HIP 11915

Database links to HIP 11915

Star HIP 11915
Artist's impression of HIP 11915 with the planet HIP 11915 b in the foreground
AladinLite
Observation dates equinox :  J2000.0 , epoch : J2000.0
Constellation	whale
Right ascension	02 h 33 m 49.02 s
declination	−19 ° 36 ′ 42.5 ″
Apparent brightness	8.58 likes
Typing
Known exoplanets	1
Spectral class	G5V
Astrometry
Radial velocity	14.1 ± 0.5 km / s
distance	57.3 ± 3.5  pc
Proper movement
Rec. Share:	218.76 ± 1.01  mas / a
Dec. portion:	35.06 ± 0.92  mas / a
Physical Properties
Dimensions	1.0  M ☉
Effective temperature	5,760 ± 4  K
Metallicity [Fe / H]	−0.059 ± 0.004
Age	4.0 ± 0.6 billion  a
Other names and catalog entries
Bonn survey BD −20 ° 481 Henry Draper Catalog HD 16008 [1] Hipparcos catalog HIP 11915 [2] SAO catalog SAO 148468 [3] Tycho catalog TYC 5862-2032-1 [4] 2MASS catalog 2MASS J02334900-1936425 [5]

HIP 11915 is a yellow dwarf in the constellation of the whale , the approximately 186 light years from the sun away. It has a sun approximately the same mass, temperature and metallicity and are close in age and is therefore a so-called " solar twin " (English. Sun Gemini ). In 2015, the discovery of a roughly Jupiter-sized exoplanet around the star was announced, orbiting HIP 11915 at about the same distance as Jupiter from the sun.

With an apparent magnitude of 8.58 mag, the star is far too faint to be seen with the naked eye. However, it can be observed with binoculars.

Planetary system

HIP 11915 is one of a series of around 60 stars classified as “solar twins” that have been investigated since 2011 as part of a search program for exoplanets around such stars with the Échelle spectrograph HARPS of the European Southern Observatory (ESO). In July 2015, an international team of astronomers led by Brazilian scientists announced evidence of a planet orbiting HIP 11915. The discovery was made using the radial velocity method . However, a stellar cycle of activity as an alternative explanation (instead of a planet) for the results of the radial velocity measurements is not completely ruled out by the explorers.

According to the model calculation of the discovery team, the planet with the designation HIP 11915 b has a minimum mass of around 0.99 Jupiter's masses, a major orbit half-axis of around 4.8  AU , and an orbital period of around 3830 days. The planet can thus be described as a “Jupiter twin”, which has a mass comparable to that of Jupiter in the solar system and orbits its central star at a similar distance as Jupiter orbits the sun.

The results of the radial velocity measurements rule out the existence of another gas giant within an orbital radius of 1000 days around HIP 11915, which leaves open the possibility of terrestrial planets orbiting further inward . The HIP 11915 planetary system is one of the most promising candidates for a planetary system similar to our own , according to an ESO press release .

Individual evidence

1. ↑ ^{a b c d e} SIMBAD: HIP 11915. Accessed July 17, 2015 . 
2. ↑ ^{a b c} The Extrasolar Planets Encyclopaedia: Planet HIP 11915. Retrieved July 17, 2015 . 
3. ↑ ^{a b c d e f g h} M. Bedell, J. Melendez, J. Bean, I. Ramirez, M. Asplund, among others: The Solar Twin Planet Search II. A Jupiter twin around a solar twin . arxiv : 1507.03998 .
4. ↑ ^{a b c} European Southern Observatory: Jupiter twin discovered around solar twin. Retrieved July 17, 2015 . 
5. ↑ ^{a b} Stars and Space from July 15, 2015: A twin of Jupiter orbits a twin of the sun. Retrieved July 17, 2015 . 
6. ↑ European Southern Observatory: The star HIP 11915 in the constellation Cetus. Retrieved July 17, 2015 . 
7. ^ I. Ramirez, J. Melendez, J. Bean, among others: The Solar Twin Planet Search. I. Fundamental parameters of the stellar sample . arxiv : 1408.4130 .