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]

  1. ^ Cite error: The named reference MAST was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference GaiaDR3 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Tycho2000 was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference Samus2017 was invoked but never defined (see the help page).
  5. ^ a b c d e f g Cite error: The named reference Zorec2012 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Houk1975 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Johnson1966 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Kervella2004 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Gontcharov20122 was invoked but never defined (see the help page).
  12. ^ a b Cite error: The named reference Levato2004 was invoked but never defined (see the help page).
  13. ^ a b Cite error: The named reference Gontcharov20121 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Gould1879 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference Gontcharov2017 was invoked but never defined (see the help page).
  17. ^ Cite error: The named reference Waelkens1998 was invoked but never defined (see the help page).
  18. ^ Cite error: The named reference Kazarovets1999 was invoked but never defined (see the help page).