HD 92945
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hydra[2] |
| Right ascension | 10h 43m 28.2716s[3] |
| Declination | −29° 03′ 51.433″[3] |
| Apparent magnitude (V) | 7.72[4] |
| Characteristics | |
| Evolutionary stage | main sequence[3] |
| Spectral type | K1V[5] |
| U−B color index | +0.55[6] |
| B−V color index | +0.88[6] |
| Variable type | BY Dra[4] |
| Astrometry | |
| Radial velocity (Rv) | 22.706±0.14[3] km/s |
| Proper motion (μ) | RA: −215.484[3] mas/yr Dec.: −49.892[3] mas/yr |
| Parallax (π) | 46.4931±0.0198 mas[3] |
| Distance | 70.15 ± 0.03 ly (21.509 ± 0.009 pc) |
| Absolute magnitude (MV) | 6.07[2] |
| Details | |
| Mass | 0.86±0.01[7] M☉ |
| Radius | 0.77[8] R☉ |
| Luminosity | 0.38[8] L☉ |
| Surface gravity (log g) | 4.39[9] cgs |
| Temperature | 5000[10] K |
| Metallicity [Fe/H] | −0.17[10] dex |
| Rotation | 6.2 days[9] |
| Rotational velocity (v sin i) | 4[10] km/s |
| Age | 294±23[8] Myr |
| Other designations | |
| V419 Hydrae, V419 Hya, CD−28 8394, CPD−28 4175, GJ 3615, HIP 52462, LTT 3932, NLTT 25167, PPM 258065, SAO 179168, 2MASS J10432828-2903513[11] | |
| Database references | |
| SIMBAD | data |
HD 92945 is a K-type main sequence star located 70 light years away in the northern constellation of Hydra. Its apparent visual magnitude varies by 0.02 magnitudes and is approximately 7.72 at maximum brightness.[4]
Debris disk
Image of the debris disk with the REASONS survey[12]
In 2007, a debris disk with estimated dust mass 0.047±0.003 M🜨[13] has been observed around the star by coronagraphic imaging, using the ACS and NICMOS instruments on the Hubble Space Telescope. It appears to extend 45 to 175 astronomical units from HD 92945.[14]
The disk has a gap 20+10
−8 AU wide at a radius of 73±3 AU, which may be being carved by a planet.[13] No planet with mass exceeding 1-2 MJ was observed in the gap,[15] but a lower-mass planet or a chain of two planets are still possible.[7]
Evidence for a planet via astrometric observations was presented in 2024.[16] It could be explain the presence of the gap through long-term resonances with the disk, as its orbital separation is much less than the gap's radius and thus the planet would not be carving the disk directly. Alternatively, both the inner planet and an additional planet within the gap could be shepherding the disk through long-term gravitational interactions.[7]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (years) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| Debris disk | 50[13]–140[13] AU | 65.4±0.9[13]° | — | |||
| (unconfirmed) | 0.4 – 5[7] MJ | 2.5 – 30[7] | — | — | — | — |
References
- ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
- ^ a b Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. XHIP record for this object at VizieR.
- ^ a b c d e f g 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.
- ^ a b c V419 Hya, database entry, The combined table of GCVS Vols I-III and NL 67-78 with improved coordinates, General Catalogue of Variable Stars Archived 2017-06-20 at the Wayback Machine, Sternberg Astronomical Institute, Moscow, Russia. Accessed on line February 2, 2011.
- ^ Torres, C. A. O.; Quast, G. R.; Da Silva, L.; de la Reza, R.; Melo, C. H. F.; Sterzik, M. (2006). "Search for associations containing young stars (SACY). I. Sample and searching method". Astronomy and Astrophysics. 460 (3): 695. arXiv:astro-ph/0609258. Bibcode:2006A&A...460..695T. doi:10.1051/0004-6361:20065602.
- ^ a b Koen, C.; Kilkenny, D.; Van Wyk, F.; Marang, F. (2010). "UBV(RI)C JHK observations of Hipparcos-selected nearby stars". Monthly Notices of the Royal Astronomical Society. 403 (4): 1949. Bibcode:2010MNRAS.403.1949K. doi:10.1111/j.1365-2966.2009.16182.x.
- ^ a b c d e Bendahan-West, R; Marino, S; Carter, A L; Squicciarini, V; James, A D; Sefilian, A A; Pearce, T D; Friebe, M F; Lazzoni, C; Lakeland, B; Ray, S; Wyatt, M C; Matrà, L; Milli, J; Faramaz, V C (2025-12-22). "JWST /MIRI coronagraphic search for planets in systems with gapped exoKuiper belts and proper motion anomalies". Monthly Notices of the Royal Astronomical Society staf2255. arXiv:2601.02156. doi:10.1093/mnras/staf2255. ISSN 0035-8711.
- ^ a b c Plavchan, Peter; et al. (June 2009). "New Debris Disks Around Young, Low-Mass Stars Discovered with the Spitzer Space Telescope". The Astrophysical Journal. 698 (2): 1068–1094. arXiv:0904.0819. Bibcode:2009ApJ...698.1068P. doi:10.1088/0004-637X/698/2/1068. S2CID 51417657.
- ^ a b Hojjatpanah, S.; Oshagh, M.; Figueira, P.; Santos, N. C.; Amazo-Gómez, E. M.; Sousa, S. G.; Adibekyan, V.; Akinsanmi, B.; Demangeon, O.; Faria, J.; Gomes Da Silva, J.; Meunier, N. (2020). "The correlation between photometric variability and radial velocity jitter. Based on TESS and HARPS observations". Astronomy and Astrophysics. 639. arXiv:2005.10105. Bibcode:2020A&A...639A..35H. doi:10.1051/0004-6361/202038035.
- ^ a b c HD 92945, database entry, The Geneva-Copenhagen Survey of Solar neighbourhood, J. Holmberg et al., 2007, CDS ID V/117A. Accessed on line February 2, 2011.
- ^ "V* V419 Hya". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved February 2, 2011.
- ^ Matrà, L.; Marino, S.; Wilner, D. J.; Kennedy, G. M.; Booth, M.; Krivov, A. V.; Williams, J. P.; Hughes, A. M.; Burgo, C. del (2025-01-15). "REsolved ALMA and SMA Observations of Nearby Stars (REASONS): A population of 74 resolved planetesimal belts at millimetre wavelengths". Astronomy and Astrophysics. 693. arXiv:2501.09058. Bibcode:2025A&A...693A.151M. doi:10.1051/0004-6361/202451397.
- ^ a b c d e Marino, S.; Yelverton, B.; Booth, M.; Faramaz, V.; Kennedy, G. M.; Matrà, L.; Wyatt, M. C. (2019). "A gap in HD 92945's broad planetesimal disc revealed by ALMA". Monthly Notices of the Royal Astronomical Society. 484: 1257–1269. arXiv:1901.01406. doi:10.1093/mnras/stz049.
- ^ Golimowski, D.; John Krist, J.; Chen, C.; Stapelfeldt, K.; Ardila, D.; Clampin, M.; Schneider, G.; Silverstone, M.; Ford, H.; Illingworth, G. (2007). "Observations and Models of the Debris Disk around the K dwarf HD 92945". In the Spirit of Bernard Lyot: The Direct Detection of Planets and Circumstellar Disks in the 21st Century: 46. Bibcode:2007lyot.confE..46G.
- ^ Mesa, D.; et al. (2021). "Limits on the presence of planets in systems with debris discs: HD 92945 and HD 107146". Monthly Notices of the Royal Astronomical Society. 503: 1276–1289. arXiv:2102.05353. doi:10.1093/mnras/stab438.
- ^ Gratton, R.; Bonavita, M.; Mesa, D.; Desidera, S.; Zurlo, A.; Marino, S.; D’Orazi, V.; Rigliaco, E.; Nascimbeni, V.; Barbato, D.; Columba, G.; Squicciarini, V. (2024-05-01). "Stellar companions and Jupiter-like planets in young associations". Astronomy & Astrophysics. 685: A119. arXiv:2402.02148v1. doi:10.1051/0004-6361/202348393. ISSN 0004-6361.