HIP 13044: Difference between revisions
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'''HIP 13044''' is a red [[horizontal branch|horizontal-branch]] star about 2,300 [[light year]]s (700 [[parsec|pc]]) from Earth in the constellation [[Fornax]].<ref name="Setiawan2010" /><ref name="Than2010-11-18" /> The star is part of the [[Helmi stream]], a former [[dwarf galaxy]] that merged with the [[Milky Way]] between six and nine billion years ago.<ref name=Klement2010 /> As a result, HIP 13044 circles the galactic center at a highly irregular orbit with respect to the [[galactic plane]]. HIP 13044 is slightly less massive than the Sun, but is approximately seven times its size. The star, which is estimated to be at least nine billion years old, has passed the [[red giant|red-giant]] phase. The relatively fast rotation of the star may be due to having engulfed one or more planets during the red-giant phase.<ref name=Klement2010 /> |
'''HIP 13044''' is a red [[horizontal branch|horizontal-branch]] star about 2,300 [[light year]]s (700 [[parsec|pc]]) from Earth in the constellation [[Fornax]].<ref name="Setiawan2010" /><ref name="Than2010-11-18" /> The star is part of the [[Helmi stream]], a former [[dwarf galaxy]] that merged with the [[Milky Way]] between six and nine billion years ago.<ref name=Klement2010 /> As a result, HIP 13044 circles the galactic center at a highly irregular orbit with respect to the [[galactic plane]]. HIP 13044 is slightly less massive than the Sun, but is approximately seven times its size. The star, which is estimated to be at least nine billion years old, has passed the [[red giant|red-giant]] phase. The relatively fast rotation of the star may be due to having engulfed one or more planets during the red-giant phase.<ref name=Klement2010 /> |
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==Observational history== |
==Observational history== |
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A science team from the [[Max Planck Institute for Astronomy]] first observed HIP 13044 using [[Fiber-fed Extended Range Optical Spectrograph]] (FEROS) at the [[European Southern Observatory]]'s [[La Silla Observatory]] in Chile. The first follow-up led to the collection of 36 [[radial velocity]] measurements taken between September 2009 and July 2010.<ref name=Klement2010 /> |
A science team from the [[Max Planck Institute for Astronomy]] first observed HIP 13044 using [[Fiber-fed Extended Range Optical Spectrograph]] (FEROS) at the [[European Southern Observatory]]'s [[La Silla Observatory]] in Chile. The first follow-up led to the collection of 36 [[radial velocity]] measurements taken between September 2009 and July 2010.<ref name=Klement2010 /> |
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==Characteristics== |
==Characteristics== |
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HIP 13044 is an [[Stellar classification#Class F|F-type]] star located approximately 701 [[parsec]]s (2,286 [[light year]]s) away from Earth in the [[Helmi stream]]<ref name=Klement2010 />—a group of low metallicity stars moving with large velocities relative to the Sun. The star follows an eccentric galactic orbit, with a distance from the galactic center ranging from 7 to 16 [[kiloparsec]]s.<ref name="HIP 13044 b at Exoplanet.eu" /> The orbit does not lie in [[galactic plane]], and can reach distances as high as 13 kpc above it. This indicates that it once was part of a satellite galaxy of the [[Milky Way]], which was disrupted 6–9 billion years ago.<ref name="Setiawan2010"/> The star itself is estimated to be at least nine billion years old.<ref name="HIP 13044 b at Exoplanet.eu" /> |
HIP 13044 is an [[Stellar classification#Class F|F-type]] star located approximately 701 [[parsec]]s (2,286 [[light year]]s) away from Earth in the [[Helmi stream]]<ref name=Klement2010 />—a group of low metallicity stars moving with large velocities relative to the Sun. The star follows an eccentric galactic orbit, with a distance from the galactic center ranging from 7 to 16 [[kiloparsec]]s.<ref name="HIP 13044 b at Exoplanet.eu" /> The orbit does not lie in [[galactic plane]], and can reach distances as high as 13 kpc above it. This indicates that it once was part of a satellite galaxy of the [[Milky Way]], which was disrupted 6–9 billion years ago.<ref name="Setiawan2010"/> The star itself is estimated to be at least nine billion years old.<ref name="HIP 13044 b at Exoplanet.eu" /> |
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Revision as of 11:34, 10 February 2015
| Observation data Epoch J2000.0 [1] Equinox J2000.0 [1] | |
|---|---|
| Constellation | Fornax |
| Right ascension | 02h 47m 37.442s [1] |
| Declination | −36° 06′ 27.05″ [1] |
| Astrometry | |
| Radial velocity (Rv) | 300[2] km/s |
| Distance | 701 ± 20[2] pc |
| Characteristics | |
| Spectral type | F2III [1] |
| Apparent magnitude (V) | 9.982[1] |
| Details | |
| Mass | 0.8 ± 0.1[2] M☉ |
| Radius | 6.7 ± 0.3[2] R☉ |
| Temperature | 6025 ± 63[2] K |
| Metallicity | −2.09 ± 0.26 [Fe/H][2] |
| Rotation | 5.53 ± 0.73 d[2] |
| Other designations | |
HIP 13044 is a red horizontal-branch star about 2,300 light years (700 pc) from Earth in the constellation Fornax.[2][3] The star is part of the Helmi stream, a former dwarf galaxy that merged with the Milky Way between six and nine billion years ago.[4] As a result, HIP 13044 circles the galactic center at a highly irregular orbit with respect to the galactic plane. HIP 13044 is slightly less massive than the Sun, but is approximately seven times its size. The star, which is estimated to be at least nine billion years old, has passed the red-giant phase. The relatively fast rotation of the star may be due to having engulfed one or more planets during the red-giant phase.[4]
Observational history
A science team from the Max Planck Institute for Astronomy first observed HIP 13044 using Fiber-fed Extended Range Optical Spectrograph (FEROS) at the European Southern Observatory's La Silla Observatory in Chile. The first follow-up led to the collection of 36 radial velocity measurements taken between September 2009 and July 2010.[4]
The team also used photometric data that had been passively collected by and publicly released into the archive of the SuperWASP collaboration, which had been observing the region where the star was located. In this data, HIP 13044 was found to oscillate; the signal was blocked roughly every sixteen days. Analysis of the SuperWASP and FEROS data led to the supposed discovery of the planet HIP 13044 b,[4] although this claim was later refuted.
Characteristics
HIP 13044 is an F-type star located approximately 701 parsecs (2,286 light years) away from Earth in the Helmi stream[4]—a group of low metallicity stars moving with large velocities relative to the Sun. The star follows an eccentric galactic orbit, with a distance from the galactic center ranging from 7 to 16 kiloparsecs.[5] The orbit does not lie in galactic plane, and can reach distances as high as 13 kpc above it. This indicates that it once was part of a satellite galaxy of the Milky Way, which was disrupted 6–9 billion years ago.[2] The star itself is estimated to be at least nine billion years old.[5]
HIP 13044 is fairly evolved core helium burning star, which has already passed the red-giant phase of its evolution.[2] It lies near the blue end of the red horizontal branch bordering the instability strip.[2] Its surface temperature is about 6025 K and its radius is about 6.7 solar radii. The star is also estimated to be 0.8 solar masses.[5] Having the rotation period of 5–6 days, HIP 13044 is a fast rotating star for its type. It is possible that this is because it may have swallowed planets during its red-giant phase.[3]
The star has an apparent magnitude of 9.94. It cannot be seen with the unaided eye.[5]
Claims of a planetary system
In 2010, it was announced that a giant planet in a 16.2-day orbit had been discovered by the radial velocity measurements. This would have had implications for planet formation in metal-poor systems and survival of planets being engulfed by expanded giant stars.[4] Subsequent analysis of the data revealed problems with the detection: for example an erroneous barycentric correction had been applied (the same error had also led to claims of planets around HIP 11952 that were subsequently refuted). After applying the corrections, there is no evidence for a planet orbiting the star.[6]
References
- ^ a b c d e "SIMBAD query result". Retrieved 2010-11-19.
- ^ a b c d e f g h i j k Setiawan, Johny; et al. (2010). "A Giant Planet Around a Metal-poor Star of Extragalactic Origin". Science. 330 (6011): 1642–1644. arXiv:1011.6376. Bibcode:2010Sci...330.1642S. doi:10.1126/science.1193342. PMID 21097905.
- ^ a b Than, Ker (2010-11-18). "New Planet Discovered: First Spotted Outside Our Galaxy". NationalGeographic.com. National Geographic Society. Retrieved 2010-11-19.
- ^ a b c d e f
Klement, R.; Setiawan, J.; Thomas Henning; Hans-Walter Rix; Boyke Rochau; Jens Rodmann; Tim Schulze-Hartung; MPIA Heidelberg; ESTEC (2011). "The visitor from an ancient galaxy: A planetary companion around an old, metal-poor red horizontal branch star". The Astrophysics of Planetary Systems: Formation, Structure, and Dynamical Evolution. IAU Symposium. Vol. 276. Proceedings of the International Astronomical Union. pp. 121–125. arXiv:1011.4938. Bibcode:2011IAUS..276..121K. doi:10.1017/S1743921311020059.
{{cite conference}}: Unknown parameter|booktitle=ignored (|book-title=suggested) (help) - ^ a b c d "Notes for Planet HIP 13044 b". exoplanet.eu. Retrieved 2010-11-22.
- ^ Jones, M. I.; Jenkins, J. S. (2014). "No evidence of the planet orbiting the extremely metal-poor extragalactic star HIP 13044". Astronomy & Astrophysics. 562: id.A129. arXiv:1401.0517. Bibcode:2014A&A...562A.129J. doi:10.1051/0004-6361/201322132.
