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HD 98617

Location of HD 98617 on the map (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Chamaeleon
Right ascension	11 18 34.40370
Declination	−79° 40′ 07.1370″
Apparent magnitude (V)	6.35±0.01
Characteristics
Evolutionary stage	main sequence
Spectral type	A8 IIIm:
U−B color index	+0.08
B−V color index	+0.26
Astrometry
Radial velocity (Rv)	−4±2.1 km/s
Proper motion (μ)	RA: +46.293 mas/yr Dec.: −37.910 mas/yr
Parallax (π)	15.7985 ± 0.069 mas
Distance	206.4 ± 0.9 ly (63.3 ± 0.3 pc)
Absolute magnitude (MV)	+2.42
Details
Mass	1.75±0.07 M☉
Radius	1.85±0.06 R☉
Luminosity	8.41 L☉
Surface gravity (log g)	4.20±0.04 cgs
Temperature	7,540±276 K
Metallicity	−0.03 dex
Age	1.06 Gyr
Other designations
30 G. Chamaeleontis[12], CD−78°457, CPD−78°638, FK5 2904, GC 15572, HD 98617, HIP 55225, HR 4385, SAO 256823, WDS J11186-7940AB
Database references
SIMBAD	data

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, placing it near the limit for naked eye. The system is located relatively close at a distance of 206 light years but is approaching the Solar System with a fairly constrained radial velocity of −4 km/s. At its current distance, HD 98617 brightness is diminished by 0.29 magnitudes due to interstellar dust.

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.

The primary has a stellar classification of A8 IIIm:, indicating that it is an evolved Am star (with uncertainty). However, Renson and Manfroid (2009) lists its chemical peculiarity to be doubtful. It has 1.75 times the mass of the Sun and 1.85 times its girth. It radiates 8.41 times the luminosity of the Sun from its photosphere at an effective temperature of 7,540 K, giving it a white hue. It is estimated to be a billion years old and has a solar metallicity. The aforementioned parameters belong to an A-type main-sequence star instead of a giant star and Gaia DR3 even models it as such.

References

1. ^ 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.
2. ^ 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.
3. ^ 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.
4. ^ 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.
5. ^ 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.
6. 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.
7. ^ 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.
8. ^ 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.
9. ^ 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.
10. ^ 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.
11. ^ 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.
12. 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.
13. "HD 98617". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved October 19, 2022.
14. 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.
15. 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.
16. 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.

v t e Constellation of Chamaeleon
List of stars in Chamaeleon Chamaeleon in Chinese astronomy
Stars	Bayer α β γ δ δ ε ζ η θ ι κ μ μ ν π Variable R T Z RS RZ CT CU DI DR DX DY HR 3393 3543 3695 4170 4268 4385 4397 4507 4509 4649 4976 5188 HD 63454 (Ceibo) 115088 116852 Other 2MASS J11011926–7732383 AB ChaHα8 CHXR 73 L 34-26 WISEA J120037.79-784508.3
Exoplanets Cha 110913−773444 ChaHα8 b COCONUTS-2b HD 63454 b OTS 44
Star clusters η Chamaeleontis cluster
Nebulae Chamaeleon complex NGC 3195 IC 2631
Galaxies	NGC 2915
Category

• Double stars
• Henry Draper Catalogue objects
• Hipparcos objects
• Bright Star Catalogue objects
• Chamaeleon
• Am stars
• Durchmusterung objects
• Gould objects
• A-type giants