HD 121439, also known as HR 5240, is a solitary, bluish-white hued star located in the southern circumpolar constellation Apus. It has an apparent magnitude of 6.08,[2] allowing it to be faintly visible to the naked eye. The object is located relatively far at a distance of 774 light years[1] based on Gaia DR3 parallax measurements but is receding with a fairly constrained radial velocity of 4 km/s.[5] At its current distance, HD 121439's brightness is diminished by 0.57 magnitudes due to interstellar dust.[13]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Apus |
| Right ascension | 14h 00m 32.81143s[1] |
| Declination | −78° 35′ 23.9308″[1] |
| Apparent magnitude (V) | 6.08±0.01[2] |
| Characteristics | |
| Spectral type | B9 III[3] |
| U−B color index | −0.17[4] |
| B−V color index | +0.03[4] |
| Astrometry | |
| Radial velocity (Rv) | 4±4.7[5] km/s |
| Proper motion (μ) | RA: −14.337 mas/yr[1] Dec.: −9.094 mas/yr[1] |
| Parallax (π) | 4.2166 ± 0.0425 mas[1] |
| Distance | 774 ± 8 ly (237 ± 2 pc) |
| Absolute magnitude (MV) | −0.80[6] |
| Details | |
| Mass | 3.26[7] M☉ |
| Radius | 5.55[8] R☉ |
| Luminosity | 168[9] L☉ |
| Surface gravity (log g) | 3.48[7] cgs |
| Temperature | 9,708±124[10] K |
| Metallicity [Fe/H] | +0.22[7] dex |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is an evolved giant star with a stellar classification of B9 III.[3] It has 3.26 times the mass of the Sun[7] but has expanded to 5.6 times its girth.[8] It radiates 168 times the luminosity of the Sun[9] from its photosphere at an effective temperature of 9,708 K.[10] Based on extinction from the Gaia passband, HD 121439 has an iron abundance 1.65 times that of the Sun.[7] This makes the object metal enriched.
References
edit- ^ a b c d e 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 Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. ISSN 0004-6361.
- ^ a b Houk, N.; Cowley, A. P. (1975). University of Michigan Catalogue of two-dimensional spectral types for the HD stars. Volume I. Declinations −90° to −53°. Bibcode:1975mcts.book.....H.
- ^ a b Johnson, H. L.; Mitchell, R. I.; Iriarte, B.; Wisniewski, W. Z. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99–110. Bibcode:1966CoLPL...4...99J.
- ^ a b Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. eISSN 1562-6873. ISSN 1063-7737. S2CID 119231169.
- ^ Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331–346. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. eISSN 1562-6873. ISSN 1063-7737. S2CID 119257644.
- ^ a b c d e Anders, F.; et al. (February 2022). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia EDR3 stars brighter than G = 18.5". Astronomy & Astrophysics. 658: A91. arXiv:2111.01860. Bibcode:2022A&A...658A..91A. doi:10.1051/0004-6361/202142369. eISSN 1432-0746. ISSN 0004-6361.
- ^ a b Kervella, Pierre; Arenou, Frédéric; Thévenin, Frédéric (20 December 2021). "Stellar and substellar companions from Gaia EDR3". Astronomy & Astrophysics. 657: A7. arXiv:2109.10912. Bibcode:2022A&A...657A...7K. doi:10.1051/0004-6361/202142146. eISSN 1432-0746. ISSN 0004-6361.
- ^ a b McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (21 November 2012). "Fundamental parameters and infrared excesses of Hipparcos stars: Parameters and IR excesses from Hipparcos". Monthly Notices of the Royal Astronomical Society. 427 (1): 343–357. arXiv:1208.2037. Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x. eISSN 1365-2966. ISSN 0035-8711.
- ^ a b Stassun, Keivan G.; et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467. eISSN 1538-3881. hdl:1721.1/124721. S2CID 166227927.
- ^ Gould, Benjamin Apthorp (1878). "Uranometria Argentina : brillantez y posicion de las estrellas fijas, hasta la septima magnitud, comprendidas dentro de cien grados del polo austral : con atlas". Resultados del Observatorio Nacional Argentino. 1. Bibcode:1879RNAO....1.....G.
- ^ "HD 121439". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved November 6, 2022.
- ^ Gontcharov, George A.; Mosenkov, Aleksandr V. (28 September 2017). "Verifying reddening and extinction for Gaia DR1 TGAS main sequence stars". Monthly Notices of the Royal Astronomical Society. 472 (4): 3805–3820. arXiv:1709.01160. Bibcode:2017MNRAS.472.3805G. doi:10.1093/mnras/stx2219. eISSN 1365-2966. ISSN 0035-8711.