Astronomy:GJ 3378
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Camelopardalis[1] |
| Right ascension | 06h 01m 11.04551s[2] |
| Declination | +59° 35′ 49.8841″[2] |
| Apparent magnitude (V) | 11.74[3] |
| Characteristics | |
| Evolutionary stage | Main sequence[3] |
| Spectral type | M4.0V[4] |
| Astrometry | |
| Radial velocity (Rv) | +1.78±0.22[2] km/s |
| Proper motion (μ) | RA: −104.942[2] mas/yr Dec.: −928.628[2] mas/yr |
| Parallax (π) | 129.3014 ± 0.0283[2] mas |
| Distance | 25.225 ± 0.006 ly (7.734 ± 0.002 pc) |
| Details[4] | |
| Mass | 0.262±0.021 M☉ |
| Radius | 0.275±0.009 R☉ |
| Luminosity | 0.0085±0.0008 L☉ |
| Surface gravity (log g) | 4.97±0.06 cgs |
| Temperature | 3340±60 K |
| Metallicity [Fe/H] | −0.09±0.08 dex |
| Rotation | 95.1±2.3 d (83.8 d?) |
| Rotational velocity (v sin i) | 2.62±0.26 km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| ARICNS | data |
GJ 3378, also known as LHS 1805,[5] is a red dwarf star located around 25.2 light years (7.73 parsecs) away from Earth in the northern constellation of Camelopardalis. It is a small star with a mass of 0.3 solar masses and a radius of 0.3 solar radii. It is also a cool and quiet star with an effective temperature of 3,340 K and a luminosity of 0.9% solar luminosity.[4]
As of 2026, only one exoplanet, a super-Earth known as GJ 3378b, has been discovered orbiting within the conservative habitable zone. While it is likely that this planet has a terrestrial composition, it is placed near the cosmic shoreline meaning that it is potentially subjected to its parent star stripping away its atmosphere.[4][6]
Characteristics
GJ 3378 has a mass of about 0.26±0.02 solar masses and a radius of 0.279±0.005 solar radii. It luminosity of 2.1 solar luminosity and has an effective temperature of 3,378±30 K.[7] It was measured to have an average density of 17.7 g/cm3. It was initially given a rotational period of 95.1±2.3 days however Sabotta et al. (2021) reported a slower rotational period of 83.4 days. It has a metallicity that is close to the solar value, with an M/H dex of −0.10±0.10.[8][6][9] The magnetic field of GJ 3378 has been clearly detected. It is small-scaled and has a mean strength of 150±50 gauss, making it a very quiet and cool star. Because GJ 3378 is a star with a mass lower than 0.35 solar masses, it is a fully-convective star.[6][10]
Planetary system
Moutou et al. (2024) proposed evidence for an exoplanet and obtained data on its orbit and mass using observations from the SPIRou (Spectropolarimètre infrarouge) located at the Canada–France–Hawaii Telescope (CFH) in Hawaii, United States. They reported that this planet has an eccentric orbit and an orbital period of 24.73±0.06 days. They proposed a minimum mass of 5.26 Earth masses making it a sub-Neptunian or Super-Earth type planet.[6] Robertson et al. (2026) conducted a survey of fully convective stars within the Solar neighborhood using the near-infrared spectrograph HPF on the Hobby-Eberly Telescope (HET) at McDonald Observatory in Texas, US. They refined the planet's orbital period down to 21.45±0.01 days and its minimum mass down to 2.3±0.4 Earth masses. They also gave estimates for its orbital distance and equilibrium temperature of 0.09673±0.00080 AU and 272±7 K respectively.[8][4]
Even with the reduced orbital period presented by Robertson et al. (2026), GJ 3378b would orbit within the conservative habitable zone (HZ) of the star where water could be present in its liquid state. Their reduced mass estimates would also make it more likely that this planet has a terrestrial composition. This could mean that it is a potentially habitable exoplanet. However GJ 3378b has been placed near the cosmic shoreline meaning that its atmosphere may have been lost due to radiative stripping by the parent red dwarf star.[4]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥2.3±0.4 M⊕ | 0.09673±0.0008 | 21.45±0.01 | — | — | — |
References
- ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific 99 (617): 695. doi:10.1086/132034. Bibcode: 1987PASP...99..695R Constellation record for this object at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 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.
- ↑ 3.0 3.1 Shan, Y. et al. (2024). "CARMENES input catalog of M dwarfs. VII. New rotation periods for the survey stars and their correlations with stellar activity". Astronomy and Astrophysics 684: A9. doi:10.1051/0004-6361/202346794. Bibcode: 2024A&A...684A...9S.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 Robertson, Paul; Endl, Michael; Cochran, William D.; Stefánsson, Gudmundur; Mahadevan, Suvrath; Cañas, Caleb I.; James, Gogod; Arendtsz, Roan; Terrien, Ryan C. (2026-05-15). "A Revised Mass and Period for the Habitable Zone super-Earth GJ 3378b: A Planet Straddling the Cosmic Shoreline". arXiv:2605.16499 [astro-ph.EP].
- ↑ 5.0 5.1 "GJ 3378". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=GJ+3378.
- ↑ 6.0 6.1 6.2 6.3 6.4 Moutou, C.; Ould-Elhkim, M.; Donati, J.-F.; Charpentier, P.; Cadieux, C.; Delfosse, X.; Artigau, E.; Arnold, L. et al. (2024-06-14). "Characterising planetary systems with SPIRou: Temperate sub-Neptune exoplanet orbiting the nearby fully convective star GJ 1289 and a candidate around GJ 3378" (in en). Astronomy & Astrophysics 688: A196. doi:10.1051/0004-6361/202450466. Bibcode: 2024A&A...688A.196M.
- ↑ Donati, J.-F.; Lehmann, L. T.; Cristofari, P. I.; Fouqué, P.; Moutou, C.; Charpentier, P.; Ould-Elhkim, M.; Carmona, A. et al. (2023-07-26). "Magnetic fields and rotation periods of M dwarfs from SPIRou spectra" (in en). Monthly Notices of the Royal Astronomical Society 525 (2): 2015–2039. doi:10.1093/mnras/stad2301.
- ↑ 8.0 8.1 "GJ 3378 | NASA Exoplanet Archive". https://exoplanetarchive.ipac.caltech.edu/overview/GJ%203378.
- ↑ Cristofari, P. I.; Donati, J.-F.; Moutou, C.; Lehmann, L. T.; Charpentier, P.; Fouqué, P.; Folsom, C. P.; Masseron, T. et al. (2023). "Measuring small-scale magnetic fields of 44 M dwarfs from SPIRou spectra with ZeeTurbo". Monthly Notices of the Royal Astronomical Society 526 (4): 5648. doi:10.1093/mnras/stad3144. Bibcode: 2023MNRAS.526.5648C.
- ↑ Chabrier, Gilles; Baraffe, Isabelle (1997). "Structure and evolution of low-mass stars". Astronomy and Astrophysics 327: 1039. Bibcode: 1997A&A...327.1039C.
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