38 Geminorum is a binary star in the constellation Gemini, best viewed on winter nights.
As a 4th magnitude binary star, 38 Geminorum, or e Gem for short, will appear as a faint point of white light to the naked eye, so backyard astronomers will need to employ binoculars or a telescope to resolve the yellow and blue pair. The primary star is an orange A-type main-sequence star classified as an A8V spectral type.
Meanwhile, the dimmer 7.8 magnitude secondary star appears 7.3 arcseconds away from the primary and is a G-type main-sequence star classified as a spectral type of G6V. The orbital period for the system is nearly 2,000 years.1
As with many double stars, 38 Geminorum has its own smattering of reports regarding the binary’s colors. According to Bob Argyle with the Webb Deep-Sky Society, several popular astronomers have their own unique take on the color: “Admiral Smyth gives light yellow and purple, but E. J. Hartung sees yellowish and pale-orange, whilst to Sissy Haas the colours appear lemon-white and greyish.” As my observation says below, I vote for orange and light blue!
My Observations
| Date | February 24, 2023 |
| Time | 9:48 P.M. |
| Location | Seattle, WA |
| Magnification | 169x |
| Scope | Meade 8″ SCT |
| Eyepiece | 12mm |
| Seeing | Below Average |
| Transparency | Below Average |
I’m sorry to say this will be one of my last observations for the night. The temperature hovers around 29°F. It’s not the cold pushing me away from the scope; it’s the high-altitude clouds sneaking in from every direction. There are now only small patches of clear sky throughout the sky’s dome.
I’m glad the last star for the evening is 38 Geminorum! The primary star’s orange light desperately tries to break through the haze. Like a match in a breeze, this star is warm and flickers as clouds pass by. The secondary jumps in and out of view. From what I can tell, it appears to be a white star with a hint of blue. Good night 38 Gem. Thank you for your time.
Key Stats
| Constellation | Gemini |
| Best Viewing | Winter |
| Visual Magnitude | +4.7, +7.8 |
| Separation | 7.3″ | 184 AU |
| Position Angle | 143° |
| Spectral Class | A=A8V, B=G6V |
| Absolute Visual Magnitude | +5.76 |
| Distance from Earth | 98 ly |
| Milky Way Location | Orion Spur |
| My Viewing Grade | B |
| Designations | e Gem, SAO 96265, HD 50635, HR 2564, STF 982 |
Sources and Notes
Banner illustration was created by the European Southern Observatory (ESO) and is under the Creative Commons Attribution 4.0 International License. Per ESO agreement: Here is the original image on the ESO website.
1 “38 Geminorum.” Wikipedia, Wikimedia Foundation, 25 Oct. 2022, https://en.wikipedia.org/wiki/38_Geminorum.
Sketch by Wayne McGraw
The Garden Astronomer 