Skip to main content

Research Repository

Advanced Search

All Outputs (1644)

On the initial-final mass relation and maximum mass of white dwarf progenitors (1997)
Journal Article
Jeffries, R. (1997). On the initial-final mass relation and maximum mass of white dwarf progenitors. Monthly Notices of the Royal Astronomical Society, 288(3), 585–588. https://doi.org/10.1093/mnras/288.3.585

The four white dwarfs (WDs) discovered in the young open cluster NGC 2516 are crucial in defining the shape of the initial-final mass relation (IFMR) and upper mass limit for WD progenitors (Mwd). The cluster metallicity has been recently determined... Read More about On the initial-final mass relation and maximum mass of white dwarf progenitors.

Excess barium in a K dwarf-white dwarf binary system. (1996)
Journal Article
Jeffries, R. D., & Smalley, B. (1996). Excess barium in a K dwarf-white dwarf binary system. Astronomy and Astrophysics, 315, L19-L22

We present spectroscopic evidence for an excess of the s-process element barium, in the rapidly rotating, K-dwarf component of the wide binary system 2REJ0357+283. The secondary star is a hot white dwarf (WD) and our result argues for a model where t... Read More about Excess barium in a K dwarf-white dwarf binary system..

2RE J0241-525: a nearby post-T Tauri visual binary system (1996)
Journal Article
Jeffries, R., Buckley, D., James, D., & Stauffer, J. (1996). 2RE J0241-525: a nearby post-T Tauri visual binary system. Monthly Notices of the Royal Astronomical Society, 281(3), 1001–1015. https://doi.org/10.1093/mnras/281.3.1001

We present high-spatial-resolution X-ray observations, photometry and spectroscopy of the two low-mass, active stars proposed as optical counterparts to the extreme ultraviolet source 2RE J0241 —525 (=EUVE J0241—530). It is confirmed that both stars,... Read More about 2RE J0241-525: a nearby post-T Tauri visual binary system.

The appearance of broad H$α$ in BL Lacertae (1996)
Journal Article
Corbett, E., Robinson, A., Axon, D., Hough, J., Jeffries, R., Thurston, M., & Young, S. (1996). The appearance of broad H$α$ in BL Lacertae. Monthly Notices of the Royal Astronomical Society, 281(3), 737–749. https://doi.org/10.1093/mnras/281.3.737

We present optical spectropolarimetry confirming Vermeulen et al.' recent discovery of a broad Ha emission line in BL Lacertae. This feature, which is present at about the same strength in spectra taken two days apart, is comparable in width (FWHM ≈... Read More about The appearance of broad H$α$ in BL Lacertae.

Wind-accretion induced rapid rotation and a new class of active star (1996)
Journal Article
Jeffries, R., & Stevens, I. (1996). Wind-accretion induced rapid rotation and a new class of active star. Monthly Notices of the Royal Astronomical Society, 279(1), 180–190. https://doi.org/10.1093/mnras/279.1.180

A physical model is presented to explain the occurrence of wide binary systems discovered at EUV wavelengths, such as 2RE J0044 + 093, which consist of a hot white dwarf and an ultra-rapidly rotating K-dwarf. It is difficult to explain the rapid rota... Read More about Wind-accretion induced rapid rotation and a new class of active star.

Are there any isolated old neutron stars in the ROSAT Wide Field Camera survey? (1996)
Journal Article
Manning, R., Jeffries, R., & Willmore, A. (1996). Are there any isolated old neutron stars in the ROSAT Wide Field Camera survey?. Monthly Notices of the Royal Astronomical Society, 278(2), https://doi.org/10.1093/mnras/278.2.577

We present the results of Monte Carlo simulations to predict the number of isolated old neutron stars (IONs) that are observed in the ROSAT Wide Field Camera (WFC) survey as a result of accretion-powered extreme ultraviolet (EUV) emission. Magnetic f... Read More about Are there any isolated old neutron stars in the ROSAT Wide Field Camera survey?.

Is 2RE J0357+283 the most coronally active star in the Galaxy? (1996)
Journal Article
Jeffries, R. D., Burleigh, M. R., & Robb, R. M. (1996). Is 2RE J0357+283 the most coronally active star in the Galaxy?. Astronomy and Astrophysics, 305,

The late-type stellar counterpart to the EUV source 2RE J0357+283 is found to be an ultra-fast rotating K2V star, with a rotation period of 8.76 hrs and vsini of 141+/-5km/s. If this were the only source of the EUV emission, then it would be the most... Read More about Is 2RE J0357+283 the most coronally active star in the Galaxy?.

New Extreme Ultraviolet-Selected Active Binaries from the ROSAT Wide Field Camera all Sky Survey (1995)
Journal Article
Jeffries, R., Bertram, D., & Spurgeon, B. (1995). New Extreme Ultraviolet-Selected Active Binaries from the ROSAT Wide Field Camera all Sky Survey. Monthly Notices of the Royal Astronomical Society, 276(2), 397–408. https://doi.org/10.1093/mnras/276.2.397

We present the results of radial velocity measurements for an EUV-selected sample of 11 new G- and K-type binary systems, discovered in a sample of 22 EUV sources from the ROSAT Wide Field Camera (WFC) all-sky survey. The physical status of each syst... Read More about New Extreme Ultraviolet-Selected Active Binaries from the ROSAT Wide Field Camera all Sky Survey.

The kinematics of lithium-rich, active late-type stars: evidence for a low-mass Local Association (1995)
Journal Article
Jeffries, R. D. (1995). The kinematics of lithium-rich, active late-type stars: evidence for a low-mass Local Association. Monthly Notices of the Royal Astronomical Society, 273(3), https://doi.org/10.1093/mnras/273.3.559

An EUV-selected sample of late-type stars has been observed for lithium abundances and radial velocity radiations. It is found that essentially all of the single stars have lithium abundances comparable to or greater than late-type stars in the Pleia... Read More about The kinematics of lithium-rich, active late-type stars: evidence for a low-mass Local Association.

RE 0044+09: A new K dwarf rapid rotator with a white dwarf companion? (1995)
Journal Article
Kellett, B. J., Bromage, G. E., Brown, A., Jeffries, R. D., James, D. J., Kilkenny, D., …Clayton, C. (1995). RE 0044+09: A new K dwarf rapid rotator with a white dwarf companion?. Astrophysical Journal, 438, https://doi.org/10.1086/175080

We report the discovery of a new K dwarf rapid rotator with a potential white dwarf companion. The white dwarf accounts for over 90% of the observed extreme ultraviolet flux detected from this system. Analysis of ROSAT Wide Field Camera (WFC) and IUE... Read More about RE 0044+09: A new K dwarf rapid rotator with a white dwarf companion?.

RE 1816+541: a northern hemisphere analogue to the low-mass rapid rotator HK Aqr. (1994)
Journal Article
Jeffries, R., James, D., & Bromage, G. (1994). RE 1816+541: a northern hemisphere analogue to the low-mass rapid rotator HK Aqr. Monthly Notices of the Royal Astronomical Society, 271(2), https://doi.org/10.1093/mnras/271.2.476

Spectroscopic observations of the optical counterpart to the ROSAT Wide Field Camera source RE 1816 + 541 are presented. We find that the counterpart is a chromospherically active, rapidly rotating, dM1-2e star with a sin of 61 km s−1. No evide... Read More about RE 1816+541: a northern hemisphere analogue to the low-mass rapid rotator HK Aqr..

BD+22DEG4409 - a Rapidly Rotating Low-Mass Member of the Local Association (1994)
Journal Article
Jeffries, R., Byrne, P., Doyle, J., Anders, G., James, D., & Lanzafame, A. (1994). BD+22DEG4409 - a Rapidly Rotating Low-Mass Member of the Local Association. Monthly Notices of the Royal Astronomical Society, 270(1), 153–172. https://doi.org/10.1093/mnras/270.1.153

We present spectroscopic and photometric observations of BD + 22°4409, a nearby, low-mass star which, on the basis of its Galactic space motions and high EUV-to-bolometric luminosity ratio, has been previously assigned membership of the young kinemat... Read More about BD+22DEG4409 - a Rapidly Rotating Low-Mass Member of the Local Association.

RE 0618 + 7 5 - A very short-period, binary dMe system (1993)
Journal Article
Jeffries, R., Elliott, K., Kellett, B., & Bromage, G. (1993). RE 0618 + 7 5 - A very short-period, binary dMe system. Monthly Notices of the Royal Astronomical Society, 265(1), https://doi.org/10.1093/mnras/265.1.81

We report on the discovery of a new, very short-period, chromospherically active, late-type binary system. Observations performed with the ROSAT Wide Field Camera revealed the EUV source RE 0618 + 75, and subsequent optical spectroscopy identified th... Read More about RE 0618 + 7 5 - A very short-period, binary dMe system.

The Kinematics of Active Late Type Stars Observed by the ROSAT Wide-Field Camera (1993)
Journal Article
Jeffries, R., & Jewell, S. (1993). The Kinematics of Active Late Type Stars Observed by the ROSAT Wide-Field Camera. Monthly Notices of the Royal Astronomical Society, 264(1), https://doi.org/10.1093/mnras/264.1.106

A sample of single, main-sequence late-type stars detected during the ROSAT Wide Field Camera EUV all-sky survey is kinematically investigated. It is confirmed that the galactic velocity dispersion of magnetically active objects, as defined by the ra... Read More about The Kinematics of Active Late Type Stars Observed by the ROSAT Wide-Field Camera.

Prominence activity on the rapidly rotating field star HD 197890 (1993)
Journal Article
Jeffries, R. D. (1993). Prominence activity on the rapidly rotating field star HD 197890. Monthly Notices of the Royal Astronomical Society, 262(2), https://doi.org/10.1093/mnras/262.2.369

Time-resolved H αspectra are presented of the recently discovered, rapidly rotating young field star HD 197890. The observations contain rapid absorption and emission transients that cross the rotationally broadened Hα profile from blue to red on tim... Read More about Prominence activity on the rapidly rotating field star HD 197890.

Gliese 841A - an EUV-selected chromospherically active binary system (1993)
Journal Article
Jeffries, R., & Bromage, G. (1993). Gliese 841A - an EUV-selected chromospherically active binary system. Monthly Notices of the Royal Astronomical Society, 260(1), https://doi.org/10.1093/mnras/260.1.132

We report the discovery of a new short-period, main-sequence, chromospherically active late-type binary system. EUV observations performed by the ROSAT Wide Field Camera have identified the late-type star GL 841A as a possible very active star by vir... Read More about Gliese 841A - an EUV-selected chromospherically active binary system.

The ROSAT Wide Field Camera all-sky survey of extreme-ultraviolet sources. I - The Bright Source Catalogue (1993)
Journal Article
Pounds, K., Allan, D., Barber, C., Barstow, M., Bertram, D., Branduardi-Raymont, G., …Wonnacott, D. (1993). The ROSAT Wide Field Camera all-sky survey of extreme-ultraviolet sources. I - The Bright Source Catalogue. Monthly Notices of the Royal Astronomical Society, 260(1), https://doi.org/10.1093/mnras/260.1.77

The first all-sky survey for cosmic sources of extreme-ultraviolet radiation has been carried out with the UK Wide Field Camera on ROSAT. A first reduction of the survey data has yielded a catalogue of 383 relatively bright EUV sources, forming the W... Read More about The ROSAT Wide Field Camera all-sky survey of extreme-ultraviolet sources. I - The Bright Source Catalogue.