for 38 Geminorum plotted from
TESS data The primary component, e Geminorum Aa, is an
A-type main-sequence star which has about 1.61 times the
mass of the Sun, 1.97 times the
radius of the Sun and an
effective temperature of 7,150
K. It is a suspected
chemically peculiar star of subtype CP1 (an
Am star), which Slettebak (1955) classified as kA8mF0Vp. This notation indicates the star displays the
calcium K line of an
A8 star and the
metal lines of an
F0V star. In 1949, J. Hopmann catalogued it as a suspected
Delta Scuti variable. The primary is closely orbited by companion e Geminorum Ab, which is a smaller
F-type main-sequence star with 1.16 times the radius of the Sun and a temperature of 6,300 K. It can explain the
X-ray emission coming from the system. The system has been resolved using
interferometry, which obtained an
projected separation of . Combined with the masses, this results in an estimated orbital period of about two months. The Aa-Ab system is orbited by the component B, which has a
projected separation of . Two sets of low quality
orbital elements have been computed for this system, yielding
periods of and , and
eccentricities of 0.150 and 0.485, respectively. As of 2018, the pair had an
angular separation of (implying a projected separation of 220 au) along a
position angle of 143°. Star B is a
G-type main-sequence star with a class of G6V, 0.95 times the
Sun's mass, 0.89 times the
Sun's radius and an estimated
effective temperature of 5,583 K. The most distant component, UPM J0654+1310, has a
projected separation of 4,560 au and is believed to be a
red dwarf with a mass of just . ==References==