GSC 02652-01324
Orange dwarf star in the constealltion Lyra
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GSC 02652-01324, also known as V672 Lyrae, is an orange dwarf main sequence star approximately 521 light-years away in the constellation of Lyra (the Lyre).[2][3] It hosts one known exoplanet, TrES-1b.[5]
| Observation data Epoch J2000.0 Equinox ICRS | |
|---|---|
| Constellation | Lyra[2] |
| Right ascension | 19h 04m 09.8516s[3] |
| Declination | +36° 37′ 57.447″[3] |
| Apparent magnitude (V) | +11.806[4] |
| Characteristics | |
| Evolutionary stage | main sequence[3] |
| Spectral type | K0V[5] |
| Apparent magnitude (B) | 12.405±0.005[4] |
| Apparent magnitude (J) | 10.294±0.022[6] |
| Apparent magnitude (H) | 9.887±0.021[6] |
| Apparent magnitude (K) | 9.819±0.019[6] |
| Variable type | Planetary transit[5][7] |
| Astrometry | |
| Radial velocity (Rv) | −20.54±0.40[3] km/s |
| Proper motion (μ) | RA: −32.168(12) mas/yr[3] Dec.: −20.463(13) mas/yr[3] |
| Parallax (π) | 6.2648±0.0111 mas[3] |
| Distance | 520.6 ± 0.9 ly (159.6 ± 0.3 pc) |
| Absolute magnitude (MV) | +5.847+0.097 −0.095[8] |
| Details[8] | |
| Mass | 0.878+0.038 −0.040 M☉ |
| Radius | 0.807+0.017 −0.016 R☉ |
| Luminosity | 0.438+0.035 −0.033 L☉ |
| Surface gravity (log g) | 4.567+0.012 −0.015 cgs |
| Temperature | 5230±50 K |
| Metallicity [Fe/H] | +0.02±0.05 dex |
| Rotation | 40.2+22.9 −14.6 d[9] |
| Rotational velocity (v sin i) | 1.30±0.30[10] km/s |
| Age | 3.7+3.4 −2.8 Gyr |
| Other designations | |
| TrES-1 Parent Star, V672 Lyr, KIC 875283, TOI-1236, TIC 120757718, TYC 2652-1324-1, GSC 02652-01324, 2MASS J19040985+3637574[11] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
There is a small, cool companion star at a separation of 13.2 arcseconds, corresponding to 2111 AU.[12]
Nomenclature
The designation GSC 02652-01324 comes from the Guide Star Catalog.
The star is sometimes called TrES-1,[13] in reference to its planet discovered by the Trans-Atlantic Exoplanet Survey (TrES). The discovery paper[5] and the SIMBAD database[11] use this designation for the planet itself, but other sources call the star TrES-1[14] and the planet TrES-1b,[15] following the standard exoplanet naming convention.
Since the planet transits the star, the star is classified as a planetary transit variable and has received the variable star designation V672 Lyrae. The transits last a little over an hour, about 4% of the orbital period, and the brightness diminishes by a few hundredths of a magnitude.[7]
Planetary system
In 2004, the exoplanet TrES-1b was found to be orbiting this star by the Trans-Atlantic Exoplanet Survey using the transit method. The planet was detected crossing its parent star using a small 4-inch-diameter (100 mm) telescope. The discovery was confirmed by the Keck Observatory using the radial velocity method, allowing its mass to be determined.[5][16] The planet is a hot Jupiter, with a mass and size similar to those of Jupiter but an orbital period of only three days.
Evidence of a candidate second planet, designated TrES-1c, was found in 2025 by the radial velocity method. If existing, this planet would have a minimum mass about that of Saturn, and an eccentric orbit with a 1,200-day period.[17]
An additional planet in the system is suspected due to transit-timing variations (TTVs) of TrES-1b,[15] but has not been detected.[17] For a planet causing the observed TTVs to remain undetected, it would need to have a mass less than ~0.25 MJ and an orbital period less than ~7 days. Other than the TTVs, there is as yet no evidence of such a planet, but the observed TTVs cannot be explained by other known effects.[17]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination (°) |
Radius |
|---|---|---|---|---|---|---|
| b | 0.697+0.028 −0.027 MJ |
0.03926+0.00058 −0.00060 |
3.0300689(7)[15] | <0.012 | 90.0+0.0 −1.1 |
1.067+0.022 −0.021 RJ |
| c (unconfirmed) | ≥0.36 MJ | 2.1 | 1200+26 −20 |
0.65±0.10 | — | — |