HIP 11915
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cetus |
| Right ascension | 02h 33m 49.025s[1] |
| Declination | –19° 36′ 42.5032″[1] |
| Apparent magnitude (V) | 8.58[2] |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | G5V[2] |
| Astrometry | |
| Radial velocity (Rv) | +14.1[1] km/s |
| Parallax (π) | 17.45 ± 1.07[1] mas |
| Distance | 190 ± 10 ly (57 ± 4 pc) |
| Absolute magnitude (MV) | 4.8[3] |
| Details | |
| Mass | 1.0[2] M☉ |
| Radius | 1.01[4] R☉ |
| Luminosity | ~1.1 L☉ |
| Surface gravity (log g) | 4.46[5] cgs |
| Temperature | 5760 ± 4[2] K |
| Metallicity [Fe/H] | −0.059[5] dex |
| Rotational velocity (v sin i) | 0.99[5] km/s |
| Age | 4.16 ± 0.65[5] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HIP 11915 is a G-type main-sequence star located about 190 light-years from Earth in the constellation Cetus.[2] It is best known for its characteristics, which are very similar to those of the Sun, including the mass, radius, temperature, metallicity and age, which means that it is a solar twin, being just 500 million years younger than the Sun and with a lower metallicity.[lower-alpha 1] It is also known for its planetary companion, HIP 11915 b, which has a mass and orbital distance very similar to that of Jupiter, but probably with a slightly higher orbital eccentricity.
This star is entry number 11915 in the Hipparcos Catalogue. The star is located at 02:33:49.02495 right ascension, −19° 36' 42.5032" dec,[1][8] Too faint to be seen with the unaided eye, the star can be spotted with good binoculars.[8]
Stellar characteristics
HIP 11915 is a G-type main sequence star that is approximately the same mass of and likely 101% the radius of the Sun. It has a temperature of 5760 K and is 4.16 billion years old,[2][4][5] nearly 500 million years younger than the Sun, which is about 4.6 billion years old[9] and has a temperature of 5778 K.[10]
The star is slightly poor in metals, with a metallicity ([Fe/H]) of about –0.059, or about 87% of the amount of iron and other heavier metals found in the Sun.[5] Given the similar properties of the Sun, HIP 11915's luminosity is likely close to the same as the Sun (give or take about 10% in uncertainty).
Planetary system
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 0.99 ± 0.06 MJ | 4.8 ± .01 | 3830.0 ± 150 | 0.1 ± 0.07 | — | — |
The system contains a gas giant, HIP 11915 b, with a mass and orbit very similar to that of Jupiter, located at approximately the same distance from its star. The discovery of HIP 11915 b is significant, because it is the first, and to date only, distant planetary system found that may be somewhat like the Solar System.[11][12] The radial velocity data also indicates that there is no large gas giant in this system with an orbital period of less than 1000 days. This means that there could be one or more terrestrial planets in the inner parts of the system, and the possibility of a habitable Earth-like planet.
This new discovery was made at the La Silla Observatory in Chile, using the High Accuracy Radial Velocity Planet Searcher instrument mounted on the European Southern Observatory’s 3.6-meter telescope.[13][14]
According to Jorge Meléndez, who led the University of São Paulo, Brazil team that discovered HIP 11915 b, "the quest for an Earth 2.0, and for a complete Solar System 2.0, is one of the most exciting endeavors in astronomy".[15]
Comparison to the Sun
This chart compares the properties of the Sun to HIP 11915.
| Identifier | J2000 Coordinates | Distance (ly) |
Stellar Class |
Mass (M☉) |
Radius (R☉) |
Temperature (K) |
Metallicity (dex) |
Age (Gyr) |
Notes | |
|---|---|---|---|---|---|---|---|---|---|---|
| Right ascension | Declination | |||||||||
| Sun | — | — | 0.00 | G2V | 1 | 1 | 5,778 | +0.00 | 4.6 | [7] |
| HIP 11915 [16] | 02h 33m 49.02s | −19° 36′ 42.5″ | 190 | G5V | 1.00 | 1.01 | 5,760 | –0.059 | 4.1 | [17] |
Footnotes
- ↑ An exact solar twin would be a G2V star with a 5778 K temperature, be 4.6 billion years old, with the correct metallicity and a 0.1% solar luminosity variation.[6][7]
References
- 1 2 3 4 5 6 "Simbad Astronomical Database". Retrieved 16 July 2015.
- 1 2 3 4 5 6 7 "Planet HIP 11915". Retrieved 17 July 2015.
- ↑ From apparent magnitude and parallax.
- 1 2 "Jupiter Has A Twin". Apex Tribune. 16 July 2015. Retrieved 6 July 2016.
- 1 2 3 4 5 6 Dos Santos, Leonardo A.; Meléndez, Jorge; Do Nascimento, José-Dias; Bedell, Megan; Ramírez, Iván; Bean, Jacob L.; Asplund, Martin; Spina, Lorenzo; Dreizler, Stefan; Alves-Brito, Alan; Casagrande, Luca (2016). "The Solar Twin Planet Search: IV. The Sun as a typical rotator and evidence for a new rotational braking law for Sun-like stars". 1606: arXiv:1606.06214. arXiv:1606.06214
[astro-ph.SR]. Bibcode:2016arXiv160606214D. - ↑ "Solar Variability and Terrestrial Climate - NASA Science". Retrieved 8 January 2013.
- 1 2 Williams, D.R. (2004). "Sun Fact Sheet". NASA. Retrieved 2009-06-23.
- 1 2 "The star HIP 11915 in the constellation of Cetus". European Southern Observatory. 15 July 2015. Retrieved 17 July 2015.
- ↑ Fraser Cain (16 September 2008). "How Old is the Sun?". Universe Today. Retrieved 19 February 2011.
- ↑ Fraser Cain (15 September 2008). "Temperature of the Sun". Universe Today. Retrieved 19 February 2011.
- ↑ "Jupiter's twin spotted". business standard. IANS. July 16, 2015. Retrieved 16 July 2015.
- ↑ "Jupiter's twin discovered orbiting star similar to our sun". daily mail. Retrieved 16 July 2015.
- ↑ "HIP 11915b: Jupiter Twin Found Orbiting Sun-Like Star". Sci-News.com. Jul 15, 2015. Retrieved 16 July 2015.
- ↑ Bora, Kukil (16 July 2015). "Jupiter Look-Alike Discovered Orbiting Sun-Like Star; Could There Be An Earth Twin?". ib times. Retrieved 16 July 2015.
- ↑ "Jupiter Twin Discovered Around Solar Twin". European Southern Observatory. Retrieved 16 July 2015.
- ↑ HIP 11915 at SIMBAD - Ids - Bibliography - Image.
- ↑ M. Bedell; J. Meléndez; J. L. Bean; I. Ramírez; M. Asplund; A. Alves-Brito; L. Casagrande; S. Dreizler; T. Monroe; L. Spina; M. Tucci Maia (June 26, 2015). "The Solar Twin Planet Search II. A Jupiter twin around a solar twin" (PDF). The European SouthernObservatory(ESO): 8. Retrieved 17 July 2015.
External links
- M. Bedell; J. Meléndez; J. L. Bean; I. Ramírez; M. Asplund; A. Alves-Brito; L. Casagrande; S. Dreizler; T. Monroe; L. Spina; M. Tucci Maia (June 26, 2015). "The Solar Twin Planet Search II. A Jupiter twin around a solar twin" (PDF). The European SouthernObservatory(ESO): 8. Retrieved 17 July 2015.
Coordinates: 
02h 33m 49.025s, −19° 36′ 42.5032″