Astronomy:AB Pictoris

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Short description: Star in the constellation Pictor
AB Pictoris
The Star AB Pictoris and its Companion - Phot-14d-05-normal.jpg

Coronagraphic image of AB Pictoris showing its tiny companion (bottom left). The data was obtained on 16 March 2003 with NACO on the VLT, using a 1.4 arcsec occulting mask on top of AB Pictoris.
Observation data
Equinox J2000.0]] (ICRS)
Constellation Pictor
Right ascension  06h 19m 12.913s[1]
Declination −58° 03′ 15.53″[1]
Apparent magnitude (V) 9.13[2] (9.21 to 9.35)[3]
Characteristics
Spectral type K1V(e)[2]
B−V color index 0.861±0.027[4]
Variable type BY Dra[3]
Astrometry
Radial velocity (Rv)22.6±0.3[2] km/s
Proper motion (μ) RA: 14.314±0.015[1] mas/yr
Dec.: 45.234±0.017[1] mas/yr
Parallax (π)19.9452 ± 0.0124[1] mas
Distance163.5 ± 0.1 ly
(50.14 ± 0.03 pc)
Absolute magnitude (MV)5.82[4]
Details
Mass0.90±0.10[5] M☉
Radius0.92±0.03[6] R☉
Luminosity0.51[4] L☉
Surface gravity (log g)4.67±0.09[5] cgs
Temperature5,188±50[6] K
Metallicity [Fe/H]−0.54[4] dex
Rotation3.90±0.08 d[7]
Rotational velocity (v sin i)10.87±0.08[7] km/s
Age30–40[8] Myr
Other designations
AB Pic, CD−58 1409, CPD−58 670, HD 44627A, 44627, HIP 30034, SAO 234448, PPM 335089[9]
Database references
SIMBADdata

AB Pictoris (abbreviated AB Pic, also catalogued as HD 44627) is a K-type main-sequence star, located 163.5 light-years away in the southern constellation of Pictor.[1] It has been identified as a member of the young (30 million years old) Tucana–Horologium association.[10] The star has been classified as a BY Draconis variable,[3] indicating it has an active chromosphere. It is an X-ray source and displays emission lines in its spectrum.[11][2]

In 2005 it was announced that an astronomical object (AB Pictoris b, abbreviated AB Pic b) had been imaged in 2003 and 2004 close to and apparently in orbit around the star. Its mass suggests that it is at the borderline between being a brown dwarf or a planet.[12]

A visual band light curve for AB Pictoris. The main plot shows the long-term variability, and the inset plot shows the periodic variation. Adapted from Kiraga (2012)[13]

Possible planetary system

In 2003 and 2004, an object (now catalogued as AB Pictoris b) was observed close to the star by a team of astronomers at the European Southern Observatory. Since it had common proper motion with AB Pictoris, it was concluded that it was physically close to the star. Its spectral type was estimated as between L0V and L3V. Using evolutionary models, its mass was estimated as from 13 to 14 Jupiter masses.[12] However, because modelling such young objects is difficult, this estimate is very uncertain; some models give masses as low as 11 Jupiter masses or as high as 70 Jupiter masses. Temperature estimates range from 1600 K to 2400 K.[8] As it is not known if the mass of the object exceeds the deuterium burning limit of 13 Jupiter masses, it is not clear whether the object should be classified as an extrasolar planet or a brown dwarf.[12] The planetary orbit is significantly misaligned with its spin axis orientation (obliquity), possibly due to gravitational interactions with the additional inner planet.[14]

The planetary system[15][14]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b 10±1 MJ 190+200−50 — — 90±12° —
c (suspected[14]) 6 MJ 6±4 — — — —

See also

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 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.
  2. ↑ 2.0 2.1 2.2 2.3 Torres, C. A. O. et al. (September 12, 2006). "Search for associations containing young stars (SACY)". Astronomy & Astrophysics 460 (3): 695–708. doi:10.1051/0004-6361:20065602. ISSN 0004-6361. Bibcode: 2006A&A...460..695T. 
  3. ↑ 3.0 3.1 3.2 Samus', N. N et al. (2017). "General catalogue of variable stars". Astronomy Reports. GCVS 5.1 61 (1): 80. doi:10.1134/S1063772917010085. Bibcode: 2017ARep...61...80S. 
  4. ↑ 4.0 4.1 4.2 4.3 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A. 
  5. ↑ 5.0 5.1 Ghezzi, L.; Cunha, K.; Smith, V. V.; de Araújo, F. X.; Schuler, S. C.; de la Reza, R. (August 19, 2010). "Stellar Parameters and Metallicities of Stars Hosting Jovian and Neptunian Mass Planets: A Possible Dependence of Planetary Mass on Metallicity". The Astrophysical Journal 720 (2): 1290–1302. doi:10.1088/0004-637X/720/2/1290. ISSN 0004-637X. Bibcode: 2010ApJ...720.1290G. 
  6. ↑ 6.0 6.1 van Belle, Gerard T.; von Braun, Kaspar (2009). "Directly Determined Linear Radii and Effective Temperatures of Exoplanet Host Stars". The Astrophysical Journal 694 (2): 1085–1098. doi:10.1088/0004-637X/694/2/1085. Bibcode: 2009ApJ...694.1085V. 
  7. ↑ 7.0 7.1 Bowler, Brendan P. et al. (April 2023). "Rotation Periods, Inclinations, and Obliquities of Cool Stars Hosting Directly Imaged Substellar Companions: Spin-Orbit Misalignments Are Common". The Astronomical Journal 165 (4): 164. doi:10.3847/1538-3881/acbd34. 164. Bibcode: 2023AJ....165..164B. 
  8. ↑ 8.0 8.1 Homogeneous comparison of directly detected planet candidates: GQ Lup, 2M1207, AB Pic, Ralph Neuhaeuser, ESO Workshop Proceedings on Multiple Stars, Bibcode: 2005astro.ph..9906N, arXiv:astro-ph/0509906.
  9. ↑ "V* AB Pic". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=V%2A+AB+Pic. 
  10. ↑ Inseok Song, B. Zuckerman; Bessell, M. S. (December 2003). "New Members of the TW Hydrae Association, β Pictoris Moving Group, and Tucana/Horologium Association". The Astrophysical Journal 599 (1): 342–350. doi:10.1086/379194. Bibcode: 2003ApJ...599..342S. .
  11. ↑ Haakonsen, Christian Bernt; Rutledge, Robert E. (September 2009). "XID II: Statistical Cross-Association of ROSAT Bright Source Catalog X-ray Sources with 2MASS Point Source Catalog Near-Infrared Sources". The Astrophysical Journal Supplement 184 (1): 138–151. doi:10.1088/0067-0049/184/1/138. Bibcode: 2009ApJS..184..138H. 
  12. ↑ 12.0 12.1 12.2 A companion to AB Pic at the planet/brown dwarf boundary, G. Chauvin, A.-M. Lagrange, B. Zuckerman, C. Dumas, D. Mouillet, I. Song, J.-L. Beuzit, P. Lowrance, and M. S. Bessell, Astronomy and Astrophysics 438, #3 (August 2005), pp. L29–L32, Bibcode: 2005A&A...438L..29C, doi:10.1051/0004-6361:200500111, arXiv:astro-ph/0504658.
  13. ↑ Kiraga, M. (March 2012). "ASAS Photometry of ROSAT Sources. I. Periodic Variable Stars Coincident with Bright Sources from the ROSAT All Sky Survey". Acta Astronomica 62 (1): 67–95. Bibcode: 2012AcA....62...67K. https://ui.adsabs.harvard.edu/abs/2012AcA....62...67K. Retrieved 20 February 2022. 
  14. ↑ 14.0 14.1 14.2 Palma-Bifani, P. et al. (2023), "Peering into the young planetary system AB Pic", Astronomy & Astrophysics 670: A90, doi:10.1051/0004-6361/202244294 
  15. ↑ Jean Schneider (2011). "Notes for Planet AB Pic b". Extrasolar Planets Encyclopaedia. https://exoplanet.eu/catalog/ab_pic_b--280/. 

External links



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