HD 98617, also known HR 4385, is a double star located in the southern circumpolar constellation Chamaeleon. The system has a combined apparent magnitude of 6.35,[2] placing it near the limit for naked eye. The system is located relatively close at a distance of 206 light years[1] but is approaching the Solar System with a fairly constrained radial velocity of −4 km/s.[5] At its current distance, HD 98617 brightness is diminished by 0.29 magnitudes due to interstellar dust.[14]
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Chamaeleon |
| Right ascension | 11h 18m 34.40370s[1] |
| Declination | −79° 40′ 07.1370″[1] |
| Apparent magnitude (V) | 6.35±0.01[2] |
| Characteristics | |
| Evolutionary stage | main sequence[1] |
| Spectral type | A8 IIIm:[3] |
| U−B color index | +0.08[4] |
| B−V color index | +0.26[4] |
| Astrometry | |
| Radial velocity (Rv) | −4±2.1[5] km/s |
| Proper motion (μ) | RA: +46.293 mas/yr[1] Dec.: −37.910 mas/yr[1] |
| Parallax (π) | 15.7985 ± 0.069 mas[1] |
| Distance | 206.4 ± 0.9 ly (63.3 ± 0.3 pc) |
| Absolute magnitude (MV) | +2.42[6] |
| Details | |
| Mass | 1.75±0.07[7] M☉ |
| Radius | 1.85±0.06[8] R☉ |
| Luminosity | 8.41[9] L☉ |
| Surface gravity (log g) | 4.20±0.04[7] cgs |
| Temperature | 7,540±276[10] K |
| Metallicity [Fe/H] | −0.03[11] dex |
| Age | 1.06[11] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The system's nature as a double star was first observed in a 1991 Hipparcos multiplicity survey. Their current separation is six-tenths of an arcsecond, making it difficult to measure the properties of the individual components. Nevertheless, the 10th magnitude companion is located along a position angle of 237° as of 2018.[15]
The primary has a stellar classification of A8 IIIm:, indicating that it is an evolved Am star (with uncertainty).[3] However, Renson and Manfroid (2009) lists its chemical peculiarity to be doubtful.[16] It has 1.75 times the mass of the Sun[7] and 1.85 times its girth.[8] It radiates 8.41 times the luminosity of the Sun[9] from its photosphere at an effective temperature of 7,540 K,[10] giving it a white hue. It is estimated to be a billion years old and has a solar metallicity.[11] The aforementioned parameters belong to an A-type main-sequence star instead of a giant star and Gaia DR3 even models it as such.[1]
References
edit- ^ 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 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 Allende Prieto, C.; Lambert, D. L. (December 1999). "Fundamental parameters of nearby stars from the comparison with evolutionary calculations: masses, radii and effective temperatures". Astronomy and Astrophysics. 352: 555–562. arXiv:astro-ph/9911002. Bibcode:1999A&A...352..555A. ISSN 0004-6361.
- ^ 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.
- ^ a b Chandler, Colin Orion; McDonald, Iain; Kane, Stephen R. (17 February 2016). "The Catalog of Earth-Like Exoplanet Survey Targets (CELESTA): A Database of Habitable Zones Around Nearby Stars". The Astronomical Journal. 151 (3): 59. arXiv:1510.05666. Bibcode:2016AJ....151...59C. doi:10.3847/0004-6256/151/3/59. eISSN 1538-3881.
- ^ a b Bai, Yu; Liu, JiFeng; Bai, ZhongRui; Wang, Song; Fan, DongWei (2 August 2019). "Machine-learning Regression of Stellar Effective Temperatures in the Second Gaia Data Release". The Astronomical Journal. 158 (2): 93. arXiv:1906.09695. Bibcode:2019AJ....158...93B. doi:10.3847/1538-3881/ab3048. eISSN 1538-3881.
- ^ a b c Gontcharov, G. A. (December 2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters. 38 (12): 771–782. arXiv:1606.08814. Bibcode:2012AstL...38..771G. doi:10.1134/S1063773712120031. eISSN 1562-6873. ISSN 1063-7737.
- ^ 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 98617". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved October 19, 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.
- ^ Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (December 2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466–3471. Bibcode:2001AJ....122.3466M. doi:10.1086/323920. ISSN 0004-6256.
- ^ Renson, P.; Manfroid, J. (19 March 2009). "Catalogue of Ap, HgMn and Am stars". Astronomy & Astrophysics. 498 (3): 961–966. Bibcode:2009A&A...498..961R. doi:10.1051/0004-6361/200810788. eISSN 1432-0746. ISSN 0004-6361.