Ross 248

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Ross 248
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension 23h 41m 54.99s[1]
Declination +44° 10′ 40.8″[1]
Apparent magnitude (V) 12.29[2]
Characteristics
Spectral type M6 V[3]
Apparent magnitude (J) 6.9[2]
U−B color index +1.48[2]
B−V color index +1.92[2]
Variable type Flare star
Astrometry
Radial velocity (Rv) –81[4] km/s
Proper motion (μ) RA: +111[5] mas/yr
Dec.: –1,584[5] mas/yr
Parallax (π) 316.72 ± 0.72[6] mas
Distance 10.30 ± 0.02 ly
(3.157 ± 0.007 pc)
Absolute magnitude (MV) 14.79[7]
Details
Mass 0.136[3] M
Radius 0.16[8] R
Luminosity 0.0018[9] L
Surface gravity (log g) 5.12[10] cgs
Temperature 2,799[10] K
Rotational velocity (v sin i) 1.2[3] km/s
Other designations
HH Andromedae, HH And, 2MASS J23415498+4410407, G 171-010, GCTP 5736.00, GJ 905, LHS 549.[2]

Ross 248 (HH Andromedae) is a small star located approximately 10.30 light-years (3.16 parsecs)[11] from Earth in the northern constellation of Andromeda. Despite its proximity to the Earth, this star is too dim to be seen with the naked eye.[12] Ross 248 was first catalogued by Frank Elmore Ross in 1926 with his second list of proper motion stars.[13]

This star has about 12% of the Sun's mass and 16% of the Sun's radius, but only 0.2% of the Sun's luminosity. It has a stellar classification of M6 V,[3] which indicates it is a type of main sequence star known as a red dwarf. This is a flare star that occasionally increases in luminosity.[14] With high probability there appears to be a long-term cycle of variability with a period of 4.2 years. This variability causes the star to range in visual magnitude from 12.23 to 12.34.[15] In 1950, this became the first star to have a small variation in magnitude attributed to spots on its photosphere.[16]

Long term observations of this star by the Sproul Observatory show no astrometric perturbations by an unseen companion.[16] The proper motion of this star was examined for a brown dwarf or stellar companion orbiting at a wide separation (between 100–1400 AU) but none was found.[17] A search for a faint companion using the Hubble Space Telescope Wide Field Planetary Camera revealed nothing,[7] nor did a search with near-infrared speckle interferometry.[18] However, none of these searches rule out a companion that is smaller than the detection minima.

Distances of the nearest stars from 20,000 years ago until 80,000 years in the future

The space velocity components of this star in the galactic coordinate system are [U, V, W] = [–32.9 ± 0.7, –74.3 ± 1.3, 0.0 ± 1.4] km/s.[11] The trajectory of Ross 248 will bring it closer to the Solar System in the future. In 1993 Matthews suggested that in about 33,000 years Ross 248 would be the closest star to the Sun, approaching within a minimum distance of 3.024 light-years (0.927 parsecs) in 36,000 years.[19] However, it will recede thereafter and will again be further from the Sun than Proxima Centauri 42,000 years from now.[19]

The spacecraft Voyager 2 is traveling on a path headed roughly in the direction of Ross 248, and is expected to come within 1.76 light-years (0.54 parsecs) of the star in 40,176 years.[20] A spacecraft that escaped the Solar System with a velocity of 25.4 km/s would reach this star 37,000 years from now when the star is just past its nearest approach. By comparison, the Voyager 1 has an escape velocity of 16.6 km/s.[21]

Distance[edit]

Ross 248 distance estimates

Source Parallax, mas Distance, pc Distance, ly Distance, Pm Ref.
Woolley et al. (1970) 318 ± 4 3.14 ± 0.04 10.26 ± 0.13 97 ± 1.2 [22]
Gliese & Jahreiß (1991) 315.6 ± 1.6 3.169 ± 0.016 10.33 ± 0.05 97.8 ± 0.5 [23]
van Altena et al. (1995) 316.0 ± 1.1 3.165 ± 0.011 10.32 ± 0.04 97.6 ± 0.3 [24]
Gatewood (2008) (MAP-based study) 315.67 ± 1.35 3.168+0.014
−0.013
10.33 ± 0.04 97.8 ± 0.4 [6]
Gatewood (2008) (MAC-based study) 316.72 ± 0.72 3.157 ± 0.007 10.298 ± 0.023 97.43 ± 0.22 [6]
RECONS TOP100 (2012) 316.37 ± 0.55[note 1] 3.161+0.006
−0.005
10.309 ± 0.018 97.53 ± 0.17 [25][6]

Non-trigonometric distance estimates are marked in italic. The best estimate is marked in bold.

Field star[edit]

This star is located nearly along the line of sight to Ross 248, but it is not physically associated.

Name PLX 5735
Right ascension 23h 41m 54s
Declination +44° 14′ 00″
Apparent magnitude (V) 12.6
Spectral type A5
Database references Simbad

See also[edit]

References[edit]

  1. ^ a b Cutri, R. M. et al. (June 2003). 2MASS All Sky Catalog of point sources. NASA/IPAC. Bibcode:2003tmc..book.....C. 
  2. ^ a b c d e "V* HH And – Flare Star". SIMBAD Astronomical Object Database. Centre de Données astronomiques de Strasbourg. Retrieved 2009-09-06. 
  3. ^ a b c d Pinfield, Y. (October 2009), "Rotational Velocities for M Dwarfs", The Astrophysical Journal 704 (2): 975–988, arXiv:0908.4092, Bibcode:2009ApJ...704..975J, doi:10.1088/0004-637X/704/2/975 
  4. ^ Wilson, Ralph Elmer (1953). General Catalogue of Stellar Radial Velocities. Washington: Carnegie Institution of Washington. Bibcode:1953QB901.W495..... 
  5. ^ a b Shara, Michael M (March 2005). "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)". The Astronomical Journal 129 (3): 1483–1522. arXiv:astro-ph/0412070. Bibcode:2005AJ....129.1483L. doi:10.1086/427854. 
  6. ^ a b c d Gatewood, George (2008). "Astrometric Studies of Aldebaran, Arcturus, Vega, the Hyades, and Other Regions". The Astronomical Journal 136 (1): 452–460. Bibcode:2008AJ....136..452G. doi:10.1088/0004-6256/136/1/452.  edit
  7. ^ a b Schroeder, Daniel J. et al. (2000). "A Search for Faint Companions to Nearby Stars Using the Wide Field Planetary Camera 2". The Astronomical Journal 119: 906–922. Bibcode:2000AJ....119..906S. doi:10.1086/301227. 
  8. ^ Johnson, H. M.; Wright, C. D. (November 1983). "Predicted infrared brightness of stars within 25 parsecs of the Sun". Astrophysical Journal Supplement Series 53: 643–711. Bibcode:1983ApJS...53..643J. doi:10.1086/190905.  See p. 705.
  9. ^ West, Frederick R. (June 1999). "Monitoring Nearby Stars for Transits by Extrasolar Jovial Planets, II: Transits of M-Type (Red) Dwarf Stars by Close Extrasolar Giant (Jovian) Planets". The Journal of the American Association of Variable Star Observers 27 (1): 77–78. Bibcode:1999JAVSO..27...77W. 
  10. ^ a b Cenarro, A. J. et al. (2007). "Medium-resolution Isaac Newton Telescope Library of Empirical Spectra – II. The Stellar Atmospheric Parameters". Monthly Notices of the Royal Astronomical Society 374 (2): 664–690. arXiv:astro-ph/0611618. Bibcode:2007MNRAS.374..664C. doi:10.1111/j.1365-2966.2006.11196.x. 
  11. ^ a b Leggett, S. K. (September 1992). "Infrared colors of low-mass stars". Astrophysical Journal Supplement Series 82 (1): 351–394. Bibcode:1992ApJS...82..351L. doi:10.1086/191720. 
  12. ^ Routray, Sudhir K. (2004), Light Years Away: The Whole Creation at a Glance, iUniverse, p. 31, ISBN 0-595-33582-9 
  13. ^ Ross, Frank E. (February 1926). "New proper-motion stars, (second list)". Astronomical Journal 36 (856): 124–128. Bibcode:1926AJ.....36..124R. doi:10.1086/104699. 
  14. ^ Poveda, Arcadio; Allen, Christine; Herrera, Miguel Angel (1996). "Workshop on Colliding Winds in Binary Stars to Honor Jorge Sahade" 5. Universidad Nacional Autonoma de Mexico. pp. 16–20.  |chapter= ignored (help)
  15. ^ Weis, Edward W. (March 1994). "Long term variability in dwarf M stars". Astronomical Journal 107 (3): 1135–1140. Bibcode:1994AJ....107.1135W. doi:10.1086/116925. 
  16. ^ a b Lippincott, S. L. (July 1978). "Astrometric search for unseen stellar and sub-stellar companions to nearby stars and the possibility of their detection". Space Science Reviews 22: 153–189. Bibcode:1978SSRv...22..153L. doi:10.1007/BF00212072. 
  17. ^ Hinz, Joannah L. et al. (February 2002). "A Near-Infrared, Wide-Field, Proper-Motion Search for Brown Dwarfs". The Astronomical Journal 123 (4): 2027–2032. arXiv:astro-ph/0201140. Bibcode:2002AJ....123.2027H. doi:10.1086/339555. 
  18. ^ McCarthy, D. W., Jr. (September 1997). "A search for companions to nearby southern M dwarfs with near-infrared speckle interferometry". Astronomy and Astrophysics 325: 159–166. Bibcode:1997A&A...325..159L. 
  19. ^ a b Matthews, R. A. J. (Spring 1994). "The Close Approach of Stars in the Solar Neighborhood". Quarterly Journal of the Royal Astronomical Society 35 (1): 1. Bibcode:1994QJRAS..35....1M. 
  20. ^ Littmann, Mark (2004). Planets Beyond: Discovering the Outer Solar System. Courier Dover Publications. p. 167. ISBN 0-486-43602-0. 
  21. ^ West, F. R. (March 1985). "A Suggested Future Space Mission to the Low-Luminosity Star Ross 248=Gliese 905". Bulletin of the American Astronomical Society 17: 552. Bibcode:1985BAAS...17..552W. 
  22. ^ Woolley R.; Epps E. A.; Penston M. J.; Pocock S. B. (1970). "Woolley 905". Catalogue of stars within 25 parsecs of the Sun. Retrieved 2014-10-20. 
  23. ^ Gliese, W. and Jahreiß, H. (1991). "Gl 905". Preliminary Version of the Third Catalogue of Nearby Stars. Retrieved 2014-10-20. 
  24. ^ Van Altena W. F., Lee J. T., Hoffleit E. D. (1995). "GCTP 5736". The General Catalogue of Trigonometric Stellar Parallaxes, Fourth Edition. Retrieved 2014-10-20. 
  25. ^ "RECONS TOP100". THE ONE HUNDRED NEAREST STAR SYSTEMS brought to you by RECONS (Research Consortium On Nearby Stars). 2012. Retrieved 2014-10-20. 

Notes[edit]

  1. ^ Weighted parallax based on parallaxes from van Altena et al. (1995), Gatewood (2008) (MAP-based study) and Gatewood (2008) (MAC-based study).

External links[edit]