HD 48265
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Puppis |
| Right ascension | 06h 40m 01.72703s[1] |
| Declination | −48° 32′ 31.0433″[1] |
| Apparent magnitude (V) | 8.07[2] |
| Characteristics | |
| Evolutionary stage | subgiant[1] |
| Spectral type | G5IV/V[3] |
| Apparent magnitude (B) | ~8.80[2] |
| Apparent magnitude (J) | 6.842±0.021[4] |
| Apparent magnitude (H) | 6.529±0.061[4] |
| Apparent magnitude (K) | 6.449±0.020[4] |
| Astrometry | |
| Radial velocity (Rv) | +23.51±0.13[1] km/s |
| Proper motion (μ) | RA: +26.513 mas/yr[1] Dec.: +29.760 mas/yr[1] |
| Parallax (π) | 11.0065±0.0162 mas[1] |
| Distance | 296.3 ± 0.4 ly (90.9 ± 0.1 pc) |
| Absolute magnitude (MV) | 3.34[5] |
| Details | |
| Mass | 1.312±0.064[6] M☉ |
| Radius | 1.901±0.126[6] R☉ |
| Luminosity | 3.84±0.19[7] L☉ |
| Surface gravity (log g) | 3.970±0.048[6] cgs |
| Temperature | 5,733±55[6] K |
| Metallicity [Fe/H] | +0.30±0.04[6] dex |
| Rotation | ~45 days[6] |
| Rotational velocity (v sin i) | 3.1±0.3[7] km/s |
| Age | 4.201±0.625[6] Gyr |
| Other designations | |
| Nosaxa, CD−48 2430, HD 48265, HIP 31895, SAO 218115[8] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 48265, also named Nosaxa, is a star in the southern constellation Puppis. It has an apparent visual magnitude of 8.07,[2] which makes it too faint to be seen with the naked eye. Based upon parallax measurements made during the Gaia mission, it is located at a distance of 296 light-years (91 parsecs) from Earth.[1] It hosts two known planets, HD 48265 b and c.[9]This star appears close in the sky to Canopus, the second-brightest star in earth's sky, and is also a similar distance away. Because of this Canopus is the brightest star in the sky of Nosaxa's planets (other than Nosaxa itself), and, at magnitude -5.87 would appear far brighter than any star or planet seen from earth.[a]
Nomenclature
HD 48265 is the star's designation in the Henry Draper Catalogue.
This was one of the systems selected to be named in the 2019 NameExoWorlds campaign during the 100th anniversary of the IAU, which assigned each country a star and planet to be named. This system was assigned to Argentina. HD 48265 is named Nosaxa 'springtime' and HD 48265 b Naqaỹa 'brother' in the Moqoit (Mocoví) language.[10][11]
Stellar properties
This star has a stellar classification of G5IV/V,[3] suggesting that, at an age of 4.8 billion years,[12] it has reached an intermediate evolutionary stage between a main sequence star and a subgiant. It has but 93% of the mass of the Sun,[5] while its outer atmosphere has begun to expand, reaching about 2.3 times the Sun's radius.[13] HD 48265 is radiating 62%[13] of the Sun's luminosity from its atmosphere at an effective temperature of 5,508 K,[12] giving it the yellowish glow of a G-type star.[14] Measurement of the chemical abundances of this star indicate that, compared to the Sun, it has a 95%[2] greater proportion of elements other than hydrogen and helium—what astronomers term the star's metallicity.
Planetary system
In October 2008 an exoplanet, HD 48265 b (later named Naqaỹa), was reported to be orbiting this star. This object was detected using the radial velocity method during an astronomical survey conducted by the Magellan Planet Search Program using the MIKE echelle spectrograph on the 6.5-m Magellan II (Clay) telescope.[5] A second planet was found in 2026 using a combination of radial velocity and astrometry. Both are gas giants more massive than Jupiter; they may be on mutually inclined orbits.[9]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b / Naqaỹa | ≥1.67±0.06 MJ | 1.87+0.02 −0.04 |
789.6±1.1 | 0.35±0.02 | 11.7+11.0 −3.4 or 160.1+8.3 −31° |
— |
| c | 4.45+0.75 −0.37 MJ |
10.4+1.6 −1.0 |
10418+2451 −1412 |
0.41+0.08 −0.06 |
89±29° | — |
See also
Notes
- ^ calculated using each star's distance, position in the sky, and brightness
- ^ Planet b is listed with its minimum mass; including astrometric data suggests a larger true mass of 7.4+3.7
−3.9 MJ, but this is uncertain since this planet's astrometric signal is not significant.
References
- ^ 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 d Jenkins, J. S.; et al. (July 2008), "Metallicities and activities of southern stars", Astronomy and Astrophysics, 485 (2): 571–584, arXiv:0804.1128, Bibcode:2008A&A...485..571J, doi:10.1051/0004-6361:20078611, S2CID 8813298
- ^ a b Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 2, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H
- ^ a b c Cutri, R. M.; et al. (June 2003), 2MASS All Sky Catalog of point sources, NASA/IPAC, Bibcode:2003tmc..book.....C
- ^ a b c Minniti, Dante; et al. (2009), "Low-Mass Companions for Five Solar-Type Stars From the Magellan Planet Search Program", The Astrophysical Journal, 693 (2): 1424–1430, arXiv:0810.5348, Bibcode:2009ApJ...693.1424M, doi:10.1088/0004-637X/693/2/1424, S2CID 119224845
- ^ a b c d e f g Barbato, D.; Sozzetti, A.; et al. (August 2018). "Exploring the realm of scaled solar system analogues with HARPS". Astronomy & Astrophysics. 615: A175. arXiv:1804.08329. Bibcode:2018A&A...615A.175B. doi:10.1051/0004-6361/201832791.
- ^ a b Jenkins, J. S.; et al. (2017), "New planetary systems from the Calan–Hertfordshire Extrasolar Planet Search", Monthly Notices of the Royal Astronomical Society, 466 (1): 443–473, arXiv:1603.09391, Bibcode:2017MNRAS.466..443J, doi:10.1093/mnras/stw2811, S2CID 18016219
- ^ "HD 48265". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-03-15.
- ^ a b c Wu, Yiyun; Xiao, Guang-Yao; et al. (January 2026). "Detection of four cold Jupiters through combined analyses of radial velocity and astrometry data". arXiv:2601.11280 [astro-ph.EP].
- ^ "Argentina", NameExoworlds, retrieved 2019-12-18
- ^ Javier Salas (2019-12-20), "Rosalía de Castro ya tiene su estrella", El País, retrieved 2020-01-06
- ^ a b Nordström, B.; et al. (May 2004), "The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ˜14 000 F and G dwarfs", Astronomy and Astrophysics, 418: 989–1019, arXiv:astro-ph/0405198, Bibcode:2004A&A...418..989N, doi:10.1051/0004-6361:20035959, S2CID 11027621
- ^ a b "HD 48265", NASA Exoplanet Archive, NASA, retrieved 2012-03-15
- ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on March 18, 2012, retrieved 2012-01-16
External links
- "HD 48265". Exoplanets. Archived from the original on 2016-03-03. Retrieved 2009-06-10.