Astronomy:UU Aurigae

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Short description: Star in the constellation of Auriga
UU Aurigae
Auriga constellation map.svg
Red circle.svg
Location of UU Aurgae (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Auriga
Right ascension  06h 36m 32.83710s[1]
Declination +38° 26′ 43.8190″[1]
Apparent magnitude (V) 4.9–7.0[2]
Characteristics
Spectral type C5,3-C7,4(N3)[2]
B−V color index 2.61
R−I color index 1.43
Variable type SRb[2]
Astrometry
Radial velocity (Rv)13.40[3] km/s
Proper motion (μ) RA: 0.500[1] mas/yr
Dec.: −19.758[1] mas/yr
Parallax (π)2.0387 ± 0.1661[1] mas
Distance341[4] pc
Absolute magnitude (MV)−3.65[5]
Details
Radius370[6] R☉
Luminosity16,443[7] L☉
Temperature2,760[7] K
Other designations
GC 8581, SAO 59280, BD+38° 1539, HD 46687, HIP 31579, HR 2405[8]
Database references
SIMBADdata

UU Aurigae is a carbon star in the constellation Auriga. It is approximately 341 parsecs (1,110 light-years) from Earth.

Description

UU Aurigae in optical light

UU Aurigae is a carbon-rich asymptotic giant branch star. The spectral type listed in the General Catalogue of Variable Stars (GCVS) is C5,3-C7,4(N3). The N3 refers back to an older type of classification where carbon stars were given spectral types of N or R, although the numeric index was correlated more with the strength of the carbon chemistry rather than temperature. The C5 to C7 indicates various classifications using the newer Morgan-Keenan system where the numeric index corresponds better to the temperature of the star. C5 to C7 types are approximately equivalent to early-M stars. The second numeric index, 3 or 4 for UU Aurigae indicates the strength of the Swan bands in the spectrum, on a scale of 1 to 5.[9] Using the more modern revised Morgan-Keenan scheme, a spectral type of C-N5- C2 6- has been published, with the C-N5 indicating an N-type carbon star with a temperature index of 5-, and a Swan band strength of 6- on a scale of 1 to 8.[10]

A 28 year long visual band light curve for UU Aurigae, adapted from Howarth (2001)[11]

UU Aurigae is classified as a semiregular variable of type SRb, indicating it is a giant star with poorly defined variations. Its brightness varies from magnitude +4.9 to +7.0 in visual apparent magnitude.[2] The period is given in the GCVS as 441 days, but there is also a strong variation with a period of 235 days.[12] Using British Astronomical Association observations from 1971 to 1998, the periods are calculated as 439.4 and 233.1 days.[13]

The angular diameter of UU Aurigae has been measured at 12.07 ± 0.22 mas using very-long-baseline interferometry (VLBI).[14] Around the star is a shell of dust made up largely of amorphous carbon and silicon carbide (SiC), with the SiC appearing at three times the star's radius and the amorphous carbon at nine times its radius. Further out is a carbon-rich shell at 300 stellar radii and two oxygen-rich shells even further away.[15] UU Aurigae also has a bow shock 0.14 parsec wide, created by its motion through the interstellar medium.[4]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  2. ↑ 2.0 2.1 2.2 2.3 Samus, N. N. 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. 
  3. ↑ Gontcharov, G. A (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759–771. doi:10.1134/S1063773706110065. Bibcode: 2006AstL...32..759G. 
  4. ↑ 4.0 4.1 Cox, N. L. J; Kerschbaum, F; Van Marle, A.-J; Decin, L; Ladjal, D; Mayer, A; Groenewegen, M. A. T; Van Eck, S et al. (2012). "A far-infrared survey of bow shocks and detached shells around AGB stars and red supergiants". Astronomy & Astrophysics 537: A35. doi:10.1051/0004-6361/201117910. Bibcode: 2012A&A...537A..35C. 
  5. ↑ Alksnis, A; Balklavs, A; Dzervitis, U; Eglitis, I (1998). "Absolute magnitudes of carbon stars from HIPPARCOS parallaxes". Astronomy and Astrophysics 338: 209. Bibcode: 1998A&A...338..209A. 
  6. ↑ Luttermoser, Donald G.; Brown, Alexander (1992). "A VLA 3.6 centimeter survey of N-type carbon stars". Astrophysical Journal 384: 634. doi:10.1086/170905. Bibcode: 1992ApJ...384..634L. 
  7. ↑ 7.0 7.1 Bergeat, J; Knapik, A; Rutily, B (2002). "Carbon-rich giants in the HR diagram and their luminosity function". Astronomy and Astrophysics 390 (3): 967. doi:10.1051/0004-6361:20020525. Bibcode: 2002A&A...390..967B. 
  8. ↑ "V* UU Aur". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=V%2A+UU+Aur. 
  9. ↑ Keenan, P. C. (1993). "Revised MK Spectral Classification of the Red Carbon Stars". Publications of the Astronomical Society of the Pacific 105: 905. doi:10.1086/133252. Bibcode: 1993PASP..105..905K. 
  10. ↑ 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. doi:10.1086/192323. Bibcode: 1996ApJS..105..419B. 
  11. ↑ Howarth, J. J. (June 2001). "The semiregular variable UU Aurigae - analysis in adversity?". Journal of the British Astronomical Association 111: 150–152. Bibcode: 2001JBAA..111..150H. https://ui.adsabs.harvard.edu/abs/2001JBAA..111..150H. Retrieved 1 November 2021. 
  12. ↑ Kiss, L. L; Szatmáry, K; Cadmus, R. R; Mattei, J. A (1999). "Multiperiodicity in semiregular variables. I. General properties". Astronomy and Astrophysics 346: 542. Bibcode: 1999A&A...346..542K. 
  13. ↑ Howarth, J. J (2001). "The semiregular variable UU Aurigae ( analysis in adversity?". Journal of the British Astronomical Association 111: 150. Bibcode: 2001JBAA..111..150H. 
  14. ↑ Quirrenbach, A; Mozurkewich, D; Hummel, C. A; Buscher, D. F; Armstrong, J. T (1994). "Angular diameters of the carbon stars UU Aurigae, Y Canum Venaticorum, and TX PISCIUM from optical long-baseline interferometry". Astronomy and Astrophysics 285: 541. Bibcode: 1994A&A...285..541Q. 
  15. ↑ Bagnulo, S; Skinner, C. J; Doyle, J. G; Camphens, M (1997). "Carbon stars with detached dust shells: The circumstellar envelope of UU Aurigae". Astronomy and Astrophysics 321: 605. Bibcode: 1997A&A...321..605B. 

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