Astronomy:CD Ceti
| Observation data Epoch J2000.0 Equinox (celestial coordinates) | |
|---|---|
| Constellation | Cetus |
| Right ascension | 03h 13m 22.92s[1] |
| Declination | +04° 46′ 29.3″[1] |
| Apparent magnitude (V) | +13.81 to 13.87[2] |
| Characteristics | |
| Spectral type | M5.0V[3] |
| Variable type | BY Dra[2] |
| Astrometry | |
| Radial velocity (Rv) | +28.16±0.46[1] km/s |
| Proper motion (μ) | RA: +1741.875[1] mas/yr Dec.: +86.494[1] mas/yr |
| Parallax (π) | 116.2678 ± 0.0427[1] mas |
| Distance | 28.05 ± 0.01 ly (8.601 ± 0.003 pc) |
| Details[3] | |
| Mass | 0.161±0.010 M☉ |
| Radius | 0.175±0.006 R☉ |
| Luminosity | 0.002934(53) L☉ |
| Surface gravity (log g) | 4.93±0.04 cgs |
| Temperature | 3,130±51 K |
| Metallicity [Fe/H] | +0.13±0.16 dex |
| Rotation | 126.2 days |
| Rotational velocity (v sin i) | ≤2.0 km/s |
| Age | 1–5 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | Cet data |
CD Ceti (CD Cet, GJ 1057) is a star in the constellation of Cetus. With an apparent magnitude of +13.8, it is not visible to the naked eye. Based on its parallax, it is located 8.6 parsecs (28 light-years) from the Solar System.[3]
CD Ceti is a faint red dwarf of spectral type M5.0V.[3] Similar to GJ 1156 or the well-known Proxima Centauri - the nearest star to the Solar System - it has an effective temperature of 3,240 K.[5]
Small in size, its radius is 18% of the solar radius, and it rotates with a projected rotational velocity of less than 3 km/s.[6]
Its rotation period is approximately 126.2 days, as determined from MEarth photometry.[3] Its weak stellar magnetic field, below 2 kG, is associated with its slow rotation.[5] It has a mass equal to 15.5-16% of the solar mass.[6][7]
CD Ceti is a relatively quiet star, with a low chromospheric activity level and no detected Hα emission.[3] High-resolution imaging searches found no stellar or substellar companions, confirming that CD Ceti is a single star.[3]
CD Ceti is classified as a BY Draconis variable. These variables - among which DK Ceti and EX Ceti are found in the same constellation - show variations in luminosity due to spots on their surface or other types of chromospheric activity. The brightness variation of CD Ceti is 0.06 magnitudes, with no known period.[8]
Planetary system
In 2020, the CARMENES spectrograph detected a super-Earth companion, CD Cet b, orbiting the star.[3] The planet has a minimum mass of approximately 4.0 ± 0.4 M⊕ and completes one orbit every 2.29 days.[3] The signal was detected independently in both the visible and near-infrared channels of CARMENES and subsequently confirmed with the ESPRESSO spectrograph at the Very Large Telescope.[3] No transit was detected in TESS photometry, indicating that the planet does not transit its host star as seen from Earth.[3] Depending on its Bond albedo, the planet's equilibrium temperature is estimated to range from approximately 325 to 464 K.[3]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥3.95+0.42 −0.43 M⊕ |
0.0185±0.0013 | 2.29070±0.00012 | — | — | — |
References
- ↑ 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.
- ↑ 2.0 2.1 Samus', N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports 61 (1): 80. doi:10.1134/S1063772917010085. Bibcode: 2017ARep...61...80S.
- ↑ 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 3.12 Bauer, F. F.; Zechmeister, M.; Kaminski, A. et al. (2020). "The CARMENES search for exoplanets around M dwarfs. Measuring precise radial velocities in the near infrared: The example of the super-Earth CD Cet b". Astronomy & Astrophysics 640: A50. doi:10.1051/0004-6361/202038031.
- ↑ "CD Cet". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=CD+Cet.
- ↑ 5.0 5.1 Reiners, A.; Basri, G. (2007). "The First Direct Measurements of Surface Magnetic Fields on Very Low Mass Stars". The Astrophysical Journal 656 (2): 1121–1135. doi:10.1086/510304. Bibcode: 2007ApJ...656.1121R. http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?2007ApJ...656.1121R.
- ↑ 6.0 6.1 Reiners, A.; Basri, G.; Browning, M. (2009). "Evidence for Magnetic Flux Saturation in Rapidly Rotating M Stars". The Astrophysical Journal 692 (1): 538–545. doi:10.1088/0004-637X/692/1/538.
- ↑ Jenkins, J. S.; Ramsey, L. W.; Jones, H. R. A.; Pavlenko, Y.; Gallardo, J.; Barnes, J. R.; Pinfield, D. J. (2009). "Rotational Velocities for M Dwarfs". The Astrophysical Journal 704 (2): 975–988. doi:10.1088/0004-637X/704/2/975.
- ↑ "CD Ceti". General Catalogue of Variable Stars. http://vizier.u-strasbg.fr/viz-bin/VizieR-S?V*%20CD%20Cet.
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