Astronomy:38 Geminorum
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Gemini |
| Right ascension | 06h 54m 38.63478s[1] |
| Declination | +13° 10′ 40.2207″[1] |
| Apparent magnitude (V) | 4.75 + 7.80[2] |
| Characteristics | |
| Spectral type | A8V[3] + G6V[4] |
| U−B color index | +0.07[5] |
| B−V color index | +0.30[5] |
| Variable type | Suspected δ Sct[6] |
| Astrometry | |
| A | |
| Radial velocity (Rv) | +24±5[7] km/s |
| Proper motion (μ) | RA: 68.745[8] mas/yr Dec.: −86.832[8] mas/yr |
| Parallax (π) | 33.9184 ± 0.8248[8] mas |
| Distance | 96 ± 2 ly (29.5 ± 0.7 pc) |
| B | |
| Radial velocity (Rv) | +22.6±2[7] km/s |
| Proper motion (μ) | RA: 89.235[9] mas/yr Dec.: −77.171[9] mas/yr |
| Parallax (π) | 33.3308 ± 0.0847[9] mas |
| Distance | 97.9 ± 0.2 ly (30.00 ± 0.08 pc) |
| Details | |
| 38 Gem A | |
| Mass | 1.55[10] M☉ |
| Surface gravity (log g) | 4.23[11] cgs |
| Temperature | 7,410±252[11] K |
| Metallicity [Fe/H] | −0.08±0.06[12] dex |
| Rotational velocity (v sin i) | 147.5±10.5[13] km/s |
| Age | 1.179[11] Gyr |
| 38 Gem B | |
| Mass | 0.89[10] M☉ |
| Radius | 0.89[9] R☉ |
| Luminosity | 0.694[9] L☉ |
| Temperature | 5,583[9] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
| A | |
| B | |
38 Geminorum is a binary star system in the northern zodiac constellation of Gemini. It has the Bayer designation e Geminorum, while 38 Geminorum is the Flamsteed designation. This system is visible to the naked eye as a faint, white-hued point of light with an apparent visual magnitude of 4.71. The primary component is a magnitude 4.75 star, while the secondary is magnitude 7.80.[2] The system is located about 98 light years away from the Sun based on parallax, and is drifting further away with a radial velocity of +16 km/s.[14] It is a potential member of the Tucana–Horologium stellar kinematic group.[15]
This is a wide binary system with a projected separation of 184.3 astronomical unit|AU.[10] Two sets of low quality orbital elements have been computed for this system, yielding periods of 1,943.8 years and 3,190 years, and eccentricities of 0.150 and 0.485, respectively.[16] As of 2018, the pair had an angular separation of 7.4″ along a position angle of 143°.[2]
Abt and Morrell (1995) classified the primary component as an A-type main-sequence star with a stellar classification of A8V.[3] It is a suspected chemically peculiar star of subtype CP1 (an Am star),[13] which Slettebak (1955) classified as kA8mF0Vp.[17] This notation indicates the star displays the calcium K line of an A8 star and the metal lines of an F0V star. In 1949, J. Hopmann catalogued it as a suspected Delta Scuti variable.[6] The secondary is a G-type main-sequence star with a class of G6V.[4]
References
- ↑ 1.0 1.1 van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V.
- ↑ 2.0 2.1 2.2 Mason, B. D. et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal 122 (6): 3466, doi:10.1086/323920, Bibcode: 2001AJ....122.3466M
- ↑ 3.0 3.1 Abt, Helmut A.; Morrell, Nidia I. (1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". The Astrophysical Journal Supplement Series 99: 135. doi:10.1086/192182. Bibcode: 1995ApJS...99..135A.
- ↑ 4.0 4.1 Adams, Walter S. et al. (1935). "The Spectroscopic Absolute Magnitudes and Parallaxes of 4179 Stars". Astrophysical Journal 81: 187. doi:10.1086/143628. Bibcode: 1935ApJ....81..187A.
- ↑ 5.0 5.1 Johnson, H. L. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory 4: 99. Bibcode: 1966CoLPL...4...99J.
- ↑ 6.0 6.1 Starikova, G. A. (July 1979). "Absolute magnitudes and masses for three types of variable stars". Soviet Astronomy Letters 5: 188–192. Bibcode: 1979SvAL....5..188S.
- ↑ 7.0 7.1 Evans, D. S. (1967). "The Revision of the General Catalogue of Radial Velocities". Determination of Radial Velocities and Their Applications 30: 57. Bibcode: 1967IAUS...30...57E.
- ↑ 8.0 8.1 8.2 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 9.0 9.1 9.2 9.3 9.4 9.5 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 10.0 10.1 10.2 Tokovinin, A.; Kiyaeva, O. (February 2016). "Eccentricity distribution of wide binaries". Monthly Notices of the Royal Astronomical Society 456 (2): 2070–2079. doi:10.1093/mnras/stv2825. Bibcode: 2016MNRAS.456.2070T.
- ↑ 11.0 11.1 11.2 David, Trevor J.; Hillenbrand, Lynne A. (2015). "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets". The Astrophysical Journal 804 (2): 146. doi:10.1088/0004-637X/804/2/146. Bibcode: 2015ApJ...804..146D.
- ↑ Gáspár, András et al. (2016). "The Correlation between Metallicity and Debris Disk Mass". The Astrophysical Journal 826 (2): 171. doi:10.3847/0004-637X/826/2/171. Bibcode: 2016ApJ...826..171G.
- ↑ 13.0 13.1 Paunzen, E. et al. (February 2013). "A photometric study of chemically peculiar stars with the STEREO satellites - II. Non-magnetic chemically peculiar stars". Monthly Notices of the Royal Astronomical Society 429 (1): 119–125. doi:10.1093/mnras/sts318. Bibcode: 2013MNRAS.429..119P.
- ↑ 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.
- ↑ Nakajima, Tadashi; Morino, Jun-Ichi (2012). "Potential Members of Stellar Kinematic Groups within 30 pc of the Sun". The Astronomical Journal 143 (1): 2. doi:10.1088/0004-6256/143/1/2. Bibcode: 2012AJ....143....2N.
- ↑ Abt, Helmut A. (August 2005). "Observed Orbital Eccentricities". The Astrophysical Journal 629 (1): 507–511. doi:10.1086/431207. Bibcode: 2005ApJ...629..507A.
- ↑ Slettebak, Arne (May 1955). "The Spectra and Rotational Velocities of the Bright Stars of Draper Types A3-G0.". Astrophysical Journal 121: 653. doi:10.1086/146031. Bibcode: 1955ApJ...121..653S.
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