K.; Pablo, H. (2020). "BRITE-Constellation photometry of π5 Orionis, an ellipsoidal SPB variable". Monthly Notices of the Royal Astronomical Society 496 (2): 2391. doi:10.1093/mnras/staa1665. Bibcode: 2020MNRAS.496.2391J.
- ↑ Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick, Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, 30, University of Toronto: International Astronomical Union, p. 57, Bibcode: 1967IAUS...30...57E.
- ↑ Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A.
- ↑ 8.0 8.1 8.2 8.3 McDonald, I. et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society 427 (1): 343–57, doi:10.1111/j.1365-2966.2012.21873.x, Bibcode: 2012MNRAS.427..343M.
- ↑ 9.0 9.1 Soubiran, C. et al. (June 2010), "The PASTEL catalogue of stellar parameters", Astronomy and Astrophysics 515: A111, doi:10.1051/0004-6361/201014247, Bibcode: 2010A&A...515A.111S.
- ↑ 10.0 10.1 Abt, Helmut A.; Boonyarak, Chayan (November 2004), "Tidal Effects in Binaries of Various Periods", The Astrophysical Journal 616 (1): 562–566, doi:10.1086/423795, Bibcode: 2004ApJ...616..562A.
- ↑ 11.0 11.1 Tetzlaff, N. et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society 410 (1): 190–200, doi:10.1111/j.1365-2966.2010.17434.x, Bibcode: 2011MNRAS.410..190T.
- ↑ "pi.05 Ori". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=pi.05+Ori.
- ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html.
- ↑ Pourbaix, D. et al. (2004), "SB9: The ninth catalogue of spectroscopic binary orbits", Astronomy & Astrophysics 424 (2): 727–732, doi:10.1051/0004-6361:20041213, Bibcode: 2004A&A...424..727P.
External links
- Kaler, James B. (February 6, 2009), "Pi-5 Orionis", Stars (University of Illinois), http://stars.astro.illinois.edu/sow/pi5ori.html, retrieved 2016-11-22.
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