107 Piscium
A K1V star with a disputed magnitude variation and unconfirmed binary status.
107 Piscium is a single star in the constellation of Pisces, also known by the Flamsteed designation 2 Arietis due to an accidental double numbering by John Flamsteed in his Catalogus Britannicus (1725). It is a K-type main-sequence star faintly visible to the naked eye, with an apparent visual magnitude that has been measured varying between 5.14 and 5.26, though this variation was not confirmed and is likely spurious.
- Flamsteed designation
- 107 Piscium (also 2 Arietis)
- Apparent visual magnitude
- 5.14–5.26 (variation unconfirmed, likely spurious)
- Stellar classification
- K1V
- Mass
- 86% of the Sun
- Radius
- 80.8% of the Sun
- Luminosity
- 44% of the Sun
- Age
- approximately 6 billion years
Lore & Background
107 Piscium is a K-type main-sequence star with a stellar classification of K1V, generating energy from core hydrogen fusion. It is somewhat older than the Sun, at about 6 billion years old, and has 86% of the Sun's mass, 80.8% of its radius, and shines with 44% of its luminosity. The star's metallicity is slightly lower than that of the Sun, and its chromospheric activity level is similar, showing a simple cycle of variation. It rotates slowly, though the rotation period is not specified in available data. The star is drifting closer to the Sun with a radial velocity of −33.6 km/s and is predicted to come as close as 4.7302 parsecs in about 135,800 years.
In 1997, data from the Hipparcos mission led to the star being categorized as an astrometric binary with a period, but this result has not been confirmed. No infrared excess from exozodiacal dust has been detected. The habitable zone for this star, where liquid water could exist on an Earth-like planet, lies at a radius of 0.52–1.00 AU.
Reader's Guide
107 Piscium's significance lies in its role as a nearby K-type main-sequence star that has been studied for variability, binary companions, and circumstellar dust. The unconfirmed variation in its apparent magnitude (5.14–5.26) highlights the challenges of photometric measurement and the need for careful verification. Its classification as an astrometric binary from Hipparcos data, though unconfirmed, places it among stars that may host a companion, yet the lack of confirmation leaves its status as a single star intact. The star's age, metallicity, and chromospheric activity—similar to the Sun—make it a useful analog for solar-type stellar evolution, particularly for stars slightly older and less massive than the Sun. The absence of detected exozodiacal dust and the defined habitable zone (0.52–1.00 AU) provide constraints for models of planetary system formation around K-dwarfs. Its predicted close approach to the Sun in about 135,800 years (to 4.7302 pc) adds a dynamic element to its long-term trajectory. The accidental double Flamsteed numbering (also 2 Arietis) is a historical curiosity reflecting the early cataloging of stars. Overall, 107 Piscium serves as a case study in stellar characterization, variability assessment, and binary detection, with unresolved questions that invite further observation.
Did You Know?
- 107 Piscium was accidentally numbered twice by John Flamsteed, also receiving the designation 2 Arietis.
- The star's apparent magnitude variation between 5.14 and 5.26 was not confirmed and is likely spurious.
- In 1997, Hipparcos data categorized it as an astrometric binary, but this result has not been confirmed.
Frequently Asked Questions
What is 107 Piscium?
107 Piscium is a K1-type main-sequence star in the constellation Pisces, just barely visible to the naked eye at a visual magnitude near 5.2. It packs roughly 86 percent of the Sun's mass while producing only about 44 percent of its luminosity.
Why does 107 Piscium carry the alternate name 2 Arietis?
John Flamsteed inadvertently assigned the same object two separate numbers in his 1725 Catalogus Britannicus, listing it as both 107 Piscium and 2 Arietis. The dual designation is a historical cataloging slip, not evidence of two distinct stars.
Is 107 Piscium a confirmed binary or multiple system?
No; its status as a binary remains unconfirmed. It is currently catalogued as a single K1V dwarf, and no companion has been reliably detected despite its appearance in multiple-star reference lists.
What are the key physical properties of 107 Piscium?
The star has a radius of about 80.8 percent of the Sun's and a luminosity near 44 percent of solar output. Its mass sits at roughly 86 percent of the Sun's, making it a slightly smaller, cooler, and dimmer solar analog.
Does 107 Piscium genuinely vary in brightness?
Reported magnitudes span from 5.14 to 5.26, but this range has never been independently verified and is widely regarded as spurious. The star is generally treated as a steady, non-variable K-type main-sequence object.
More in Binary and Multiple Stars, Part 4 1-24
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