38 Cancri

38 Cancri

A visual band light curve for BT Cancri, plotted from data published by Gupta (1979)[1]
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Cancer
Right ascension 08h 39m 42.65445s[2]
Declination +19° 46′ 42.4386″[2]
Apparent magnitude (V) 6.65[3]
Characteristics
Evolutionary stage subgiant
Spectral type F0 IV[4]
B−V color index 0.248±0.010[3]
Variable type δ Sct[5]
Astrometry
Radial velocity (Rv)+32.0±2.0[6] km/s
Proper motion (μ) RA: −36.879[2] mas/yr
Dec.: −13.103[2] mas/yr
Parallax (π)5.3700 ± 0.0705 mas[2]
Distance607 ± 8 ly
(186 ± 2 pc)
Absolute magnitude (MV)0.36[3]
Details
Mass1.786[7] M☉
Radius1.834[7] R☉
Luminosity59.31[3] L☉
Surface gravity (log g)2.92±0.20[8] cgs
Temperature7300±200[8] K
Metallicity [Fe/H]−0.16±0.10[8] dex
Rotation0.670 d[7]
Rotational velocity (v sin i)138.5[7] km/s
Other designations
38 Cnc, BT Cancri, BD+20°2149, HD 73575, HIP 42485, SAO 98006[9]
Database references
SIMBADdata

38 Cancri is a variable star in the zodiac constellation Cancer, located around 607 light years from the Sun. This object has the variable star designation BT Cancri; 38 Cancri is the Flamsteed designation. It is a member of the Praesepe cluster[10] but is a challenge to view with the naked eye, having an apparent visual magnitude of 6.65.[3] The star is moving closer to the Earth with a heliocentric radial velocity of +32 km/s.[6]

This is an evolving subgiant star with a stellar classification of F0 IV.[4] It was found to be a pulsating variable by Michel Breger in 1970[11] and is classed as a Delta Scuti variable. The star displays a pattern of variation showing up to 22 different frequencies, with three being dominant.[12] The brightness varies by up to 0.07 in magnitude.[5] The star has a magnetic field with a computed longitudinal field strength of −215±149 G.[8] It has 1.8[7] times the mass of the Sun and 1.8[7] times the Sun's radius. The star is radiating 59[3] times the Sun's luminosity from its photosphere at an effective temperature of around 7,300 K.[8]

  1. ^ Cite error: The named reference Gupta was invoked but never defined (see the help page).
  2. ^ a b c d e Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  3. ^ a b c d e f Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Gray2001 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Samus2017 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference deBruijne2012 was invoked but never defined (see the help page).
  7. ^ a b c d e f Cite error: The named reference vanSaders2013 was invoked but never defined (see the help page).
  8. ^ a b c d e Cite error: The named reference Fossati2007 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Michel1999 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Breger1970 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Breger2012 was invoked but never defined (see the help page).