Sand 364

Sand 364 is a K type giant star on the Red Giant Branch within the cluster Messier 37, which is located in the constellation Auriga. With an apparent magnitude of 9.8, it is too faint to be seen with the naked eye but is visible through binoculars or a small telescope under clear, dark skies. It is located at a distance of about 2665 light years (816.876 parsecs) from the Sun based on parallax, and has an absolute magnitude of -0.18.

Sand 364

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Observation data Epoch {{{epoch}}}      Equinox
Constellation	Auriga
Right ascension	08h49m56.81s
Declination	+11d41m32.94s
Apparent magnitude (V)	9.8
Characteristics
Evolutionary stage	Red Giant Branch
Spectral type	K3III
U−B color index	4.06
B−V color index	1.63
Variable type	SR/L
Astrometry
Distance	2665 ly (816.876 pc)
Absolute magnitude (MV)	-0.18
Details
Mass	1.35±0.05  M☉
Radius	39.59 R☉
Luminosity	2.07157257+0.02647122 −0.02819003 L☉
Temperature	4284±9 K
Metallicity	[Fe/H] -0.05±0.04 dex
Age	4.15±0.65 Gyr
Database references
SIMBAD	data

Physical Characteristics

Sand 364 is an aging Red Giant star, with about 1.35 solar masses, and a measured luminosity of around 2 times the Sun's. It has a surface temperature of about 4,284 Kelvin meaning spectral type is K3III, which is orange with a slight part of yellow in it, it is thought to be a old Red Giant with an age of around 4.1 billion years, and most likely evolved from an early F type star, or a late A type star. Its radius is 39.59 times, bigger than the sun, and, its expanded outer layers give it a vast surface area, causing the star to glow with a warm, reddish-orange light that dominates its appearance. The star’s atmosphere is cooler than that of the Sun, leading to strong molecular absorption bands in its spectrum, characteristic of evolved giant stars. Sand 364’s internal structure has changed dramatically from its main sequence phase. Hydrogen fusion now occurs in a shell surrounding an inert helium core, causing the star to swell and cool on its outer envelope. This stage is relatively brief in stellar terms but crucial for understanding the life cycle of stars with masses similar to our Sun.

Possible Planetary System

Discovery of Sand 364b

A radial velocity survey of M67 revealed that Sand 364 had a planet, with a mass of about 1-6 Jupiters, and a radius of about 0.9 Jupiters.

False Planet

A newer analysis revealed that the previously reported planet orbiting Sanders 364 was likely a false positive. While the original detection by Brucalassi et al. identified a 121-day periodic signal in the star's radial velocity data — consistent with a giant planet — further independent studies failed to confirm its planetary origin.

Instead, more extensive datasets revealed that Sanders 364 exhibits multiple long-period, quasiperiodic radial velocity variations, not just the 121-day signal. These signals, though initially suggestive of orbital motion, lack the coherence and dynamical consistency expected from a true planetary companion. Crucially, none of the six detected signals show the stability or amplitude pattern characteristic of a planetary-induced Doppler shift over the long term.