HD 118285

HD 118285

A light curve for DY Chamaeleontis, plotted from TESS data[1]
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Chamaeleon
Right ascension 13h 39m 11.99015s[2]
Declination −75° 41′ 01.6128″[2]
Apparent magnitude (V) 6.32[3] (6.34 - 6.38)[4]
Characteristics
Evolutionary stage main sequence star[5]
Spectral type B8 IV[6]
U−B color index −0.26[7]
B−V color index +0.01[7]
Variable type SPB[4]
Astrometry
Radial velocity (Rv)18.2±2.3[8] km/s
Proper motion (μ) RA: −20.690 mas/yr[2]
Dec.: −14.712 mas/yr[2]
Parallax (π)3.7743 ± 0.0289 mas[2]
Distance864 ± 7 ly
(265 ± 2 pc)
Absolute magnitude (MV)−0.54[9]
Details
Mass3.63±0.12[5] M☉
Radius5.52±0.28[10] R☉
Luminosity293+50
−42[5] L☉
Temperature11,350+79
−78[5] K
Metallicity [Fe/H]0.00[11] dex
Rotational velocity (v sin i)67[12] km/s
Age309[13] Myr
Other designations
49 G. Chamaeleontis[14], DY Cha, CD−75°632, CPD−75°882, FK5 503, GC 18406, HD 118285, HIP 66607, HR 5115, SAO 257069[15]
Database references
SIMBADdata

HD 118285, also known as HR 5115, is a variable star located in the southern circumpolar constellation Chamaeleon. DY Chamaeleontis (DY Cha) is its variable star designation. It has an average apparent magnitude of 6.32,[3] placing it near the limit for naked eye visibility. The object is located relatively far at a distance of 864 light years based on Gaia DR3 parallax measurements but is receding with a heliocentric radial velocity of 18 km/s.[8] At its current distance, HD 118285's brightness is diminished by 0.58 magnitudes due to interstellar dust.[16]

HD 118285's variability was first observed in a 1998 Hipparcos survey focusing on the discovery of slowly pulsating B-type stars (SPB).[17] It was later confirmed to be an SPB star and given the variable designation DY Chamaeleontis.[18] It fluctuates between magnitudes 6.34 and 6.38 in the visual passband with a period of 23 hours.[4]

This is a slightly evolved B-type star with a stellar classification of B8 IV.[6] Contrary to the classification, stellar evolution models from Zorec and Royer (2012) model it as a dwarf star that has completed 89.1% of its main sequence life.[5] It has 3.6 times the mass of the Sun[5] and 5.5 times its girth.[10] It radiates 293 times the luminosity of the Sun from its photosphere at an effective temperature of 11,350 K,[5] giving it a bluish-white hue. It is estimated to be 309 million years old[13] and spins modestly with a projected rotational velocity of 67 km/s.[12]

References

  1. ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2022.
  2. ^ a b c d 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.
  3. ^ 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.
  4. ^ a b c Samus’, N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (January 2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. eISSN 1562-6881. ISSN 1063-7729. S2CID 125853869.
  5. ^ a b c d e f g Zorec, J.; Royer, F. (January 2012). "Rotational velocities of A-type stars IV: Evolution of rotational velocities". Astronomy & Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691. eISSN 1432-0746. ISSN 0004-6361. S2CID 55586789.
  6. ^ 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.
  7. ^ 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.
  8. ^ 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.
  9. ^ 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.
  10. ^ a b Kervella, P.; Thévenin, F.; Di Folco, E.; Ségransan, D. (October 2004). "The angular sizes of dwarf stars and subgiants". Astronomy & Astrophysics. 426 (1): 297–307. arXiv:astro-ph/0404180. Bibcode:2004A&A...426..297K. doi:10.1051/0004-6361:20035930. eISSN 1432-0746. ISSN 0004-6361.
  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. ^ a b Levato, H.; Grosso, M. (June 2004). "New Projected Rotational Velocities of All Southern B-type Stars of the Bright Star Catalogue". Astronomical Society of the Pacific. 215: 51. Bibcode:2004IAUS..215...51L.
  13. ^ a b Gontcharov, G. A. (November 2012). "Spatial distribution and kinematics of OB stars". Astronomy Letters. 38 (11): 694–706. arXiv:1606.09028. Bibcode:2012AstL...38..694G. doi:10.1134/S1063773712110035. eISSN 1562-6873. ISSN 1063-7737. S2CID 255202762.
  14. ^ 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.
  15. ^ "DY Cha". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved December 5, 2022.
  16. ^ 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.
  17. ^ Waelkens, C.; Aerts, C.; Kestens, E.; Grenon, M.; Eyer, L. (February 1998). "Study of an unbiased sample of B stars observed with Hipparcos: the discovery of a large amount of new slowly pulsating B stars". Astronomy and Astrophysics. 330: 215–221. Bibcode:1998A&A...330..215W. ISSN 0004-6361.
  18. ^ Kazarovets, E. V.; Samus, N. N.; Durlevich, O. V.; Frolov, M. S.; Antipin, S. V.; Kireeva, N. N.; Pastukhova, E. N. (January 1999). "The 74th Special Name-list of Variable Stars". Information Bulletin on Variable Stars. 4659: 1. Bibcode:1999IBVS.4659....1K. ISSN 0374-0676.