Astronomy:Pi Mensae

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Short description: Star in the constellation Mensa
Pi Mensae
Observation data
Equinox J2000.0]] (ICRS)
Constellation Mensa
Right ascension  05h 37m 09.88684s[1]
Declination −80° 28′ 08.8346″[1]
Apparent magnitude (V) +5.65[2]
Characteristics
Spectral type G0 V[3]
U−B color index 0.11[2]
B−V color index 0.60[2]
V−R color index 0.31
R−I color index 0.29
Variable type none
Astrometry
Radial velocity (Rv)10.71±0.12[1] km/s
Proper motion (μ) RA: 310.909[1] mas/yr
Dec.: 1,049.060[1] mas/yr
Parallax (π)54.6825 ± 0.0354[1] mas
Distance59.65 ± 0.04 ly
(18.29 ± 0.01 pc)
Absolute magnitude (MV)+4.35±0.01[4]
Details[5]
Mass1.11±0.01 M
Radius1.15±0.01 R
Luminosity1.532±0.004 L
Surface gravity (log g)4.35±0.01 cgs
Temperature6,013±18 K
Metallicity [Fe/H]0.09[6] dex
Rotational velocity (v sin i)2.96[6] km/s
Age3.4±0.6 Gyr
Other designations
Database references
SIMBADdata
ARICNSdata

Pi Mensae (π Men), also known as HD 39091, is a yellow dwarf star[3] in the constellation of Mensa. This star has a high proper motion. The apparent magnitude is 5.67, which can be visible to the naked eye in exceptionally dark, clear skies. It is nearly 60 light-years away. The star is slightly larger than the Sun in terms of mass, size, luminosity, temperature and metallicity, and is about 730 million years younger. It hosts three known planets.

Planetary system

On October 15, 2001, an extrasolar planet was found orbiting the star.[7] Pi Mensae b is one of the most massive planets ever discovered, and has a very eccentric orbit that takes approximately 2,151 days (5.89 years) to complete. Because of its eccentricity, and being a massive brown dwarf that passes through the habitable zone, it would have disrupted the orbits of any Earth-like planets, and possibly thrown them into the star, or out into the interstellar medium.

Incorporating more accurate Hipparcos data yields a mass range for the companion to be anywhere from 10.27 to 29.9 times that of Jupiter, confirming its substellar nature with the upper limit of mass putting it in the brown dwarf range.[8] In 2020, the true mass of Pi Mensae b was measured to be 14.1 ||J}}}}}} via astrometry.[9] Since this is greater than 13 Jupiter masses, the object could be considered a brown dwarf, although more recent astrometric results suggest a slightly lower mass. Pi Mensae was ranked 100th on the list of top 100 target stars for the planned (but now-canceled) Terrestrial Planet Finder mission to search for Earth-like planets.

On September 16, 2018, a preprint was posted to arXiv detailing the discovery of a super-Earth on a 6.27-day orbit around the star, the first exoplanet detection by the Transiting Exoplanet Survey Satellite (TESS) submitted for publication.[10] This was confirmed two days later, where the attention was called that the system is amenable for future planet atmospheric studies.[11]

In 2020, an analysis with Gaia DR2 and Hipparcos astrometry showed that planets b and c are located on orbits mutually inclined by 49°−131° (1 sigma), which causes planet c to not transit most of the time, and acquire large misalignments with its host star's spin axis.[12]

Planet c likely formed on a wide orbit, and then migrated inward under the gravitational influence of the planet or brown dwarf b.[13] It is likely to retain a portion of primordial, highly volatile atmosphere.[14]

In 2022, the discovery by the radial velocity method of a third planet, Pi Mensae d, on a 125-day orbit was announced.[15] Another 2022 study did not confirm this planet,[16] but a 2023 study did detect it.[17]:24

The Pi Mensae planetary system[10][14][15][16]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
c 3.63±0.38 M 0.06839±0.00050 6.267852±0.000016 0 87.05±0.15° 2.131+0.037
−0.042
 R
d 13.38±1.35 M 124.64+0.48
−0.52
0.220±0.079
b 12.325+1.192
−1.384
 MJ
3.311+0.134
−0.148
2088.8±0.4 0.642+0.0007
−0.0006
54.436+5.945
−3.719
°

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 Johnson, H. L. et al. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory 4 (99): 99. Bibcode1966CoLPL...4...99J. 
  3. 3.0 3.1 Gray, R. O. et al. (July 2006). "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal 132 (1): 161–170. doi:10.1086/504637. Bibcode2006AJ....132..161G. 
  4. Holmberg, J. et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics 501 (3): 941–947, doi:10.1051/0004-6361/200811191, Bibcode2009A&A...501..941H. 
  5. Bonfanti, A. et al. (2015). "Revising the ages of planet-hosting stars". Astronomy and Astrophysics 575: A18. doi:10.1051/0004-6361/201424951. Bibcode2015A&A...575A..18B. http://www.aanda.org/articles/aa/full_html/2015/03/aa24951-14/aa24951-14.html. 
  6. 6.0 6.1 Delgado Mena, E. et al. (April 2015), "Li abundances in F stars: planets, rotation, and Galactic evolution", Astronomy & Astrophysics 576: 24, doi:10.1051/0004-6361/201425433, A69, Bibcode2015A&A...576A..69D. 
  7. Jones et al. (2002). "A probable planetary companion to HD 39091 from Anglo-Australian Planet Search". Monthly Notices of the Royal Astronomical Society 333 (4): 871–875. doi:10.1046/j.1365-8711.2002.05459.x. Bibcode2002MNRAS.333..871J.  (web Preprint)
  8. Reffert, S.; Quirrenbach, A. (2011). "Mass constraints on substellar companion candidates from the re-reduced Hipparcos intermediate astrometric data: nine confirmed planets and two confirmed brown dwarfs". Astronomy & Astrophysics 527: id.A140. doi:10.1051/0004-6361/201015861. Bibcode2011A&A...527A.140R. 
  9. Damasso, M. et al. (2020), "A precise architecture characterization of theπMensae planetary system", Astronomy & Astrophysics 642: A31, doi:10.1051/0004-6361/202038416, Bibcode2020A&A...642A..31D 
  10. 10.0 10.1 Huang, Chelsea Xu et al. (2018). "TESS Discovery of a Transiting Super-Earth in the π Mensae System". The Astrophysical Journal Letters 868 (2): L39. doi:10.3847/2041-8213/aaef91. PMID 31360431. Bibcode2018ApJ...868L..39H. 
  11. Gandolfi, D.; Barragan, O.; Livingston, J.; Fridlund, M.; Justesen, A. B.; Redfield, S.; Fossati, L.; Mathur, S. et al. (2019). "TESS's first planet: a super-Earth transiting the naked-eye star Pi Mensae". Astronomy & Astrophysics 619 (1): L10. doi:10.1051/0004-6361/201834289. Bibcode2018A&A...619L..10G. 
  12. Xuan, Jerry W.; Wyatt, Mark C. (2020), "Evidence for a high mutual inclination between the cold Jupiter and transiting super Earth orbiting π Men", Monthly Notices of the Royal Astronomical Society 497 (2): 2096–2118, doi:10.1093/mnras/staa2033 
  13. Kunovac Hodžić, Vedad; Triaud, Amaury H M J.; Cegla, Heather M.; Chaplin, William J.; Davies, Guy R. (2021), "Orbital misalignment of the super-Earth π Men c with the spin of its star", Monthly Notices of the Royal Astronomical Society 502 (2): 2893–2911, doi:10.1093/mnras/stab237 
  14. 14.0 14.1 Huber, Daniel et al. (2022), "A 20 Second Cadence View of Solar-type Stars and Their Planets with TESS: Asteroseismology of Solar Analogs and a Recharacterization of π Men C", The Astronomical Journal 163 (2): 79, doi:10.3847/1538-3881/ac3000, Bibcode2022AJ....163...79H 
  15. 15.0 15.1 Hatzes, Artie P. et al. (2022), "A Radial Velocity Study of the Planetary System of π Mensae: Improved Planet Parameters for π Mensae c and a Third Planet on a 125 Day Orbit", The Astronomical Journal 163 (5): 223, doi:10.3847/1538-3881/ac5dcb, Bibcode2022AJ....163..223H 
  16. 16.0 16.1 Feng, Fabo et al. (August 2022). "3D Selection of 167 Substellar Companions to Nearby Stars". The Astrophysical Journal Supplement Series 262 (21): 21. doi:10.3847/1538-4365/ac7e57. Bibcode2022ApJS..262...21F. 
  17. Laliotis, Katherine et al. (February 2023). "Doppler Constraints on Planetary Companions to Nearby Sun-like Stars: An Archival Radial Velocity Survey of Southern Targets for Proposed NASA Direct Imaging Missions". The Astronomical Journal 165 (4): 176. doi:10.3847/1538-3881/acc067. Bibcode2023AJ....165..176L. 

External links

Coordinates: Sky map 05h 37m 09.89s, −80° 28′ 08.84″