42 Leonis Minoris
{{Short description|Star in the constellation Leo Minor}}
{{Starbox begin
| name = 42 Leonis Minoris
}}
{{Starbox image
| image=
{{Location mark
|image=Leo Minor constellation map.svg|alt=|float=center|width=240
|label=|position=right
|mark=Red circle.svg|mark_width=10|mark_link=42 Leonis Minoris
|x=260|y=600
}}
|caption=Location of 42 Leo Minoris (circled)
}}
{{Starbox observe
| epoch = J2000
| constell = Leo Minor
}}
{{Starbox character
}}
{{Starbox astrometry
| parallax = 7.915
| p_error = 0.0813
| prop_mo_ra = −20.344
| prop_mo_dec = −38.234
}}
{{Starbox detail
| temperature = 10,703{{±|206}}
| metal_fe =
}}
{{Starbox catalog
| names = {{odlist|F = 42 LMi|AG = +30°1079|BD = +31°2180|FK5 = 407|GC = 14798|HIP = 52638|HR = 4203|SAO = 62236|HD = 93152|WDS J10459+3041A}}
}}
{{Starbox reference
| Simbad = 42+LMi
}}
{{Starbox end}}
42 Leonis Minoris (42 LMi) is a solitary, bluish-white hued star located in the northern constellation Leo Minor. It has a visual apparent magnitude of 5.35, allowing it to be faintly seen with the naked eye. Parallax measurements place it at a distance of 412 light years. The object has a heliocentric radial velocity of {{val|12|ul=km/s}}, indicating that it is drifting away from the Solar System.
42 LMi has a general stellar classification of B9 V, indicating that it is an ordinary B-type main-sequence star. However, Cowley et al. (1969) gave a slightly cooler class of A1 Vn, 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 {{val|3.3|ul=solar radius}}. It radiates at 107 times the luminosity of the Sun from its photosphere at an effective temperature of {{val|10703|ul=K|fmt=commas}}. 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 {{val|145|ul=km/s}}.
There are two optical companions located near this star. BD+31°2181 is a 7th magnitude K2 giant star separated {{val|146|ul=arcsecond}} away along a position angle of {{val|174|ul=deg}}. An 8th magnitude companion has been detected at a distance of over {{val|400|ul=arcseconds}} along a position angle of {{val|92|ul=deg}}. Both have no relation to 42 LMi and is just moving with it by coincidence.
An X-ray emission with a luminosity of {{val|278.2e20|ul=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.
References
{{reflist||refs=
{{Cite Gaia EDR3|735156362212375424}}
}}
{{Stars of Leo Minor}}