42 Leonis Minoris

42 Leonis Minoris
Location of 42 Leo Minoris (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Leo Minor
Right ascension 10h 45m 51.8947s[1]
Declination +30° 40′ 56.307″[1]
Apparent magnitude (V) 5.35±0.01[2]
Characteristics
Spectral type B9 V[3]
U−B color index −0.16[4]
B−V color index −0.06[4]
Astrometry
Radial velocity (Rv)12±3.7[5] km/s
Proper motion (μ) RA: −20.344 mas/yr[1]
Dec.: −38.234 mas/yr[1]
Parallax (π)7.915 ± 0.0813 mas
Distance412 ± 4 ly
(126 ± 1 pc)
Absolute magnitude (MV)+0.02[6]
Details
Mass2.77±0.36[7] M☉
Radius3.29±0.11[7] R☉
Luminosity107[8] L☉
Surface gravity (log g)4±0.2[9] cgs
Temperature10,703±206[7] K
Rotational velocity (v sin i)145[10] km/s
Age69+199
−59[9] Myr
Other designations
42 LMi, AG+30°1079, BD+31°2180, FK5 407, GC 14798, HD 93152, HIP 52638, HR 4203, SAO 62236
Database references
SIMBADdata

42 Leonis Minoris (42 LMi) is a solitary,[11] bluish-white hued star located in the northern constellation Leo Minor. It has a visual apparent magnitude of 5.35,[2] allowing it to be faintly seen with the naked eye. Parallax measurements place it at a distance of 412 light years.[1] The object has a heliocentric radial velocity of 12 km/s,[5] indicating that it is drifting away from the Solar System.

42 LMi has a general stellar classification of B9 V,[3] indicating that it is an ordinary B-type main-sequence star. However, Cowley et al. (1969) gave a slightly cooler class of A1 Vn,[12] indicating that it is instead an A-type main-sequence star with 'nebulous' (broad) absorption lines due to rapid rotation. Nevertheless, it has 2.77 times the mass of the Sun and a radius of 3.3 R☉.[7] It radiates at 107 times the luminosity of the Sun[8] from its photosphere at an effective temperature of 10,703 K.[7] Its high luminosity and slightly enlarged diameter suggests that the object might be evolved. Like most hot stars, 42 LMi spins rapidly with a projected rotational velocity of 145 km/s.[10]

There are two optical companions located near this star. BD+31°2181 is a 7th magnitude K2 giant star separated 146″ away along a position angle of 174°.[13] An 8th magnitude companion has been detected at a distance of over 400 arcseconds along a position angle of 92°.[13] Both have no relation to 42 LMi and is just moving with it by coincidence.

An X-ray emission with a luminosity of 278.2×1020 W has been detected around the object. A-type stars are not expected to emmit X-rays, so it must be coming from an unseen companion.[14]

  1. ^ a b c d Cite error: The named reference EDR3 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Tycho2000 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Osawa1959 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Crawford1963 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Karchenko2007 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ a b c d e Cite error: The named reference Stassun2019 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference McDonald2017 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Gullikson2016 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Dworetsky1974 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Cowley1969 was invoked but never defined (see the help page).
  13. ^ a b Cite error: The named reference Mason2001 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Schröder2007 was invoked but never defined (see the help page).