Gliese 754

Gliese 754 is a dim star in the southern constellation of Telescopium. It has an apparent visual magnitude of 12.25,^[2] which requires a telescope to view. The star is located at a distance of 19.3 light-years from the Sun based on parallax, and it is drifting further away with a radial velocity of +6 km/s.^[1] It is one of the hundred closest stars to the Solar System. Calculations of its orbit around the Milky Way showed that it is eccentric, and indicate that it might be a thick disk object.^[7]

Gliese 754

Gliese 754 Location of Gliese 754 in the constellation Telescopium
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Telescopium
Right ascension	19h 20m 47.98432s[1]
Declination	−45° 33′ 29.6435″[1]
Apparent magnitude (V)	12.25[2]
Characteristics
Spectral type	M4V[2]
Astrometry
Radial velocity (Rv)	+6.04±0.19[1] km/s
Proper motion (μ)	RA: +658.775 mas/yr[1] Dec.: −2,896.150 mas/yr[1]
Parallax (π)	169.2351 ± 0.0588 mas[1]
Distance	19.272 ± 0.007 ly (5.909 ± 0.002 pc)
Details[3]
Mass	0.173 M☉
Radius	0.205 R☉
Luminosity	0.005[4] L☉
Temperature	3,202±100[5] K
Metallicity [Fe/H]	−0.169[5] dex
Rotation	132.651 days
Other designations
GJ 754, L 347-14, LHS 60, LTT 7652, 2MASS J19204795-4533283[6]
Database references
SIMBAD	data

The stellar classification of Gliese 754 is M4V,^[2] indicating that this is a small red dwarf star on the core hydrogen fusing main sequence. It has 17% of the mass of the Sun and 21% of the Sun's radius.^[3] The star is fully convective and is a source of X-ray emission.^[8] It is rotating slowly with a period of about 133 days.^[3] The metallicity is sub-solar,^[5] indicating it has a lower abundance of heavy elements compared to the Sun. It is radiating just 0.5%^[4] of the luminosity of the Sun from its photosphere at an effective temperature of around 3,202 K.^[5]

Search for planets

In June 2019, a candidate exoplanet in orbit around Gliese 754 was reported in a preprint. It was detected using the Doppler method and is orbiting at a distance of 0.28 AU with a period of 78 days. The orbit is essentially circular, to within the margin of error.^[9] The habitable zone for this star ranges from 0.05 AU to 0.14 AU;^[4] inside the orbit of this proposed companion. However, a 2024 study could not confirm any planet around this star. A 77-day signal was detected, similar to the orbital period of this putative planet, but this may be caused by stellar activity.^[10]

References

1. 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.
2. Henry, Todd J.; et al. (2018). "The Solar Neighborhood XLIV: RECONS Discoveries within 10 parsecs". The Astronomical Journal. 155 (6): 265. arXiv:1804.07377. Bibcode:2018AJ....155..265H. doi:10.3847/1538-3881/aac262. S2CID 53983430.
3. Newton, Elisabeth R.; et al. (November 2018). "New Rotation Period Measurements for M Dwarfs in the Southern Hemisphere: An Abundance of Slowly Rotating, Fully Convective Stars". The Astronomical Journal. 156 (5): 11. arXiv:1807.09365. Bibcode:2018AJ....156..217N. doi:10.3847/1538-3881/aad73b. S2CID 119209638. 217.
4. Mayor, M.; et al. (2009). "The HARPS search for southern extra-solar planets. XIII. A planetary system with 3 Super-Earths (4.2, 6.9, & 9.2 Earth masses)". Astronomy and Astrophysics. 493 (2): 639–644. arXiv:0806.4587. Bibcode:2009A&A...493..639M. doi:10.1051/0004-6361:200810451. S2CID 116365802.
5. Houdebine, E. R.; et al. (May 2016). "Rotation-Activity Correlations in K and M Dwarfs. I. Stellar Parameters and Compilations of v sin I and P/sin I for a Large Sample of Late-K and M Dwarfs". The Astrophysical Journal. 822 (2): 38. arXiv:1604.07920. Bibcode:2016ApJ...822...97H. doi:10.3847/0004-637X/822/2/97. S2CID 119118088. 97.
6. "L 347-14". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-12-12.
7. Innanen, K.A.; Flynn, C. (2010). "The Radial Velocity, Space Motion, and Galactic Orbit of GJ 754". Journal of the Royal Astronomical Society of Canada. 104 (6): 223–24. Bibcode:2010JRASC.104..223I.
8. Wright, Nicholas J.; et al. (September 2018). "The stellar rotation-activity relationship in fully convective M dwarfs". Monthly Notices of the Royal Astronomical Society. 479 (2): 2351–2360. arXiv:1807.03304. Bibcode:2018MNRAS.479.2351W. doi:10.1093/mnras/sty1670.
9. Tuomi, M.; Jones, H. R. A.; Butler, R. P.; Arriagada, P.; Vogt, S. S.; Burt, J.; Laughlin, G.; Holden, B.; Shectman, S. A.; Crane, J. D.; Thompson, I.; Keiser, S.; Jenkins, J. S.; Berdiñas, Z.; Diaz, M.; Kiraga, M.; Barnes, J. R. (2019-06-11). "Frequency of planets orbiting M dwarfs in the Solar neighbourhood". arXiv.org. Retrieved 2024-12-24.
10. Mignon, L.; Delfosse, X.; et al. (September 2024). "Radial velocity homogeneous analysis of M dwarfs observed with HARPS". Astronomy & Astrophysics. 689: A32. doi:10.1051/0004-6361/202346570.