D Eridani

d Eridani
Location of d Eri (circled)
Observation data
Epoch J2000      Equinox ICRS
Constellation Eridanus
Right ascension 04h 20m 42.8341s
Declination −07° 35′ 32.986″
Apparent magnitude (V) 5.84
Characteristics
Spectral type B5III or B7II
Apparent magnitude (U) 5.23
Apparent magnitude (B) 5.710
Apparent magnitude (G) 5.829944
Apparent magnitude (J) 6.026
Apparent magnitude (H) 6.109
Apparent magnitude (K) 6.113
Variable type SPB
Astrometry
Radial velocity (Rv)11.20±4.3 km/s
Proper motion (μ) RA: 3.540 mas/yr
Dec.: −2.298 mas/yr
Parallax (π)3.7763±0.0612 mas
Distance860 ± 10 ly
(265 ± 4 pc)
Absolute magnitude (MV)−1.05
Details
Mass4.3 M☉
Radius2.8 R☉
Luminosity687 L☉
Surface gravity (log g)3.69 cgs
Temperature13,315 K
Rotational velocity (v sin i)34 km/s
Age180 Myr
Other designations
d Eri, 210 G. Eri, EM Eri, HR 1363, HD 27563, HIP 20271, BD−07 798, TIC 37777866, 2MASS J04204283−0735329
Database references
SIMBADdata

d Eridani, also known as HD 27563, is a single star in Eridanus, in the direction of the Orion–Eridanus Superbubble, that is faintly visible to the naked eye at a magnitude of about 5.84. Cowley (1972) classifies this star as spectral type B5III, but Houk and Swift (1999) catalog it as B7II.

A light curve for EM Eridani, plotted from TESS data. The 3.8 day period is marked in red.

It was used as a comparison star for 46 Eridani in four separate runs at La Silla Observatory in the 1970s and 1980s, but in 1989, both stars were found to be variable with similar periods of about four days, and d Eridani was assigned the designation EM Eridani. Despite the lack of reliable comparisons for EM Eridani, it was found that the power spectrum of its light curve is remarkably noisy, with two or four prominent oscillation periods centered around 3.9215 d, and is classified as a slowly pulsating B-type star.

References

  1. 1 2 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. XHIP record for this object at VizieR.
  2. 1 2 3 4 5 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  3. 1 2 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: B/GCVS. Bibcode:2009yCat....102025S.
  4. 1 2 Cowley, A. (1 November 1972). "Spectral classification of the bright B8 stars". The Astronomical Journal. 77: 750–755. Bibcode:1972AJ.....77..750C. doi:10.1086/111348. ISSN 0004-6256.
  5. 1 2 Houk, N.; Swift, C. (1 January 1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey. 5: 0. Bibcode:1999MSS...C05....0H.
  6. 1 2 3 4 Fouesneau, M.; Andrae, R.; Dharmawardena, T.; Rybizki, J.; Bailer-Jones, C. A. L.; Demleitner, M. (2022). "Astrophysical parameters from Gaia DR2, 2MASS, and AllWISE". Astronomy and Astrophysics. 662: A125. arXiv:2201.03252. Bibcode:2022A&A...662A.125F. doi:10.1051/0004-6361/202141828. S2CID 245837778.
  7. ↑ Stassun, Keivan G.; Oelkers, Ryan J.; Pepper, Joshua; Paegert, Martin; De Lee, Nathan; Torres, Guillermo; Latham, David W.; Charpinet, Stéphane; Dressing, Courtney D.; Huber, Daniel; Kane, Stephen R.; Lépine, Sébastien; Mann, Andrew; Muirhead, Philip S.; Rojas-Ayala, Bárbara; Silvotti, Roberto; Fleming, Scott W.; Levine, Al; Plavchan, Peter; the TESS Target Selection Working Group (2018). "The TESS Input Catalog and Candidate Target List". The Astronomical Journal. 156 (3): 102. arXiv:1706.00495. Bibcode:2018AJ....156..102S. doi:10.3847/1538-3881/aad050. S2CID 73582386.
  8. ↑ Bowman, D. M.; Burssens, S.; Simón-Díaz, S.; Edelmann, P. V. F.; Rogers, T. M.; Horst, L.; Röpke, F. K.; Aerts, C. (2020). "Photometric detection of internal gravity waves in upper main-sequence stars. II. Combined TESS photometry and high-resolution spectroscopy". Astronomy and Astrophysics. 640: A36. arXiv:2006.03012. Bibcode:2020A&A...640A..36B. doi:10.1051/0004-6361/202038224. S2CID 260542391.
  9. ↑ Gontcharov, G. A. (December 2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters. 38 (12): 771–782. arXiv:1606.08814. Bibcode:2012AstL...38..771G. doi:10.1134/S1063773712120031. ISSN 0320-0108. S2CID 255201789.
  10. ↑ "EM Eri". simbad.u-strasbg.fr. Retrieved 20 May 2023.
  11. ↑ Welsh, B. Y.; Sallmen, S.; Jelinsky, S. (September 2005). "NaI and CaII absorption components observed towards the Orion-Eridanus Superbubble". Astronomy & Astrophysics. 440 (2): 547–557. Bibcode:2005A&A...440..547W. doi:10.1051/0004-6361:20052691. S2CID 122007577.
  12. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 30 March 2025.
  13. ↑ "EM Eri". The International Variable Star Index. AAVSO. Retrieved 31 March 2025.
  14. ↑ Mathys, G.; Manfroid, J.; Renson, P. (1 March 1986). "Photometric variability of some early-type stars". Astronomy and Astrophysics Supplement Series. 63: 403–416. Bibcode:1986A&AS...63..403M. ISSN 0365-0138.
  15. 1 2 Manfroid, J. (1 March 1989). "On the Light Curve of HD 27563". Information Bulletin on Variable Stars. 3297: 1. Bibcode:1989IBVS.3297....1M. ISSN 0374-0676.
  16. ↑ Manfroid, J.; Renson, P. (1 October 1989). "Photometric variations of 46 Eridani and 210 G. Eridani". Astronomy and Astrophysics. 223: 187–195. Bibcode:1989A&A...223..187M. ISSN 0004-6361.
  17. ↑ Dziembowski, W. A.; Moskalik, P.; Pamyatnykh, A. A. (1 December 1993). "The opacity mechanism in B-type stars - II. Excitation of high-order g-modes in main-sequence stars". Monthly Notices of the Royal Astronomical Society. 265 (3): 588–600. Bibcode:1993MNRAS.265..588D. doi:10.1093/mnras/265.3.588. ISSN 0035-8711.