Astronomy:PZ Telescopii
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Telescopium |
| Right ascension | 18h 53m 05.87351s[2] |
| Declination | −50° 10′ 49.8974″[2] |
| Apparent magnitude (V) | 8.33 - 8.63[3] |
| Characteristics | |
| Spectral type | G9 IV[4] + M7±1[5] |
| B−V color index | +0.784±0.021[6] |
| Variable type | BY Dra[3] |
| Astrometry | |
| Radial velocity (Rv) | −4.2±0.2[6] km/s |
| Proper motion (μ) | RA: +16.272(18)[2] mas/yr Dec.: −85.519(17)[2] mas/yr |
| Parallax (π) | 21.1621 ± 0.0223[2] mas |
| Distance | 154.1 ± 0.2 ly (47.25 ± 0.05 pc) |
| Absolute magnitude (MV) | 4.88[6] |
| Orbit[7] | |
| Period (P) | 120+110 −30 yr |
| Semi-major axis (a) | 27+14 −4 astronomical unit|AU |
| Eccentricity (e) | 0.52+0.08 −0.10 |
| Inclination (i) | 91.73+0.36 −0.32° |
| Longitude of the node (Ω) | 238.62+0.21 −0.23° |
| Periastron epoch (T) | 1997.2+4.7 −1.8 |
| Argument of periastron (ω) (secondary) | 50+50 −30° |
| Details[8] | |
| Mass | 1.13±0.03 M☉ |
| Radius | 1.23±0.04 R☉ |
| Luminosity | 0.993+0.004 −0.005[9] L☉ |
| Surface gravity (log g) | 4.41±0.10 cgs |
| Temperature | 5,338±200 K |
| Metallicity [Fe/H] | +0.05±0.20 dex |
| Rotation | 0.943±0.002[5] |
| Rotational velocity (v sin i) | 69.0±0.1[4] km/s |
| Age | 24±3 Myr |
| B | |
| Mass | 27+25 −9[7] MJup |
| Surface gravity (log g) | < 4.5[5] cgs |
| Temperature | 2,700±100 K |
| Other designations | |
| Database references | |
| SIMBAD | data |
PZ Telescopii, also known as HD 174429 or simply PZ Tel, is a young star in the constellation Telescopium. Based on parallax measurements, it is located at a distance of 154 light-years from the Sun. The star is drifting closer with a radial velocity of −4 km/s.[6] It is too faint to be visible to the naked eye and is classified as a BY Draconis variable that ranges in apparent visual magnitude from 8.33 down to 8.63 over a period of 22.581 hours (0.94088 days).[3] It is one of the closest and hence brightest pre-main-sequence stars to Earth.[8]
PZ Telescopii has an effective surface temperature of around 5,338 K (the Sun has an approximate surface temperature of 5,778 K), a mass around 1.13 times, and diameter 1.23 times that of the Sun.[8] The star has a high rate of spin, showing a projected rotational velocity of 69 km/s[4] and a rotation period of 22.6 h.[5] It is radiating about the same luminosity as the Sun. PZ Telescopii was originally considered to be a member of the Beta Pictoris moving group; however in a 2012 paper, James Jenkins of Universidad de Chile and colleagues used three methods to calculate its age and came up with a figure of around 24 million years—significantly older than the 12 million years of the association.[8]
This star has an orbiting debris disk calculated to span from a radius of 35 to 165 astronomical units (AU), as well as a substellar companion with about 36 times the mass of Jupiter orbiting at a distance of about 16 AU, discovered in 2009.[11] The companion, currently known as PZ Tel B, is thought to be a brown dwarf; however it is possible (though very unlikely) that it is an extremely large Jupiter-like planet, in which case it would be PZ Tel b, and the first such planet to be directly imaged.[8] Preliminary orbital elements from 2016 give a best fit orbital period of 622.2 years with an eccentricity of 0.755.[5]
The mass and orbit of this companion were updated in 2023 based on Hipparcos and Gaia astrometry, finding a somewhat lower mass, and an edge-on orbit that is eccentric but less so than previous results.[7] It is now included in the NASA Exoplanet Archive since its nominal mass of 27 |♃|J}}}}}} is below their upper limit of 30 MJ, although the margin of error is large enough that it is still possible that the mass exceeds 30 MJ.[12][13]
References
- ↑ Innis, J. L.; Coates, D. W.; Thompson, K.; Lloyd Evans, T. (January 1990). "Observations of active-chromosphere stars III - photometry of PZ Tel 1979-1985". Monthly Notices of the Royal Astronomical Society 242 (3): 306–310. doi:10.1093/mnras/242.3.306. Bibcode: 1990MNRAS.242..306I.
- ↑ 2.0 2.1 2.2 2.3 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 3.0 3.1 3.2 Samus, N. N. et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports. 5.1 61 (1): 80–88. doi:10.1134/S1063772917010085. Bibcode: 2017ARep...61...80S.
- ↑ 4.0 4.1 4.2 Torres, C. A. O.; Quast, G. R.; Silva, L. da; Reza, R. de la; Melo, C. H. F.; Sterzik, M. (December 1, 2006). "Search for associations containing young stars (SACY) - I. Sample and searching method" (in en). Astronomy & Astrophysics 460 (3): 695–708. doi:10.1051/0004-6361:20065602. ISSN 0004-6361. Bibcode: 2006A&A...460..695T.
- ↑ 5.0 5.1 5.2 5.3 5.4 Maire, A. -L. et al. (March 2016). "First light of the VLT planet finder SPHERE. II. The physical properties and the architecture of the young systems PZ Telescopii and HD 1160 revisited". Astronomy & Astrophysics 587: 24. doi:10.1051/0004-6361/201526594. A56. Bibcode: 2016A&A...587A..56M.
- ↑ 6.0 6.1 6.2 6.3 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A.
- ↑ 7.0 7.1 7.2 Franson, Kyle; Bowler, Brendan P. (June 2023). "Dynamical Mass of the Young Brown Dwarf Companion PZ Tel B". The Astronomical Journal 165 (6): 246. doi:10.3847/1538-3881/acca18. Bibcode: 2023AJ....165..246F.
- ↑ 8.0 8.1 8.2 8.3 8.4 Jenkins, J. S.; Pavlenko, Y. V.; Ivanyuk, O.; Gallardo, J. et al. (2012). "Benchmark Cool Companions: Ages and Abundances for the PZ Telescopii System". Monthly Notices of the Royal Astronomical Society 420 (4): 3587–98. doi:10.1111/j.1365-2966.2011.20280.x. Bibcode: 2012MNRAS.420.3587J.
- ↑ Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ "V* PZ Tel". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=V%2A+PZ+Tel.
- ↑ Biller, Beth A. et al. (September 2010). "The Gemini NICI Planet-finding Campaign: Discovery of a Close Substellar Companion to the Young Debris Disk Star PZ Tel". The Astrophysical Journal Letters 720 (1): L82–L87. doi:10.1088/2041-8205/720/1/L82. Bibcode: 2010ApJ...720L..82B.
- ↑ "PZ Tel". NASA Exoplanet Archive. https://exoplanetarchive.ipac.caltech.edu/overview/PZ%20Tel.
- ↑ "Exoplanet Criteria for Inclusion in the Archive". NASA Exoplanet Archive. https://exoplanetarchive.ipac.caltech.edu/docs/exoplanet_criteria.html.
External links
- Watson, Christopher (19 April 2012). "PZ Telescopii". AAVSO Website. American Association of Variable Star Observers. http://www.aavso.org/vsx/index.php?view=detail.top&oid=36567. Retrieved 1 July 2014.
 |  |
