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U Camelopardalis: Difference between revisions

Coordinates: Sky map 03h 41m 48.17393s, +62° 38′ 54.3906″
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[[File:UCamLightCurve.png|thumb|left|A [[Photometric_system#Photometric_letters|visual band]] [[light curve]] for U Camelopardalis, plotted from AAVSO data<ref name="aavso"/>]]
[[File:UCamLightCurve.png|thumb|left|A [[Photometric_system#Photometric_letters|visual band]] [[light curve]] for U Camelopardalis, plotted from AAVSO data<ref name="aavso"/>]]
U Camelopardalis is a [[carbon star]]. These types of stars have greater levels of [[carbon]] in their atmospheres than [[oxygen]], which means they form carbon compounds that make the star appear strikingly red. U Camelopardalis is nearly 4 magnitudes fainter at blue wavelengths than in the centre of the visual range. In the [[infra red]] [[K band (infrared)|K band]] it has an apparent magnitude of 0.37.<ref name=knapp/> Its brightness varies without a dominant period and it is classified as [[Semiregular variable star|semi-regular]], although a period of 400 days has been published.<ref name=knapp>{{cite journal|bibcode=2003A&A...403..993K|title=Reprocessing the Hipparcos data of evolved stars. III. Revised Hipparcos period-luminosity relationship for galactic long-period variable stars|journal=Astronomy and Astrophysics|volume=403|issue=3|last1=Knapp|first1=G. R.|last2=Pourbaix|first2=D.|last3=Platais|first3=I.|last4=Jorissen|first4=A.|year=2003|pages=993–1002|doi=10.1051/0004-6361:20030429|arxiv = astro-ph/0301579 |s2cid=5603380}}</ref> In the [[UBV photometric system|V photometric band]] the brightness varies by around half a magnitude,<ref name=adelman>{{cite journal|bibcode=2001BaltA..10..589A|title=Stars with the Largest Hipparcos Photometric Amplitudes|journal=Baltic Astronomy|volume=10|page=589|last1=Adelman|first1=Saul J.|year=2001}}</ref> but the amplitude is nearly two magnitudes at blue wavelengths.<ref name=gcvs/> The maximum visual magnitude has been given as 7.2.<ref name=olson/>
U Camelopardalis is a [[carbon star]]. These types of stars have greater levels of [[carbon]] in their atmospheres than [[oxygen]], which means they form carbon compounds that make the star appear strikingly red. U Camelopardalis is nearly 4 magnitudes fainter at blue wavelengths than in the centre of the visual range. In the [[infrared]] [[K band (infrared)|K band]] it has an apparent magnitude of 0.37.<ref name=knapp/> Its brightness varies without a dominant period and it is classified as [[Semiregular variable star|semi-regular]], although a period of 400 days has been published.<ref name=knapp>{{cite journal|bibcode=2003A&A...403..993K|title=Reprocessing the Hipparcos data of evolved stars. III. Revised Hipparcos period-luminosity relationship for galactic long-period variable stars|journal=Astronomy and Astrophysics|volume=403|issue=3|last1=Knapp|first1=G. R.|last2=Pourbaix|first2=D.|last3=Platais|first3=I.|last4=Jorissen|first4=A.|year=2003|pages=993–1002|doi=10.1051/0004-6361:20030429|arxiv = astro-ph/0301579 |s2cid=5603380}}</ref> In the [[UBV photometric system|V photometric band]] the brightness varies by around half a magnitude,<ref name=adelman>{{cite journal|bibcode=2001BaltA..10..589A|title=Stars with the Largest Hipparcos Photometric Amplitudes|journal=Baltic Astronomy|volume=10|page=589|last1=Adelman|first1=Saul J.|year=2001}}</ref> but the amplitude is nearly two magnitudes at blue wavelengths.<ref name=gcvs/> The maximum visual magnitude has been given as 7.2.<ref name=olson/>


The shell of gas surrounding U Camelopardalis was imaged by the [[Hubble Space Telescope]] in 2012, showing a nearly perfect sphere of gas surrounding the star.<ref>{{cite news|title=Red Giant Blows a Bubble|url=http://www.spacetelescope.org/images/potw1227a/|access-date=18 February 2017|newspaper=ESA/Hubble Picture of the Week}}</ref>
The shell of gas surrounding U Camelopardalis was imaged by the [[Hubble Space Telescope]] in 2012, showing a nearly perfect sphere of gas surrounding the star.<ref>{{cite news|title=Red Giant Blows a Bubble|url=http://www.spacetelescope.org/images/potw1227a/|access-date=18 February 2017|newspaper=ESA/Hubble Picture of the Week}}</ref>

Revision as of 14:33, 16 September 2022

U Camelopardalis

U Camelopardalis is a bright star surrounded by a tenuous shell of gas. Its atmosphere contains more carbon than oxygen.
Observation data
Epoch J2000      Equinox J2000
Constellation Camelopardalis
Right ascension 03h 41m 48.17393s[1]
Declination +62° 38′ 54.3906″[1]
Apparent magnitude (V) 7.55[2]
Characteristics
Spectral type C-N55.5 (MS4)[3]
U−B color index +3.50[2]
B−V color index +1.95[2]
Variable type SRb[4]
Astrometry
Radial velocity (Rv)-3.00[5] km/s
Proper motion (μ) RA: 3.50[1] mas/yr
Dec.: -3.62[1] mas/yr
Parallax (π)1.03 ± 0.59 mas[1]
Distance530[6] pc
Absolute magnitude (MV)−2.4 (max)[7]
Details
Luminosity8,472[8] L☉
Temperature3,000[9] K
Other designations
U Cam, BD+62° 596, HD 22611, HIP 17257, SAO 12870, GC 4371
Database references
SIMBADdata

U Camelopardalis is a semiregular variable star in the constellation Camelopardalis. Based on parallax measurements made by the Hipparcos spacecraft, it is located about 3,000 light-years (1,000 parsecs) away from the Earth.[1] Its apparent visual magnitude is about 8, which is dim enough that it cannot be seen with the unaided eye.

The spectral type of U Camelopardalis in the revised MK system is C-N5, which indicates a classical carbon star spectrum approximately corresponding to late K or early M.[10] The C2 index is 5.5 which is typical of a C-N star.[11] It is also given an alternative spectral type of MS4, indicating a star similar to an M4 class but with somewhat enhanced ZrO bands.[3] The spectral type may vary between C3,9 and C6,4e.[4]

A visual band light curve for U Camelopardalis, plotted from AAVSO data[12]

U Camelopardalis is a carbon star. These types of stars have greater levels of carbon in their atmospheres than oxygen, which means they form carbon compounds that make the star appear strikingly red. U Camelopardalis is nearly 4 magnitudes fainter at blue wavelengths than in the centre of the visual range. In the infrared K band it has an apparent magnitude of 0.37.[13] Its brightness varies without a dominant period and it is classified as semi-regular, although a period of 400 days has been published.[13] In the V photometric band the brightness varies by around half a magnitude,[14] but the amplitude is nearly two magnitudes at blue wavelengths.[4] The maximum visual magnitude has been given as 7.2.[7]

The shell of gas surrounding U Camelopardalis was imaged by the Hubble Space Telescope in 2012, showing a nearly perfect sphere of gas surrounding the star.[15]

U Cameloparadlis has a 10th magnitude companion 308" away. It is a B8 main sequence star, hotter but less luminous than U Cam itself. They are not thought to be physically associated.[7]

References

  1. ^ a b c d e f van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
  2. ^ a b c Nicolet, B. (1978). "Catalogue of homogeneous data in the UBV photoelectric photometric system". Astronomy and Astrophysics. 34: 1–49. Bibcode:1978A&AS...34....1N.
  3. ^ a b Barnbaum, Cecilia; Stone, Remington P. S.; Keenan, Philip C. (1996). "A Moderate-Resolution Spectral Atlas of Carbon Stars: R, J, N, CH, and Barium Stars". Astrophysical Journal Supplement. 105: 419. Bibcode:1996ApJS..105..419B. doi:10.1086/192323.
  4. ^ a b c Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
  5. ^ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
  6. ^ Guandalini, R.; Busso, M.; Ciprini, S.; Silvestro, G.; Persi, P. (2006). "Infrared photometry and evolution of mass-losing AGB stars. I. Carbon stars revisited". Astronomy and Astrophysics. 445 (3): 1069–1080. arXiv:astro-ph/0509739. Bibcode:2006A&A...445.1069G. doi:10.1051/0004-6361:20053208. S2CID 16797565.
  7. ^ a b c Olson, B. I.; Richer, H. B. (1975). "The absolute magnitudes of carbon stars - Carbon stars in binary systems". Astrophysical Journal. 200: 88. Bibcode:1975ApJ...200...88O. doi:10.1086/153763.
  8. ^ Bergeat, J.; Chevallier, L. (2005). "The mass loss of C-rich giants". Astronomy and Astrophysics. 429: 235–246. arXiv:astro-ph/0601366. Bibcode:2005A&A...429..235B. doi:10.1051/0004-6361:20041280. S2CID 56424665.
  9. ^ Tanaka, Masuo; Letip, Ahmatjan; Nishimaki, Yuichirou; Yamamuro, Tomoyasu; Motohara, Kentaro; Miyata, Takashi; Aoki, Wako (2007). "Near-Infrared Spectra of 29 Carbon Stars: Simple Estimates of Effective Temperature". Publications of the Astronomical Society of Japan. 59 (5): 939. Bibcode:2007PASJ...59..939T. doi:10.1093/pasj/59.5.939.
  10. ^ Keenan, Philip C. (1993). "Revised MK spectral classification of the red carbon stars". Astronomical Society of the Pacific. 105: 905. Bibcode:1993PASP..105..905K. doi:10.1086/133252.
  11. ^ Keenan, P. C.; Morgan, W. W. (1941). "The Classification of the Red Carbon Stars". The Astrophysical Journal. 94: 501. Bibcode:1941ApJ....94..501K. doi:10.1086/144356.
  12. ^ "Download Data". aavso.org. AAVSO. Retrieved 1 October 2021.
  13. ^ a b Knapp, G. R.; Pourbaix, D.; Platais, I.; Jorissen, A. (2003). "Reprocessing the Hipparcos data of evolved stars. III. Revised Hipparcos period-luminosity relationship for galactic long-period variable stars". Astronomy and Astrophysics. 403 (3): 993–1002. arXiv:astro-ph/0301579. Bibcode:2003A&A...403..993K. doi:10.1051/0004-6361:20030429. S2CID 5603380.
  14. ^ Adelman, Saul J. (2001). "Stars with the Largest Hipparcos Photometric Amplitudes". Baltic Astronomy. 10: 589. Bibcode:2001BaltA..10..589A.
  15. ^ "Red Giant Blows a Bubble". ESA/Hubble Picture of the Week. Retrieved 18 February 2017.
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