Lacaille 9352

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Lacaille 9352
Piscis Austrinus constellation map.svg
Red pog.png
Lacaille 9352
Location of Lacaille 9352 in the constellation Piscis Austrinus

Observation data
Epoch J2000       Equinox J2000
Constellation Piscis Austrinus [1] : 84 
Right ascension 23h 05m 52.03579s [2]
Declination −35° 51′ 11.0552″ [2]
Apparent magnitude  (V)7.34 [3]
Characteristics
Spectral type M0.5V [4]
U−B color index +1.18 [3]
B−V color index +1.50 [3]
Variable type Suspected [5]
Astrometry
Radial velocity (Rv)+8.31±0.13 [2] km/s
Proper motion (μ)RA: +6,765.995 mas/yr [2]
Dec.: +1,330.285 mas/yr [2]
Parallax (π)304.1354±0.0200  mas [2]
Distance 10.7241 ± 0.0007  ly
(3.2880 ± 0.0002  pc)
Absolute magnitude  (MV)9.8 [6]
Details
Mass 0.479+0.011
−0.010 [7]   M☉
Radius 0.474±0.008 [7]   R☉
Luminosity 0.0368±0.0006 [7]   L☉
Habitable zone inner limit0.16 [8] AU
Habitable zone outer limit0.40 [8] AU
Surface gravity (log g)4.78 [9]   cgs
Temperature 3,672+36
−34 [7]   K
Metallicity [Fe/H]−0.22±0.09 [10]   dex
Rotation 38.7±0.5  d [11]
Rotational velocity (v sin i)1 [12]  km/s
Age 4.57 [13]   Gyr
Other designations
Lacaille 9352, NSV 14420, CD−36°15693, GJ 887, HD 217987, HIP 114046, SAO 214301, LFT 1758, LHS 70, LTT 9348, PLX 5584, UGP 591, [14] Cordoba 31353 [15]
Database references
SIMBAD data
Exoplanet Archive data
ARICNS data

Lacaille 9352 (Lac 9352), also commonly called Gliese 887 (GJ 887), is a red dwarf star in the southern constellation of Piscis Austrinus. With an apparent visual magnitude of 7.34, [3] this star is too faint to be viewed with the naked eye except possibly under excellent seeing conditions. Parallax measurements place it at a distance of about 10.72 light-years (3.29 parsecs ) from Earth. [2] It is the twelfth closest star system to the Solar System [16] and is the closest star in the constellation Piscis Austrinus. [1] : 84  Its closest neighbour is the EZ Aquarii triple star system at about 4.1 ly away.

Contents

Properties

The neighborhood of the Solar System, which includes Lacaille 9352 Nearby Stars (14ly Radius).svg
The neighborhood of the Solar System, which includes Lacaille 9352

This star has the fourth highest known proper motion, [17] (which was first noticed by Benjamin Gould in 1881 [18] ) moving a total of 6.9 arcseconds per year. However, this is still a very small movement overall, as there are 3,600 arcseconds in a degree of arc. The space velocity components of this star are (U, V, W) = (−93.9, −14.1, −51.4) km/s. [19] If the radial velocity (Vr) equals +9.7 km/s then about 2,700 years ago Lacaille 9352 was at its minimal distance of approximately 10.63 ly (3.26 pc) from the Sun. [20]

The spectrum of Lacaille 9352 places it at a stellar classification of M0.5V, [4] indicating it is a type of main sequence star known as a red dwarf. This was the first red dwarf star to have its angular diameter measured, [21] with the physical diameter being about 47% of the Sun's radius. [7] It has around half the mass of the Sun [4] and the outer envelope has an effective temperature of about 3,670 K. [7]

Planetary system

In June 2020, two super-Earth planets were reported, as well as a third candidate planet with a period of 50.7 days, located within the habitable zone. They were detected using the radial velocity method from observations with HARPS in Chile and HIRES in Hawaii. [22] [23] A 2026 follow-up study confirmed the 50-day planet and detected a fourth, Earth-mass planet closer to the star. A fifth candidate signal is also suspected. [11] The habitable-zone planet, GJ 887 d, is the second-nearest known exoplanet in the habitable zone after Proxima Centauri b, though it is significantly more massive than Earth and its composition is unknown. It may be possible to characterize it with proposed direct imaging missions such as the Habitable Worlds Observatory. [11]

Additionally, the star presents a difference in proper motion measurements taken by the Hipparcos and Gaia spacecraft, suggesting the possible presence of an outer giant planet. [8]

The Lacaille 9352 planetary system [11]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
f(unconfirmed)≥ 0.47±0.11 M🜨 0.0263±0.00092.2166±0.0001———
e≥ 1.46+0.19
−0.18  M🜨 		0.0417+0.0014
−0.0015		4.4249±0.0001———
b≥ 3.9±0.5  M🜨 0.0683+0.0022
−0.0024		9.2619±0.00050.14±0.06——
c ≥ 6.5+1.0
−0.9  M🜨 		0.121+0.004
−0.005		21.784±0.0040.17±0.06——
d≥ 6.1±1.4  M🜨 0.212+0.007
−0.008		50.77±0.050.25+0.20
−0.15 [22] 		——

See also

References

  1. 1 2 Kirkpatrick, J. Davy; Marocco, Federico; et al. (April 2024). "The Initial Mass Function Based on the Full-sky 20 pc Census of ~3600 Stars and Brown Dwarfs". The Astrophysical Journal Supplement Series . 271 (2): 55. arXiv: 2312.03639 . Bibcode:2024ApJS..271...55K. doi: 10.3847/1538-4365/ad24e2 .
  2. 1 2 3 4 5 6 7 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  3. 1 2 3 4 Cousins, A. W. J. (1973). "UBV photometry of some southern stars". Monthly Notes of the Astronomical Society of Southern Africa. 32: 11. Bibcode:1973MNSSA..32...11C.
  4. 1 2 3 Demory, Brice-Olivier; Ségransan, Damien; Forveille, Thierry; Queloz, Didier; Beuzit, Jean-Luc; Delfosse, Xavier; Di Folco, Emmanuel; Kervella, Pierre; Le Bouquin, Jean-Baptiste; Perrier, Christian; Benisty, Myriam; Duvert, Gilles; Hofmann, Karl-Heinz; Lopez, Bruno; Petrov, Romain (October 2009). "Mass-radius relation of low and very low-mass stars revisited with the VLTI". Astronomy and Astrophysics. 505 (1): 205–215. arXiv: 0906.0602 . Bibcode:2009A&A...505..205D. doi:10.1051/0004-6361/200911976. S2CID   14786643.
  5. ↑ Micela, G.; Pye, J.; Sciortino, S. (April 1997). "Coronal properties of nearby old disk and halo dM stars". Astronomy and Astrophysics. 320: 865–877. Bibcode:1997A&A...320..865M.
  6. ↑ Murdin, Paul, ed. (November 2000). "Lacaille 9352". Encyclopedia of Astronomy and Astrophysics. Bristol: Institute of Physics Publishing. Bibcode:2000eaa..bookE5158.. doi:10.1888/0333750888/5158. ISBN   0333750888. absolute magnitude is 9.8
  7. 1 2 3 4 5 6 Pineda, J. Sebastian; et al. (September 2021). "The M-dwarf Ultraviolet Spectroscopic Sample. I. Determining Stellar Parameters for Field Stars". The Astrophysical Journal. 918 (1): 23. arXiv: 2106.07656 . Bibcode:2021ApJ...918...40P. doi: 10.3847/1538-4357/ac0aea . S2CID   235435757. 40.
  8. 1 2 3 Painter, Katie E.; Bowler, Brendan P.; Franson, Kyle; Becker, Juliette C.; Burt, Jennifer A. (2025-06-26). "Astrometric Accelerations of Provisional Targets for the Habitable Worlds Observatory". The Astronomical Journal. 170 (3): 147. arXiv: 2506.21768 . Bibcode:2025AJ....170..147P. doi: 10.3847/1538-3881/ade442 .
  9. ↑ Rabus, Markus; Lachaume, Régis; Jordán, Andrés; Brahm, Rafael; Boyajian, Tabetha; Von Braun, Kaspar; Espinoza, Néstor; Berger, Jean-Philippe; Le Bouquin, Jean-Baptiste; Absil, Olivier (2019). "A discontinuity in the Teff–radius relation of M-dwarfs". Monthly Notices of the Royal Astronomical Society. 484 (2): 2674–2683. arXiv: 1901.08077 . Bibcode:2019MNRAS.484.2674R. doi: 10.1093/mnras/sty3430 . S2CID   119189542.
  10. ↑ López-Morales, Mercedes (May 2007). "On the Correlation between the Magnetic Activity Levels, Metallicities, and Radii of Low-Mass Stars". The Astrophysical Journal. 660 (1): 732–739. arXiv: astro-ph/0701702 . Bibcode:2007ApJ...660..732L. doi:10.1086/513142. S2CID   119530297.
  11. 1 2 3 4 Hartogh, C.; Jeffers, S. V.; et al. (January 2026). "RedDots: Multiplanet system around M dwarf GJ 887 in the solar neighborhood". Astronomy & Astrophysics . forthcoming. doi:10.1051/0004-6361/202554984.
  12. ↑ Torres, G. R.; et al. (December 2006). "Search for associations containing young stars (SACY). I. Sample and searching method". Astronomy and Astrophysics. 460 (3): 695–708. arXiv: astro-ph/0609258 . Bibcode:2006A&A...460..695T. doi:10.1051/0004-6361:20065602. S2CID   16080025.
  13. ↑ Yee, Samuel W.; Petigura, Erik A.; von Braun, Kaspar (2017). "Precision Stellar Characterization of FGKM Stars using an Empirical Spectral Library". The Astrophysical Journal. 836 (1): 77. arXiv: 1701.00922 . Bibcode:2017ApJ...836...77Y. doi: 10.3847/1538-4357/836/1/77 . S2CID   6302522.
  14. ↑ "LACAILLE 9352 -- Pre-main sequence Star". SIMBAD. Centre de Données astronomiques de Strasbourg . Retrieved 2010-01-20.
  15. ↑ Luyten, Willem Jacob; Shapley, Harlow (1930). "A study of the near-by stars". Annals of the Astronomical Observatory of Harvard College. 85 (5): 73. Bibcode:1930AnHar..85...73L.
  16. ↑ Reylé, Céline; Jardine, Kevin; Fouqué, Pascal; Caballero, Jose A.; Smart, Richard L.; Sozzetti, Alessandro (30 April 2021). "The 10 parsec sample in the Gaia era". Astronomy & Astrophysics . 650: A201. arXiv: 2104.14972 . Bibcode:2021A&A...650A.201R. doi:10.1051/0004-6361/202140985. S2CID   233476431. Data available at https://gruze.org/10pc/ Archived 12 March 2023 at the Wayback Machine
  17. ↑ "High Proper Motion Stars in the Hipparcos Catalogue". European Space Agency. July 1, 2007. Retrieved 2010-01-20.
  18. ↑ Gould, B. A. (1881). "Corrigenda in the Uranometria Argentina. Star with large proper motion". Astronomische Nachrichten. 100 (1): 7–10. Bibcode:1881AN....100....7G. doi:10.1002/asna.18811000104.
  19. ↑ "ARICNS star page of Lacaille 9352". Astronomisches Rechen-Institut Heidelberg. Archived from the original on 2012-09-16. Retrieved 2010-04-16.
  20. ↑ "Annotations on NAME LACAILLE 9352 object". SIMBAD . Centre de Données astronomiques de Strasbourg. Retrieved 2010-04-16.
  21. ↑ Glindemann, Andreas; Paresce, Francesco. "Giant Eyes for the VLT Interferometer". European Southern Observatory . Retrieved 2010-01-20.
  22. 1 2 Jeffers, S. V.; Dreizler, S.; Barnes, J. R.; Haswell, C. A.; Nelson, R. P.; Rodríguez, E.; López-González, M. J.; Morales, N.; Luque, R.; et al. (2020), "A multiple planet system of super-Earths orbiting the brightest red dwarf star GJ887", Science, 368 (6498): 1477–1481, arXiv: 2006.16372 , Bibcode:2020Sci...368.1477J, doi:10.1126/science.aaz0795, PMID   32587019, S2CID   220075207
  23. ↑ Witze, Alexandra (2020). "Why boring could be good for this star's two intriguing planets" . Nature . doi:10.1038/d41586-020-01905-5. PMID   34168349. S2CID   220507688 . Retrieved 2020-06-30.
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